A BARRIER ISLAND ER ATLAS OF OSION STUDY G 1853 T0989 0 RELIN E CHAN EST IN LOUISIANA FROM LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES IN LOUISIANA FROM 1853 to 1989 S. Jeffress Williams‘, Shea Penlandz, and Asbury H. Sallenger, Jr.3, Editors Contributions by Donald W. Davisz, C. G. Groatz, Matteson W. Hilandz, Bruce E. Jaffe“, Randolph A. McBridez, Shea Penlandz, Asbury H. Sallenger, Jr.3, Karen A. Westphalz, S. Jeffress Williams“ Cartography by Susan S. Birnbaumz, Michael C. lerardil, David J. McCrawz, Edwin B. Milletz, Robert L. Paulsellz, Lisa G. Pond2 * Production Coordinator: James E. Queen1 Cartographic Manager: John I. Snead2 Technical editing by Michael A. Coffeyz, David A. Emeryl, Jacquelyn L. Monday2 * * Listed in alphabetical order. 1 U.S. Geological Survey, Reston, Virginia 2 Louisiana Geological Survey, Baton Rouge, Louisiana 3 U.S. Geological Survey, St. Petersburg, Florida 4 U.S. Geological Survey, Menlo Park, California 1992 W» (n G) '0 070 U qgeas On U.S. DEPARTMENT OF THE INTERIOR MANUEL LUJAN, JR., Secretary U.S. GEOLOGICAL SURVEY Dallas L. Peck, Director Prepared in cooperation with the LOUISIANA GEOLOGICAL SURVEY C. G. Groat, Director 8: State Geologist The Louisiana Barrier Island Erosion Study, a cooperative investigation between the U.S. Geological Survey (USGS) and the Louisiana Geological Survey (LGS), focused on the processes and geological conditions responsible for the wide- spread erosion of Louisiana's delta-plain coast. Many people within the two organizations participated in the preparation of this atlas, which is one of several products of the study. Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government. Library of Congress Cataloging—in—Publication Data Louisiana Geological Survey. Atlas of shoreline changes in Louisiana from 1853 to 1989: [Louisiana] / prepared by the U.S. Geological Survey in cooperation with the Louisiana Geological Survey; S. Jeffress Williams, Shea Penland, and Asbury H. Sallenger, editors; cartography by John I. Snead...[et al.]. p. cm. — — (Miscellaneous investigations; l—2150—A) (Louisiana barrier island erosion study; l—2150—A) Includes bibliographical references. 1. Coastal changes — — Louisiana — — Maps. 2. Shorelines — — Louisiana - - Maps. 1. Geological Survey (U.S.) 11. Title. III. Series. IV. Series: Miscellaneous investigations series (Geological Survey (U.S.)) ; I—2150—A. GlB62.C6C2L6 1992 551.4 ' 58 ' 09763022 - - dc20 92—4709 CIP MAP Manuscript approved for publication on July 22, 1991 no 3-“ INTERIOR—GEOLOGICAL SURVEY, RESTON, VIRGINIA—1992 For sale by U.S. Geological Survey, Map Distribution Box 25286, Federal Center, Denver, CO 80225 and the Louisiana Geological Survey Box G, University Station, Baton Rouge, LA 70893 Foreword It is with pleasure that we present this Atlas of Shoreline Changes. This atlas is one of many products of the Louisiana Barrier Island Erosion Study, conducted jointly by the US. Geological Survey and the Louisiana Geological Survey over the past five years. It demon— strates the positive results that are possible when Federal and State agencies work together to solve problems that concern many seg— ments of the population. The erosion of our Nation’s coasts and the degradation and loss of valuable wetlands affect all of us. Coastal businesses and homeown- ers endure the immediate consequences. But when one individual suffers, many suffer indirectly through higher prices, insurance premiums, and taxes. Diminished coasts and wetlands also affect those who value them as wildlife habitat, as abundant food re— sources, and as recreational areas. Cooperative efforts, such as the Louisiana Barrier Island Erosion Study, allow the pooling of knowledge and resources. As a result, planners and decision makers, who must determine courses of re- medial action, receive critical information expeditiously. This atlas is a small but important contribution to the information transfer pro— cess. We trust that it will provide not only evidence of the dramatic effects of coastal erosion and wetland loss in Louisiana but also un— derstanding to those who must deal with mitigation approaches that will benefit society as a whole. W M7244 C. G. Groat Dallas Peck Director and State Geologist Director Louisiana Geological Survey US. Geological Survey TABLE OF CONTENTS — Karen A. Westphal and Shea Penland Isles Dernieres Barrier System ...................................................................................... 24 Bayou Lafourche Barrier System ................................................................................... 26 Plaquemines Barrier System ......................................................................................... 28 Chandeleur Islands Barrier System ................................................................................ 32 Foreword ................................................................................................................................... iii Chapter 4. Analysis of Barrier Shoreline Change in Louisiana from 1853 to 1989 ...... 36 Randolph A. McBride, Shea Penland, Matteson W. Hiland, An Introduction to Coastal Erosion and Wetland Loss Research .......................................... 1 S. Jeffress Williams, Karen A. Westphal, Bruce E. Jaffe, S. Jeffress Williams and Asbury H. Sallenger, Jr. and Asbury H. Sallenger, Jr. Chapter 1. Barrier Island Erosion and Wetland Loss in Louisiana .................................... 2 Introduction ................................................................................................................ 36 Shea Penland, S. Jeffress Williams, Donald W. Davis, Shoreline Mapping ...................................................................................................... 36 Asbury H. Sallenger, Jr., and C. G. Groat Materials and Techniques ............................................................................................. 37 Sources of Error .......................................................................................................... 37 Introduction .................................................................................................................. 2 Isles Dernieres Barrier Island System—1853 to 1988 ..................................................... 38 Coastal Land Loss ......................................................................................................... 2 Barrier System Morphology ........................................................................... 38 Coastal Erosion .............................................................................................. 2 Shoreline Movement ..................................................................................... 38 Wetland Loss ................................................................................................. 2 Area and Width Change ................................................................................ 38 Barrier Island Landscape ................................................................................................ 3 Bayou Lafourche Barrier System—1887 to 1988 .......................................................... 48 Regional Geology ........................................................................................... 3 Timbalier Islands ........................................................................................... 48 Louisiana Barrier Systems ............................................................................... 4 Morphology ........................................................................................ 48 Bayou Lafourche ................................................................................... 4 Shoreline Movement ............................................................................ 48 Plaquemines .......................................................................................... 4 Timbalier Island ............................................................................ 48 Isles Dernieres ....................................................................................... 4 East Timbalier Island .................................................................... 48 Chandeleur ........................................................................................... 4 Timbalier Islands Summary ........................................................... 48 Barrier Island Erosion Research ...................................................................................... 5 Area and Width Change ....................................................................... 48 Previous Research .......................................................................................... 5 Timbalier Island ............................................................................ 48 US. Army Corps of Engineers ................................................................ 5 East Timbalier Island .................................................................... 48 Louisiana Attorney General .................................................................... 5 Timbalier Islands Summary ........................................................... 48 Louisiana Department of Transportation and Development ....................... 5 Caminada—Moreau Headland and Grand Isle ................................................... 58 Louisiana Department of Natural Resources ............................................. 5 Morphology ........................................................................................ 58 Current USGS—LGS Research in Louisiana ....................................................... 6 Shoreline Movement ............................................................................ 58 Coastal Research Summary ............................................................................................ 7 Caminada-Moreau Headland ......................................................... 58 Grand Isle .................................................................................... 58 Chapter 2. A Pictorial and Historical Review of Louisiana’s Barrier Islands .................... 8 Caminada—Moreau Headland and Grand 1519 Summary -------------------- 58 Donald W. Davis Area and Width Change at Grand Isle .................................................... 58 Plaquemines Barrier System—1884 to 1988 ................................................................. 68 Settling Louisiana’s Coastal Fringe .................................................................................. 9 Morphology ------------------------------------------------------------------------------------------------- 68 Louisiana’s Coastal Lowlands .................................................................. 9 Shoreline Movement ..................................................................................... 68 Louisiana’s Settlement History: From Natural Levees to Marshes to Barrier Islands ........... 10 Area and Width Change ................................................................................ 68 The Ethnic Mix _________________________________________________________________________________ 10 Grand Terre ........................................................................................ 68 Isles Dernieres: Louisiana’s First Coastal Resort .............................................................. 10 Shell Island ------------------------------------------------------------------------------------------ 68 The 1856 Last Island Hurricane ............................................................ 10 Chandeleur Islands Barrier System ................................................................................ 78 Hurricanes in the Coastal Zone ..................................................................................... 10 SOUth Chandeleur Islands Shoreline—1869 to 1989 --------------------------------------- 78 Grand Isle: A Potpourri of Uses .................................................................................... 12 MOYPhOIOQV ---------------------------------------------------------------------------------------- 78 The Recreational Resort ______________________________________________________________________ 12 Shoreline Movement ............................................................................ 78 The Islands Economic Base .................................................................. 12 Area and Width Change ----------------------------------------------------------------------- 78 The Islands Resident Turtle Herd .......................................................... 12 Breton Island ............................................................................... 78 Hotels and Hurricanes .................................................................................................. 13 Grand Gosier and Curlew Islands ---------------------------------------- L ----------- 7 8 The Kranz Hotel .................................................................................. 13 SOUth Chandeleur Islands Summary ----------------------------------------------- 78 The Ocean Club .................................................................................. 13 North Chandeleur Islands Shoreline—1855 to 1989 --------------------------------------- 86 Grand Terre: Home of Pirates and Plantations ............................................................... 14 MOYPhOIOQV --------------------------------------------------------------------------------------- 86 The Home of Jean Lafitte the Pirate ...................................................... 14 Shoreline Movement ............................................................................ 86 Grand Terre Sugar Plantation ............................................................... 14 Area and Width Change ----------------------------------------------------------------------- 86 Floor Plan of Fort Livingston ........................................................................................ 15 Classification 0i Shoreline Change -------------------------------------------------------------------------------- 96 Cheniere Caminada: The Disappearance of a Community ______________________________________________ 16 Conclusions ................................................................................................................ 96 Cheniere Caminada .................................................................................................. 17 Summary Map ------------------------------------------------------------------------------------------------------------ 97 Louisiana’s Worst Hurricane Disaster ............................................................................ 17 Wetlands Harvest ........................................................................................................ 18 Appendix A- Louisiana Hurricanes ---------------------------------------------------------------------------------------- 98 Wetlands Trapping in French Louisiana ......................................................................... 19 Appendix 3- Coastal Erosion and Wetland L055 Tables ------------------------------------------------------- 99 Muskrat and Nutria ....................................................................................... 19 Table 131- Raie of shoreline change for US coastal states and regions ----------------------------- 99 The American Alligator ................................................................................. 19 Table 32- Distribution of coastal wetlands in the United States ---------------------------------------- 99 Louisiana’s Prolific Oysterbeds ...................................................................................... 20 Table 133- Distribution 0f coastal wetlands in the GU11: Of Mexico -------------------------------------- 99 Oystering in Bayou Country .......................................................................... 20 Shrimp Drying: An Ancient Chinese Art ........................................................................ 21 Acknowledgments ................................................................................................................. 100 Platform Settlements .................................................................................... 21 References ............................................................................................................................ 101 The Gear Required ....................................................................................... 21 Conversion Factors ............................................................................................................... 103 The Community of Balize ............................................................................................. 22 The Wetlands’ Mineral Fluids ...................................................................................... 23 Chapter 3. Aerial Photographic Mosaics of Louisiana’s Barrier Shoreline ..................... 24 An Introduction to Coastal Erosion And Wetlands Loss Research _ S. Jeffress Williams and Asbury H. Sallenger, Jr. COASTAL EROSION AND WETLANDS LOSS Louisiana leads the Nation in coastal erosion and wetlands loss. In places, erosion of the barrier islands, which lie offshore of the estuaries and wetlands and separate and protect them from the open marine en— vironment, exceeds 20 m/yr (Penland and Boyd, 1981; McBride and others, 1989). Within the past 100 years, Louisiana’s barrier islands have decreased on average in area by more than 40 percent, and some islands have lost 75 percent of their area (Fenland and Boyd, 1981). A few of the islands are expected to disappear within the next three decades; their absence will contribute to further loss and deterioration of wetlands and back—barrier estuaries (McBride and others, 1989). Louisiana contains 25 percent of the vegetated wetlands and 40 percent of the tidal wetlands in the 48 conterminous states. These coastal wetland environments, which include associated bays and estuaries, sup- port a harvest of renewable natural resources with an estimated annual value of over $1 billion (Turner and Cahoon, 1987). Louisiana also has the highest rate of wetlands loss: 80 percent of the Nation’s total loss of wetlands has occurred in this state. Several scientists have estimated the rate of wetlands loss in the Mississippi River delta plain to be more than 100 kayr (Gagliano and others, 1981). Since 1956, over 2,500 km2 of freshwater wetlands in Louisiana have been eroded or converted to other habitats. If these rates continue, an estimated 4,000 km2 of wetlands will be lost in the next 50 years. The physical processes that cause barrier island erosion and wetlands loss are complex, varied, and poorly understood. There is much debate in technical and academic communities about which of the many contributing processes, both natural and human-induced, are the most significant. There is further controversy over some of the proposed measures to alleviate coastal land loss. Much of the discussion focuses on the reliability of predicted results of a given management, restoration, or erosion mitigation technique. With a better understanding of the processes that cause barrier island erosion and wetland loss, such predictions will become more accurate, and a clearer consensus of how to reduce and mitigate land loss is likely to appear. The US. Geological Survey (USGS) is undertaking two studies of coastal erosion and wetlands loss in Louisiana. The first, the Louisiana Barrier Island Erosion Study, is a cooperative effort with the Louisiana Geological Survey. Begun in fiscal year 1986, the study, as described in Sallenger and Williams (1989), will be completed in fiscal year 1990. During fiscal year 1988, Congress directed the USGS, jointly with the US. Fish and Wildlife Service, to develop a study plan extending the ongoing barrier island research to include coastal wetlands processes. This plan resulted in the Louisiana Wetlands Loss Study, which was begun in the latter part of fiscal year 1988. The wetlands study is scheduled for completion in 1993. This introduction discusses the role of USGS research in understanding the processes of shoreline erosion and wetlands loss, followed by an overview of the study and an atlas summary. ROLE OF USGS RESEARCH IN COASTAL EROSION AND WETLANDS LOSS MITIGATION The two current USGS Louisiana studies focus on developing a better understanding of the processes that cause coastal erosion and wetlands loss, particularly the rapid deterioration of Louisiana’s barrier islands, estuaries, and associated wetlands environments. With a better understand— ing of these processes, the ability to predict erosion and wetlands loss should improve. More accurate predictions will, in turn, allow for proper management of coastal resources, such as setting new construction a safe distance from an eroding shoreline. Improved predictions will also allow for better assessments of the utility of different mitigation schemes. For instance, increased understanding of the processes that force sediment and freshwater dispersal over wetlands will make possible more accurate assessments of the practicality and usefulness of large—scale freshwater sediment diversions from the Mississippi River. Understanding the pro— cesses responsible for barrier island erosion will also aid in evaluating the relative merits of beach nourishment techniques and using hard coastal engineering structures. While the USGS conducts relevant research on coastal erosion and land loss, other Federal and State agencies design and construct projects and otherwise implement measures for management of the coastal zone and for mitigation of coastal erosion or wetlands loss. The State of Louisiana, through Article 6 of the Second Extraordinary Session of the 1989 Louisiana Legislature, created the Wetlands Conservation and Restoration Authority within the Office of the Governor, the Office of Coastal Restoration and Management within the Department of Natural Resources, and the statutorily dedicated Wetlands Conservation and Restoration Fund. In March 1990, the Louisiana Wetlands Conservation and Restoration Authority submitted the Coastal Wetlands Conservation and Restoration Plan to the State House and Senate Natural Resource Committees for their approval. This plan proposed both short— and long— term projects to conserve, restore, enhance, and create vegetated wet— lands. Also, the U.S. Army Corps of Engineers has completed the first phase of the Louisiana Coastal Comprehensive Wetlands Plan to mitigate land loss in Louisiana. In the second phase, the Corps of Engineers is working with appropriate Federal and State agencies, including the USGS, to assess the cost and utility of engineering projects to mitigate land loss. Most scientists agree that some proposed projects and policies already are supported by an information base sufficient to justify their being undertaken now, without further research. However, for many potential projects, such as the use of hard engineering structures on beaches and large freshwater and sediment diversions, existing information is not sufficient, and decision making and planning will benefit from additional field investigations. Mitigation and control of coastal erosion and wetlands loss thus can be approached through a two—pronged effort. The appropri ate Federal and State agencies could implement projects about which sufficient information already exists. At the same time, relevant research should continue on critical processes; this will allow incremental improve- ment in both erosion and land loss mitigation techniques and in evaluating the success of the implemented projects. The State of Louisiana, through the Wetlands Conservation and Restoration Authority, has provided its recommendations for both action and further research to the Louisiana Legislature in accord with this approach. OVERVIEW OF THE STUDY The Louisiana Barrier Island Erosion Study covers the barrier islands in the delta—plain region of coastal Louisiana. The study focuses on three overlapping elements: geologic framework and development of the barrier islands, processes of barrier island erosion, and transfer and application of results. The first step in identifying erosion processes was to establish the shallow geologic framework within which the barriers formed, eroded, and migrated landward. This analysis, which relies on both stratigraphy and geomorphology, is the basis for a regional model of erosion that incorpo— rates many processes. The study focuses on the important processes that are not well understood but that are approachable experimentally: sea—level rise, storm overwash, onshore—offshore movement of sand, and longshore sediment transport. The methods include direct measurement of waves and currents during storms, computer modeling, and a compilation of historical patterns of erosion and accretion. The results of the study are directly applicable to various practical problems. For example, a better understand— ing of the rates at which sand is removed from beaches is crucial to determining how often an artificially nourished beach will need to be replenished. Investigations of the geologic framework within which the barriers formed lead to the identification and assessment of offshore sand resources that can be used for beach nourishment, as well as a greater capacity to accurately forecast future shoreline positions and coastal conditions. A particularly important finding is the role of barrier islands in protecting the wetlands, bays, and estuaries behind the islands. Barrier islands help reduce wave energy at the margin of wetlands and thus limit mechanical erosion. Barriers also limit storm surge heights and retard saltwater intrusion. The bays between Louisiana’s barriers and wetlands are ecologically productive and would be significantly altered if the barriers erode away. Proposals have been made to restore and protect Louisiana’s barrier islands in order to preserve estuaries and reduce wetlands loss, but until now there has not been enough information about the erosion processes to make a thorough assessment of their significance. For example, the Corps of Engineers, in a limited feasibility study, estimated that protecting the island of Grand Terre with engineering techniques would limit wetlands loss by 10 percent. This reconnaissance study, based on a modest computer modeling effort, was suitable for problem identifi— cation, but not for making the policy decision to proceed nor for developing details of engineering design. The results of the present USGS study will fill that gap by quantitatively assessing the importance of barriers protecting back—barrier wetland and estuary environments. ATLAS SUMMARY AND RESEARCH STUDY RESULTS This is the first in a series of three atlases and a set of scientific reports and publications that will present the results of the Louisiana Barrier Island Erosion Study. This atlas examines the magnitude and impact of historic shoreline change on the physical and cultural landscape of Louisiana’s barrier islands. The ensuing chapters discuss coastal geomorphology and barrier island research in Louisiana over the past 40 years (Chapter 1) and cultural resources in Louisiana’s coastal zone (Chapter 2). In Chapter 3, the Louisiana barrier shoreline is depicted in a vertical aerial photo mosaic, and Chapter 4 concludes with an extensive and quantitative compilation of shoreline changes from 1853 to 1989. Two subsequent atlases will illustrate historical changes in offshore bathymetry (I—2150—B), and the shallow geologic framework (I—2150—C). Along with the series of atlases, which will present the data in maps and graphics with limited interpretation, several narrative reports, to be re— leased as papers and maps, in the scientific literature, will summarize the study's scientific findings. Those reports will discuss the application of the LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A study’s results to the practical problems of erosion and land loss mitigation. This information will contribute to the basic data sets and technical knowledge needed by Federal, State, and local agencies to formulate realistic and cost—effective approaches to coastal restoration and erosion mitigation. In addition, the presentation of the research results in scientific forums and public programs increases the awareness of the public and scientific community that erosion in Louisiana is widespread and a serious problem. Landsat-5 image of the South Central delta-plain coast of Louisiana by the U.S. Geological Survey as part of the New Orleans, Louisiana Satellite Image Map Folio no. LA1137, 1986 image. US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVE Chapter 1 Y Barrier Island Erosion and Wetland Loss in Louisiana LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A "by Shea Fenland, S. Jeffress Williams, Donald W. Davis, Asbury H. Sallenger, Jr. and C. G. Groat 30° 93° . Lake Charles 30° 29° FIGURE 2.— Coastal land loss in Louisiana, 1955—1978 (redrawn and adapted from van Beek and Meyer—Arendt, 4000 1982, p. 16). 95° 90° 85°. 80° \w—\ OKLAHOMA I ’ .1\I,\V/M~\\I ? MISSISSIPPI ALABAMA GEORGIA LOUISIANA ' “ ”M ‘ " ””7 I \ TEXAS 0 Lake Charles ~’~’\\_w~_’/" FLORIDA Houston 0 Tampa ANNUAL SHORELINE CHANGE Accretion Erosion Brownsville L 5 Meters or More 3.0 - 4.9 Meters " 1.0 - 2.9 Meters Less Than 1 Meter No Data FIGURE l.— Coastal erosion and accretion on the US. Gulf Coast (redrawn from US. Geological Survey, 1988). 10~ U 9 8'9 TABLE 1. —Contributors to coastal land loss in Louisiana COASTAL ZONE BOUNDARY I 29°05 Natural Human-Induced Delta cycle process Flood control Subsidence Canal dredging Eustasy Pipelines 29°02 Saltwater intrusion Subsurface fluid withdrawal Storm impact Brine disposal Water logging Water pollution . . . 29°05' Geosynclmaldownwarping Herbivory Herbivory (ac/miZ/yr) Very Severe (>4) 11000 0 Severe (2—4) 1 000 m Moderate (12) 9000 Low (0-1) 8000 7000 6000 5000 3000 2000 1000 0 1900 1920 1940 1960 1980 2000 FIGURE 4.— Coastal land loss, in ha/yr, in Louisiana’s Mississippi River delta plain, 1955-1978. (data from Gagliano and others, 1981, p. 298). 29°02' 50' INTRODUCTION Coastal erosion and wetland loss are serious and widespread national problems with long—term economic and social consequences (fig. 1). The highest rates of erosion and wetland loss in the United States, and possi- bly the world, are found in coastal Louisiana (Morgan and Larimore, 1957; Gagliano and van Beek, 1970; Adams and others, 1978; Gosselink and others, 1979; Craig and others, 1980; Wicker, 1980; Sasser and others, 1986; Walker and others, 1987; Coleman and Roberts, 1989; Britsch and Kemp, 1990, Dunbar and others, 1990; Penland and others, 1990a; Williams and others, 1990). Louisiana’s bar— rier systems protect an extensive estuarine system from offshore waves and saltwater intrusion from the Gulf of Mexico, but these islands are be- ing rapidly eroded (Peyronnin, 1962; Penland and Boyd, 1981, 1982; Morgan and Morgan, 1983). The disappearance of Louisiana’s barrier systems will result in the destruction of the large estuarine bay systems and the acceleration of wetland loss. Coastal land loss severely impacts the fur, fish, and waterfowl indus- tries, valued at an estimated $1 billion per year, as well as the environ- mental quality and public safety of south Louisiana’s citizens (Gagliano and van Beek, 1970; Gosselink, 1984; Turner and Cahoon, 1987; Chabreck, 1988; Davis, 1990a; Davis, 1990b). In addition, the region’s renewable resource base depends on the habitat provided by the fragile estuarine ecosystems. Understanding the geomorphological processes, both natural and human—induced (table 1), that control barrier island erosion, estuarine deterioration, and wetland loss in Louisiana is essential to evaluating the performance of the various restoration, protection, and management methods currently envisioned or employed (Penland and others, 1990a). The challenge of coping with and combatting coastal erosion and wetland loss grows as the Gulf Coast population becomes more concen- trated and dependent upon coastal areas. The Environmental Protection Agency (EPA) and National Research Council (NRC) have predicted that the rates of sea level rise will increase over the next century, which will re- sult in dramatically accelerated coastal land loss (Barth and Titus, 1984; National Research Council, 1987). Because of its geologic setting, Louisiana provides a worst-case scenario for the future coastal conditions predicted by the EPA and NRC. More importantly, Louisiana’s coastal problems illustrate the importance of understanding the processes driving coastal land loss. Many solutions to coastal land loss problems emphasize stopping the result of the geologic process and give inadequate considera— tion to the process itself. This approach results in engineering solutions that rely on expensive brute force rather than more sophisticated, less ex— pensive approaches that operate in concert with natural processes re- vealed by scientific study (Penland and Suter, 1988a). This lack of under- standing leads to oversimplified concepts and the false hope that easy so- lutions exist. A key objective of the US. Geological Survey (USGS) and Louisiana Geological Survey (LGS) cooperative coastal research program is to improve our knowledge and understanding of the processes and pat— terns of coastal land loss in order to help develop a strategy to conserve and restore coastal Louisiana. 45' 90°35’ FIGURE 3.— Shoreline change in the Isles Dernieres, 1853-1978 (redrawn and adapted, by per- mission, from Penland and Boyd, 1981, p. 216; © 1981 by IEEE). TABLE 2.—Solutions to Louisiana’s coastal land loss problem Tactics Relative costs Strategic management and retreat $ $ $$ Sediment diversions $$$ Marsh management $$ Coastal erosion control $ Research and development ¢ (Reprinted from Penland and others, 1990a, p. 686.) COASTAL LAND LOSS Behind Louisiana’s protective barrier systems lie extensive estuaries that are rapidly disintegrating because of pond development, bay expan- sion, coastal erosion, and human impacts (Morgan, 1967). The chronic problem of wetland loss in Louisiana is well documented but poorly un— derstood (Wicker 1980; Britsch and Kemp, 1990; Dunbar and others, 1990). Previous studies show that coastal land loss has persisted and ac- celerated since the 1900’s. Much speculation and debate in the research, governmental, and environmental communities surrounds the issue of coastal land loss, the natural and human—induced processes that drive coastal change, and the strategy for coastal protection and restoration (table 2) (Penland and others, 1990a). Coastal land loss is the result of a set of processes that convert land to water. Coastal change is a more complex concept. It describes the set of processes driving the conversion of one geomorphic habitat type into another. Coastal land loss and change typically involve first the conversion of vegetated wetlands to an estuarine water body, followed by barrier sys— tem destruction and the conversion of the estuarine water bodies to less productive open water. There are two major types of coastal land loss: coastal erosion and wetland loss. Coastal erosion is the retreat of the shoreline along the exposed coasts of large lakes, bays, and the Gulf of Mexico. In contrast, wetland loss is the development of ponds and lakes in the interior wetlands and the expansion of large coastal bays behind the barrier islands and mainland shoreline (Penland and others, 1990a). COASTAL EROSION Shoreline change in Louisiana averages -4.2 m/yr with a standard deviation of 3.3 and a range of +3.4 to -15.3 m/yr (US. Geological Survey, 1988) (table B1 in appendix B). This is the average of long-term (over 50-year) conditions per unit length of 600 km of shoreline. The av— erage Gulf of Mexico shoreline change rate is -1.8 m/yr, the highest in the United States. By comparison, the Atlantic is being eroded at an aver- age rate of 0.8 m/yr, while the Pacific coast is relatively stable with an av- erage rate of change of 0.0 m/yr (US. Geological Survey, 1988). Most coastal erosion in Louisiana is concentrated on the barrier systems that front the Mississippi River delta plain (fig. 2). Coastal erosion is not a steady process; bursts of erosion occur during and after the passage of major cold fronts, tropical storms, and hurricanes (Harper, 1977; Penland and Ritchie, 1979; Dingler and Reiss, 1988; Ritchie and Penland, 1988; Dingler and Reiss, 1990). Field measurements have documented 20—30 m of coastal erosion during a single 3— to 4—day storm. These major storms produce energetic overwash conditions that erode the beach and produce a lower-relief barrier landscape (Penland and others, 1989a; Penland and others, 1990a). This beach erosion has resulted in a significant (41 percent) decrease in the total area of Louisiana’s barrier islands, from 98.6 km2 in 1880 to 57.8 km2 in 1980—a rate of 0.41 ka/yr (Penland and Boyd, 1982). The Isles Dernieres, in Terrebonne Parish, have the highest rate of coastal erosion of any Louisiana barrier system (fig. 3). From 1890 to 1988, the Isles Dernieres shoreline was eroded 1,644 m at an average rate of 16.8 m/yr. The most erosion took place in the central barrier is— land arc at Whiskey Island, where the beach retreated a total of 2,573 m at an average rate of 26.3 m/yr. This erosion resulted in a 77 percent de- crease in the total area of the Isles Dernieres, from 3,360 ha in 1890 to 771 ha in 1988—an average rate of 26.4 ha/yr (Penland and Boyd, 1981; McBride and others, 1989a). Of immediate threat to Louisiana, and particularly to Terrebonne and Lafourche parishes, is the predicted loss of the Isles Dernieres by the early 215t century. Coastal erosion is ex- pected to destroy East Island first, by 1998, and Trinity Island ultimately, by 2007. After the Isles Dernieres are destroyed, the stability and quality of the Terrebonne Bay barrier—built estuary and the associated coastal wetlands will be dramatically diminished (Penland and others, 1990a). WETLAND LOSS Louisiana contains at least 40 percent of the Nation’s coastal wet- lands, but is suffering 80 percent of its wetland loss. Most of the 4,697,100 ha of coastal wetlands found in the continental United States (except the Great Lakes area) lie along the Atlantic coast (52.7 percent) and the northern Gulf of Mexico (45.8 percent). Louisiana contains 55.5 percent of the northern Gulf of Mexico’s coastal wetlands, or 1,193,900 ha (Alexander and others, 1986; Reyer and others, 1988) (table B2 in appendix B). Within Louisiana, the Mississippi River delta plain comprises 995,694 ha of salt marsh, fresh marsh, and swamp, representing 74 per- cent of the State’s coastal wetlands. The chenier plain accounts for the remaining 26 percent or 347,593 ha. Cameron Parish (on the chenier plain) has the largest expanses of salt and fresh marsh of a single parish, a total of 302,033 ha. Terrebonne Parish has the delta plain’s largest ex- panse of coastal wetlands, with 233,711 ha, followed by Plaquemines Parish with 167,980 ha, Lafourche Parish with 118,224 ha, and St. Bernard Parish, with 104,906 ha (Alexander and others, 1986) (table B3 in appendix B). Louisiana’s wetland parishes constitute the single largest concentration of coastal marshes in the contiguous United States. The current rate of coastal land loss in south Louisiana is estimated to be over 12,000 ha/yr; 80 percent of the loss occurs in the delta plain (fig. 4) and 20 percent in the chenier plain (Gosselink and others, 1979; Gagliano and others, 1981). Previous studies indicate that the rate of coastal land loss has accelerated over the last 75 years. Rates of loss within the delta plain alone have increased from 1,735 ha/yr in 1913, to 4,092 ha/yr in 1946, to 7,278 ha/yr in 1967, and finally to 10,205 ha/yr in 1980. In 1978, it was estimated that accelerating coastal land loss would destroy Lafourche Parish in 205 years, St. Bernard Parish in 152 years, Terrebonne Parish in 102 years, and Plaquemines Parish in 52 years (Gagliano and others, 1981). New research indicates that coastal land loss is proceeding more slowly now than it did in the 1970’s; further, today’s loss rate is lower than it was expected to be. Britsch and Kemp’s (1990) mapping study of coastal land loss used 50 15-minute USGS quadrangle maps of the Mississippi River delta plain and 1932—1933 US. Coast and Geodetic Survey Air Photo Compilation sheets (1:20,000 original scale) for inter— pretation for 1956—1958, 1974, and 1983. Coastal land loss rate curves were generated for each quadrangle and the entire delta plain. This study showed that rates increased after the 1930s from 3,339 ha/yr during the 1956—1958 period to 7,257 ha/yr in 1974 (Britsch and Kemp,1990). After 1974, the land loss rate decreased to 5,949 ha/yr in 1983 (fig. 5). This rate corresponds closely to those measured by Gagliano and others (1981) through 1967; however, the maximum land loss rate for 1978 ex- ceeded the maximum land loss rate from Britsch and Kemp (1990) for 1974. Dunbar and others (1990) mapped a land loss rate trend for the chenier plain similar to that found in the delta plain. The land loss rates in the chenier plain accelerated after the 19305 from 582 ha/yr to a maximum of 3,589 ha/yr in 1974 (fig. 6). Since 1974, the land loss rates have decreased to 2,004 ha/yr in 1983. Dunbar and others (1990) combined the results from the chenier plain study and the results of the Britsch and Kemp (1990) delta plain study to develop a comprehensive and accurate perspective on Louisiana’s total coastal land loss problem. The most surprising aspect of these two studies is that they document that land loss rates for the entire coastal zone have decreased despite the fact that they were expected to accelerate for the foreseeable future. Consistent with the land loss rate curves for the individual delta and chenier plains, the composite land loss rate curve for the entire coastal zone depicts an acceleration in land loss from 3,921 ha/yr in 1932 to 10,846 ha/yr in 1974 (fig. 7); by 1983 the rate had decreased to 7,953 ha/yr. Land loss rates had been expected to exceed 13,000 ha/yr by that date. As the composite land loss time series show, the general trend across Louisiana’s coastal zone is primarily toward decreasing or constant rates with isolated quadrangles of increasing rates. The areas of decreasing or constant land loss in the delta plain include the interior wetlands, Pontchartrain basin, Atchafalaya basin, and the Mississippi River mouth (table 3). Areas of increasing land loss in the delta plain include Lake Maurepas, Thibodaux, Chandeleur Sound marshes, lower Barataria basin, and lower Terrebonne basin. On the chenier plain the regional trend is toward decreasing or constant land loss rates, by quadrangle, except in the Grand Lake area, where the rates are increasing (table 4). The Britsch and Kemp (1990) and Dunbar and others (1990) studies document that, although the rates are not as high now as they once were, Louisiana still faces a catastrophic coastal land loss problem. TABLE 3.—Land loss rates on the Mississippi River delta plain Quadrangle Time Average Loss Time , Average Loss Time Average Loss Name Period1 (mi2/yr) Period2 (mizlyr) Period3 (miz/yr) Barataria 1939—1956 1.08 1956—1974 1.20 1974—1983 0.70 Bay Dogris 1932—1958 0.42 1958—1974 1.44 1974—1983 1.26 Bayou Du Large 1932—1958 0.18 1958—1974 1.61 1974—1983 0.65 Bayou Sale 1937—1956 0.31 1956—1974 0.36 1974—1983 0.19 Belle Isle 1940—1956 0.38 1956—1974 0.32 1974—1983 0.15 Black Bay 1932—1958 0.21 1958—1974 0.37 1974—1983 0.52 BonnetCarre 1936—1958 0.10 1958—1974 0.44 1974—1983 0.19 Breton Island 1932—1958 0.26 1958—1974 0.18 1974—1983 0.11 Caillou Bay 1932—1958 0.22 1958—1974 0.40 1974—1983 0.43 Catlsland 1932—1958 0.0 1958—1974 0.09 1974—1983 0.11 ChefMenteur 1932—1958 0.49 1958—1974 0.41 1974—1983 0.28 Covington 1932—1958 0.02 1958—1974 0.18 1974—1983 0.02 Cut Off 1939—1958 0.22 1958—1974 0.53 1974—1983 0.39 Derouen 1932—1956 0.24 1956—1974 0.22 1974—1983 0.24 Dulac 1932—1958 0.37 1958—1974 0.98 1974—1983 1.99 East Delta 1932—1958 1.17 1958—1974 1.90 1974—1983 0.27 Empire 1932—1958 0.35 1958—1974 1.12 1974—1983 2.66 Fort Livingston 1932—1958 0.34 1958—1974 0.53 1974—1983 0.89 Gibson 1939—1958 0.11 1958—1974 1.50 1974—1983 0.45 Hahnville 1935—1958 0.11 1958—1974 0.57 1974—1983 0.43 Houma 1939—1958 0.13 1958—1974 0.24 1974—1983 0.17 Jeanerette 1937—1956 0.08 1956—1974 0.08 1974-1983 0.06 LacdesAlIemands 1945—1958 0.13 1958—1974 0.11 1974—1983 0.66 1974—1983 0.38 1974—1983 1.61 1974—1983 0.90 1956—1974 1.31 1958-1974 1.32 1958-1974 0.40 Lake Decade 1931—1956 0.25 Lake Felicity 1932—1958 0.29 Leeville 1932—1958 0.28 Marsh Island 1932—1956 0.23 1956—1974 0.39 1974—1983 0.24 Mitchell‘Key 1932—1956 0.05 1958—1974 0.03 1974-1983 0.07 Morgan City 1931—1956 0.20 1955-1974 1.37 1974-1983 0.93 Morgan Harbor 1932—1958 0.19 1958—1974 0.32 1974—1983 0.38 MountAiry 1939—1958 0.05 1958—1974 0.08 1974—1983 0.08 NewOrIeans 1935—1958 0.17 1958—1974 0.26 1974—1983 0.14 Oyster Bayou 1931—1956 0.07 1956—1974 0.18 1974—1983 0.15 Point Chicot 1932—1958 0.08 1958—1974 0.08 1974—1983 0.07 Pointau Fer 1931—1956 0.11 1956—1974 0.16 1974—1983 0.17 Pointeala Hache 1932—1958 0.28 1958—1974 0.75 1974—1983 0.71 Pontchatoula 1939—1958 0.07 1958-1974 0.09 1974—1983 0.08 Rigoiets 1932—1958 0.11 1958—1974 0.24 1974—1983 0.26 Slidell 1939-1958 0.06 1958-1974 0.15 1974-1983 0.05 Southwest Pass 1932—1958 0.10 1958—1974 0.12 1974—1983 0.02 Spanish Fort 1936—1958 0.03 1958—1974 0.01 1974—1983 0.003 Springfield 1939—1958 0.01 1958-1974 0.01 1974-1983 0.03 St. Bernard 1932—1958 0.29 1958—1974 1.23 1974—1983 0.70 Terrebonne Bay 1932—1958 0.18 1958-1974 0.29 1974—1983 0.49 Thibodaux 1949-1958 0003 1958—1974 0.02 1974—1983 0.07 Three Mile Bay 1932—1958 0.08 1958—1974 0.11 1974—1983 0.10 TimbalierBay 1934—1958 0.21 1958—1974 0.22 1974—1983 0.41 1974—1983 0.54 1974~1983 1.04 1974—1983 0.53 1956-1974 1.50 1958—1974 2.0 1958—1974 0.60 Venice 1932—1958 0.61 West Delta 1932—1958 1.41 Yscloskey 1932—1958 0.12 (Data from Britsch and Kemp, 1990, p. 15—16.) TABLE 4.—Coastal land loss rates on the Louisiana chenier plain Quadrangle1 Time Average Loss Time Average Loss Time Average Loss Name Period1 (miz/yr) Period2 (mi2/yr) Period3 (mIZ/yr) Abbeville 1934—1954 0075 1954—1974 0.245 1974—1983 0.255 Cameron 1933—1955 0.077 1955—1974 2.468 1974—1983 0.596 1974—1983 0.127 1974—1983 0.495 1974—1983 0.145 1951—1974 0.358 1955—1974 0.822 1955—1974 0.152 1955—1974 0.438 1974—1983 1.643 1955—1974 1.116 1974—1983 1302 1955—1974 0.723 1974—1983 0151 1955—1974 3.119 1974—1983 1.022 1951—1974 0.792 1974—1983 0.752 1955-1974 1.823 1974-1983 0.395 1955—1974 1.796 1974~1983 0.839 CheniereAuTigre 1935—1951 0.076 Constance Bayou 1932—1955 0.641 Forked Island 1935—1955 0.019 Grand Lake East 1932—1955 0.324 Grand LakeWest 1933—1955 0.048 Hog Bayou 1932—1955 0.537 Johnsons Bayou 1933—1955 0.088 Pecan Island 1935—1955 0.063 Sulphur 1933—1955 0.047 Sweet Lake 1933—1955 0.129 ‘Approximate area of a 15—minute quadrangle is 300 miz. (Data from Dunbar and others, 1990, p. 10.) TABLE 5.—Barrier systems of Louisiana Back-barrier System Headland Islands Tidal Inlets Water Bodies Bayou Lafourche Caminada—Moreau Timbalier Island Cat Island Pass Timbalier Bay E. Timbalier island Little Pass Caminada Bay Grand Isle Timbalier Barataria Bay Caillou island Raccoon Pass Belle Pass Caminada Pass Barataria Pass Plaquemines Bayou Robinson Cheniere Ronquille Barataria Pass Barataria Bay Grand Bayou Grand Terre Islands Pass Abel Bay Ronquille Dry Cypress Bayou Shell Island Guatre Bayoux Pass Bay La Mer Sandy Point Pass Ronquille Bay Joe Wise Pass La Mer Bastian Bay Chaland Pass Bay Couquette Grand Bayoux Pass Shell Island Coupe Fontanelle Pass Schotield Pass Bay Couquette Pass Isles Dernieres Bayou Petit Caillou Raccoon Island Boca Caillou Caillou Bay Whiskey Island Coupe Colin Lake Pelto Trinity Island Whiskey Pass Terrebonne Bay East Island Coupe Carmen Wine Island Shoal Coupe Juan Chandeleur St. Bernard Chandeleur Island Curlew Island Grand Gosier Island Breton Island Wine Island Pass Cat island Pass Pass Curlew Grand Gosier Pass Breton Island Pass Chandeleur Sound Breton Sound Land Loss (ha/yr) Land Loss (ha/ yr) 1950 1960 1970 1980 1990 Elapsed Time (years) FIGURE 5.— Coastal land loss rate curve for the Mississippi River delta plain (data from Britsch and Kemp, 1990, p. 22). BARRIER ISLAND LANDSCAPE REGIONAL GEOLOGY The geology of Louisiana’s coastal zone is intimately tied to the his- tory of the Mississippi River during the Holocene Epoch. The Mississippi River has built a delta plain consisting of seven delta complexes, ranging in age from about 7,000 years old to the contemporary Balize and Atchafalaya complexes (Fisk, 1944; Kolb and Van Lopik, 1958; Frazier; 1967; Coleman, 1988). The main distributary of the Mississippi River shifts to a more hydraulically efficient course about every 1,000 years, re— sulting in the complex geomorphology of Louisiana’s coastal zone (fig. 8). When avulsion occurs, a new delta complex begins prograding in a differ- ent area. Deprived of its former sediment supply, the abandoned delta complex experiences transgression due to relative sea level rise, which in turn is driven by compactional subsidence of the deltaic sediments. The delta—switching process builds new deltas and establishes the framework necessary for barrier island development (Coleman and Gagliano, 1964; Kwon, 1969; Penland and others, 1981). During transgression, the deltaic landscape is dominated and re— worked by marine processes. In what can be visualized as a three-stage process, coastal erosion transforms the once-active delta into a succession of transgressive depositional environments (fig. 9) (Penland and others, 1988a). The first stage is an erosional headland with flanking barrier is— lands. Long-term relative sea level rise and erosional shoreface retreat lead to stage 2, the detachment of the barrier system from the mainland and the formation of a barrier island arc (Boyd and Penland, 1988). The final stage occurs when relative sea level rise and repeated storm impacts overcome the ability of the barrier island arc to maintain its subaerial integrity. The arc becomes submerged, forming an inner-shelf shoal (Penland and others, 1986a). Shoreface retreat processes then continue to drive the inner—shelf shoal landward across the subsiding continental shelf and smooth the mainland shoreline. The modern Mississippi River delta plain is North America’s largest deltaic estuary (fig. 10). Two distinct types of estuaries occur here: barrier— built and delta-front (Schubel, 1982). Barrier-built estuaries develop as a result of delta abandonment; barrier islands form, lakes develop into larger bays, and salt marshes encroach upon the surrounding freshwater marshes and swamps under the effects of submergence (Scruton, 1960; Penland and others, 1988a). In contrast, the delta-front estuaries are as- sociated with active delta building and the development of freshwater swamps and marshes (van Heerden and Roberts, 1988; Tye and Coleman, 1989). The coastline of the Modern delta plain stretches 350 km from Point au Fer east to Hewes Point in the northern Chandeleur Islands. It is sur- rounded by 17 barrier islands attached to several major deltaic headlands (table 5). These islands and headlands can be organized into four distinct barrier systems, each tied to an abandoned delta complex: from west to east they are the Isles Dernieres, Bayou Lafourche, Plaquemines, and Chandeleur barrier systems. The back-barrier lagoons are connected to the Gulf of Mexico by 25 tidal inlets, which allow the exchange of a diur- nal tidal regime. Within the official Louisiana coastal zone boundary of the delta plain, alluvium, fresh marsh, salt marsh, bay, and barrier island envi- ronments occur (Snead and McCulloh, 1984). The Bayou Lafourche, Plaquemines, Isles Dernieres, and Chandeleur barrier—built estuarine sys- tems make up 62 percent of the Mississippi River delta plain, whereas the delta-front estuaries account for 18 percent, and the remaining area is mapped as alluvium. Barrier-built estuaries are the most productive com- ponent of the delta cycle (Gagliano and van Beek, 1970). 4000 3500 3000 2500 '2000 1500 1000 500 In I‘ I. \ II II‘, ,I 1930 1940 12000 11000 10000 9000 8000 7000 6000 5000 Land Loss (ha/ yr) 3000 2000 1000 1960 1970 1980 1990 Elapsed Time (years) FIGURE 6.— Coastal land loss rate curve for the Mississippi River chenier plain (data from Dunbar and others, 1990, p. 12). 30° 290 V l STAGE 1 EROSIONAL HEADLAND WITH FLANKING BARRIERS ACTIVE DELTA I Abandonment BARRIER ARC Submergence I w 92° 91° Pleistocene Holocene Subaqueous Sand Bodies Barrier Shoreline I I “All l II III“ I ‘ In, III ,II.,I, III \ III“, II, I‘I IIIIIII \;,, I I I II II I I I I III I ‘II‘ ,' III II ‘I II , III \\ \‘Il II III II III III 4000 - II III, (II , I VIIIA II ‘ III III "\I IIII I II III .IIII 1930 1940 1950 1960 1970 1980 1990 Elapsed Time (years) FIGURE 7.— Composite coastal land loss rate curve for the Mississippi River delta and chenier plains in Louisiana (data from Dunbar and others, 1990, p. 14). 90° 890 III I\ III III II. II I III III \IIIIII \ I I\‘\\\IIII\\\IIII\II I) I \\l\,I\I1III\I\\§I , III III III IIIIIIII I I II I II , (II (III ‘ III III II I ‘ II III I I III \ I l( I II In I I I ‘ \II\ \\\II \III \IIIII III I \\ \I \I \\ I Inn, III,\\. III I I I I \ \ I ‘ II III ,W, IIIIII N IIIII III,I II III III I ‘I I II \ I IIIIII‘IIl‘IIII III \II I \ l l I l I‘ ‘IWIM‘IMI \,\I I \I\ I I III . , \ImI I III , I I», I, II M, \ NI, \ I. III III II I I I , , I I I I I I IIIIIII II I I“, II , I “I I In . v M II \III‘II I« \ 1III I I I . II - I l ,n ' III II I I III I I l l W‘I'IIl geese/2;» \I \ II II I FIGURE 8.— The Mississippi River delta complex, with barrier islands indicated (redrawn and adapted, by permission, from Frazier, 1967, p. 289; © 1967 by the Gulf REGRESSIV!= ENVIRONMENTS 'A Distributary ‘ Saltwater Marsh Recurved Spits Shell Reefs Tidal Inlet Coast Association of Geological Societies). 91° 90° 89° 30° 29° Alluvium Fresh Marsh Coastal zone 7 Beach Ridges boundary ' TRANSGRESSIVE Reoccupation l Submergence ENV'RONMENTS Subaerial Barrier STAGE 3 STAGE 2 . INNER SHELF SHOAL TRANSGRESSIVE _ SUbaqueous Baffler l V A A ° Sand Sheet Fresh Marsh Barrier-built EIstuary Saltwater Marsh Delta-front Estuary FIGURE 10.— Distribution of barrier-built and delta-front estuaries in the Mississippi River delta plain. FIGURE 9.-— A model of barrier island development (redrawn Penland and Boyd, 1981, p. 211; © 1981 by IEEE). and adapted, by permission, from LOUISIANA BARRIER SYSTEMS Bayou Lafourche The Bayou Lafourche barrier system forms the seaward geologic framework of the eastern Terrebonne and western Barataria basins in Terrebonne, Lafourche, and Jefferson parishes; the system consists of Timbalier Island, East Timbalier Island, the Caminada—Moreau Headland, Caillou Island, and Grand Isle (fig. 11). The system stretches over 60 km between Cat Island Pass and Barataria Pass, enclosing Timbalier Bay and Caminada Bay (Penland and others, 1986b). Little Pass Timbalier, Raccoon Pass, and Caminada Pass connect these back-barrier water bod- ies with the Gulf of Mexico. The Caminada—Moreau Headland is a low- profile mainland beach with marsh and mangrove cropping out on the lower beach face, reflecting rapid shoreline retreat. Over the last 300 years, erosion of the Caminada—Moreau Headland has supplied sand for barrier island development. The amount of sediment in the surf zone increases downdrift to the east and west away from the central headland, leading to the development of higher-relief washover terraces (fig. 12). These landforms eventually coalesce farther downdrift to form a higher, more continuous dune terrace, and a continuous foredune ridge on the margins of the Caminada—Moreau Headland. Continuous dunes are also found on the downdrift ends of the Timbalier Islands and Grand Isle. The Caminada spit is attached to the eastern side of this aban— doned deltaic headland. The Timbalier Islands and Grand Isle also are lat— erally—migrating, flanking barrier islands built by recurved spit processes. Flanking barrier islands typically are formed through a series of pro— cesses that includes recurved spit building, longshore spit extension, sub- sequent hurricane impact and breaching, and island formation. The mor— phology of Timbalier Island and Grand Isle reflects the geomorphic im— print of the recurved spit process. The recent (1887—1978) history of the Bayou Lafourche barrier system illustrates erosion of the central headland with concurrent development and lateral migration of the flanking barrier islands (fig. 13). Plaquemines The Plaquemines barrier system, which derives its name from the abandoned Plaquemines distributary network of the Modern delta com- plex, forms the seaward geologic framework of the eastern Barataria basin in Jefferson and Plaquemines parishes (fig. 14). The system is 40— 50 km long and consists of the Grand Terre Islands attached to the Robinson Bayou and Grand Bayou headlands and Shell Island attached to the Dry Cypress Bayou headland. It encloses Barataria Bay, Bay Ronquille, Bay La Mer, Bastian Bay, and many other smaller water bod— ies. Barataria Pass, Pass Abel, Quatre Bayoux Pass, Pass Ronquille, Pass La Mer, Chaland Pass, Grand Bayoux Pass, and Schofield Pass are the major tidal inlets that connect the back—barrier areas with the Gulf of Mexico. The morphology varies from washover flats and terraces concen- trated in headland areas to dunes and dune terraces concentrated on the flanking barrier islands (Ritchie and others, 1990). Grand Terre is the largest flanking barrier island of the Plaquemines barrier system. Erosion of the Bayou Robinson and Grand Bayou head- lands over the last 400 years has supplied sand for the northwest exten— sion of Grand Terre across the southern entrance to the Barataria basin. Repeated hurricanes and barrier island breaching, combined with an in— creasing tidal prism in Barataria Bay, has led to the development of Pass Abel and Quatre Bayoux Pass over the last 100 years, dividing Grand Terre (fig. 15). Shell Island Is the second-largest flanking barrier island in the Plaque— mines system. Enclosing Bastian Bay, Shell Island at one time protected this prolific oyster ground from the direct influence of the Gulf of Mexico. With construction of the Empire jetties and placement of a shore-parallel pipeline system, the natural pattern of sediment transport was disrupted, leading to the breaching of Shell Island by Hurricane Bob in 1979. In re— cent years, this breach has been dramatically enlarged, allowing open wa— ter to destroy much of the Bastian Bay oyster grounds (fig. 16). Isles Dernieres The Isles Dernieres barrier system forms the seaward geologic framework of the southwestern Terrebonne basin in Terrebonne Parish (fig. 17). “Isle Derniere” means Last Island in Cajun French and was used in the 1800’s to describe a single large island not separated by tidal inlets. Today, the plural form, Isles Dernieres, is used to account for the multiple islands and tidal inlets. The barrier island arc consists of four main islands: Raccoon Island, Whiskey Island, Trinity Island, and East Island. More than 30 km long, the Isles Dernieres enclose Caillou Bay, Lake Pelto, and Terrebonne Bay, which are connected to the Gulf of Mexico by Boca Caillou, Coupe Colin, Whiskey Pass, Coupe Carmen, Coupe Juan, Wine Island Pass, and Cat Island Pass. Whiskey Island and Trinity Island are dominated by washover flats and terraces (Ritchie and others, 1989). Raccoon Island is dominated by washover and dune terraces and East Island by dune terraces and continuous dunes. .The Isles Dernieres barrier system originated from the erosion of the Bayou Petit Caillou headland distributaries and beach ridges over the last 600—800 years (Penland and others, 1985; Penland and others, 1987a). Coastal changes in the Caillou headland observed between 1853 and 1978 illustrate the transition from an erosional headland into a barrier is— land arc (see fig. 9). In 1853, Pelto and Big Pelto bays separated the Caillou headland and the flanking barriers from the mainland by a narrow tidal channel less than 500 m wide. By 1978, the size of these bays had increased three—fold and they had coalesced to form Lake Pelto. During this period, the Gulf shoreline of the Caillou headland eroded landward over 1 km. The Isles Dernieres now lie several kilometers seaward of the retreating mainland, and at current rates, they will be destroyed by 2007 (McBride and others, 1989a). Chandeleur The Chandeleur barrier island arc forms the seaward geologic frame- work of the St. Bernard delta complex (Treadwell, 1955; Penland and others, 1985; Suter and others, 1988). It encloses the Mississippi River delta plain’s largest barrier—built estuary (fig. 18). Over 75 km long, the Chandeleur Islands enclose Breton Sound and Chandeleur Sound in Plaquemines and St. Bernard parishes, and incorporate Chandeleur Island, Curlew Island, Grand Gosier Island (north and south) and Breton Island (north and south). The tidal inlets separating the southern islands include Pass Curlew, Grand Gosier Pass, and Breton Island Pass. The Chandeleur Islands derive their name from the Catholic candle mass, which was performed on the islands several hundred years ago. The Chandeleur Islands are the oldest transgressive barrier island arc found on the Mississippi River delta plain and are the product of the ero- sion of the St. Bernard delta complex over the last 1,500 years. The arc’s asymmetric shape is the result of its oblique orientation to the dominant southeast wave approach, which leads to the northward transport of sediment. Toward the north, the Chandeleur Islands’ morphology is domi- nated by large washover fans and flood-tidal deltas separated by hum- mocky dune fields. The islands” wide beaches, with multiple bars in the surf zone, reflect an abundance of sediment. To the south, island widths narrow, heights decrease, and washover channels and fans give way to discontinuous washover terraces and flats. Farther south, the island arc fragments into a series of small, ephemeral islands and shoals separated by tidal inlets. The Chandeleur Islands have historically retreated landward, undergo- ing fragmentation by hurricane impact and subsequent rebuilding (fig.19). Chandeleur and Breton sounds average 3—5 m deep and separate the Chandeleur Island arc from the retreating mainland shoreline by a lagoon more than 20 km wide. . 4 90°30’ 90°00’ 29°25’ TRANSGRESSIVE ENVIRONMENTS Subaerial Barrier Subaqueous Barrier Salt Marsh Bay~Lagoon Sand Sheet Tidal Channel Recurved Spits 29°05’ 10 Miles 5 1 10 Kilometers FIGURE ll.— Coastal environments of the Bayou Lafourche barrier system (redrawn from Penland and others. 1988b, p. 19). 90°06 BAYOU LAFOURCHE BARRIER SHORELINE 10 Miles EAST Tlltéiffiklgl? 10 Kilometers \ TIMBALIER iSLAND \ O FIGURE 13.— Shoreline change along the Bayou Lafourche barrier system, 1887—1978 (redrawn from Penland and Boyd, 1985, p. 86). 89°55’ 89°30’ 29°1 5' GRAND TERRE ISLANDS 0 5 Miles i—HT—l—fl—FH 0 5 Kilometers FIGURE 14.— Coastal environments of the Plaquemines barrier system (redrawn, by permission, from Boyd and Penland, 1988, p. 449; © 1988 by the Gulf Coast Association of Geological Societies). REGRESSIVE ENVIRONMENTS .‘\ ‘ Distributary . . Fresh Marsh // Beach Ridges 90°05’ 29°15' J FIGURE 12.— Landforms of Louisiana’s barrier systems. 1978 ’11 SHELL ISLAND . 009 C ofi’ofi" New 90°00' 89°55' 89°50’ 89°45’ / d} | / l ~90 / 7o. / / / / CHENIERE RONQUILLE FCIIIO SURVEY / ""3 AREA .. 4 q / GRAND TERRE ’ ISLANDS ___/ T — o’\ 19 6:90 7o Mew—44 0 5 Kilometers l l l . _\ K M 1 Mile 1 Kilometer o’\1‘ FIGURE 15.— Shoreline change at Grand Terre, 1880—1978 (redrawn, by per— mission, from Penland and Suter, 1988a, p. 335; © 1988 by the Gulf Coast Association of Geological Societies). 29°10’ 29°02' TRANSGRESSIVE ENVIRONMENTS Subaerial Barrier Subaqueous Barrier Salt Marsh Bay-Lagoon Sand Sheet Tidal Channel Recurved Spits Shoal REGRESSIVE ENVIRONMENTS Wine Island Distributary I (If Fresh Marsh Beach Ridges FIGURE l7.—- Coastal environments of the Isles Dernieres barrier system (redrawn and adapted, by permission, from Penland and Suter, 1983, p. 370; © 1988 by the Gulf Coast Association of Geological Societies). FIGURE 16.—- Shoreline change at Shell Island, 1978-1988 (redrawn, by permission, from Penland and Suter, 1988a, p. 337; © 1988 by the Gulf Coast Association of Geological Societies). 88°50' FIGURE 18.— Coastal environments of the Chandeleur barrier system (redrawn, by permission, from Penland and others, 1988a, p. 939; © 1988 by the Society of Economic Paleontologists and Mineralogists). 22». >89. . ab. 9 s s. it, . ‘3: %_ 99°® "3: QB 99$ 9% 9% 99°00 63% S9966 \ \ \ 6' %go\ FREEMASON ISLANDS BRETON f ISLANDS {3 $57 0‘ a Sea a Cu $1 ISLANDS / 9’ €933 / GRAND GOSIER \' T O. \ ISLANDS 0 R ERROL NEW HARBOR a ISLAND ISLANDS a? s CURLEW $9 . ISLAND / were V‘D9n 06/ T336187" Tim s9° - 1978 .43 511. 5 Miles . 5Kilometers \ \ \ \ FIGURE 19.—- Shoreline change on the Chandeleur Islands, 1870—1978 (redrawn, by permission. from Penland and others, 1985, p. 220; © 1985 by Elsevier Science Publishers). 91°00’ 55’ - ISLES DERNIERES 29°05’ “ Raccoon Point 196 29°01’ 90°30' 2 5' TIMBALIER ISLANDS 29°05’ 50' 45' 90°40’ ISLES DERNIERES 20' _15' EAST ‘I‘iMBAUER ' lSLAND _ Q30 é W GULF OF MEXICO 90°10' GULF OF MEXICO FIGURE 20.— Shoreline change on the Isles Dernieres and Timbalier Islands between 1890 and 1960 (redrawn, by permission, from Peyronnin, 1962, © 1962 by the 90° R—3 45.07;» {-17.175114 R-l ~62.0Vyr (37.27“) GULF OF MEXICO " 1° 2“ I) 10 20 89° 12-4 43.77;» (—18.0’/yr) 30 40 Miles 30 40 50 Kilometers FIGURE 21.-— Rate of shoreline change in eastern Louisiana, 1812—1954 and 1954-1969 (redrawn 5 Miles 2 9°01 ' 5 Kilometers American Society of Civil Engineers). 91° i RATE OF SHORELINE CHANGE E. LOUISIANA 1812-1954 (also 1954-1969) W RE I RFATINQ SHQBELINE A-1 Modern Della R-l More Than 50 It/Vr (Major Accretion) R72 25-50 it/yr R-3 15-25 ft/yr R-4 Less Than 15 ft/yr 30° R~4 v9.2’/yr 913.775”) 29° -27.G‘/yr (23.0731?) from Morgan and Morgan, 1983, p. 11). 93° 92° 30° 290 O 50 Miles 0 50 Kilometers LIMITS (Latitude 3 or 1 Longitude) 1 28° ‘ SHORELINE j LENGTH 3 (miles) 91° 90° 29°20’ 89° 29°02’ 29°00’ FIGURE 22.— Natural sectors used to evaluate shoreline and areal change on Louisiana’s coast (redrawn from Morgan and Morgan, 1983, p. 14). New Orleans District.) 90°30' 90°00’ 89°45’ I" ‘ ‘ Barataria g 9 I; Buy ‘ tiff ‘5 ‘ ' "BA Caminada Bay A . I GRAND ISLE CAMINADA- MOREAU COAST Bay Champagne Bay Marchand EMBAUER ISLAND 10 Miles 10 Kilometers FIGURE 23.— Distribution and rate of shoreline change on the Bayou I‘ T ‘- RATARIA BAY BARRIERS Lafourche barrier system (redrawn from Penland and Boyd, 1982, p. 25). 90°55' 90°40' 151.53 DERNIERES FIGURE 25.— Distribution and rate of shoreline change for the Isles Dernieres barrier system (redrawn from Penland and Boyd, 1982, p. 32). m/yr >15 1015 5—10 0-5 0-5 5-10 >10 UOISOJH uonaroov o 30°00' 29°30’ FIGURE 24.— Historical breaching at the Caminada spit. (A) Pre-breach conditions in 1950. (B) After Hurricane Flossy in 1956; note the pattern of seaward-oriented overwash features. (C) After Hurricane Betsy in 1965; note the pattern of landward-oriented overwash features. (Photos from US. Army Corps of Engineers, BARRIER ISLAND EROSION RESEARCH PREVIOUS RESEARCH U.S. Army Corps of Engineers The U.S. Army Corps of Engineers has conducted several regional planning studies since the 1930’s to facilitate the design of beach erosion projects. The Corps of Engineers” first detailed barrier island erosion study was conducted for Grand Isle in 1936; subsequent coastal erosion reports were issued for Grand Isle in 1955, 1962, 1972, and 1980 (U.S. Army Corps of Engineers, 1936, 1978, 1980). All of these investigations ana— lyzed the erosion conditions along the coast, reviewed the causative pro— cesses, and proposed and analyzed several designs for beach protection. The most comprehensive study of Grand Isle was the 1980 Corps of Engineers report, which contains extensive information on coastal ero- sion, coastal processes, sand resources, and designs for the Corps of Engineers’ beach erosion and hurricane protection project, which was built in 1984. Combe and Soileau (1987) reported on the successful per- formance Of this project at Grand Isle during and after Hurricanes Danny, Elena, and Juan in 1985. Another series of studies concentrated on coastal geomorphology, shallow subsurface geology, coastal processes, and coastal erosion in the area between Raccoon Point and Belle Pass, which includes the Isles Dernieres and the Timbalier Islands (Peyronnin, 1962). It was reported that at Belle Pass the coast had been eroded 2,027 m between 1890 and 1960 (fig. 20). The Timbalier Islands were reported to be undergoing ero— sion at the rate of 10—30 m/yr, and the Isles Dernieres at a rate of 8—10 m/yr. Peyronnin (1962) estimated that the total material lost from these islands between 1890 and 1934 was 84,100,000 m3—a rate of net loss of 1,911,500 m3/yr. Peyronnin (1962) concluded that the barrier islands be— tween Raccoon Point and Belle Pass are important defenses against sea attack on the mainland, and recommended beach nourishment as the most viable remedial action. The Corps of Engineers updated the 1962 Raccoon Point—to—Belle Pass report in 1975 (U.S. Army Corps of Engineers, 1975a). The shore— line change history was updated from 1959 to 1969; beach erosion had accelerated and the land loss rates were placed at 60 ha/yr. This report also evaluated a variety of erosion control scenarios, including no action, beach nourishment, barrier restoration, and building rock seawalls. The recommended plan was the construction of earthen dikes designed to close existing breaches in the barrier islands, and a maintenance proce- dure to close future breaches. The Corps of Engineers (1975a) estimated that this project would preserve more than 1,950 ha of marshlands over the next 10 years. Another Corps of Engineers (1975b) report indicated that, if the barrier islands were left unprotected, the Isles Dernieres and Timbalier Islands would continue to deteriorate and wetland loss could ap— proach 16,500 ha of marshland over the next 50 years. The Corps of Engineers” first comprehensive inventory of the coastal erosion problem in Louisiana was part of a national shoreline study of the extent and nature of shoreline erosion, which culminated in the publica— tion of an atlas (U.S. Army Corps of Engineers, 1971). The atlas identi— fied the physical characteristics of the Louisiana shoreline, historical changes, and the ownership and use of the coastal areas. Louisiana Attorney General The first comprehensive study of coastal erosion in Louisiana was conducted by Morgan and Larimore (1957) for the Office of the Attorney General of the State of Louisiana (Morgan, 1955). At the time, Louisiana was engaged in a dispute with the Federal government about the owner- ship of offshore oil and gas rights. The study aimed to document the his— torical trends in coastal change in order to establish the position of the State’s 1812 shoreline, which was critical in determining Louisiana’s three—mile limit. The study used historical cartographic data dating back to 1838 from the U.S. Coast and Geodetic Survey (formerly the U.S. Coastal Survey and currently the National Oceanic and Atmospheric Administration [NOAA]), the USGS, the Corps of Engineers, and the State of Louisiana. Aerial photographs from 1932 and 1954 were analyzed to update the historical maps. Measurements of shoreline change were made at intervals of one minute of longitude from the Texas border to the Mississippi bor— der. For continuity, all maps were enlarged or reduced to a common scale of 1:20,000. 89°OO’ l t I; 1. Chandeleur '3" I Lighthouse . “J _ a. ' ‘ O O .0 ~ "’ NORTH lSLANDEa.‘ C U) ' Q NEW ‘ g FREE MASON HARBOR 92 ISLANDS ISLANDS Chandeleur Sound STAKE ISLAND CURLEW ISLAND O GRAND GOSIER ISLAND BRETON lSLAND ‘ __ ,0 5 10 Miles 0 5 10 Kilometers i FIGURE 26.— Distribution and rate of shoreline change for the Chandeleur barrier system (redrawn from Penland and Boyd, 1982, p. 34). The erosion rates around the Mississippi River delta plain ranged from 2.8 to 18.9 m/yr (Morgan and Larimore, 1957). Only the mouth of the Mississippi River was mapped as accretional, The most severe erosion was taking place on the Timbalier Islands and the Caminada—Moreau Headland. Morgan and Larimore (1957) interpreted the regional variation in shoreline change as a function of geologic control due to natural subsi— dence. Because young deltas subside faster than older ones, the higher rates of coastal erosion were found on recently abandoned delta com— plexes. Using newer aerial photography and the same method of analy— sis, Morgan and Morgan (1983) updated that study to 1969 (figs. 21 and 22). Measurements were again made every minute of longitude and were supplemented with measurements of changes in land area. The average shoreline erosion rate in Louisiana between 1932 and 1954 was measured at 2.0 m/yr (Morgan and Larimore, 1957); it increased to 5.2 m/yr between 1954 and 1969 (Morgan and Morgan, 1983). The loss of land area followed a similar pattern. Morgan and Morgan (1983) calculated a loss rate of 144.4 ha/yr due to shoreline erosion between 1932 and 1954 and an increase in the rate to 171.4 ha/yr for the 1954—1969 period. This increase represents a change from 0.5 ha/yr per mile of coast (1932—1954) to 0.6 ha/yr per mile of coast (1954—1969). The erosion rates on the barrier islands from the Isles Dernieres and the Timbalier Islands as far east as the Caminada-Moreau Headland slowed from 11.2 to 7.0 m/yr and from 18.9 to 11.3 m/yr, respectively. In contrast, the erosion rates in the Barataria Bight and Chandeleur Islands increased from 4.9 to 5.2 m/yr and from 4.2 to 5.5 m/yr, respectively. Morgan and Morgan (1983) suggested that the increasing rates of erosion were associated with areas of more extensive human impacts. Louisiana Department of Transportation and Development Using the same methods, Adams and others (1978) updated the Morgan and Larimore (1957) study from 1954 to 1974, to make the third statewide assessment of shoreline change. The State was subdivided into eight management units to assess the patterns of erosion and accre— tion along lake shores, tidal inlets, and interior marshes. The Terrebonne and Barataria basin shorelines were found to be subject to the most ero— sion in the State; they retreated 207 m between 1954 and 1969 at a rate of 13.8 m/yr. Erosion on the Chandeleur Islands was found to be pro— ceeding at a slower rate, 5.4 m/yr. Louisiana Department of Natural Resources The first comprehensive study focusing on Louisiana’s barrier islands was conducted by the Laboratory for Wetland Soils and Sediments at Louisiana State University between 1978 and 1983 under the sponsor- ship of NOAA’s Office of Coastal Zone Management (Mendelssohn and others, 1986). The analysis of shoreline change was based on two inde— pendent sets of data. Changes in Gulf shoreline positions were derived by applying the Orthogonal Grid Mapping System technique to a series of historical aerial photographs and National Ocean Survey T-charts; this produced a high—water line location for every 100 m of shoreline (Shabica and others, 1984). The data base for the Chandeleur Islands included eight sets of imagery for the 1922—1978 period: the rest of Louisiana’s barrier islands were covered by 12 sets of imagery from 1934 to 1978. The second data set was obtained by digitizing the surface area of each barrier island on the Louisiana coast. This method analyzed U.S. Coast and Geodetic Survey maps for 1869—1956 together with a series of land cover maps (scale 1:10,000) based on 1979 aerial photography. The re- sults were presented as a time series of variation in island area (Penland and Boyd, 1981, 1982). The most serious shoreline erosion problems identified were along the Caminada—Moreau Headland, where erosion rates ranged from 10 to 20 m/yr (fig. 23). The highest rate of shoreline retreat measured for the 44-year period was 22.3 m/yr in the vicinity of Bays Marchand and Champagne. Erosion rates decreased eastward to 9.6 m/yr at Bayou Moreau. Field measurements made along the Caminada-Moreau Headland in 1979 showed that tropical cyclones eroded the shoreline more than 40 m—over 70 percent of the total erosion for that year (Penland and Boyd, 1982). Erosion rates in the Belle Pass area were found to have averaged 18.6 m/yr before 1954; after that, shoreline erosion slowed, and switched to accretion after 1969. In 1934, jetties 150 m long and 60 m wide were built at Belle Pass to improve the navigation channel at Bayou Lafourche. The jetty system had little effect on the local sediment dispersal pattern; the shoreline continued to be eroded at rates averaging 18 m/yr, with no significant updrift sand accumulation. In fact, the system had to be extended landward several times to keep pace with the retreating shoreline. In 1968, however, the jetties were expanded to 220 m long and 140 m wide and the channel was dredged to a depth of 6 m, expanded to a width of 90 m, and extended 2 km offshore. After that, sedimentation began taking place along the eastern side of Belle Pass. Since 1969, accretion rates there have averaged 5.5 m/yr; the area is a sink for material that would otherwise be transported farther west to the Timbalier Islands (Dantin and others, 1978). Timbalier Island and East Timbalier Island are the western—flanking barriers of the Caminada—Moreau Headland. East Timbalier Island, a marginal recurved spit, is being eroded at a rate of over 15 m/yr. Updrift erosion and downdrift accretion cause the rapid lateral migration of these islands. Timbalier Island, for example, has been eroded on its updrift end at an average rate of 18.6 m/yr. Downdrift, erosion decreases and switches to accretion at the western end, averaging 17.4 m/yr. Between 1935 and 1956, the combined area of the Timbalier Islands increased, reflecting the low frequency of tropical storms during that pe— riod. After 1956, the area of both islands began decreasing rapidly. These reductions were determined to be a result of the extension of the jetties at Belle Pass and the seawall along East Timbalier Island. The structures in— terrupted the transport of sediment from its source within the Caminada- Moreau Headland (Penland and Boyd, 1982). East of the Caminada—Moreau Headland, the rates of shoreline change were found to vary from 5 m/yr of erosion on the west where the Caminada spit is attached to the erosional headland, to near stability adja- cent to Caminada Pass. This pattern of shoreline change reflects the in— creasing sediment abundance in the nearshore zone, downdrift toward Grand Isle. The Caminada spit was breached several times in this century by hurricane landfall, the major breaches were caused by Hurricane Flossy in 1956 and Hurricane Betsy in 1965 (fig. 24). These breaches were un— stable and filled rapidly because of the ready supply of sediment from the Caminada-Moreau Headland (Penland and Boyd, 1982). Before 1972, the western end of Grand Isle adjacent to Caminada Pass had been eroded, while accretion had occurred on its downdrift, eastern end at Barataria Pass. With construction of the jetty system on the western shore of Caminada Pass in 1973, the west—end erosion tem- porarily stopped. Before jetty construction at Barataria Pass in 1958, the eastern end of Grand Isle had accreted 3—6 m/yr; after that it increased to over 10 m/yr. The land area of Grand Isle increased from 7.8 km2 in 1956 to 8.8 km2 in 1978. This increase has been attributed to repeated beach nourishment projects and to the construction of the Barataria Pass and Caminada Pass jetties (Penland and Boyd, 1982). The highest erosion rates found within the Isles Dernieres (over 15 m/yr) were along the central portion of the island arc (fig. 25). Downdrift, erosion rates decreased to approximately 5 m/yr. Because no coastal structures have been built in the Isles Dernieres, the sediment dispersal system is undisturbed. The island area has decreased steadily from 34.8 km2 in 1887 to 10.2 km2 in 1979 (Penland and Boyd, 1982). . The pattern of shoreline change in the Chandeleur Islands is the re— sult of their oblique orientation to the dominant wave approach. Erosion rates exceed 15 m/yr on the southern end of the islands. Northward, beach erosion rates decrease to about 5 m/yr at the Chandeleur light- house (Penland and Boyd, 1982) (fig. 26). Periodically, hurricanes destroy the southernmost areas of the Chandeleur Islands, and are followed by the partial reemergence and re— building of the islands. Between 1869 and 1924, nine tropical cyclones made landfall, but only two were above force 2 in strength. These hurri- canes resulted in a slight decrease in island area. Between 1925 and 1950, five tropical cyclones made landfall, but only one was of hurricane force. During this period, the island area increased slightly. Between 1950 and 1969, a rapid decrease in island area (from 29.7 to 21 km2) was observed—the result of the landfall of five major hurricanes, one of which was Camille, a force 5 storm. Between 1969 and 1979, when few hurricanes occurred, the island area increased again (Penland and Boyd, 1982). A report to the Louisiana Department of Natural Resources (van Beek and Meyer—Arendt, 1982) analyzed the processes of coastal land loss, Louisiana’s coastal geomorphology, erosion and accretion patterns, and potential remedial measures. Maps were constructed to depict the variability in annual shoreline change from 1955 to 1978, structural mod— ifications, physical characteristics, shorefront use, hydrologic units, and place names. The barrier islands were described as “hot spots" of coastal erosion in Louisiana. The average rates of shoreline change calculated for Louisiana’s barrier systems were: Isles Dernieres, —11.8 m/yr; Timbalier Islands, -12.1 m/yr; the Caminada—Moreau Headland, -12.7 m/yr; Grand Isle +1.8 m/yr; the Plaquemines barrier system, -8.0 m/yr; and the Chandeleur Islands, -10 m/yr. The report concluded that Louisiana’s bar- rier systems provide important protection for human life and property, and for the renewable resources of the remaining estuarine wetlands. Beach nourishment, barrier restoration using fill, the creation of back—bar— rier marshes, and revegetation projects were recommended as the most cost-effective remedial actions (van Beek and Meyer-Arendt, 1982). CURRENT USGS-LGS RESEARCH IN LOUISIANA In 1982, in response to the seriousness of the State’s coastal land loss problems, the LGS began a program of basic and applied coastal ge- omorphological and geologic research. This included the inventory of coastal resources; provision of technical assistance to local, State, and Federal agencies; sharing geoscience information about coastal land loss in Louisiana and the Gulf of Mexico; and assessing various coastal protec— tion and restoration practices. It was realized from the start that the for- mulation and implementation of effective policies and practices to create, restore, and protect Louisiana’s coastal zone would be hindered until a sufficient understanding of the causes and processes of coastal land loss in Louisiana was acquired. Since 1982, the LGS has been working cooperatively with the USGS to conduct geologic framework studies to assess the hard mineral re- sources available for projects to control coastal erosion. In 1986, the USGS entered into a cooperative research effort on barrier erosion with the LGS and the Coastal Studies Institute at Louisiana State University (Sallenger and others, 1987, 1989). In 1988 the USGS expanded its ef— fort in Louisiana by directing new research aimed at the critical processes of wetland loss, as well as establishing the Louisiana Coastal Geographic Information System Network (Sallenger and Williams, 1989; Williams and Sallenger, 1990). The current program focuses not only on research on coastal geomorphology, geology, and land loss but also on the transfer of the research results through scientific journals, conference proceedings, in-house publications, geographic information system (GIS) networks, field trips, and organized symposia. 94° 92° 31° 29° \‘ I 31° 290. 90° The framework studies have focused on the evolution of coastal Louisiana during the Quaternary (figs. 27 and 28). The history of sea level fluctuations was delineated and correlated with the development of Wisconsinan and Holocene shelf-phase and shelf—margin deltas for the Mississippi River by means of high-resolution seismic surveys combined with vibracores and deep borings (Boyd and Penland, 1984; Suter and Berryhill, 1985; Suter and others, 1985; Suter, 1986a, b; Tye, 1986; Tye and Kosters, 1986; Penland and others, 1987a; Suter and others, 1987; Suter, 1987; Berryhill and Suter, 1987; Boyd and Penland, 1988; Penland and Suter, 1989; Kindinger, 1989; Kindinger and others, 1989; Boyd and others, 1989a; Boyd and others, 1989b; Penland and others, 1989b; Penland, 1990; McBride and others, 1990). Within the Mississippi River delta plain, emphasis has been placed on understanding the transgressive phase of the delta—cycle process and in particular the formation and evolution of barrier systems (Penland and others, 1985; Suter and Penland, 1987a; Penland and others, 1988a; Suter and others, 1988; Dingler and Reiss, 1989). A thorough strati- graphic analysis of Louisiana’s barrier systems led to the development of new depositional models explaining the sedimentary sequences, facies structure, and patterns of coastal evolution found in the transgressive de— positional systems of the Mississippi River delta plain (figs. 9 and 29). Of particular interest have been the sedimentary and botanical factors that af- fect the formation of coastal marshes as well as the contribution of or— ganic and inorganic sediment in maintaining the surface elevation of marshes against the effects of subsidence and eustasy (Kosters and Bailey, 1983; Kosters and others, 1987; Kosters, 1987; Penland and others, 1988b; Rosters, 1989). Kosters (1989) developed a model describing the dynamics of vertical marsh accretion as it relates to the formation of wet— land peats in the Barataria basin (fig. 30). The LGS houses an extensive collection of high—resolution seismic and vibracore data from coastal Louisiana to the seaward margin of the continental shelf. The collection contains more than 15,000 km of Geopulse, Uniboom, and 3.5-kHz subbottom seismic profiles, and over 500 vibracores from the delta and chenier plains and the inner continental shelf of Louisiana. The accurate mapping of coastal changes is fundamental to any coastal research program. Using zoom transfer photogrammetry com- bined with computer mapping and GIS technology, LGS has developed a precise system for accurately documenting coastal erosion and wetland loss in Louisiana and the Gulf of Mexico (McBride, 1989a, b; McBride and others, 1989a). To complement the coastal mapping system, LGS uses airborne videotape surveys to map high-resolution geomorphic changes, storm impacts, and oil spills. Since 1984, LGS has conducted an aerial videotape survey of coastal Louisiana each summer and of Louisiana, Mississippi, Alabama, and Florida after the impact of hurri— canes Danny, Elena, Juan, Florence, and Gilbert (fig. 31) (Penland and others, 1986c; Penland and others, 1987b, c, d, e; Penland and others, 1988c; McBride and others, 1989b; Penland and others, 1989c, d). These surveys are the baseline for monitoring both natural and human— caused geomorphic changes along the coast. Aerial videotapes have also been made of the Mississippi River delta and chenier plains from the inte— rior wetlands to the Gulf of Mexico. The videotape surveys are housed in an archive at the LGS and facilities are available for public viewing. The rates of subsidence and relative sea level rise, the primary causes of coastal land loss in Louisiana, have been determined using tide gages, geodetic leveling lines, and radiocarbon data (Ramsey and Moslow, 1987; Penland and others, 1988b; Penland and others, 1989e; Ramsey and Penland, 1989; Nakashima and Louden, 1989; Penland and Ramsey, 1990). The rates of relative sea level rise range from 0.9—1.3 cm/yr on the delta plain to 0.4—0.6 cm/yr on the chenier plain (fig. 32). The thick— ness of the Holocene sequence and the relative age of the sediment ap- pear to be the regional controls of subsidence (fig. 33). 88° 86° 1984 1985 1985 Post - Danny, 1985 Post — Juan — 1985 Post - Elana — — — — 1986 1987 1988 1990 1988 Post - Florence and Gilbert FIGURE 31.— Location of Louisiana Geological Survey aerial videotape surveys in Louisiana and the northern Gulf of Mexico, (A) 1984-1986; (B) 1987-1991. A. CONTINENTAL SHELF B. SHELF MARGIN C. CONTINENTAL SLOPE Ravmement Surface Position of shoreline at low 3b . .~ stand of sea level FIGURE 27.— Idealized model of Quaternary facies deposition on the Louisiana continental shelf. (1) Transgressive and aggradational deposits from previous sea-level rise. (2) Sediments associated with regressive phase of cycle: (a) fluvial and distributary channel fill; (b) shelf-phase deltaic deposits; (c) shelf-margin deltaic deposits; (d) mass trans- port deposits resulting from instabilities in shelf-margin deltas. (3) Sediments primarily associated with rising sea level: (a) fine-grained sediments relating to deltaic deposition during initial sea level rise and (or) abandonment of delta; (b) transgressive sands reworked from coarse-grained deltaic and alluvial deposits; (c) transgressive fluvial and estuarine sediments within fluvial channels; ((1) aggradational deposits, thin on outer shelf, thickening landward. Application of the concepts of Vail and others (1977) produces a depositional sequence consisting of 1, 2b, 2c, 2d, and 3d; an overlying sequence incorporates 2a, 3a, 3b, and 3c. Unconformities A and B represent lowstand surfaces modified by shoreface erosion during transgression (redrawn, by permission, from Suter and others, 1987, p. 203; © 1987 by the Society of Economic Paleontologists and Mineralogists). TECHE DELTA COMPLEX LAFOURCHE DELTA COMPLEX D\ s as a BEE %§ 11 a o — E 0 t. ses ip N é '— 6?) a 8 fi 8 E 5) Dernieres Shoal S 0 , v . LAFOURCHE RAVINEMENT DEPTH (M) 30 0 50 100 150 Distance (km) REGRESSIVE FACIES TRANSGRESSIVE FACIES UNCONFORMITIES Fresh Marsh I Salt Marsh — —— Ravinement Surface Bay Fill Brackish Marsh Levee Bay _____ , . Beach Ridge Lagoon Transmonal Distributary Delta Front - Barrier Shoreline Prodelta Inner—Shelf Shoal FIGURE 28.— Idealized model of the development of shelf-phase delta plains of the Mississippi River during the Holocene transgression (reprinted, by permission, from Penland and others, 1987a, p. 1696; © 1987 by the American Society of Civil Engineers). 5 S .9 (U (I) (U 8 IE) 3 79 5-4 2 § 8 .‘L’ 2 A I— _1 2 LL. m i 1 2 Q A 0 E C 2 2 a m a a g e 8 é’ ’5 g .1? c» "o m ,_ fi 1: 3 C 8 (U r a O 8 9 °’ 3 *3 g 0.. (D 9‘ Q 0.. 6‘5 ENTIRE PERIOD OF RECORD A 65 2 E 1 ”HI” n B e .m-flflmfln M “In"... 0 S E 3 8 8 fi "5 5 5 E n? 8 E 5% 13’ 93 '3 13 .§ .3 >« m .2 >\ >\ o o o E (a Q o : ._. «1 o 0 LL] c 5 <3) .0 m (a m ,_1 ,_l _1 3 Z) 3 O '0 LL] g o 4.. Q, a) E .5 :5 m m S: s: E (U (E, s: I C 1;: 3 8 “a: E “5 n: (u >- =~ o o o O m m 9 G o 4: Q, m U +4 <9 0’ :2 ."_1 z c L 0’ O a, *" — 3 I g: g: g: ".1 .... .._ Q) 0 5-. 5 3: 2 o o o E E E m E O o ._ E O O =— s.. 5- 5 U) .—I ~ a a s s s “J g .8 (>3 .8 C .E .S .S .E .E 2 g 3 g; 2 g g S E E g 3 L9 s: .2 E -,_ T) w .H E 8 Q g a Q g Q l" <9 b< c) ’0 ru C: ‘5 N "‘ _: C: CO 3 a U o “5 E ,1 .9 CG Q) g 9,3 m. D- [3 fi FIGURE 32.— (A) Relative sea level rise in the Gulf of Mexico between 1908 and 1983, based on National Ocean Survey tide gage stations (redrawn, by permission, from Penland and others, 1989c, p. 50; © 1989 by the Louisiana Geological Survey). (B) Relative sea level rise in Louisiana between 1931 and 1983, based on Corps of Engineers tide gage stations (redrawn, by permission, from Penland and others, 1989e. p. 51; © 1989 by the Louisiana Geological Survey). TECHE RAVINEMENT RATE (CM/Y R) O SUBSIDENCE (CM/Y R) T1 — BARRIER ISLAND TRANSGRESSION Barrier Island Arc Tidal Inlet Scar SL2 SI.1 T2 - BARRIER ISLAND SUBMERGENCE bmerged Barrier Island SL3 SL2 Sand Sheet ' SL 1 T3 — INNER-SHELF SHOAL MIGRATION " l . , \ , , , , , SL4 5L2 5L1 Retreat Path ' REGRESSIVE Deltaic Sediments TRANSGRESSIVE Barrier Sands . Lagoonal Muds Shelf Sands T,time SL, sea level FIGURE 29.— A model of transgressive submergence, the process of shoreline and shelf sand generation on the Mississippi River delta plain. Transgression occurs when the shoreline migrates landward in response to delta abandonment, leading to erosion and reworking during shoreline and shoreface retreat. Submergence occurs when the depth of water increases as a re- sult of eustatic, isostatic, or tectonic processes (redrawn, by per— mission, from Penland and others, 1988a, p. 947; © 1988 by the Society of Sedimentary Geology). FIGURE 30.— Model of marsh accretion in the Barataria basin (redrawn, by permission, from Kosters, 1989, p. 110; © 1989 by the Society of Sedimentary Geology). TERREBONNE . ,xsrRA’nGRAPHiC . SUBSIDENCE BATES 1750 2500 2000 2250 1000 1250 1500 AGE (YR BP) 250 500 750 1.0 0.8 0.6 0.4 0'2 l . \l . l l I \ O Chenier Plain 0'0 \ A Delta Plain 0 50 100 150 200 250 HOLOCENE THICKNESS (M) FIGURE 33.— (A) The relationship between sediment age and the rate of stratigraphic subsidence in Terrebonne Parish, Louisiana (redrawn from Penland and others, 1988b, p. 95). (B) The relationship between rate of relative sea level rise (RSL) based on tide gage records and the thickness of the Holocene sediments at the referenced station location. Note that the highest rates correlate to the thickest Holocene areas in the Mississippi River delta plain (redrawn, by permission, from Penland and Ramsey, 1990, p. 340; © 1990 by the Coastal Education and Research Foundation). .s 29°00’ 28°50' Z :1: I— 0., LL) 0 0 2000 4000 6000 8000 10.000 12.000 YEARS (BP) FIGURE 34.— The relationship between changes in relative sea level (RSL) and coastal stability in the Mississippi River delta plain during the last stages of the Holocene transgression. PHYSICAL CHARACTERISTICS OF THE LOWER MISSISSIPPI RIVER g 2 g Tarbert Stl Baton New Belle Head Pass ER; 2 5 g 3, Landing Francisville Rouge Orleans Chasse Main Pass 0f Passes a Loutre Z < E w E Coochie l] l \ l / South 0 U z w > . j, :8 8,55 \ , . . . . . . « Pass %% §§§ River Mllel 300 250 200 150 loo 50 0 weighing“ E% d 5 ‘5 Old River Bonnet Carre 7 one oi Zone of ass It? 0 E Control Structure Morganza Floodway Floodway Controlled Diversions Uncontrolled Diversions 'U 9; so 1973 ‘927 1927 1927 1973 Flood Crest Elevation Discharge Maximum (CFS) I 2000.000 5 i 50 /1927 Bankiull Stage Mean (CFS) : J2 m g 40 1927 Mlnlmum(CFS) 1500000 A“: {‘5 .5 ‘g in“ a 30 LL I5 E E 20 1969 1 000 000 5 £8 E 1965 1969 1969 ‘ i 5 mg i3 10 .E E E 0 .................................................... _ 500,000 :‘q’l (0 El 2 .2 ,0 s 8, 5 g 20 l I l | Mile 300 200 100 0 3 Water Discharge 9C E 73 Below Average 250.000 CFS E 3 o w 0 m 0) o E 9 =15 g 2 Average 450.000 CPS 1000 %Z z I— ,8 '— , - . :, » ‘fi «ii 8 E E 800 1 Above Avera 1 000 00 CF 500 3 ‘3 "‘ 9e ' 'U z 3 E E 3 0 ' 0 5 a W 0 § E a a 5% m” g. vi 8 5 Mile 300 200 100 _ Gravel Coarse Sand Medium Sand Gravel 2’ § 100 _ -~ , M <2 5 V 2 g 5550 8 s {I} U 0 I | I l ,_ E Mile 300 200 100 0 Z 2 o 2 ~ 0.2 E : D C 0.1 - 0.1 g T: 0 0 ‘— l0 0 o 6 . _ . MSLO 60lAMll/lll illll . . r“ 0 V LU VVl Wl l/l lllll/llll I l l l '- ‘5 100 . . . 1 . l . s a: \lvulvVN VV VNVVVVVVV l E a. 8 H .150 l I V l .200 , , I ‘ Mile 300 200 100 0 FIGURE 37.—- Physical characteristics of the lower Mississippi River alluvial valley and delta plain (redrawn, by permission, from Mossa, 1988, p. 305; © 1988 by the Gulf Coast Association of Geological Societies). 91 °OO’ 90°50' 90°40' Raccoon Point Limit of 1987 sample area - Silty-sand - Sand Muddy— sand ‘ ’ Sandy» l . mud Sandy-silt - Mud l DERNIERES Nautical Miles 0 Kilometers Isobaths in Meters FIGURE 38.— Seven major sediment facies of the inner shelf off south-central Louisiana (redrawn, by permission, from Williams and others, 1989a, p. 573; © 1989 by the Gulf Coast Association of Geological Societies). DUNE DEVELOPMENT to 10 YEAR COASTAL EROSION SUBSIDENCE FIGURE 35.— Model of sand dune development in Louisiana as a function of storms and the return period of hurricane impact. Increasing volume of supratidal sand storage leads to dune development and revegetation, increasing the stability of the barrier shoreline. Major storms are hurri- canes; minor storms are cold fronts (redrawn, by permission, from Ritchie and Penland, 1988, p. 121; © 1988 by Elsevier Science Publishers). The geologic studies of the barrier systems and continental shelf re— vealed the occurrence of several stillstands in sea level during the last stages of the Holocene transgression. Three major delta plains have been identified to date, each separated by a maximum flooding or ravinement surface that was the product of a significant rise in sea level. It appears that whenever relative sea level rises rapidly (over 2 cm/yr) for centuries, the delta cycle process of the Mississippi River stops, and the wetlands, estuarine bays, and barrier islands gradually disappear. In contrast, it ap— pears that whenever relative sea level rise rates drop below 2 cm/yr, the delta cycle process creates new wetlands, estuarine bays, and barrier is- lands (fig. 34). The implication of this pattern, in light of the EPA and NRC scenarios for future sea level rise, is that the delta and chenier plains of the Mississippi River already are in a cycle of coastal land loss; if the rate of sea level rise approaches 3 cm/yr over the next century, as pre— dicted, drastic changes in the coastal area can be expected. Overwash processes associated with cold fronts, tropical storms, and hurricanes are important contributors to beach erosion, high rates of sed— iment transport, and dramatic landscape changes (Ritchie and Penland, 1988; Dingler and Reiss, 1988; Penland and others, 1989a; Ritchie and Penland, 1989; Dingler and Reiss, 1990; Ritchie and Penland, 1990a). Because sand dunes provide protection from storm surge and high—energy wave impacts, understanding their formative processes and vegetation dy— namics is critical to the development of effective sediment management practices (Ritchie and others, 1989; Ritchie and Penland, 1990b; Ritchie and others, 1990). Extensive field work over the last decade has docu- mented a predictable pattern of storm impact, beach erosion, overwash, and sand dune development controlled by frequent minor cold fronts, in— frequent major hurricanes, and sand supply (fig. 35). A sediment budget analysis of barrier island erosion and deposition between Raccoon Point and Sandy Point is in progress to determine the volume of sediment transported and the regional trends of dispersal (Jaffe and others, 1988; Jaffe and others, 1989; Williams and others, 1989a). The sediment budget analysis compares historical bathymetric surveys with new ones conducted by the USGS to determine the volumetric trends in erosion or deposition on the seafloor and shoreline changes (fig. 36). The results will aid in the development of effective sediment management practices for the barrier systems. A V .‘ 1890-1934 SHOREFACE RETREAT - Accretion >0.5 Meters Erosion >0.5 Meters 1934—1986 INLET BYPASSING Limit of 1986 Survey FIGURE 36.— Seafloor and island changes along the Isles Demieres barrier system (a)1890 -1934; (b)1934 - 1986. (l) Shoreface erosion; (2) sediment deposited from longshore transport in shallow water close to Timbalier Island; (3) sediment deposited from longshore transport offshore of Timbalier Island. The 5-m depth contour is from 1986 (redrawn, by permission, from Jaffe and others, 1989, p. 407; © 1989 by the Gulf Coast Association of Geological Societies). In order to better understand the availability of water and sediment, , Mossa (1988, 1989) has investigated the discharge—and—sediment dynam— ics of the lower Mississippi River system. The study shows that optimum conditions for diverting surplus fresh water and sediment from the Mississippi River occur in winter and spring (Mossa and Roberts, 1990). The use of diversions will require different management strategies during high and low flow years due to the physical characteristics of the Mississippi River (fig. 37). During yearswith high discharges, the sediment concentration and load maxima typically precede discharge maxima by several months. By the time the maxima discharge peaks, the sediment load is greatly reduced. In low-discharge years, the highest suspended sediment concentrations and loads closely coincide with the discharge maxima. - The performance and impact of coastal structures have been investi- gated to determine the best approach to coastal erosion control. The re— sults indicate that projects using sediment and vegetation in beach nour— ishment and shoreline restoration projects are the most cost—effective (Mossa and others, 1985; Penland and others, 1986d; Nakashima and others, 1987; Nakashima, 1988, 1989; Penland and Suter, 1988a; Mossa and Nakashima, 1989). For controlling coastal erosion, the location, quality, and quantity of sediment resources must be known. High resolution seismic surveys, using vibracores to ground truth the interpretations, were used to define the availability of sediment resources for barrier island erosion control. To support the subsurface sand resource mapping, extensive surficial sedi— ment surveys were conducted between Raccoon Point, Sandy Point, and offshore to Ship Shoal in order to map the surface texture distribution (Circe and Holland, 1987, 1988; Circe and others, 1988, 1989; Williams and others, 1989b). Seven major surficial sediment facies were identified and mapped by collecting sediment samples from selected sites through— out the region (fig. 38). A Submergence V Sea Level Rise A Dunes Beach Erosion , Washover Terrace Storm Overwash > Salt Marsh 4 Shoreline Erosion ~~~~~~ "until 7 Bay ‘ B Artificial Protective Dune / Planted Dune Vegetation Artificial Protective Beach Artificial Dunes , ‘V I Protective Backbarrler Marsh Planted Marsh Vegetation FIGURE 39.— Three designs for using sediment and vegetation to preserve and protect Louisiana’s barrier systems. (A) Barrier island erosion problems. (B) Beach nourishment. (C) Barrier island restoration. (D) Back-barrier marsh building. New research results must be made available in forms that decision— makers can understand and use. One of the goals of the cooperative LGS and USGS coastal research program is to make information available in the form of atlases, journal papers, and conference proceedings. This at las of Louisiana shoreline change between 1853 and 1989 builds on pre— vious work by Morgan and Larimore (1957), Morgan and Morgan (1983), Adams and others (1978), Penland and Boyd (1981, 1982), van Beek and Meyer—Arendt (1982), McBride and others (1989a), and the US. Army Corps of Engineers (1975, 1978, 1980). The information and new research results presented are the most accurate analysis to date of barrier island changes surrounding the Mississippi River delta plain in Louisiana. The chapters in this atlas are intended to provide the reader with insight to the geomorphology, geology, and resources of Louisiana’s barrier sys- tems as well as the status of previous research and current USGS—LGS re- search on the coastal land loss problem. Sediment can be used in three ways: beach nourishment, shoreline restoration, and back—barrier marsh building (fig. 39). Beach nourishment projects are intended for developed shorelines, such as Grand Isle, which have an existing infrastructure that must be protected from beach erosion and storm impacts. Shoreline restoration and back—barrier marsh building are for uninhabited barrier islands; they aim to restore habitat integrity in order to preserve the estuary protected by a barrier system. The sediment resource inventory documented that there is enough material available for the foreseeable future to protect and restore Louisiana’s barrier systems (Suter and Penland, 1987b; Penland and Suter, 1988b; Penland and oth— ers, 1988d; Williams and Penland, 1988; Suter and others, 1989; ‘ Penland and others, 1990b, c). COASTAL RESEARCH SUMMARY Louisiana’s coastal land loss crisis cannot be managed effectively until the patterns of coastal change and the factors that influence them are un— derstood. The search for this knowledge has been the theme of coastal re— search in Louisiana over the last half century, and is the continuing objec— tive of the LGS and USGS coastal research programs today. The studies have concentrated on identifying the land loss problem; analyzing the geo- logic framework and accompanying coastal processes, including the dy- namics of vegetation and sediment loss; and assessing the feasibility of erosion control projects. All of this work aims to develop new geoscience information useful for developing management policies and strategies. Louisiana’s coastal land loss problem is becoming more severe be— cause of global climate changes that are causing the rate. of worldwide sea level rise to accelerate. At the same time, both the population and indus- trial development are moving onto the fragile barrier—built estuaries and low-lying deltaic wetlands, which are at the highest risk. The management of Louisiana’s coastal zone over the next century will require a compro- mise between these socioeconomic demands and the protection and restoration of sensitive coastal environmental resources. Continued ignorance of or disregard for the geologic processes that continually reshape Louisiana’s coastal zone will result in the failure of any comprehensive coastal protection or restoration plan. Predicting the per— formance of projects to control coastal land loss and assessing likely future coastal conditions requires an understanding of how a particular coastal environment has formed and what natural changes have taken place in recent geologic history. To make wise decisions, coastal planners, engi- neers, and managers as well as political decisionmakers and the public must be made aware of the new results of scientific investigations so that they can understand the range of management approaches and the asso- ciated social, financial, and environmental costs as well as the risks associ- ated with each approach. Cooperation is necessary among federal, state, and local agencies to ensure that scientific information and expertise is applied to site-specific projects. Recommended citation for this chapter: Penland, Shea, Williams, S. J., Davis, D. W., Sallenger, A. H., Jr., and Groat, C. G., 1992, Barrier island erosion and wetland loss in Louisiana, in Williams, S. J., Penland, Shea, and Sallenger, A. H., Jr., eds, Louisiana barrier island erosion study—atlas of barrier shoreline changes in Louisiana from 1853 to 1989: US. Geological Survey Miscellaneous Investigations Series I-2150—A, p. 2—7. US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY Chapter 2 A Historical and Pictorial Review of Louisiana’s Barrier Islands _ by Donald W. Davis WWW Wm“ Harvesting oysters from beds in Terrebonne Parish, ca. 1920: (Randolph Bazet Collection, Houma, Louisiana). Fisherman's wife baking bread in an outdoor oven (pain chaud in a bousillage four de campagne) at Cheniere Caminada, 1891: (National Archives, Negative No. 22—FCD—36). Oyster luggers and skiffs at Grand Isle, 1891: Typical palmetto (Sabal minor) house built by (National Archives, Negative No. 22—FCD—31). the residents of Cheniere Caminada, Louisi- ana's largest pre-1900 coastal community, 1891: (National Archives, Negative No. 22-FCD—40). A two-master sailing lugger going to market. Shallow-draft boats often had to be pulled with tow ropes attached to a horse, mule, or man—a process called cordelling, ca. 1940: (Louisiana State Library, Louisiana Collection, WPA Photographic Archives). Typical isolated Barataria Bay oyster camp, ca. 1935: (Louisiana State Library, Louisiana Collection, WPA Photographic Archives). Many Houma Indians lived in raised structures, close to and facing the bayou. This family's home on Lower Bayou Grand Caillou is one example, no date: (Louisiana State Library, Louisiana Collection, WPA Photographic Archives). The belief that quality furs came only from cold climates was unfounded. Louisiana's marshes were one of North America's preeminent fur-producing regions, ca. 1930: (Louisiana State Library, Louisiana Collection, WPA Photographic Archives). Grand Isle children, no date: (Louisiana State Library, Louisiana Collection, WPA Photographic Archives). Louisiana's oyster beds were so prolific that oystermen from Mississippi harvested the sites for canning plants at Biloxi, no date: (Anthony V. Ragusin, Louisiana State Library, Louisiana Photographic Archives). An isolated marsh settlement provided quick and easy access to harvesting areas, ca. 1920: (Randolph Bazet Collection, Houma, Louisiana). Before the arrival of the Yugoslavians, those en- Using hand-woven china baskets to unload shrimp at a Terrebonne Parish drying platform, ca. gaged in the oyster business were Italians and Four large tarpon caught in the inland waters of Terrebonne Parish, ca. 1924: (Randolph 1920: (Randolph Bazet Collection, Houma, Louisiana). Bazet Collection, Houma, Louisiana). Sicilians, no date: (Fonville Winans, Louisiana State Library, Louisiana Photographic Archives). 8 Harvests such as this allowed Louisiana to adopt the nickname "Sportsman's Paradise," ca. 1920: (Randolph Bazet Collection, Houma, Louisiana). SETTLING LOUlSlANA'S COASTAL FRINGE The Gulf of Mexico's northern coast is dominated by a series of barrier islands separated by water bodies less than 10 meters deep. This 870—kilometer chain parallels the Gulf Coast and represents nearly 35 per— cent of the United States' barrier islands (Ringold and Clark, 1980). Most of these islands and adjacent peninsulas have a cross section composed of several shore—parallel envi- ronments. Typically, the nearshore zone is identified by a system of bars and troughs parallel to the strandline. The active beach has a moderate sand slope, but grasses cover the dunes that customarily frame the foreshore berms. An island's midsection is frequently a series of beach ridges and intervening swales, covered by salt—tolerant vegetation, scattered shrubs, and clus— ters of trees. Marsh tidal-flat ecosystems, as well as mangrove communities, lie on the bay—shore side (Vincent and others, 1976; Davis and others, 1987). These features vary in physiography and cross—sectional profile according to the amount and type of eolian ma— terial, winds, tides, and the frequency of hurricanes. The same natural laws of beach—barrier dynamics, how— ever, apply equally, regardless of the barriers location. Unfortunately, human uses do not follow such an or— derly pattern; whether in Louisiana, Maine, North Carolina, Florida, or Texas, people introduce to the ex— isting physical and biological systems an additional complex set of variables. The Gulf of Mexico barrier islands have served humanity since the seventeenth century when farmers discovered that cattle released on barrier islands would forage and reproduce. Eventually, settlers moved onto the barrier islands following an annual-use cycle—mak- ing a living using the different renewable resources that were available from season to season. In the late nine- teenth and early twentieth centuries, the islands were used for military bases, small settlements, hotels, and other recreation endeavors, such as lavish hunting clubs and camps. The sea has reclaimed human features repeatedly, but they have been rebuilt. Like lemmings, people con— tinue to move toward the boundary between the land and water to see and hear the ocean, regardless of the consequences. Coastal citizens, especially those on the barrier islands, are at the mercy of hurricanes, north- easters, and other storms. The conflict that results from the incompatibility of human and natural processes is most evident when the barrier islands are overrun by hurricanes that generate walls of water over six meters high. Often storms hit the shoreline with such intensity that they sweep far in— land and destroy homes, businesses. and public build— ings; frequently, nothing is spared. Along the Atlantic and Gulf coasts today, millions of Americans are exposed to hurricanes. Many live on barrier islands; their homes and businesses are particu— larly vulnerable because they live dangerously close to v.1! Pleat I. , ATC'IIAFALAYA ,, 0 BAY Plum FtrLtH. 4 Two physiographic provinces dominate the natural setting: the chenier and delta plains. The former ex— tends from a site near High Island, Texas, eastward to Marsh Island, Louisiana, and has a relatively smooth and typical shoreline. Near the shoreface, the chenier plain (from the French, Cherie, meaning oak) is fronted by mudflats and backed by marsh with an intervening series of beach ridges capped with live oak trees (Quercus virginiana) (Howe and others, 1935). The delta plain is east of Marsh Island; within its boundaries lie more than 7,000 years of deltaic morphology. Numerous bays, lakes, and barrier islands characterize its highly irregular shoreline. Barrier islands and marshes absorb wave energy and help retard natural or storm—induced erosion. The islands serve as the first line of defense against destruc— tive hurricanes and storms and therefore receive the full force of their impacts. Washover fans, new tidal passes, diminished dunes, rearranged beaches, and general profile changes, via accretion, deposition, and erosion, are by—products of the passage of a hurricane. The is— lands are in a constant state of change. Moore (1899, p. 73) noted The topographical changes in the re— gion between Timbalier and Terre— bonne bays are quite extensive and rapid, and islands were observed there in all stages of destruction, some of them cut into pieces, others barely showing above the water, and still others whose former positions were marked merely by shoals or by dead brush projecting above the surface. Barrier islands are bulwarks that protect the valu- able wetlands and slow a storm's forward momentum, but the damage can still be catastrophic. In fact, since the 1950’s over $20 billion in property losses due to hurricanes have been assessed in the United States, with the barrier islands absorbing the initial punishment (Ringold and Clark, 1980; Daily Comet, 1985; Wang, 1990). Although Louisiana's coast does not have a bar— rier island 50 kilometers long, such as Galveston Island, Texas, the Chandeleurs, Grand Isle, Grand Terre, Timbalier, and Isles Dernieres (Last Island) are impor- tant settlement sites. Unlike those on most coasts, Louisiana's barriers are not completely developed. Grand Isle is the excep- tion; even so, it does not possess an extensive array of hotels, motels, high—rise buildings, or single—family resi- dences. The permanent and seasonal recreational population nevertheless is in danger because Louisiana's coast is particularly sensitive to storm dam— age. Before 1985, Hurricanes Betsy and Camille severely damaged Louisiana's coast. In 1985, Louisiana became the first state to be struck by three hurricanes in one year—Danny, Elena, and Juan. Barrier island residents have been susceptible to dangerous weather for over two centuries. Villages, recreational hotels, and scattered trapper-fisher—hunter camps are part of the barrier islands' folklore. Pirates, bootleggers, smugglers, and others have used these is- lands. Scattered recreational dwellings and petroleum— related industries now dominate the barrier islands' hu— man—made landscape. LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A Oystermen often built homes on bird-like wooden legs, two meters above the water; oyster shells thrown around the camp created an artificial island, 1940: (in Justin F. Bordenave, ed., Jefferson Parish Yearly Review, Special Collections Division, Hill Memorial Library, Louisiana State University Libraries, p. 72). An oysterman tonging oysters into a bateau plat—a flat-bottom boat with a blunt bow and stern, ca. 1920: (Randolph Bazet Collection, Houma, Louisiana). run/.rjull' _ .1 ' » ryum}”Hymn/r; S‘Iiioliislm ~ I z \ \ . -. \ ‘ . . . ‘° ' \ :\ Mgmm «1w: ‘ l \ > : , \ \ ., ..; , 33/! ’5 f , / {WWW j. , [my]; 5, 3,77,, 1",“ 3 m /._ xx 5&1 .1 (‘bh‘Igzlelenr \\Suz11\1\zi / . I \ I Under full sail, a Louisiana oyster lugger moved easily across the in- land waterways, no date: (National Archives, Negative No. 22—FCD-30). ’ ‘\ . \ (Ll/ajéeun’n ' S,“ \\.. .. \_ f \ . . . n‘hon \ \: g \ \,... . \ \ , Lake A (UM!!! or "71:111. NEW ORLEANS ," ..Mzrfello L2 ‘ “R gflawphirell I. . i :- S‘iyfih/{bire 1. ' . (‘Iltmd’ch-m’ t'eum' ,_ 111.7,.)- My / / / / A» , ‘J‘ flaldednrclpfi - __ # Muskrat and nutria were trapped in Louisiana's marshes to provide nearly 60 percent of the nation's fur harvest, ca. 1930: (Louisiana Department of Wild Life and Fisheries, Photographic Archives). ITS. Coast 510qu ADBar/ee Superintendent SKETCH H. «. S/Ion’zhg tilt; pmyress qf t/w Surrey ‘ in .522an 1112.8 1846 *1853 \‘ \ Gram Bar PL. ;\ \ \_ e \ \ :4 4 ' ’. BIindBay vi “'3‘ sir I {a Louisiana's barrier islands have served as a recreational resource since the ‘ early nineteenth century. Surf fishing at Timbalier Island was a popular sport, ca. 1920: (Randolph Bazet Collection, Houma, Louisiana). the water's edge. The citizens of northwest Florida, for example, thought they were immune to dangerous storms; they were incorrect. In 1975, Hurricane Eloise struck the Florida Panhandle; numerous beach—front buildings—believed to be hurricane proof—were "toppled like dominoes” (Frank, 1976, p. 221). Inadequate building codes and improper construction techniques were responsible for the extensive destruc- tion of beach-front property (Frank, 1976). LOUISIANA’S COASTAL LOWLANDS Near—featureless marshes and adjacent water bod— ies span the Louisiana coast and vary in width from 25 to 80 kilometers. Exposed salt domes are over 40 me— ters above the sea—level marshes. There is less than a four—meter height difference between the marsh and adjacent natural levees, cheniers, and beaches, and one meter in elevation can provide firm, habitable land. The St. Bernard Parish community of St. Malo, elevated above the marsh "muck." Asian immigrants used planter boxes and "night soils" to raise fresh vegetables. Rain water from roof drainage was collected in barrels, no date: (Harper's Weekly, March 31, 1883, p. 197). Louisiana's trapper-farmer-fisher folk built their homes from indigenous materials to create func- tional structures; these were covered with palmetto and equipped with barrel cisterns, ca. 1910: (Swanton Collection, Smithsonian Institution, Photo No. 1536). 9 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY LOUISIANA'S SETTLEMENT HISTORY: FROM NATURAL LEVEES TO MARSHES TO BARRIER ISLANDS Louisiana's coastal lowlands have been occupied for 12,000 to 14,000 years. During that time the adjacent alluvial wetlands have sup- ported a range of cultures and settlements which include prehistoric Indian sites, and Yugoslavian, Chinese, Italian, and Acadian communities (Johnson, 1831). Prehistoric Indians settled the dry land adjacent to many of the region's water bodies. Over 500 of these relic encampments, distin- guished by middens (shell mounds), have been located and mapped. The region's settlement and economic history has, in fact, been generally dic— tated by the availability or unavailability of high ground. From barrier is- lands to beaches, natural levees, cheniers, coteaux (hills or ridges), bays, and estuaries, people have had to adjust to floods, subsidence, hurricane— induced storm surges, and sea level rise. Settlement clusters were scattered throughout the wetlands, along the shoreline, and on the barrier islands by the late 1800's. Mauvais Bois, a small community south of Houma, was located on a levee remnant ap— proximately 10 kilometers long and 75 meters wide and supported an economy based on agriculture, fishing, and trapping. At Mauvais Bois and other coastal communities, cattle ranged the open marsh. In contrast, Camardelle inhabitants at Barataria Bay were totally dependent upon sea- sonal fishing and trapping because there was no space available for agri- culture. Camardelle citizens lived on wharves and houseboats and took their homes with them, even if the dwellings had to be dismantled, as sea- sonal activities changed. The elevated community of Manila Village was supported entirely by the shrimp industry. Cheniere Caminada was dominated by trapper- hunter-fisher folk, groups who based their subsistence economy on the annual changes in the seasons and who cultivated small gardens to add to the quality of their diet (figure 1). Cheniere Caminada had a school, a church, and several stores, facilities usually unavailable in marsh communities. By the mid—1800's Louisiana's wetlands supported over 150 commu— nities that were connected to the settlers' resource areas, markets, and supply sources by well—defined routes of circulation—the region's natural and human-made waterways. One of the earliest sites was Cheniere Caminada—a community just across the Caminada Bay from Grand Isle, which served as a harbor for net fishermen. Because the marshes were devoid of "high" land, the region's narrow riverine strips became the focal point for settlement. A settlement pattern developed from the region's distinctive deltaic morphology. With time, this dense, unorganized network of distributary ridge, wetland, and barrier is— land communities became a large, isolated, and permanent population. Each settlement was economically homogeneous in that all inhabitants were supported by variations of the same means of making a living. The hamlets' farmer—trapper—fisher folk were aware of their environment and developed skills that allowed them to harvest the local wildlife. THE ETHNIC MIX The Spanish, French, Italians, Yugoslavians, Irish, Germans, Cubans, Greeks, Latin Americans, and Chinese settled within Louisiana's coastal lowlands. The foreign fishing population was larger than any other in the Gulf states (Collins and Smith, 1893). Based on its cultural heritage, each group interpreted the environment differently. Louisiana exhibits, there- fore, a distinctive ethnic and cultural heterogeneity, but the French are the biggest and oldest ethnic group. French and German peasant (habitant) farmers first settled along the Mississippi River in the Cote des Allemands (German Coast) (American States Papers, 1803). As early as 1718 the area was settled by people enticed into moving to Louisiana from France by the propaganda of John Law's Mississippi Company. They were generally the more prosperous and better educated class living in Louisiana (Bertrand and Beale, 1965). These urban dwellers enjoyed the fine goods offered to them by the priva— teer Jean Lafitte, whose barrier island fortress was one of the earliest set— tlements on Louisiana's coast. After deportation from British-controlled Nova Scotia in September 1755, nearly 4,000 refugee Acadians also migrated to Louisiana and set— tled the alluvial wetlands. These people continued to arrive in small groups from 1760 to 1790 (Detro and Davis, 1974). The Acadians were accus— tomed to working the land and settled on the prairies, cheniers, bayous, marshes, swamps, and barrier islands in south central and southeastern Louisiana. They were French—speaking Roman Catholics who provided south Louisiana with its own unique ethnic community. Eventually the Acadians abandoned French as a written language. Their language is no longer spoken in France, and many of the family surnames survive there only in historical literature. The Acadians enjoyed the isolation provided by south Louisiana's physical geography. Their communities were accessible by means of winding streams called bayous (from the Choctaw bayuk, or creek) and close to fishing, hunting, trapping, and agricultural areas. The rich alluvial soil of the Mississippi valley, the area's abundant hide— and fur-bearing animals, and the easily harvested aquatic life were infinitely attractive to the Acadians, who were also trappers and net fishermen (Evans, 1963). Besides the French, a group of Yugoslavian oyster fishermen settled along the bayous, bays, and lakes southeast of New Orleans. Chinese and Filipinos built shrimp-drying communities in the estuaries. British, French, and Americans settled the barrier islands. By the early 1830's, a relatively dense network of settlements was functioning at isolated points within the marsh. The barrier islands—Grand Isle, Grand Terre, Cheniere Caminada, Isles Dernieres, and the Chandeleur Islands—had established their own identities. Throughout the wetlands' waterways, red-sailed luggers, isolated pal— metto—covered houses, or the rustic, cypress—gray gables of Chinese camps or lake dwellers were a part of the visual landscape (Sampsell, 1893). Although many considered the wetlands valuable only for their intrinsic qualities, Acadians, Yugoslavians, Chinese, Italians, and others recognized the coastal lowlands for their resources and were able to make a living from them through trapping, shrimping, and oystering. manure» or; «r 1:511wa on LAST {MAXI}, 4:1,: or 3123390, war or panama. In 1853 Isles Dernieres' (Last Island) Village Bayou was destroyed by a hurricane that inundated Louisiana's first coastal recreation site, ca. 1856: (Frank Leslie's Illustrated Weekly, Historic New 1 0 Orleans Collection, Museum/Research Center, Accession No. 197425.466). ISLES DERNIERES: LOUISIANA'S FIRST COASTAL RESORT Isles Dernieres was: no ordinary island, but the proudest summering place of the Old South - a private little world dedicated to fine living. Here, to the massive, two—story hotel in the myr— tle—shadowed village at the island's western tip, and to the hundreds of graceful houses decorating 25 miles of beach, wealthy planters and merchants, who bore the most illustrious names in all Louisiana, brought their families to escape the summer heat and to live accord— ing to the unchanging code of French and Spanish an— cestors. (Deutschman, 1949, p. 143) In the early 1850's Isles Dernieres, known also and especially histori— cally as Last Island and located at the southern fringe of Terrebonne Parish, was about "thirty miles [48 kilometers] long and half a mile [09 kilometers] in width" (Daily Delta [New Orleans], 1850). The wooded is- land was the site of about half a dozen light—framed summer cottages on Village Bayou. Erected on posts stuck in the sand, they were not built to withstand the force of a hurricane, but the visitors were only concerned about enjoying the relaxed atmosphere of the island (Silas, 1890). The houses are fine, particularly those of Lawyer Maskell and Captain Muggah. These houses serve for the reception of visitors during the summer season, at which time the enjoyers of elegant leisure flock to the isle in great number, and not as a dernier resort, but for the veritable purpose of enjoying themselves. (Daily Delta [New Orleans], 1850, p. 2) Isles Dernieres was one of Louisiana's first coastal recreation sites. Families came to swim, fish, hunt, and enjoy the tranquility (Liddell, 1851). Most visitors to the resort were wealthy planters from the Lafourche and Atakapa areas. “It was a delightful place to escape the summer heat, enjoy the sea breeze” (Wailes, 1854), and listen to the "skill and taste of the old German, whose violin furnished exquisite music" (Pugh 1881, p. 3). The extensive beach served as a shell road where "one's buggy whirls over it with a softness, and airy, swinging motion, that is perfectly intoxicating" (The Daily Picayune [New Orleans], 1852, p. 1). The Village Bayou on the bay side of the island provided a safe place for packet steamers and sailboats to land. In fact, as early as 1848 Louisiana requested its legislative delegation to lobby for a lighthouse at the west end of the island to improve the navigation of the State's western coast (Johnson, 1848). Two hotels, the Ocean House and Captain Muggah's Hotel, or The Muggah Billiard House, provided rooms for guests. The Ocean House was equipped with a bar, amiable accommodations, a billiard table, and tenpin alley. Captain Muggah built cabins on the beach as alternate facilities to his hotel (Pugh, 1881). A large public livery stable housed the guests' horses and buggies. an... ' Eklmu'rc Mud Flat hm: all-what. THE 1856 LAST ISLAND HURRICANE Sunday, August 10, 1856, the island resort was destroyed by the Last Island hurricane. During the storm every solid object became a mobile battering ram, destroying nearly all the structures on the island. Many families were lost; about half of the island's population survived. In the legends of coastal Louisiana, over 400 people attended a Sunday ball at the hotel on Village Bayou at which the Creole aristocracy "danced until they died" in the hurricane. With time, stories of the disaster became part of the region's folklore. For example, through a blend of fact and fiction, the two hotels were visu— alized as one. Consequently, numerous imaginary embellishments of the Isles Dernieres legend crystallized in Lafcadio Hearn's book, Chita: A Memory of Last Island, which purports to document the storm. Newspaper accounts of the period reported that from 260 to 300 people died (Ellis, no date). Entire families were swept off the island. Some rode out the storm on floating debris and were rescued 24 kilometers from the resort (Schlatre, 1937). Horses, cattle, and fish lay strewn about the island among the human victims. At the center of the island, one small hut and several head of cattle survived the storm (Cole, 1892a). Property loss was estimated at over $100,000 (Ludlum, 1963). Because earlier reports were revised as more survivors were located, the final death toll was about 140 persons (Ludlum, 1963). From that time the wind blew a perfect hurricane; every house upon the island giving way, one after another, until nothing remained. At this moment everyone sought the most elevated point on the island, exerting themselves at the same time to avoid the fragments of buildings, which were scattered in every direction by the wind. Many per- sons were wounded; some mortally. The water at this time (about 2 o'clock P.M.) commenced rising so rapidly from the bay side, that there could no longer be any doubt that the island would be submerged. The scene at this moment forbids description. Men, women, and children were seen running in every direction, in search of some means of salvation. The violence of the wind, together with the rain, which fell like hail, and the sand blinded their eyes, prevented many from reaching the objects they had aimed at. (Ludlum, 1963, p. 166) It was a gloomy sight, not a house or shelter standing. The hull of the steamer and a number of sailing boats stranded on the island near where the hotel had stood, and some 260 or 300 people had been drowned every one was busy all day looking for and burying the bodies which had been drowned, others collecting provisions and getting something to eat, others fixing up things to make it a little more comfortable. In the meantime we had fitted out a boat and dispatched it to the Atchafalaya to report our condition. (Ellis, no date, p. 8) The steamer Star made semi—weekly trips from the railroad station in Bayou Boeuf, down the Atchafalaya River through Four League Bay, to the Isles Dernieres resort. On Sunday morning, August 10, 1856, the Star approached Isles Dernieres after a difficult journey from Morgan City, a trip that required two men to steer the vessel. She anchored in Village Bayou behind the Muggah's Hotel. During the hurricane a part of the pier gave way, and the steamer parted her moorings and slowly drifted towards the island. Those on board were ordered below. Soon the steamboat's chimneys, pilot house, and hurricane deck were gone, leaving only the hull (Ellis, no date). The wreck drifted toward the island and lodged itself in a turtle enclosure for the remainder of the storm (The Daily Picayune [New Orleans], 1856b). Approximately 250 to 275 people survived in the hull of the Star; without its body, firmly trapped in the sand, more would have perished (The Daily Picayune [New Orleans], 1856a). The destruction from the Last Island hurricane was complete, but the storm documented the value of the island itself. Isles Dernieres absorbed the storm's winds, waves, and high water; the islands on the backside were protected and did not receive as great an impact. Bayside damage was minimal. At nearby Caillou Island, in Terrebonne Bay, the water only rose about 1.5 meters. The people on these inner islands were saved from the storm's full force. They were inconvenienced but not killed (New Orleans Christian Advocate, 1856). HURRICANES IN THE COASTAL ZONE Coastal Louisiana's climate is generally described as humid subtropi- cal: warm summers and mild winters are the rule. Winter extremes, when they occur, are a product of cold fronts that can change the daily weather quickly. In the summer and fall, normal conditions can be dramatically al» tered by the periodic arrival of hurricanes. Caribbean history is punctuated by hurricanes; even the name is de- rived from the Caribbean Indians' storm—god Huracan. By nature, hurri— canes are unpredictable and can change direction abruptly. Between May and November, hurricanes move in a north-northwest direction across the Atlantic Ocean. In the Gulf of Mexico, they are most active in August, September, and October. Hurricanes are always of concern to humans; they carry high winds, extremely low pressures, vast quantities of precipitation, and large storm surges. The Saffir—Simpson scale, originated in 1972 by Herbert Saffir, consulting engineer for Dade County, Florida, and Robert Simpson, for— mer director of the National Hurricane Center, indicates on a scale of 1 to 5 the damage potential from different wind speeds and storm-surge heights (table 1). The 12 deadliest hurricanes of this century were all cate— gory 4 or 5 (extreme to catastrophic). Most Louisiana hurricanes are cate— gory 2 or 3 (moderate to extensive damage) storms. TABLEl.—Saffir-Simpson scale of damage-potential. Scale Central Pressure Winds Surge Number (Millibars) (km/hr) (meters) Damage 1 2980 119-153 1.2-1.5 Minimal 2 965-979 154-177 1.6-2.4 Moderate 3 945-964 178-209 2.5-3.6 Extensive 4 920-944 210-250 3.7-5.4 Extreme 5 <920 >250 >5.4 Catastrophic In reports of hurricane damages, two Louisiana storms are mentioned repeatedly: Betsy (1965) and Camille (1969). When Betsy struck the Louisiana coast, it had already left in its wake $119 million in damages to Florida. This fast—moving storm was highly erratic; it could not be predicted accurately because it changed course frequently. Because of this, officials took the precaution of evacuating an estimated 250,000 residents from unprotected areas. Betsy's 200 km/hr winds approached shore, its waves battering Grand Isle; approximately 90 percent of southeastern Louisiana's residents evacuated. The storm's aftermath resulted in at least $700 million in insured damages—$650 million in Louisiana, the remainder in Florida, Mississippi, and Alabama. Uninsured flood damages pushed the final fig— ure over the $1 billion mark. Seventy—four people died in Louisiana, most from drowning. Four years later, Hurricane Camille, one of only three category 5 hurricanes to enter the Gulf of Mexico in this century, took aim on the Louisiana-Mississippi coast. Camille was a compact storm, only 80 kilo- meters wide, with 320 km/hr winds, a six-meter storm surge and 75 cen- timeters of rain. This system made landfall near Pass Christian and Bay St. Louis, Mississippi. Its destructive intensity established financial and wind-speed records. Camille left 259 people dead and $1 billion in prop— erty damage. Before Betsy and Camille, two catastrophic storms occurred in the barrier islands. The first, in 1856, destroyed the recreation—oriented com- munity at Isles Dernieres, and the second, in 1893, displaced nearly 1,500 families at Cheniere Caminada. ER JANUAR}, st“ 4‘0 .59 O 0&7. JULY JUNB FIGURE 1.—Annual-use cycle of marshlands people in Louisiana. The fishing season included oystering and shrimping as well: Modified from Comeaux, 1972. United States Coast Survey, A. D. Bache, Superintendent, Western Part of the Isles Dernieres, February 1853 by F. H. Gerdes, scale 1:10,000. Two hotels, the Ocean House and The Muggah Billiard House, were lost because the wind and water rose from the 1856 hurricane, ca. 1856: (Frank Leslie's Illustrated Weekly, Historic New Orleans Collection, Museum/Research Center, Accession No. 197425.465). Grand Isle (1904) GRAND ISLE. GRAND ISLE AND BARATABIA PACKET fl Steamer GRAND ISLE, M. McSweeny, Halter. Leaves head of Conti Street at 7:80 mm. EVERY TUESDAY. via Company Canal. and EVERY SATURDAY vin.Socolas Canal. re- turning Monday and Thursday via Company Canal. Special inducement: to excursion phr- ties. For freight and passage apply on board. J¢11~tf Huber, Leonard, 1959, Advertisements of Lower Mississippi River Steamboats, 1812- 1920, West Barrington, Rhode Island, The Steamship Historical Society of America, p. 29. Typical early Grand Isle home, built on the highest portion of the island for added hurri- cane protection, no date: (Louisiana State Library, Louisiana Collection, WPA Photographic Archives). When a road and bridge were completed to Grand Isle, it became a favorite summer and weekend resort, July 4, 1938: (Fonville Winans, Louisiana State Library, Louisiana Photographic Archives). , w it Wuwfimf .' :3! Palm-lined Ludwig's Lane on Grand Isle, ca. 1933: (Pen and ink postcard drawing by George lzvolsky). as III I ll flat-Wm. , . .I mm \~ Bayou Rigaud landing at Grand Isle, ca. 1933: (Pen and ink postcard draw— ing by George lzvolsky). by George lzva/Jiéy LO U IS IA H A from pen and 1h! draw/by: George lzvolsky). (Louisiana State Library, Louisiana Collection, WPA Photographic Archives). Ca. 1933: (Pen and ink postcard drawing by Horse-drawn carts were the principal means of transportation on Grand Isle, no date: A day at the beach on Grand Isle, no date: (Louisiana State Library, Louisiana Photographic Archives). Collection, WPA LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES l—2150—A Joe Weore (1885) MWIV‘N/WWNV‘Nfi/‘f/ 1'N/WN»I‘J‘M/‘f I emu ISLI—m run: mug: U“ W KID JOE WEB . » / A. 1. Ram m. must. ’ ll - f ._ ._ , '- Loaves "oz-y TUESD ‘Y, THURSDAY and 'M "l“ " ‘ “’ 3:3 ”rwfiya‘fi‘: T53 "£13: PW??? M , . 11‘ ,. .. . . A . :Ejllj “DRIEDAYB ma run; a moompmn "“ Ganglia he 81; madam on: every Bun shianroundm inch: nous-t tho ho and on board at hum. , my! fi—fl “.11.. ‘~ “ 4/, "3,1,. '* ”v.37 (W, flEz ou£§~wmé°‘i,g ; » ' ‘ , Huber, Leonard, 1959, Advertisements of Lower ‘ WM" ”LE ‘A q“"‘“" ' 7 Mississippi River Steamboats, 1812-1920, West Home of Nez Coupe, descendant of one of Jean Lafitte's lieutenants, Barrington, Rhode Island, The Steamship Historical ca. 1933: (Pen and ink postcard drawing by George lzvolsky). Society of America, p. 36. Bayou Rigaud provided a safe and convenient harbor for the working and sporting boats looking for a safe anchorage at Grand Isle, ca. 1939: (in Justin F. Bordenave, ed., Jefferson Parish Yearly Review, Special Collections Division, Hill Memorial Library, Louisiana State University Libraries, p. 54). Grand Isle bathers leave their cars at the water's edge on hard packed sands, while they enjoy playing in the surf, 1940: (in Justin F. Bordenave, ed., Jefferson Parish Yearly Review, Special Collections Division, Hill Memorial Library, Louisiana State University Libraries, p. 77). Grand Isle oyster boats, ca. 1933: (Pen and ink postcard drawing by George lzvolsky). A group of Grand Isle bathers modeling the latest in swimwear, Collection, Museum/ Research Center, Accession No. 198123814). s . . W ..L w A. ., c ca. 1890: (Historic New Orleans Within the oak thicket at the center of Grand Isle, the local farm community established orange groves, cauliflower fields, and blackberry patches, 1943: (in Justin F, Bordenave, ed., Jefferson Parish Yearly Review, Special Collections Division, Hill Memorial Library, Louisiana State University Libraries). 11 US. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY 12 This open-air tablettes a chaudiere, or dish-washing shelf, was strong enough to hold a stout dish pan, ca. 1947: (in Justin F. Bordenave, ed., Jefferson Parish Yearly Review, GRAND ISLE: A POTPOURRI OF USES The history of Grand Isle is not as spectacular as that of Isles Dernieres, Cheniere Caminada, or Grand Terre. It was, like all of south Louisiana's coastal settle- ments, isolated. To survive economically, the island's inhabitants supported themselves through various indus- tries that included seafood canning, agriculture, and turtle farming (Davis, 1990). Grand Isle's first major economic activity was the sugar business. By 1830, four sugar plantations were in operation; this established the island as an agricultural base. These plantations were owned by Samuel Britton Bennett, Alexander and Charles Lesseps and John B. Lepretre, Pleasant Branch Cocke, and Francois Rigaud (House Document, 1832). The center of the island had always been protected to some degree from the full force of a hurricane and was therefore of agricultural interest. The eastern end of the island was under the ownership of Francois Rigaud (House Document, 1832). The island's western end was claimed in 1833 by Samuel Britton Bennett (Swanson, 1975). The middle was divided between the Lesseps/Lepretre and Cocke interests. A sugarhouse, mills, small homes, carpenter shop, stables, draining machine, cotton gin and press, black— smith shop, slave quarters, and other buildings were a part of the island's plantation morphology. Sugar and cotton were the principal crops, but sugar was always primary (Swanson, 1975). Grand Isle citizens lived in wood-framed cottages without electricity, modern plumbing, or evening news- paper, but the fishermen and vegetable farmers consid- ered them comfortable. These were simple folk houses with little wasted space. Below the window sill on many homes there was a sloping shelf called a tablettes a chaudiere, or "dish—washing shelf," large enough to hold a stout dish pan. While washing the dishes, Maman kept her eye on everything that happened in the yard and on the road. The oriental pink-to—faded-red-sailed fishing boats called luggers were a common sight in the Barataria es- tuary and were steered with a rudder by Malay fisher— men or French oystermen (Sampsell, 1893). Piled on board the vessels were big bell-shaped bamboo baskets covered with Spanish moss (Tillandsia usenoides), lashed with ribbons of latania (palmetto), and filled with the day's harvest of shrimp, oysters, fish, or crabs (Cole, 1892a). As a rule, fishermen received about half the retail price for their catch. Grand Isle, one of the fishermen's supply points, eventually developed into an important recreational site. Spanish moss, itself an important regional product, was collected, ginned, and sold for furniture or mattress stuffing. There was, in fact, a large trade in the moss along the area's inland waterways (Saxon, 1942). THE RECREATIONAL RESORT After the Civil War, Grand Isle became a mecca for fishing, recreation, and farming; visitors endured untold hardships because getting to the island was difficult. It took 12 or more hours to reach it through narrow canals scarcely wider than the passenger steamboat. This problem was resolved upon completion of the New Orleans, Fort Jackson and Grand Island Railroad, which travelled down the Mississippi's west bank to Socola's Canal at Myrtle Grove plantation. Passengers were loaded onto a steamboat that carried them the rest of the way. The entire trip took about five hours (Ross, 1889a). Although there was some thought of building a railroad to the island to lessen the travel time, this idea never materialized. Excursion packets from New Orleans were avail— able aboard numerous steamboats of the era. For $7.50 per person, a room could be reserved for an overnight packet (New Orleans Times, 1866). By 1861, there was daily service to the island via the Emma McSweeny and the Fort Jackson and Grand Isle Railroad (The Times—Democrat [New Orleans], 1891b). A well—established pattern of summer visitation evolved. Plans were made to expand the island's facilities and make it even more attractive for guests (Meyer—Arendt, 1985). In addition, the steamer St. Nicholas provided passenger service three times a week from New Orleans to the island (Tieys, 1867). In the late nineteenth century, Grand Isle attracted summer vacationers who wanted to enjoy the island's beaches and escape the heat and "yellow jack" (malaria) that plagued New Orleans. The epidemic of 1878 caused numerous families to take refuge on Grand Isle (Ross, 1889a). THE ISLAND’S ECONOMIC BASE Within the oak thicket at the center of the island, the local farm community eventually established orange groves, cauliflower fields, and blackberry patches. John Ludwig, one of the island's earliest leaders, recognized that the sandy loam soil could be used to produce mel— ons, cucumbers, cauliflower, and other commodities (House Document, 1917). The soil, however, could not be cultivated by conventional means, so Ludwig intro— duced the idea of using high hills with deep furrows to ensure proper drainage. To utilize Ludwig's technique, the islanders built new levees on the island's bay side and repaired those that had been damaged by storms. To keep out salt water, flood gates were installed. Grand Isle citizens went into the truck—farming business and used shrimp bran to fertilize the new fields (Swanson, 1975). These farms were quite successful and often shipped to northern markets between 35,000 and 50,000 bushels of cucumbers a year (Thompson, 1944). Orange groves were planted so close to the Gulf they rarely froze, and the island's cauliflower reached northern markets before that of any other producing region. Even though farms were established, farmers still endured the uncertainty of getting their products to market before other producers. Heavy losses were of— ten incurred because perishable items could not be shipped to New Orleans during sustained periods of low water (House Document, 1917). The Grand Isle and Yugoslavian fishermen gained some notoriety for the oyster beds established in Barataria Bay. On Bayou Brule, a packing plant was constructed from a renovated building used by the New Orleans' World Exposition in 1884. Unfortunately, the enterprise failed, and the harvest was sent to "Lugger Bay," a small area of water on the Mississippi River across from the French market in New Orleans. By the early 1900's, the island was served by a large number of stern—wheel gasoline boats. The Tulane, Hazel, Nevada, and J. S. & B. made the New Orleans-Grand Isle run once or twice a week to carry freight and passengers to the island. These boats and the local luggers carried shrimp, dried shrimp, shrimp bran, crabs, fish, diamond—back terrapin, game, cucum- bers, squash, beans, tomatoes, oysters, corn, and furs to the New Orleans market (House Document, 1917). THE ISLAND’S RESIDENT TURTLE HERD In the 1890's, John Ludwig, Jr., established on Grand Isle what was reputed to have been the world's largest terrapin farm, valued at over $50,000 (House Document, 1917). The turtle business was established to meet the needs of the restaurant trade (True, 1884b). The diamond-back terrapin (Malacoclemmys pal ustris) was a highly prized food and was cooked ac— cording to a Maryland or Philadelphia recipe for a stew garnished with vegetables and spices. Nationwide, the best market was Philadelphia, but turtles were sold in large numbers in many other cities (True, 1884b). Grand Isle turtles were sold to customers in New York, Baltimore, Washington DC, and Boston (Housley, 1913). Fishermen caught the animals in their nets, but to meet the industry's needs, a consistent source of dia- mond—back terrapin was needed. The turtle farm, "three low barns, separated by a road [that] look almost identical with the barns of a well-appointed race track" (Housley, 1913, p. 1), solved this problem. The barns had a low silhouette with protective latticework on the ends, a hinged roof, and floors covered with less than one—half meter of water. Encircling the ponds were small earthen levees designed to let the turtles sun themselves (Housley, 1913). These pens, or stables, housed about 20,000 fe- male and 5,000 male turtles. The females were used for breeding and market, while the males' only worth was breeding. When the female's bottom shell was 15 centimeters long, her market value would be from $1.00 to $1.50, while the male's was rarely over 25 cents (Housley, 1913). Turtles were of some commer— cial value for their meat and eggs. One turtle, for ex— ample, could weigh over 200 kilograms and yield 1,000 eggs (Fountain, 1966). Although others went into the industry, Ludwig bought them out and controlled the business in Louisiana. Grand Isle was the major source for terrapin, but the industry was widespread. In 1900, one dealer on Deer Island, Mississippi, had a herd of over 5,000. At Grand Isle, many families collected turtles for Ludwig's farm. Often dogs were used to point to where the terrapin were hiding. Besides raising his own locally caught turtles, Ludwig kept turtles shipped from other wholesalers. Dealers in New York and Philadelphia shipped their terrapins south in the fall because the cold northern winters were often fatal. A barrel of turtles could be stabled at the Ludwig farm for $10 a season (Housley, 1913). Special Collections Division, Hill Memorial Library, Louisiana State University Libraries, p. 68). A net being repaired on Grand Isle, ca. 1947: (in Justin E. Bordenave, ed., Jefferson Parish Yearly Review, Special Collections Division, Hill Memorial Library, Louisiana State University Libraries, p. 69). Grand Isle harbor scene, ca. 1940: (Historic New Orleans Collection, Museum/Research Center, Accession No. 1976.223). Col. D.S. Cage (1870) GRANDISLE For Grnnd Tale. The nwli't pnuucnger uteamcr . COL, D.S. CAGE. FLATAI', Mnstvr; DELI. Roman, Clark: Will make sc‘mi-wm'kl trim»: to the utmvn popular water.‘ fniz lace, loavinp vtw rad nt' Harvey's Urinal on TU ES- DAYS, and SATURDAYS an 8 o'clock A. M. PM- Mnaers and shi port} can rnly on this steamer leaving punctvnlly ‘8 vertired Fur fraught or passage nppl on Maud. 1:8 in; P. IIIUGINB. Advermmx Agent C.D. Jr. (1854) b‘OR THE COAST ANl) LA- FOURCHR.~—Twicn A week [rum Now Or- lruns.——Tl.ie duo new steamboat C. D.,Jr.,C. Ddtcru, mutanluvo New Orianusuvory WEDNESDAY AL 35‘ o‘clock A. IL, And SATURDAY at 0 o'clock, r. :2. Bum-lung, will luvs Limirport every Thursday M. bo’ulmzk, A. l. uzu Bunxluy at u in; l‘lilbodnuxvtllenvrry ’l'hurminy at. lo 0': och, A. 31.,nnd Sunday at 4 r. M.; Donaldnunvilloovery Fridq at fl o’clock A.I1.,Ind Manda At 6 .x. n. For lrntghl or pu Ingu, apply on board or Io AUGUSTIN .: ’I‘HIBAUT, I! Cant! “in“, New Orlcsnl. ”To Hmrruul Axn PLAITnu-.-—'l'lie steamer C. D. Jr. bu been built expruu-iy for mu an“: IIIJ‘L in hex'conuruc “an every modui'u iniprovumexit tlmt can pouibly mid to the urety, cmufnr! .m‘. conveninuco oi’ punnzera, Ind the arr]- in: a! hnlgul, In been rammed—and though of exceedingly lighldrnugnt, m. in: the Capacity to emulate burden, use will continue to tank-5 regular trip. throughout n!l m noun oi the yen. or all money paid ior [night will be minn- do-i. "fl '5! Huber, Leonard, 1959, Advertisements of Lower Mississippi River Steamboats, 1812-1920, West Barrington, Rhode Island, The Steamship Historical Society of America, p. 13. Huber, Leonard, 1959, Advertisements of Lower Mississippi River Steamboats, 1812-1 920, West Barrington, Rhode Island, The Steamship Historical Society of America, p. 16. The Kranz Hotel was partially destroyed in the 1893 hurricane, ca. 1893: (Historic New Orleans Collection, Museum/Research Center, Accession No. 198123817). Maw/n n: mummu Laclr/nv 0 ,4 .m ,, a x“ "4m mm“ as» a WWMEBEE start was? sarcasm WAT] it. \‘0‘VN AS '1‘“ E summit S I'I‘IIA'I'E II AT The row cottages that made up the Kranz Hotel, no date: (Historic New Orleans Collection, Museum/Research Center, Accession No. 198125113). ‘] \ ~i 67156 5:; 54 3:5 52 is] "0 l!” was) ' ) \ ‘1140\:59. as) \ B rat'lpja Plantation a ‘ . x14 (m ”,1 Fprmerly part of the I The 1893 hurricane severely damaged The Ocean Club. Built for an es- timated $100,000, the facility was never rebuilt in its original grand manner, ca. 1893: (in Mark Forrest, Wasted by Wind and Water: a Historical and Pictorial Sketch of the Gulf Disaster, Milwaukee, Art Gravure and Etching Company, Louisiana Lower Mississippi Valley Collections, Hill Memorial Library, Louisiana State University Libraries). The main avenue of the Kranz Hotel complex showing the rail line used by mule carts to move people to the beach and the steamboat landing, ca. 1890: (Historic New Orleans Collection, Museum/Research Center, Accession No. 1982.862). GRAND ISLE HOTELS AND HURRICANES There were three hotels on Grand Isle during the late 1800's: the Kranz Hotel, Hotel Herwig, and the Ocean Club. As is the case today, the beach was the focus of the island's tourist trade, but the island's shoreline was in motion then also. An 1878 survey indicated the island's shoreface was subject to intermittent erosion and accretion. Besides that, there was also a constant threat from hurricanes (see appendix A). All the hotels were wrecked by the storm of 1893. In addition, the steamer Joe Webre, which made regular runs to the island, washed onto the island and "crashed to her death squarely across the tracks of the streetcar line that ran from the Kranz's Grand Isle Hotel to the beach" (Van Pelt, 1943, p. 8)—"a mass of broken timbers, fit only for firewood" (Forrest, no date, p. 6). Of the estimated 650 people on the island, 25 were killed (Sampsell, 1893). THE KRANZ HOTEL At Grand Isle's west end lay the Kranz hotel and its associated cot— tages. The villa was about one kilometer from the Gulf. Cole (1892a, p. 12) described the island's first hotel as an old, popular, well known resort, built like a plantation quarters, in a series of [38] cottages along a grassy street. At one end a ballroom, at the other a dinning hall One is out of sight of the surf and the sea; but three times a day a tram car runs down to the beach where the bathhouses are. Mule carts were used to unload the steamers that made regular trips to Grand Isle, and to convoy guests to the beach during prescribed bathing hours—5:00 am, noon, and 6:00 pm. (Ross, 1889a). A partial inven- tory of the hotel's property reveals there were three carts used in this shut- tle service (Grand Isle Hotel, no date). In a report in the Daily Picayune, Mr. Kranz (The Daily Picayune [New Orleans], 1893) stated: I am 70 years old, and for many years have owned the Grand Isle Hotel. I am a widower with four children. On the night of the storm I was at home. I did not expect that anything serious would happen. The wind rose and blew hard. At 11 o'clock it changed and blew from northwest to southwest at intervals of fifteen minutes thereafter. In about half an hour the water on the grounds around the hotel was fully five feet deep. A terrible gust of wind struck the house and knocked it over. A portion of the guiding fell on me, and for a time I thought our last hour had come. Fortunately, the water continued to rise, and in about ten minutes I felt the weight pressing heavily upon my body gradually removed. I was lying on a beam. It was [w]ashed away from under the house, the water carrying me with it for a distance of twenty-five feet. I was struck and became unconscious, for several hours I did not know what had occurred to me. When I regained consciousness I was still clinging to the beam I received very serious injuries. In my feeble condition I returned to what had been the hotel, but out of the thirty—eight cottages which formerly stood there only twenty were left. There was not a particle of food to be found, everything had been washed away, including all the wearing apparel. I estimate my loss at from $75,000 to $100,000. THE OCEAN CLUB The Ocean Club hotel, built for an estimated $100,000, lay broad- side to the Gulf. Investors had grand plans for the property. The hotel was designed to be one of the "most commodious and imposing buildings along the Gulf" (Grand Isle, 1891, p. 3) and to rival or surpass the resort hotels at Newport, Saratoga, and Niagara Falls (The Daily Picayune—New Orleans, 1866). Photographs from the period indicate the investors met their goal; it was a most impressive structure. The hotel, in fact, marked the beginning of the island's resort cycle (Meyer—Arendt, 1985). Three times a week the steamer St. Nicholas carried to the island people inter- ested in leisure—time pursuits (Tieys, 1867). The two—story building took the shape of a large letter "E" (New Orleans Daily Picayune, 1891). With the hotel's long axis parallel to the Gulf, all rooms faced the surf zone. Supported by nearly 300 pilings, the hotel contained 160 bedrooms, two parlors, two dining halls, a billiard hall, a card room, a reading room, pantries, kitchen, and a laundry, and was illuminated by 320 gas lights. The dining hall alone could accommo— date 250 guests. The middle section of the "E" was the "en" suite for the hotel's stockholders and was described as "most luxurious" (New Orleans Daily Picayune, 1891; The Times—Democrat [New Orleans], 1891a). The building was constructed with double framing that required over 180,000 meters of lumber. Like Fort Livingston, the Ocean Club served as a land- mark for fishermen returning to the island (New Orleans Daily Picayune, 1891). A two-story addition to the front of the building was planned. This structure would have been at right angles to the main building and ex— tended to the beach. A 40-meter hall would have connected the main building to an immense over-water pavilion, which would have provided a covered walk to the Gulf. Bathrooms were designed into the first floor. The new structure was expected to increase the hotel's capacity to 1,000 guests (New Orleans Daily Picayune, 1891). However, the 1893 hurri- cane ruined these plans permanently. Like the hotels on Isles Dernieres, it was damaged severely—never to be rebuilt in its original grand manner. A storm in 1888 partially inundated the island. Stories circulated around New Orleans that Grand Isle's residents took refuge in Fort Livingston. The storm was described as being the most violent since the Last Island hurricane of 1856. When news of the storm's damage reached New Orleans, reporters wrote: "The rain fell in torrents and the hurricane was as severe as can be imagined" (The Daily Picayune [New Orleans], 1888, p. 1). The hotel and its associated cottages survived. Beach bath— houses were demolished and washed away, but quickly rebuilt (The Picayune [New Orleans], 1888; Cole, 1892a). Within days after the storm, the resort was back in operation with the Joe Webre bringing guests to the island on a regular basis. Five years after the 1888 storm, the enterprise had to be abandoned. Transportation to the island was not quick and easy. Those who could afford the $50 a month room rate were unaccustomed to enduring the hardships of the long rail and boat trip to the resort (Cole, 1892a). LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A The Kranz Hotel was Grand lsle's first major hotel and was described as an "old, popular, well known resort, built like a plantation quarters, in a series of [38] cottages along a grassy street" (Cole, 1892a, p. 12), no date: (Historic New Orleans Collection, Museum/Research Center, Accession No. 198125111). Grand Isle tram clearly visible in a small, covered bridge, ca. 1890: (Historic New Orleans Collection, Museum/Research Center, Accession No. 198125114). ' The Grand Isle steamer Joe Webre lay across the tracks of the Kranz Hotel's streetcar line after the 1893 hurricane, ca. 1893: (in Mark Forrest, Wasted by Wind and Water: a Historical and Pictorial Sketch of the Gulf Disaster, Milwaukee, Art Gravure and Etching Company, Louisiana and Lower Mississippi Valley Collections, Hill Memorial Library, Louisiana State University Libraries). 13 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY .\ I 9'3 ..-__._‘ 4. If n: l n dilly "gamma :znlgslz' H ,n pl H Fort Livingston saw no military action, but from its inception in the 1840's, it was at war with the elements, ca. 1935: (Fonville Winans, Louisiana State Library, Louisiana Photographic Archives). 14 GRAND TERRE: HOME OF PIRATES AND PLANTATIONS THE HOME OF JEAN LAFITTE THE PIRATE In the 1800's, Louisiana's coastal lowlands were ideally suited for smugglers. The land was inadequately mapped; consequently, government agents who were unfamiliar with the Barataria Bay water system easily be— came lost, and a skilled smuggler could outmaneuver his pursuers. Isolated ridges, or Indian middens, were utilized to unload contraband. Louisiana's geographical position was nearly perfect for the storage and movement of illicit foreign merchandise (Davis, 1990). The privateer Jean Lafitte established a base on Grand Terre. By 1810, New Orleans newspapers reported that the privateers had captured a ”richly laden” Spanish ship, removed her guns, and built a shore battery to protect their base of operations (The Louisiana Gazette-New Orleans, 1810). These beach cannon emplacements fortified the site. The ”first smugglers' convention [was] held there [Grand Terre] in 1805" (DeGrummond, 1961, p. 4). Over 30 privateer captains called Grand Terre, Grand Isle, and Cheniere Caminada their home. With 120- to 130-ton brigs and schooners, manned by crews of 90 to 200 men, the island's population often swelled to 3,000 (DeGrummond, 1961). Lafitte also had a base at Cat Island, the home of from 500 to 600 men who were protected by a 14—gun brig sunk in the pass (Gilbert, 1814). In 1814, there was a force of five or six armed vessels at Cat Island, each carrying from 12 to 14 guns and 60 to 90 men. The region profited from the"legalized" pillage practiced by the Barataria pirates. The harbor at Grand Terre served as a rallying point for the Gulf privateers' fast—sailing schooners, which were armed for victory over their adversaries. Newspapers reported that numerous New Orleans businessmen sailed to the island to acquire good bargains (The Louisiana Gazette—New Orleans, 1814a). Several huts and a storehouse were con— structed to display the captured booty. As the English closed the French-controlled Caribbean ports, more contraband was shipped to Grand Terre. Great quantities of foreign mer— chandise accumulated on the island and were distributed to the New Orleans' market. To meet the demand for storage space, Lafitte acquired a warehouse in New Orleans and built one in Donaldsonville. At Grand Terre, 40 warehouses were built along with slave pens, dwellings, a hospi- tal, and an improved fort (DeGrummond, 1961). At times, the only prudent means of disposing of merchandise was to hold a public auction (Gilbert, 1814). The warehouses attracted merchants and traders who used large pirogues to make the three-day journey to Lafitte's market at Grand Terre. The entrepreneurs purchased their goods cheaply, then retailed them at a large profit; the privateers were better with sword, cutlass, and cannon than with matters of business. A fleet of small vessels was constantly moving these resold goods into the "Crescent City." The practice was"illegal" but ignored by most of the authorities (Daily Delta [New Orleans], 1854). Hard currency was scarce in New Orleans, so these goods became part of the city's barter economy. In 1814, the United States Navy sent an expedition to stop the priva— teers. They captured all of their buildings and effectively terminated priva— teering on the Louisiana coast (The Louisiana Gazette-New Orleans, 1814b). GRAND TERRE SUGAR PLANTATION In 1795, Francois Mayronne purchased the Grand Terre sugar plan— tation from Joseph Andoeza, who claimed ownership of the island from a Spanish land grant. By 1823 Jean—Baptiste Moussier owned Grand Terre. Sixty-nine slaves worked this sugar plantation, which was valued at $38,000 and included a sugarhouse, draining house, steam engine, dwelling house, slave cabins, and other outbuildings (Chamberlain, 1942). In 1831 a hurricane completely inundated the island with water six meters deep. Two sugarhouses and the sugar cane in the field were blown down, the corn crop was destroyed, and the island's residents were forced to seek shelter in "their boats and canoes" (The Daily Picayune [New Orleans] 1863, p. 3). The Moussier family sold the island but retained most of the western tip—the future site of Fort Livingston. By the mid—nineteenth century, the eastern two—thirds of the island were under the control of F. G. and L. E. Forstall. In 1845 this property produced 300,000 lbs of sugar, but after the Civil War the plantation was abandoned because cheap field hands were no longer available. Jose Llulla bought most of the island, and until his death in 1888, he lived a quiet life raising cattle on Grand Terre. With the success of Grand Isle's hotels, several businessmen were convinced they could covert the former home of Jean Lafitte into a tourist attraction. They bought the Llulla estate for $2,500 intending "to divide it up into building sites for themselves and hold the remainder” (New Orleans Times-Democrat, 1893, p. 9). These investors believed that "if the railroad extends seven miles [11 kilometers] toward the bay they will have a small bonanza" (New Orleans Times»Democrat, 1893, p. 9). However, the railroad was never built, no hotel was constructed, and the island reverted to its original form. By the mid-1930's the western end of Grand Terre was eroded to the point where the surf was pounding on Fort Livingston's outside walls, no date: (Fonville Winans, Louisiana State Library, Louisiana Photographic Archives). I ll] l llllllll r. I ..,~ .1 (LI... .mm M l . l . ‘ \ l . “ dl‘l-ll‘hfi‘” ll 1, l (l _ P , t It III : mill ll] II _,. To build Fort Livingston, brick was shipped to the site from the Mississippi Gulf coast. Shells removed from Indian middens were also utilized. With time and the elements the structure became a derelict relic of the past, ca. 1933: (Pen and ink postcard drawing by George Izvolsky). LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A I monum- . M Ta... Sheet 1;: \‘1 1 flJJ’i‘J‘JFJ L’A‘IIUJ‘HJ LUUJS‘JAJ‘IJA 7 ‘ \: W 77 LIJ . ,Vlv/ h: I I 4:» , I” BAN DE IE REE PL“. ..r PM "I II VIN F’ "TI-3N , I 7', . Showing 1 hurizonlnl St ( lion of the Masonry : f , ~ / ' T I I I. . . / I) :‘ 44/4, , 4,6,”. ”/4 H. 472,... 4411,74 - A : _ T I (, 1.1/1 , . /,/, ,g, “/4... , ,4: 41,1 igyfifgfi/ run 1:?“ III I "I: . I (”haunt 123.3,: 131‘!” é ‘ i /T /M0 - MM : I: / I 1, and“ ' 45" 2 3;! A J . / T Shirt] If 11/! :fdc 11““ r a ' I I / , ~ 1: I // 711., dl’fl flew/r, WWW 2‘ 3.1 a g \C’ 71% / 13 ' : fl »~ fl» ai'h‘h -n l‘ b #:2- A r I! A h L H A r r a a in 1 1:1; 7¢M07GJ7vaf&/'Zl£a . . I 2173 5 . 2:» II t » ‘ ‘3 I Erosion at the eastern end of Grande Terre Island, 1840-1854: (National Archives, Record Group 77, Drawer 90, Sheet 34). . 1 , ”,3! ”a y// . . ,1, “”354 ' / Erosion at the western end of Grande Terre Island, 1840-1886: (National Archives, Record Group 77, Drawer 90, \r , ,,, ' . :/ 1/ Sheet 44). ”wk“ . ,. 1.17.1;T":;.;€:‘:: Floor Plan of , , 4:1; :22! Fort Livingston EDIITIFIBJYIIUDJE; LUUIz‘j-JAI‘IA 1 if if "N W”- Wi ' W, i if 7 .l‘rr',’ll £3 .3 1-K J\J .L] E T 7 i Iii l’lu/M‘ ml Viv/«mu 7/ orncms QUARTER! rm Lin/1.75M” / VA ’Lm’v‘? / / M '7 4...”); “I ,,l / Ih-t m A I ’ ' “"7..— rmc M Amp-r3 If mm,m W -._ Sin/- 2“ :r‘ Lana-ya yuan»: .(ndo’ ,._5.31__.__FL &@ Air-gm» I 9.”... f1) “'11 .p,’ 133;- I . E _ I - [—4 ,. » ,,. I . “mag. . I , I Lu" gran-z... ‘. .- fl \ ‘ T f. .,—-« r .__,__x Wadi/,4...“ , l {3 T _ ._.I / . fflew/ g/ €493 g. I ' mama/1.5 5A7». " / fl/JJJ .. : T u‘up‘ ‘ ‘ '7 _ ""3 . I flz‘p-l 4:!" M / 45m ”'4 In“; a. 1“- I _ .-_ _ A Mf/M” 52/,” , " 1 ”/0? ‘io -é J44“ “Q (33%;. (or; .) 15 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY In 1893 a hurricane swept Cheniere Caminada almost clean—four homes survived, no date: (Frank Leslie's Illustrated Weekly, October 26, 1893, p. 269, Biloxi Public Library Archives). Cheniere Caminada's Our Lady of Lourdes church, 1891: (National Archives, Negative No. 22—FCD—39). Fisherman's wife next to a typical south Louisiana outdoor (bousillage) oven, which could hold up to 15 loaves of bread at a time, 1891: (National Archives, Negative No. 22—FCD-37). Leon Theriot's sail-powered lugger Neptune flying the French flag, near Cheniere Caminada, 1891: (National Archives, Negative No. 22—FCD—32). 16 Father Grima, the Breton priest re- sponsible for build- ing the Catholic Church on Cheniere Caminada, no date: (Harper's Weekly, October 21, 1893, 13. 1,000, Biloxi Public Library Archives). Cheniere Caminada: The Disappearance Of A Community "P"! g I )‘ll', 4 .y, ' /L:, , '. .. filllll‘lr ~ —jfl::‘zt I -' , 2' X ‘\ "Lav-“€52 .\ (Shaman Fishefis Camp - I“ t/ , y: «., After the 1893 hurricane, the dead were buried in shallow graves, no date: (Frank Leslie's Illustrated Weekly, October 26, 1893, p. 269, the Biloxi Public Library Archives). The palmetto-covered Chinese camp at Bayou Andre, where 63 people were lost during the 1893 hurricane, 1893: (Harper's Weekly, October 21, 1893, [3. 1,000, Biloxi Public Library Archives). Typical Cheniere Caminada Creole houses, surrounded by a cypress pieux fence, 1891: (National Archives, Negative No. 22—FCD—33). % Steamboats were used to bring supplies to Louisiana's coastal fishermen, 1891: (National Archives, Negative No. 22—FCD-246). John Meralina, a Barataria Bay Malay fisherman, rescued eight persons after the 1893 storm, no date: (Harper’s Week- ly, October 21, 1893, p. 1,000, Biloxi Public Library Archives). Grand lsle's Kranz Hotel was depicted as a total loss in this line drawing, no date: (Frank Leslie’s Illustrated Weekly, October 26, 1893, p. 269, Biloxi Public Library Archives). Cheniere Caminada fishermen, 1891: (National Archives, Negative No. 22-FCD—42). The folk architecture of Cheniere Caminada included palmetto-covered struc- tures built with techniques learned from the indigenous Indian population. Cast nets were hung on the fence to dry, 1891: (National Archives, Negative No. 22-FCD— 41). e Of Louisiana's folk boats, the esquif, or skiff, is the most easily distinguished. This sail- and oar-powered boat from Cheniere Caminada would have been iden- tified locally as a peniche, chaloupe, or galere, 1891: (National Archives, Negative No. 22—FCD—47). CHENIERE CAMINADA Cheniere Caminada lifts its comb of roof and gray gable and soft-colored adobe chimneys from out the clumps and clouds of the chinaberry tree. Along the shores in the water shallows the fishermen have hung their long seines to dry. (Cole, 1892a, p. 12) At the west end of Grand Isle, less than a mile across the Caminada Bay, was the "Isle of Cheniere," or "Island of Chetimachas" (Public Lands, 1836). The island, valued at nearly $20,000 and worked by about 50 slaves, was an operating plantation in 1836 (Swanson, 1975). By 1890 Cheniere Caminada (from the French, meaning a roadway through oaks) was an important fishing settlement and the most densely populated community on Louisiana's barrier islands with its ownership roots dating back to 1763 (Public Lands, 1836). It had a cosmopolitan ambience, made up of Yugoslavians, Italians, Chinese, Malays, and a few blacks (Sampsell, 1893). The island was a thriving hamlet with a population of 1,471. About 250—450 small, gray, pleasant homes were stretched side by side in two long lines—one faced Caminada Pass parallel to the Gulf shore and a short distance from the beach, the other fronted Caminada Bay. Space was precious, so the homes were set close together—as dense as urban row housing (Cole, 1892b). The palmetto-covered, bousillage homes were spartan but neat, with brick dust floors and huge fireplaces. The smell of coffee was always in the air—"black as sin, hot as the hinges of hell, and strong as revival religion" (Frost, 1939, p. 76). Fences were made of driftwood stuck into the ground (Cole, 1892b). Homemade outdoor ovens, located behind the homes and often in a grove of orange trees, were used to bake water— bucket—sized loaves of bread (pain chaud)—12 to 15 at a time; it was some of the "best bread you ever ate" (Lenski, 1943). A Breton priest, Father Grima, built a high, narrow, brown and yellow Gothic church on the island and dedicated it Our Lady of Lourdes (Cole, 1892b). There were also nine grocery stores; each sold seines, castnets, sails, and oil coats, items the native fishermen considered essential (Cole, 1892b). All of Cheniere Caminada's outside needs were met by either these grocery stores or by supply boats that came through the Barataria water system from New Orleans (Van Pelt, 1943). The chief form of entertainment on Cheniere Caminada was a ball held on Saturday nights. Admission was free to the locals, and soft drinks, gumbo, and coffee were sold, along with a regional specialty, boiled mullet or meuil bouille. Guests could attend these functions for 25 cents, which guaranteed a supper with red wine (Cole, 1892b). Docked in front of each home were the long, shallow boats that un- der sail were well adapted to both the legal and illegal activities of the fish— ermen. Jake Kilrain, John L. Sullivan, Buffalo Bill, II Destino, and Nativita di Caminada were stenciled on the bows of these boats. Boats were the net fishermen's transportation. It is quite possible that many of these net fishermen were descendants of the crews of the privateer Jean Lafitte. Cheniere Caminada was a thriving community. Its population primar— ily harvested the region's renewable resources: shrimp, oysters, crabs, and fin fish. They practiced their seasonal occupations in virtual isolation. These net fishermen would leave their homes, often for months, to sail to their winter camps where they harvested various aquatic species. Shrimp, oysters, and crabs were shipped to New Orleans and consumed by the city's hotels, restaurants, and steamboats or exported to other markets. LOUISIANA'S WORST HURRICANE DISASTER The 1893 storm destroyed Cheniere Caminada. Four homes re- mained, and these were filled with crowds of survivors (The Weekly Thibodaux Sentinel, 1893b). The land was swept clean, and the death toll varied from 779 to 822, with only 696 people surviving (The Weekly Thibodaux Sentinel, 1893b). Some survivors drifted nearly 100 kilometers across the Gulf to Southwest Pass. There were 78 people in one home; the house collapsed, killing 74 (The Weekly Thibodaux Sentinel, 1893a). Dead were everywhere; the odor endured. Often coffins and separate graves were unavailable, so bodies were buried where they were found. There were so many dead, the graves of those who were recognizable were aligned like the rows in a plowed field (Sampsell, 1893; The Weekly Thibodaux Sentinel, 1893a). Those who survived saved themselves by using timber, roofs, and doors—anything that floated—for rafts. Of the island's fishing schooners and red-sail luggers, only the Good Mother and Counter survived (The Daily Picayune [New Orleans), 1893). The storm also took its toll on Grand Isle and many shrimp platforms in Barataria Bay, such as at Bayou Andre, Bird Island, and Bayou Dufond. Relief boats from New Orleans brought supplies and ice to be melted for drinking wa— ter; crew members were appalled by the destruction (Van Pelt, 1943). After the hurricane, Cheniere Caminada was abandoned. Some peo- ple eventually returned, but their new community was destroyed by a 1 9 1 5 hurricane (Baker, 1 946). One of the few houses that partially survived the 1893 storm, no date: (in Mark Forrest, Wasted by Wind and Water: a Historical and Pictorial Sketch of the Gulf Disaster, Milwaukee, Art Gravure and Etching Company, Louisiana and Lower Mississippi Valley Collections, Hill Memorial Library, Louisiana State University Libraries). Sixty-two people survived the Cheniere Caminada disaster under the roof of this collapsed shed, no date: (in Mark Forrest, Wasted by Wind and Water: a Historical and Pictorial Sketch of the Gulf Disaster, Milwaukee, Art Gravure and Etching Company, Louisiana and Lower Mississippi Valley Collections, Hill Memorial Library, Louisiana State University Libraries). LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A Wash day at a shrimp fisherman's home at Cheniere Caminada, with the Catholic church and other structures in the background, 1892: (National Archives, Negative No. 22-FCD-34). Out of a population of about 1,500 people, more than half did not survive; dead were every- where, no date: (in Mark Forrest, Wasted by Wind and Water: a Historical and Pictorial Sketch of the Gulf Disaster, Milwaukee, Art Gravure and Etching Company, Louisiana and Lower Mississippi Valley Collections, Hill Memorial Library, Louisiana State University Libraries). Relief steamer, surrounded by luggers, taking supplies to the survivors of the 1893 hurricane, no date: (in Mark Forrest, Wasted by Wind and Water: a Historical and Pictorial Sketch of the Gulf Disaster, Milwaukee, Art Gravure and Etching Company, Louisiana and Lower Mississippi Valley Collections Hill Memorial Library, Louisiana State University Libraries). Part of the aftermath of the Cheniere Caminada hurricane, no date: (in Mark Forrest, Wasted by Wind and Water: a Historical and Pictorial Sketch of the Gulf Disaster, Milwaukee, Art Gravure and Etching Company, Louisiana and Lower Mississippi Valley Collections, Hill Memorial Library, Louisiana State University Libraries). 17 US. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY Wetlands Harvest Louisiana Photographic Archives). Grand Isle fishermen, burned by thousands of days of exposure to A racing hull designed and built in Houma. Annual races . . . I ' ' the sun, vividly describe the history of the area's hardy inhabitants, were held at Sea Breeze—a community that has been Successfully tongmg oysters from Loursrana S prolific oys- ca. 1940: (in Justin F. Bordenave, ed., Jefferson Parish Yearly Review, eroded away, ca. 1930: (Randolph Bazet Collection, Houma, ter beds, “0 date: (Loui51ana Department Of Wlldllfe and Special Collections Division, Hill Memorial Library, Louisiana State University Louisiana). Fisherles, PhOtOQl‘aPhIC AYChlVQS). Libraries, p. 50). To maintain navigability many bayous were dredged, or canals were cut to connect existing waterways. The dredge Eclipse was active in Lafourche and Terrebonne parishes, no date: (Historic Lafourche Collection, Allen Ellender Memorial Library Archives, Nicholls State University, Thibodaux, Louisiana). .x» Fishing has always been a popular recreational activity along Louisiana's coast, no date: (Louisiana Department of Wildlife and Fisheries, Photographic Archives). »,.x. ,. ' ’ L . i ' K A successful shrimp harvest, ca. 1920: (Randolph Bazet Collection, Houma, Louisiana). Trappers built rough-hewn camps in the marsh to efficiently harvest their leases during the winter season. Entire families moved into these settlements. Schools closed because most of the students were working their families' trapping lines, ca. 1930: (Louisiana Department of Wild Life and Fisheries, Photographic Archives). an. ”gt-ml ' . »< V The Louisiana pirogue (pettyaugre) draws so little water it is said to "float on a heavy In the late 1800's and early 1900's market hunters and sportsmen harvested thousands of birds In the late 1800's, one hunter 00““ market more than 1,000 alli- dew." This shallow-draft folk boat became an indispensable tool to the coastal dweller, ca. and millions of eggs for restaurants, glue manufacturers, photographic films, and the millinery gator hides annually, ca. 1905: (Louisiana State Library, Louisiana 1935: (in Channing Stowell, ed., Jefferson Parish Yearly Review, Special Collections Division, Hill trade, ca. 1920: (Randolph Bazet Collection, Houma, Louisiana). Collection, WPA Photographic Archives). Memorial Library, Louisiana State University Libraries, p. 54). 18 Scooping up blue crabs in Barataria Bay, ca. 1930: (Fonville Winans, Louisiana State Library, December, January, and February were the traditional trap- ping months. The animal's pelt was fleshed, washed, stretched, and dried, no date: (Louisiana Department of Wild Life and Fisheries, Photographic Archives). Crab fisherman, ca. 1930: (Fonville Winans, Louisiana State Library, Louisiana Photographic Archives). A trapper "fleshing" the day's catch, no date: (from the US. Army Corps of Engineers, New Orleans District, Photographic Archives). Mixed Houmas at Little Bayou Barataria, 1907: (Swanton Collection, Smithsonian Institution, Photo No. 142D). A trainasse machine cut the narrow pirogue trails that al- lowed trappers access to their trapping areas, 1969: LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A (Donald Davis Collection, Baton Rouge, Louisiana). WETLANDS TRAPPING IN FRENCH LOUISIANA Trapping, one of the oldest means for obtaining food and clothing, originally was a profession confined primarily to the taiga and tundra regions of northern Alaska and Canada. Once alligator (Alligator mississippiensis), mink (Mustela uison), otter (Lutra canadensis), and raccoon (Procyon lotor) were recognized as valu- able hide- and fur—bearing animals, the belief that quality furs came only from cold climates was dispelled. Within 150 years Louisiana marshes became North America's preeminent fur—producing region. By the early twentieth century, Louisiana's annual harvest was greater than that of Alaska and Canada combined. Louisiana's wetlands were considered an important and easily exploited wildlife habitat (Ashbrook, 1953; O'Neil, 1965). Before the 1914—22 increase in fur prices from 8 to 50 cents a pelt (Chatterton, 1944), hunting was more profitable than trap- ping; a brace of ducks sold for 25 cents. Locals changed their win— ter subsistence activity from hunting to trapping because of the 500 percent increase in fur prices. Ten years later approximately 20,000 people were involved in Louisiana's essentially uncontrolled trapping industry. A trapper set lines on any land that suited him because he was concerned with productivity, not property ownership. To work this land a trapper Went into the marsh with his entire family. Children lived on the trapping lines and returned to school after the three—month season to "catch back" their studies (Frost, 1939). Marsh dwellers used cane poles to mark their trapping areas and brought order to what could have been chaos. Once staked out, individual plots were respected. Ditches were cut to gain ac- cess to the marsh. A trainasse or ditch, could be used to cross someone else's claim, but traps were never set on another person's land (Davis, 1976). It was folk law that trapping grounds were honored and divided according to families; often husband and wife trapped different parcels. When fur prices increased, people from outside the area became involved in the industry (Davis, 1973). These outsiders competed for the choice trapping areas. This dis— regard for individual rights culminated in a trapper's war in St. Bernard and Plaquemines parishes (Washburn, 1951). To remedy the situation, the State intervened and established a controlled harvest; pelts were, for the first time, graded to de- termine their value. In addition, landowners assigned individual trappers parcels of land, and licensed trappers, free—lancers, and bootleggers were unable to work the land easily. Competition and poaching by outlaws and outsiders were eliminated (Washburn, 1951). Arrangements with landowners varied; generally, a trapper worked on a 50-50 basis. When furs were scarce, a 65—35 share was negotiated, with the trapper receiving 65 percent (Frost, 1939). With the increased value of furs, trappers spent more time in the marsh, so they lived on their trapping leases in small, one— or two—room, palmetto—thatched huts called camps, crude by today's standards but adequate and always clean. The huts were copies of the houses built on the natural ridges by many native Americans. There was no need for a larger structure because trapping families At one time, Louisiana produced more fur than the remainder of the United States and Canada combined, 1984: (Donald Davis Collection, Baton Rouge, Louisiana). In a good year, a trapper would harvest from 50 to 200 animals a day. When brought back to camp, muskrat and nutria had to be cleaned immediately, ca. 1930: (Louisiana Department of Wild Life and Fisheries, Photographic Archives). The Argentinean coypu, or nutria, was acciden- tally introduced into Louisiana's coastal low- lands, where it has pro- liferated, 1986: (Donald Davis Collection, Baton Rouge, Louisiana). spent most of their time outdoors. The camps evolved into more permanent structures with wood; burning or butane stoves to supply heat, white-gas or kerosene lantern lights, and cistern water (Gary and Davis, 1979). These camps were rough-hewn buildings but actively used only in December, January, and February, so they were quite adequate. Everything required at the camp was hauled in by boat (Daspit, 1948). Large boats provided access, but motorized pirogues and mudboats allowed the trapper to increase his trapping from 150 to 400 traps by increasing the territory covered (O’Neil and Linscombe, 1975). At the camp the pelts were fleshed, washed, stretched, and dried. They were then sold to a local buyer who sold to one of the Louisiana fur dealers. Trapping was and is a labor-intensive industry. In fact, the method employed in trapping and handling the fur has changed little since the invention of the steel trap by Sewell Newhouse in the mid—1800’s (O’Neil, 1969). MUSKRAT AND NUTRIA Beaver, otter, and mink did not account for Louisiana’s trapping growth; it was a result rather of the willingness of the local population to exploit the region’s unique resources: muskrat (Ondatra zibethicus rivalicius) and nutria (Myocastor coypus). Before the late 1800’s the muskrat ranged as far south as southeastern Arkansas, but by 1900, it had become a permanent resident of Louisiana’s marshes (O’Neil, 1949). Although it inhabited the wetlands, Arthur (1931) and O’Neil (1949) found no documenta- tion linking muskrats to the early French fur trade. Fur buyers were interested in buffalo (Bison bison) and the American beaver (Castor canadensis). Muskrat pelts were offered to northern markets in 1870, but wholesalers considered them useless. By 1914, however, pelt prices increased. The animal was on the fur market and became the State’s number one fur product, a title it eventually lost to the nutria (Chatter- ton, 1944). To increase their marketability, muskrat pelts were often specially treated, and sold under the label French Seal or Hudson Seal (Chatter- ton, 1944). With time, the muskrat gained prestige under its own name. Because each pelt has three distinct colors: black (stripe down the back), light golden brown (sides), and silver (body), they could be used for three different garments (Murchison, 1978). A muskrat builds its house, made of woven marsh grass and plastered with mud, 1.2 to 1.5 meters above the marsh surface, from which it can forage into the surrounding terrain. These houses are the keys to production because they identify the muskrat’s brackish water habitat. The Argentinian coypu, or nutria, was inadvertently introduced into the Louisiana wetlands in 1938 and is now well established throughout the State. The rodent first was considered a nuisance because it was heavy to carry out of the marsh, difficult to skin, and confined to a single area, but with increased prices, attitudes changed (Dozier and Ashbrook, 1950). By the early 1950’s, trappers were harvesting nearly 80,000 pelts annually. Six years later, over 500,000 pelts were processed, a significant increase in less than 20 years (Davis, 1978). During that time, nutria pelts generated over $7 million a year and represented about half of the State’s fur income—all from a dozen coypu that escaped captivity (Daspit, 1950). Mule carts were used to transport pirogues to access points, ca. 1930: (Randolph Bazet Collection, Houma, Louisiana). To effectively harvest the marsh, trappers built isolated camps near the areas they trapped, 1947: (Todd Webb, Louisiana State Library, Louisiana Photographic Archives). In the 1961-62 season, nutria surpassed muskrat in number of pelts sold. Although the nutria’s habitat is shrinking, the population is ex- panding swiftly. Because fur prices are declining, it is no longer worth the time, money, and effort for trappers to harvest this rodent. Nutria, therefore, have begun to overpopulate their habitat and cause con- siderable environmental concern. Muskrats and nutrias thrive in the marshes. There is ample range to graze, and they have co-existed quite well. Nutrias prefer freshwater marshes but with increased population densities will move into the muskrat’s brackish water habitat. THE AMERICAN ALLIGATOR There are at least 500,000 alligators (Alligator mississippiensis) living in the Louisiana coastal zone’s fresh-to-slightly-brackish habitats. Muskrats, nutrias, rabbits (Syluilangus aquaticus), rails (Rallus longirostn's saturatus), and waterfowl feed in these marsh zones and naturally attract the omnivorous predator. The alligator, first described in 1718, has survived two centuries of hunting. Even after they were extensively harvested to meet the Civil War demand for shoe leather, the marshes supported an immense population (Johnson, 1969). In the late 18003, 4.5- to 6-meter alligators were so commonplace they did not attract considerable attention and were considered a nuisance. Le Page Du Pratz (1774) relates, in his History of Louisiana, the killing of a 5.8—meter alligator, whose head was 1 meter long and at least 76 centimeters wide. Alligator hunters realized their quarry’s skin and meat were valuable, so they often shot swimming gators, and although the dead reptile sinks almost immediately, it could be retrieved easily. Hunters also used baited hooks attached to about 15 meters of line suspended 15 centimeters above the water; when the bait was taken, the hook became embedded in the reptile’s stomach. The alligator was then caught, hand lined to the surface and shot. In the late 1800’s one hunter could market over 1,000 alligator hides annually. Between 1880 and 1904, the population was reduced an estimated 80%, but as late as 1890, some 280,000 alligator skins still were being processed in this country annually (Waldo, 1957). During the next 60 years, hunters were encouraged by esca— lating prices. In 1916, a 1.5—m hide brought only 40 cents. By 1928, it brought $1.25, and by the early 1960’s hide prices had increased to over $30 a meter. Consequently, the reptile’s popula- tion was nearly exhausted. To try to reestablish the reptile within its native habitat, in 1966 the alligator was placed on the Federal list of rare and endangered species. This protective action, along with habitat preservation, has allowed the reptile to make a dramatic recovery. Since then, the reptile has been removed from the federal endangered and threatened species list. Louisiana now considers the animal a renewable resource and has sanctioned a strictly regulated September hunting season. The Louisiana muskrat, ca. 1940: (Louisiana Department of Wild Life and Fisheries, Photographic Archives). Palmetto homes were a visible part of the wetlands landscape, ca. 1910: (Swanton Collection, Smithsonian Institution. Photo No. 244). Once dried, pelts were graded and sold to local buyers, ca. 1920: (Randolph Bazet Collection, Houma, Louisiana). In some places, an isolated trapping village was constructed to meet the needs of several families, ca. 1930: (Louisiana Department of Wild Life and Fisheries, Photographic Archives). Once an endangered species, the alligator has been reestablished in the wetlands. Each September, Louisiana has a con- trolled alligator hunt, 1988: (Donald Davis Collection, Baton Rouge, Louisiana). At the turn of the century, pullboats were used to harvest the swamps, ca. 1900: (courtesy of Milton Newton, Louisiana State University, Department of Geography and Anthropology, Bowie Lumber Company Collection). 19 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY For over 100 years Louisiana's waterpeople have harvested oysters from the State's estuar- ine habitats, ca. 1940: (Louisiana State Library, Louisiana Collection, WPA Photographic Archives). In Terrebonne Parish, at Boudreaux Canal on Bayou Petit Caillou, Andrew St. Martin built an oyster-shucking plant to quickly process the region's harvest, 191 12 (Randolph Bazet Collection, Houma, Louisiana). Fishermen often sold their oysters, crabs, or shrimp to larger boats, so they could remain at work, rather than losing time travelling to market, 1891: (National Archives, Negative No. 22—FCD—247). Although New Orleans was recognized as Louisiana's principal oyster market, oyster- shucking houses were built in many delta-plain communities. Houma developed into one of these regional centers, no date: (Randolph Bazet Collection, Houma, Louisiana). Eight members of the Descaricadores, a quasi- organization of Sicilians and Italians that con- trolled the unloading of New Orleans' oyster ves- sels, 1891: (National Archives, Negative No. 22-FCD- 265). In 1887, the oyster industry was well established in coastal Louisiana. Approximately 200 luggers, employing more than 600 men, supplied New Orleans' Lugger Bay with oysters, 1891: (National Archives, Negative No. 22—FCD—17). 20 To facilitate processing, oyster shops often were built on isolated sites near the oys- ter beds. This shop was located in the Terrebonne-Timbalier complex, south of Houma, ca. 1920: (Randolph Bazet Collection, Houma, Louisiana). Historically, movement through the coastal wetlands presented people with a special challenge and resulted in development of unique folk boats. The shallow-draft, sail-driven Louisiana lugger became the preferred working vessel of the region's fishermen, 1891: (National Archives, Negative Number 22-FCD—32). LOUISIANA'S PROLIFIC OYSTERBEDS Estuarine—dependent oystermen rely almost totally on one species, the American oyster (Crassostrea virginica). At the turn of the century, Louisiana and Mississippi were leaders in the production of this important bivalve. To harvest their oysters, Louisiana's watermen leased the right to harvest the state's water bottoms. Isolated settlements were established to watch the leases to ensure that poachers would not disturb the tonging grounds. To exploit the beds, oystermen used a pair of tongs, which resembled two long-handled rakes tied so the teeth were facing each other. Leaning out over their luggers, oystermen spread and lowered their tongs into the water. The opened tongs were shoved into the reef and forced closed, grabbing several bivalve clusters. The oystermen then dumped their catches into their boats. One man would tong and another would cull the undersized product. This process was repeated until the boat was full, the catch too small, or darkness or bad weather set in and forced the men to return to camp. Using this technique, oystermen could harvest 20 barrels a day. Tongs were eventually replaced by the oyster dredge—a large basket— like framework with curved teeth that was dragged through the beds to snag the oysters. With this new technology, the harvest increased. Luggers were customized with a false deck and temporary sides to ac— commodate the expanded catch. The dredge's deck became an extension of the vessel's hold and could carry from 50 to 80 barrels of oysters (Zacharie, 1898; Prindiville, 1955). The watermen who lived near their beds used small boats to work their leases, but sold to owners of larger boats. In this way, they could remain at work, rather than lose time travel- ing to the market. Eight boats from the Barataria communities of Bayou Cook, Bayou Chalous, and Four Bayous unloaded their catches in New Orleans every week. Thirty luggers delivered the harvest from Southwest Pass and Salina. From the Timbalier region another 15 luggers transported their harvest to the city from ”considerable villages composed of rude camps of the oystermen built upon piles on the sea marsh" (Moore, 1899, p. 71). In all, an estimated 4,000 people were involved, directly or indirectly, in the oyster trade (Sterns, 1887). By 1887 approximately 200 luggers, employing over 600 men, supplied New Orleans' Lugger Bay with oysters (Stems, 1887). These sail- ing vessels delivered from 50,000 to 125,000 barrels annually; a barrel held approximately 200 pounds of oysters and sold for $2.00 to $3.50. Wholesalers paid 40 cents for a sack of oysters and transported them to New Orleans where city vendors sold them for about 70 cents a sack—a profit of almost 75 percent (Ross, 1889b). Each boat was unloaded by stevedores, who controlled the discharge of New Orleans' cargo. A quasi—organization of Sicilians and Italians was solely responsible for unloading the oyster vessels (Sterns, 1887) and overseeing the crews that worked the docks. I i , l i ) Oyster luggers at the New Orleans' French Market, 1891: (National Archives, Negative No. 22-FCD—18). Locks at Empire allowed oyster luggers to move eas- ily between the Mississippi River and the estuarine complex west of the river, ca. 1938: (Fonville Winans, Louisiana State Library, Louisiana Photographic Archives). Competition between Louisiana and Mississippi over the oyster beds east of the Mississippi River became so keen, men were accused of being "oyster pirates." Using a fleet of lumber schooners capable of carrying from 1,000 to 2,000 barrels a trip, Mississippi-based watermen reportedly harvested hundreds of schooner loads of St. Bernard Parish oysters (Zacharie, 1898). The issue became a heated one, and in 1905, armed boats began patrolling the State boundary to ensure that only licensed fishermen were exploiting Louisiana's oyster beds (Fountain, 1985). Bohemians manned Biloxi schooners that operated for weeks in the marshes of the Mississippi River delta country—often illegally in Louisiana waters (Fountain, 1966). Predators were also a problem. To protect the beds from schools of drum or sheepshead, which could devour hundreds of barrels of oysters in a single night, pens were constructed of old seine supported on pickets or hardware cloth (Zacharie, 1898). At times lines with rags attached to them were used to frighten the fish away. OYSTERING IN BAYOU COUNTRY Jack's Camp, Camp Malnomme, and Bayou Landry were important harvesting sites in the barrier-island-protected leases of south central Louisiana. Small fishing villages were near these sites. Oysters harvested in one area sometimes were used to restock other beds. In this way, oystermen accumulated catches that would warrant a trip to the New Orleans' market. Fishermen worked beds at the Chandeleur Islands, Bayou Cook, Grand Bayou, Bayou Lachuto, Timbalier Bay, Isles Dernieres, Barataria Bay, Wine Island Lake, Vermilion Bay, and Calcasieu Lake. Bayou Cook oysters were generally considered the State's best (Zacharie, 1898). Prized oysters were also being harvested in Lake Felicity, Lake Barre (especially at Mud, Hatchet, and Muddy Bayous), and Bay Jocko (Moore, 1899). In the late 1800's there were at least 20 camps along Grand Bayou du Large between the Gulf of Mexico and Sister Lake. Oyster camps were also located on Pelican Lake, and the Timbalier region's oyster grounds were quite productive. Even with a relatively small number of people working the beds, Sister Lake alone yielded from 4 to 8 barrels of oysters per day (Moore, 1899). It is a region that continues to serve the oyster industry well. A pair of tongs resembling two long-handled rakes tied so their teeth were facing each other was used to harvest Louisiana's oyster beds, ca. 1930: (Fonville Winans, Louisiana State Library, Louisiana Photographic Archives). LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A At the southern limit of Dupre Cut-Off canal in Barataria Bay was the shrimp-drying settlement of Manila Village. Dominated by a large platform, this was the largest shrimp-drying community in Louisiana's alluvial wetlands, 1938: (Fonville Winans, Louisiana State Library, Louisiana Photographic Archives). Shrimp used in the shrimp-drying business were boiled in a hypersaline solution. When re- moved from the vats, the shrimp were taken by wooden wheel barrows to the platform‘s drying area, ca. 1920: (Randolph Bazet Collection, Houma, Louisiana). Hand-woven china baskets, along with wheelbarrows, were used to move shrimp around the platform, no date: (Louisiana State Library, Louisiana Collection, WPA Photographic Archives). SHRIMP DRYING: AN ANCIENT CHINESE ART The shrimp-drying procedure used in Louisiana originated in the Orient and diffused to Louisiana from the United States' west coast. In 1871, Chinese immigrants began to harvest San Francisco Bay shrimp (Jordan, 1887; Bonnot, 1932). These fish— ermen were quite successful and found it profitable to supply the markets with shrimp at three cents a kilogram. "From the very start they dried the bulk of their catch for the Oriental export trade. The shrimp industry quickly grew to large proportions and fishing was carried on at many places in San Francisco Bay” (Scofield, 1919, p. 2). By 1873, Chinese migrants from California had introduced the lucrative sun—dried—shrimp process to Louisiana, hoping to du- plicate the profits generated from the San Francisco Bay enter- prises (Padgett, 1960). Shrimp-drying villages were well-organized hamlets established to overcome the early problems of food preservation in Louisiana. The sites were dominated by large, undulating, wooden plat— forms—a term which locally had two meanings; one referred to the drying area only, the other included the associated support struc— tures as well. Shrimp in Louisiana had been a source of income and a basic food item since the colonial period. As early as 1718, the Dutch historian A. S. Le Page Du Pratz, stated The Shrimps are diminutive crayfish usually about three inches long, and of the size of the lit— tle finger in other countries they are generally found in the sea in Louisiana you will meet with great numbers of them more, than a hun— dred leagues up the rivers. (Le Page Du Pratz, 1774, p. 277) Le Page Du Pratz also noted that shrimp were not limited to the sea. Indeed, the majority of shrimp used in the sun—drying pro— cess was caught in Louisiana's inland waters. As a result, Barataria, Timbalier, Terrebonne, Caillou, and Atchafalaya bays, and Breton and Chandeleur sounds are important to the production of mar— ketable shrimp. These estuarine or estuarine-like areas also served as settlements because before ice and modern freezing techniques were available, shrimp caught in these fishing grounds were taken to one of the nearby platforms to be dried, packaged, and sold. There are conflicting reports on the original practitioner of this art in Louisiana; it was either Lee Yeun, Chen Kee, or Lee Yim (Adkins, 1973). Although the person responsible for starting this occupation is apparently lost to history, it is fairly well agreed that the first crude drying platform was built on the south side of the mouth of Grand Bayou in Barataria Bay, at a site later to be Cabinash. This camp was originally used in an effort to sun dry oysters, but when this proved to be impracti— cal the men began to dry shrimp. (Padgett, 1960, p. 142) Louisiana Land Office records show that in the early 1880's Oriental immigrants purchased, for $1.25 a hectare, several small islands in Barataria Bay for platform sites (Adkins, 1973). These tracts were ideally suited for this purpose. By 1885, the industry was well established when Yee F00 was issued Patent Number 310—811 for a process to sun-dry shrimp. Actually, the Chinese have used this method for preserving shrimp and other animal foods for centuries, but the patent made the process and established method of food preservation. (Love, 1967, p. 58) Originally, the primary market for dried shrimp was the large Oriental communities on the Pacific coast; nearly $100,000 in dried products a year were shipped there from each camp (Cole, 1892a). As production increased, distribution expanded to the Far East; the greatest volume was exported to China, the Philippine Islands, and Hawaii. Smaller quantities were shipped to the West Indies and South America (US. Department of Interior, 1950). PLATFORM SETTLEMENTS Settlements at Bassa Bassa, Manila Village, Camp Dewey, Chenier Dufon, Cabinash, Fifi Islands, and Bayou Brouilleau were established for shrimp preservation and shipment to the various markets. In Barataria Bay there were six or more of these camps, occupied by hundreds of people (House Document, 1917). Most of the shrimp seining was done by the French, the Chinese, or the Malays. Although Oriental peoples dominated the platform population, other ethnic groups also were involved. Platform crews frequently were a melange of representatives from water—oriented cultures. As many as 15 seine crews and a year- round platform population of about 100 contributed to a maximum of 500 people living on one platform. Most did not leave these iso— lated settlements because they were in this country illegally. It is rumored that some were smuggled into Louisiana by commercial fishermen who placed the aliens in barrels to bring them through coastal waters. THE GEAR REQUIRED In Louisiana's inland waters shrimp fishermen used the sail— driven Louisiana lugger. This vessel used lugsails—quadrilateral sails that bend upon a yard that crosses the mast obliquely. Effective in Louisiana, the boat never diffused from its area of origin, the State's inside waters. Prior to motor—powered vessels this was the major craft used to harvest platform shrimp. Before the introduction of the otter trawl, most of the catches were taken with haul seines operated by a single boat with a crew of from 8 to 20 men (Cole, 1892a; Johnson and Linder, 1934). Barataria seines were some of the largest in the world. Local in— formants claim that a good crew could harvest up to 900 kilograms a day. At times the catch was so great, a platform would work con— tinuously to keep up with its seine crews. Seines were efficient, but the otter trawl, introduced in 1917, revolutionized shrimping and increased production. The haul seine could be used only in shallow wa— ters, requiring a large crew. It could be operated for only a limited time during the summer and fall months, the otter trawl was adaptable for use over a much greater range, could be operated with fewer men, yielded a greater production per man, and was a much more efficient type of gear. With its introduction, entirely new fishing grounds were opened up and a rapid expansion of the fishery followed. (Padgett, 1960, p. 147) In 1930, the total shrimp harvest in Louisiana was over 13 million kilograms, nearly twice that of the preceding year (Padgett, 1960). Catch statistics normally fluctuate, but this increase in har— vest was attributed directly to the acceptance and use of the otter trawl, the availability of ice, and improved boats. Coastal fishermen used a rig called a butterfly net (in French, poupier) with haul seines and otter trawls—invented to provide smaller and cheaper shrimp to the sun—drying industry (Love, 1967). These nets were mounted on boats and wharves, rigged on iron—pipe frames from 2.1 to 4 m2, and equipped with small mesh bags about five meters long. Manila Village's buildings and wharf, built over the shallow water on hand-driven pil- ings, were used to unload the newly arrived unprocessed shrimp, no date: (Louisiana State Library, Louisiana Collection, WPA Photographic Archives). Manila Village was the largest of an estimated 75 drying platforms that served Louisiana's seine fishermen, no date: (Louisiana State Library, Louisiana Collection, WPA Photographic Archives). When the shrimp were thoroughly dried, the heads and shells were removed by laborers who "danced the shrimp" in shoes wrapped with cloths or sacks, ca. 1920: (Randolph Bazet Collection, Houma, Louisiana). To insure uniform dehydration, the shrimp were spread evenly over the cypress platform's surface with wooden rakes, no date: (Louisiana State Library, Louisiana Collection, WPA Photographic Archives). Most shrimp-drying platforms were constructed with cypress. The size of the drying sur- face varied with each site, but most had a capacity of 1,000 baskets of shrimp—about 50,000 kg, ca. 1920: (Randolph Bazet Collection, Houma, Louisiana). From isolated platform sites, waterpeople depended on their luggers to harvest the region's renewable resources, 1891: (National Archives, Negative No. 22-FCD—47). US. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY as: The Chandeleur lighthouse after the 1893 hurricane, October 1, 1893: (National Archives, Negative No. 26—LG—35—48). ngg i in g Wmfz was. “A 4, £38? A ‘31 a“ ”a"? After the 1893 hurricane, the Chan- deleur lighthouse was replaced by a steel tower, ca. 1945: (National Archives, Negative No. 26-S-153). rtzTHE BALIZE. [sax “dilemma Tim; is the name of one of the mouths of the Min- aiasippi River. A: ihe distance of 105 miles Mow New Grimm h}: the course of the river, and 90 mites in a dime iino, this majestic stream enters the Grafton“ Mexico by several mouths, the principal of which an: the: Balize, or North East Pass, in latitude 29‘ ’7’ and longitmlu 80" 10’ West, and the South “'61:: Pass, in Kashmir: 29" 8’ North and imam 80° 12%? West. The rieptlmf waitironlhcbniat emit of then: glasses is 12 to it} fwgbut much greater Witlmui am! a links «within the liar. Most vessels enter and leavs by the Balize, and hence the frequency with which we hear this Remarkable plaee referred to. The tall emotions in (he mgrarml Visw sue lookout» oonsirgcisd fur nlfien‘ing the approach of vowels, and hoisting signals, The country about the Salim its one continued swamp, (Institute of users, and covered with , a armies of Guam weds, from that to five feet high. Nothing can be more dreary than a prospect from a ship‘s mast while passing this inunense \WW» Chandeleur lighthouse and the outbuildings that survived the 1893 storm, 1893: (National Archives, Negative No. 26-LG—35-47G). In order to safely navigate the Mississippi River, a light- house was built near the mouth of the river's northeast pass, at the community of Balize (from the French word balise, meaning beacon), no date: (Louisiana State Library, Louisiana Collection, Photographic Archives). Travelling the Mississippi River has always required navigational aids. The Southwest Pass lighthouse, connected by a boardwalk, guided ships into the river's navigable channel, October 8, 1915: (National Archives, Negative No. 26—LG—39—32C). The unique architecture of the wood-framed Southwest Pass lighthouse, ca. 1890: (National Archives, Negative No. 26—LG—39—14). The Mississippi River's Pass-a-Loutre lighthouse before the 1893 storm, 1893: (National Archives, Negative No. 26—LG—37—17C). Barataria Bay lighthouse on the western end of Grand Terre, before the October 1893 hurricane, 1893: (National Archives, Negative No. 26-LG-34—1OB). 22 r The substantial lighthouse that served traffic navigating Southwest Pass, 1890: (National Archives, Negative No. 26— LG—39—34). sir I Point-Au-Fer lighthouse, ca. 1945: (National Archives, Negative No. 26—S—686). THE COMMUNITY OF BALIZE To safely navigate the Mississippi River, a lighthouse and community, Balize (from the French word balise, meaning beacon), were established near the mouth of the river's northeast pass. When the French first occu- pied Balize in 1722, it was a little flat island the locals called Toulouse (Roland, 1740); boats used a five—meter channel there to gain access to the Mississippi River. In 1803, Balize was composed of "a small block-house and some huts of the pilots, who reside only here" (American State Papers, 1803, p. 347). The structures were erected on piles; the community was so narrow there was no room to cultivate a garden. Goods had to be imported at three to four times their normal retail cost. By 1815 traffic on the Mississippi had become so great, a lighthouse was needed at the access point to the river (Louisiana Gazette, 1815). Twenty-thousand dollars was appropriated in 1812, but with the end of the War of 1812, it was deemed an unnecessary expenditure. Local inter- ests still favored its construction, however. New Orleans "in strict truth, is the emporium of Western America; and the [Mississippi] is not a mere local avenue of trade and navigation" (Magruder, 1815, p. 2). The city's Gulf of Mexico trade depended on safe passage into the Mississippi River. This argument prevailed, but justifying the Federal expenditure was a diffi— cult task. The lighthouse was built eventually at Southwest Pass. In 1851, the community was large enough to put on a ball for a number of ladies from New Orleans and all of the ”belles of the Pass and Balize" (Daily Delta [New Orleans], 1851, p. 2). One account notes the village had three large grocery stores and a dry goods store, a large church where services were held every Sunday and a good—sized town hall There were houses on both sides of the bayou, some of them two stories in height, and the town was full of children. We had two schools for them. There were fine shell roads around the Balize and levees to protect it from the Mississippi River It was a large settlement and there were possibly a thousand people there when it was abandoned. Fifty bar pilots made their headquarters in the village, and nearly everybody trapped, fished or had oyster beds. (New Orleans Times—Picayune, 1921, p. 12) The community associated with the South Pass lighthouse, with ships anchored in the channel, ca. 1893: (National Archives, Negative No. 26—LG—39-28A). The "leaning" Chandeleur lighthouse after the 1893 storm leveled the island, ca. 1893: (National Archives, Negative No. 26—LG—35—47A). :,4 , , “jimmy“. ,,,,,,, _ ,,,,,,,,,, . ,,,,, W I; Oyster Bayou lighthouse, ca. 1945: (National Archives, Negative No. 26—8—756). This community, like all of those along the coast, had to endure the hardships of hurricanes. In 1741 the French government was informed that the battery at the Balize was so much damaged that, if attacked, it could be carried by four gunboats. There was such a scarcity of everything that a cask of common wine was sold for five hundred livres of Spanish money, and eight hundred livres in the cur— rency of the colony, and the rest in proportion. As to flour, it could be commanded by no price, as there was not to be had. (The Daily Picayune—New Orleans, 1863, p. 3) In addition, there were many families reduced to such a state of destitution that fathers, when they rise in the morning, do not know where they will get the food required by their children. (The Daily Picayune—New Orleans, 1863, p. 3) In 1831, a storm destroyed the "pretty little village” (Daily Delta [New Orleans], 1846, p. 2). Logs as long as 15 meters battered the commu— nity's homes, wharves, and fences. The storm surge was knee—deep in many homes. Gardens were covered with salt water and destroyed (Daily Delta [New Orleans], 1846). In the hurricane of 1860, the water rose nearly two meters and washed away nine homes, three look-out houses and assorted boats and sheds. The telegraph house survived, but a number of flatboats used as homes were destroyed. Several "large house, more than half finished" floated away, and two buildings "belonging to and occupied by fishermen were destroyed" (New Orleans Daily Crescent, 1860, p. 1). Balize was utilized for 150 years; during that time, the Spanish spent over 20,000 pounds sterling to fortify the position (New Orleans Times— Picayune, 1921). About 1865, a crevasse diverted the flow of the Mississippi River away from Balize (New Orleans Times—Picayune, 1921). Bar pilots were forced to move to Pilottown Bayou because Southwest Pass was used to gain access to the Mississippi. In a short time Balize was completely deserted. Eventually, the land subsided, so that the town hall, church, shell road, homes, and tombs were below sea level—captured by the Gulf of Mexico. ' Wm- Barataria Bay lighthouse after the 1893 storm. The picket fence and big house were destroyed. The light sustained only minor damage, December 18, 1893: (National Archives, Negative No. 26—LG—34—1OA). LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A Drilling in coastal Louisiana has had a significant impact on the wetlands, no date: Petroleum exploration was relatively easy in the peats and mucks of (Bernard Davis Collection, Houma, Louisiana). the coastal marshes, 1935: (Randolph Bazet Collection, Houma, Louisiana). | THE WETLANDS MINERAL FLUIDS Canals were excavated for easy access to well sites. The marsh offered no re- To maintain production schedules, supplies and work crews were shuttled to isolated Since World War II, Louisiana's coastal lowlands have seen rapid €C0' sistance, so the process was relatively easy. At the turn of the century, the camps by flying boats, later replaced by helicopters, 1947: (Bernard Davis Collection, nomic growth, much 0f WhiCh can be attributed directly to development 01' Zoe B was at work clearing navigable channels, ca. 1920: (Randolph Bazet Houma, Louisiana). its hydrocarbon resources. In the 1600's, sailors exploring the Texas and Collection, Houma, Louisiana). Louisiana coasts reported oil floating on the Gulf's surface. This seepage was an early clue to the enormous reserves locked in a geosyncline, or fold in the bedrock below the land and sea surfaces from Mississippi to Texas. Commercial oil production began in Titusville, Pennsylvania, in 1856; 50 years later, wildcatters were drilling in South Louisiana. In 1901, W. Scott Heywood completed south Louisiana's first producing oil well in Jennings. Even with this discovery, oilmen ignored the wetlands for over 20 years; they favored north Louisiana's more easily exploited fields. Between 1901 and 1923, only eight fields were discovered in south Louisiana because accessibility was a problem. Wetland exploration and development required a fleet of amphibious vessels. Everything had to float or fly, so conventional methods were impractical. As geophysics and its new technologies emerged, promising fields were investigated. Also, required floating equipment was refined and fur- ther developed. In the 1930's, petroleum engineers moved aggressively into Louisiana's swamps and marshes. Systematic exploration required a well—developed infrastructure of support facilities on high ground. These logistic support sites were essential in providing the supplies drilling crews At Leeville, along Bayou Lafourche, the marsh was blanketed with oil wells, ca. 1938: required, and evolved with the industry, gradually changing the area's de— (Fonville Winans, Louisiana State Library, Louisiana Photographic Archives). mographic character. To gain access to promising exploration sites, powerful suction and bucket dredges excavated navigable channels into well locations. The one— well, one-canal system evolved into an interlocking network of human— made channels, and often over 30,000 m3 of material were removed per kilometer to open the wetlands to hydrocarbon exploration. In less than a century, the complex canal system has become a domi- nant part of the State's coastal geography and has expanded into well—de— fined, but unplanned, patterns. The canal system met the industry's needs and evolved into the most visible structural modification of the coastal zone. As oil exploration and development moved across the coastal low— lands, virtually no section of the coast was spared canalization. After the discovery of easily recoverable and marketable petroleum and natural gas, the marsh became a labyrinth of petroleum-oriented facilities, ca. 1940: (Bernard Davis Collection, Houma, Louisiana). Gaining access to well sites was a relatively simple matter because the wetlands' waterlogged soils were easy to channelize. Dredging contractors encountered few problems. Drilling engineers, however, were frustrated by the hydric soil's low weight-bearing capabilities and were forced to re— think their drilling methods because the marsh lands would only support 1,200 kg/m2. Wooden mats did work in some shallow water areas, but they were cumbersome. Pilings were used in open water, but drilling preparation was a labor- and time—intensive operation. Conventional equipment was too heavy to work in this environment. The industry needed a floating drilling platform. In 1932, the Texas Company developed a patented submersible drilling barge. Equipped with a derrick, this vessel could drill easily on the extensive leases petroleum firms obtained in south Louisiana. Within 10 years, over 70 oil and gas fields were developed in Louisiana's delta coun— try With the advent of World War II, the industry was well established; new fields were added constantly to the regional inventory. Wildcatters in— tensified their efforts in the tidal flatlands and backwater swamps. New wetland technology spurred some of this development, but the word was , . . - . . f . . * " 2. getting out about the impressive exploration results in south Louisiana. Seismic crews used marsh buggies to run their profiles, ca. 1950: (Louisiana Department of Nearly one out of every three wells drilled produced marketable hydrocar- Wild Life and Fisheries, Photographic Archives). bons. Early pessimism turned to unbridled optimism. ” ' ‘ ' ' ' ' ' ‘ ' After purchasing a fleet of airplanes used to carry mail from ships anchored in the delta to New By the mid-1940's it was apparent that operations on a "sea of mud" were no different from those on a sea of water. From a rather quiet be— ginning in 1947, when the first oil well out of sight of land was com- pleted, the search for offshore hydrocarbons grew rapidly. Expectations Orleans, Texaco became a pioneer in using aircraft to support their marsh operations, ca. 1930: (Bernard Davis Collection, Houma, Louisiana). _ were exceeded, particularly in the 1950's when the marine technological First oil well in Houma Louisiana March 18 1927; (Bernard 10 _ revolution began. Boat builders used diesel rather than gasoline; steel hulls Davis Collection Houma Louisiana) ' ' _ rather than wooden-hulled boats were added to the support fleet. ' ' ' ‘23; 8 _ . LOUISIANA I I Shipyards fabricated vessels that operated in the Gulf of Mexico's hostile 1200 I-I- GAS PRODUCTION I I waters. 2 g ‘ Onshore and offshore, the industry expanded rapidly. Early wildcat— 3 1000 I E 6- I ters and major firms who discovered the mineral fluids trapped below E LOUISIANA I I I I = ' I | I Louisiana's alluvial wetlands were right; the region was a significant hydro— _ 800 OIL PRODUCTION I .2 4- I I _ carbon province. Over 25,000 wells onshore and at least 3,000 drilling a 600 I I E _ and production platforms offshore made Louisiana's coastal lowlands one Recommended citation for this chapter: 5, I I ; 2 _ V of the country's dominant forces within the oil and natural gas industry. DaViS7 D W., 1992: A historical and pictorial ”View Of Louisiana's E 400 . l I I I barrier islands, in Williams, S. J., Fenland, Shea, and Sallenger, A. E - ' ' — I I _ _ """""" H., Jr., eds., Louisiana barrier island erosion study—atlas of barrier 200 - 0' 1950 ' —1_096 """" 1970 ' """ 198” ' shoreline changes in Louisiana from 1853 to .1989: US. Geolog- 0 : = 7 : L W : _ _ _ - - - Year 1cal Survey Mlscellaneous Invest1gat10ns Serles 1-2150-A, p. 8- 1930 1970 1980 23, Ye a r E Inland _ Coastal Zone E Outer Continental Shelf E Inland _ Coastal Zone |:l Outer Continental Shelf From Lindstedt, D.M. and others, 1991, History of oil and gas development in coastal Louisiana: Resource Information Series No. 7, Baton Rouge, Louisiana, Louisiana Geological Survey. . 23 From Lindstedt, D.M. and others, 1991, History of oil and gas development in coastal Louisiana: Resource Information Series No. 7, Baton Rouge, Louisiana, Louisiana Geological Survey. US. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY Chapter3 Aerial Photographic Mosaics of Louisiana’s Barrier Shoreline _ by Karen A. Westphal and Shea Fenland These rgiosaics kilntrolduce tfhe viewer to kalliedgfeomorphollogy or; Louisiana's arriers ore ine. T ey are assem e rom vertica aeria ° ° photography at a scale of 1:15.000 but reproduced here at 1:24.000. [Sles Dernleres Baffler SyStem The shoreline is divided into four sections and presented sequentially from west to east (Isles Dernieres. Bayou Lafourche. and Plaquemines shorelines) and south to north (Chandeleur Islands shoreline). Some overlap has been provided for continuity of the image. Significant place names for islands. tidal inlets. bays. bayous. towns. and a variety of humanamade structures and other human impacts are indicated. The photographs for the barrier shoreline west of the Mississippi River mouth between Raccoon Point and Sandy Point. except for Grand Isle. were taken on January 21. 1988. Grand Isle was photo— graphed on October 15. 1986. The viewer is encouraged to examine these mosaics carefully to better understand the character of the marshes. dunes. washover. and tidal inlet features. as well as the imprint of human activity on the landscape of Louisiana‘s barrier shoreline. 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I . . . ‘.I))). .II) ..I IIIA))).)‘ 25 U. U. 26 SD 5.6 EPARTMENT OF THE INTERIOR EOLOGICAL SURVEY Timbalier Island East Timbalier Island H/ Caminada—Moreau Headland O 5 Miles l—le—T'Ll—ll—Q O 5 Kilometers Bayou Lafourche Barrier System on win-E Bayou Lafourche Barrier System LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A I III ‘ “ \I\II"III\ W‘T T ITI I\‘IIIIIIIIIIIIIIWIIfiI ‘I TIMABLIER 5&3? TTI I TIT II I I IT I T‘II‘IIIIIII IIIII‘I‘ ‘ ‘ I I II III” III ‘ ‘II ‘ I ‘ TT _ I T IITTITIIIIIII T III II I II ‘I I WIT IIIII T IIIIIIIIIIII‘IIIIIIIII IIIIIIIII II III I IITTI‘II I T ‘ II \ T TT II TII ‘ T I I T ‘ T II II I TI ‘ l T T I I III‘II‘I VWMIII‘II‘ II IIIIIIIIIIIIIIW T TT TTIITIIIII I TITII IIT IIIIIII I III IIIIIII I II II I 3 III IIIIIII\\III‘III\III“I‘\III " ‘ II‘" I ‘ I ‘ \ ‘ TI IIIIIIIIII \I “III‘III‘I‘IIIIIII‘TIT ‘II'I I III I IIIIIIIII III IIIIIIT IIIT IIII TTII IIIIITITI II T IIIIT III T III I IIIII IIIIIII“ IIIIIII IIIIIIII‘III\II\ III II IIIIIII'IIIIII IIIII‘III‘IIIIIIIII I ‘ \I \\IIIII TTTTTITIIITITIIIIIIII‘I‘I TIIIIIIIII I'II ITTTIITITII III III I ‘ \\T‘T I III II II I I‘ I‘ T\I II ‘ II I T\ ITTII‘II II ‘\ T IHIITIIII ‘T ‘ I II T ‘II I II TT I I I I II I‘ T TI III I I I ‘ IT I ‘ W I I IT T ‘I“ II‘ T II T TIT WI T ‘II‘II\I\I\II ‘ ‘ II I ‘II III‘ “ “ ‘ I . “I. I I “W H I I T T . I MP 0 T I I I .T ‘ I I I I ‘ I 'I ‘ I T T I I‘ ‘I II I I I I T T I T I I“ V I I T I \I ‘ IT I I ‘I‘IA I I I II I\ I III III ' TTTII‘I‘I I T IIIIIIII \‘IIIII‘ I IIIIIIIII‘I IIII TTIITITITIIIIII TTITTIITIIIIIIIIII I IIITIITIIITIIII ITIIIIITTIII III II I ‘ I I I II I I I T I I T III I I IIII‘IIII T TI \‘TI II T‘ ‘ II T I ‘II I ‘T I IIIII I ‘ ‘ I I I II T I II I III “ETTTT TIIII ATTII“ “III II T I“ \ II“ VI“ III TI T IIIIIIII I I ‘II‘I‘II‘IT‘I :‘II‘III III ”II III, I“ I III II IIIIIIIIII“ ‘ II TITIIITITTIT I II ‘ TTII I T ‘I‘I‘IIIIII‘I I IIIIIITIIII IIT‘ TTT ITTIITITIIT‘ ‘ I I III ‘ III III. ‘ ‘ ‘ \x T T ‘ TT “I‘ I \fiTII‘IT‘TITIIIIITIINIIIIT T TITITIII “ 2 MILES I I 3 KILOMETERS 27 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY Bayou Lafourche Barrier System / fi‘m Grand Isle Grand Terre Island 28 5 MiIes 5 Kilometers , ,. Plaquemines Barrier System BARA'ZT’ARJA My mmm , . zmmmamu ‘ . WW' @WD) TERM? [ISLAND ”GRAND 031:3 .1 " u , Bayou Lafourche Barrier System .' Plaquemines Barrier System O———-O LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A 2 MILES | l 3 KILOMETERS 29 US. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY Cheniere Ronquille Shell Island 2» 3O 5 Miles 5 Kilometers Plaquemines Barrier System LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A Plaquemines Barrier System N WW ’ ‘ "f" . szzm MIAMI [ISLAMEID O 1 2 MILES l | | l l l | O 1 2 3 KILOMETERS 31 US. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY ’1’{ Curlew Islands “Breton Island Grand Gosier Islands ‘ O 5 Mlles 0 5 Kllometers Chandeleur Islands 32 Chandeleur Islands Barrier System LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I-2050-A Chandeleur Islands Barrier System 0 1 2 MILES | | I I | | I 0 1 2 3 KILOMETERS US. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY 34 ’\ \/ Freemason Island I .“ Islands . New Harbor\ ‘ ’ .o" Nonh Islands C Chandeleur lslands 5 Miles 5 Kilometers «:3 1:] A [NJ @1 E V' Chandeleur Islands Barrier System WW W lem a 1m. a ““4“ W ,I LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A Chandeleur Islands Barrier System ©m§§s lMeds CWDELEUR SOUND @ressbue 0 1 2 MILES | | | I | I l 0 1 2 3 KILOMETERS Recommended citation for this chapter: Westphal, K. A., and Penland, Shea, 1991, Aerial photographic mosaics of Louisiana's barrier shoreline, in Williams, S. J., Penland, Shea, and Sallenger, A. I-I., Jr., eds, Louisiana barrier island erosion study—atlas of barrier shoreline changes in Louisiana from 1853 to 1989: US. Geological Survey Miscellaneous Investigations Series I—2150-A, p. 24-35. 35 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY Chapter 4 Analysis of Barrier Shoreline Change in Louisiana from 1853 to 1989 by Randolph A. McBride, Shea Penland, Matteson W. Hiland, S. Jeffress Williams, Karen A. Westphal, Bruce E. Jaffe, and Asbury H. Sallenger, Jr. INTRODUCTION Sandy, open-ocean barrier shorelines commonly exhibit rapid move- ment in response to natural and human forces. Unconsolidated beach sediment can respond instantly to winter storms and tropical cyclones (Hayes, 1967; Leatherman and others, 1977; Nummedal and others, 1980; Penland and others, 1980; Sexton and Moslow, 1981; Kahn and Roberts, 1982; Byrnes and Gingerich, 1987; Leatherman, 1987; Roberts and others, 1987; Ritchie and Penland, 1988; Penland and others, 1989a) or gradually to normal wave and current processes and relative sea level fluctuations (Morgan and Larimore, 1957; Penland and Boyd, 198 1; Griffin and Henry, 1983; Morgan and Morgan, 1983; Everts and others, 1983; May and others, 1983; Shabica and others, 1984; Byrnes and others, 1989; Foster and Savage, 1989a, b; Anders and Reed, 1989; McBride and others, 1989a). Access canals, levees, oil and gas activities, seawalls, and jetties are just a few of the human disturbances that have exacerbated the rapid shoreline change problem in Louisiana (Larson and others, 1980; van Beek and Meyer-Arendt, 1982; Davis, 1986; Meyer- Arendt and Davis, 1988; Davis, 1990). Together these factors control the evolution of Louisiana’s barrier shoreline. The Louisiana coastline is extremely low lying (<3 m) and consists of unconsolidated sediment deposited by the Mississippi River during the past 8,000 years (Fisk, 1944; Kolb and Van Lopik, 1966; Frazier, 1967; Coleman, 1988). Louisiana‘s outer coast, which directly borders the Gulf of Mexico, extends from the Texas border at Sabine Pass to the Mississippi border at the mouth of the Pearl River and is approximately 624 km long (fig. 1). If measured around the numerous bays and estuaries, however, the shoreline is about 1,488 km long (Morgan and Larimore, 1957). Located along the Mississippi River delta plain are four barrier systems totalling about 240 km. These systems formed in response to reworking of abandoned deltas and play an integral role in the evolution of Louisiana’s complex deltaic estuarine system (Penland and others, 1988). These fea— tures provide the first line of defense against destructive nearshore pro— cesses that would otherwise directly impact productive estuarine environ— ments in the coastal zone. Each kilometer of barrier shoreline in Louisiana protects approximately 30 km2 of estuarine habitat in the delta plain. Louisiana’s four barrier systems are the Isles Dernieres, Bayou Lafourche (Timbalier and East Timbalier islands, Caminada—Moreau Headland, and Grand Isle), Plaquemines, and Chandeleur Islands (north and south) (fig. 1). The largest proportion of these systems is dominated by barrier islands, as defined by Oertel (1985), with a much smaller proportion characterized by abandoned deltaic headlands. This chapter presents methods and procedures for mapping shoreline change with cartographic data sources and near—vertical aerial photography; accurate maps of shoreline change along barrier systems of Louisiana from 1853 to 1989; and a quantitative compilation of linear, area, and width measurements and their rates of change. In addition, it identifies long—term trends for predicting future coastal change in response to wind, waves, and water level. SHORELINE MAPPING With the implementation of computer processing and computer cartography, shoreline mapping techniques have evolved extensively over the past 10 years. Powerful mapping and geographic information system (GIS) software packages for personal computers and work stations have revolutionized traditional cartographic techniques. However, computers and mapping software are only as good as the data sources utilized. Computer technology enables coastal scientists to produce maps faster and more precisely, but for mapping shoreline change, the most important step is accurately interpreting the high—water shoreline position on aerial photography. An inaccurately delineated shoreline will remain inaccurate regardless of the precision of the computer mapping system. Prior to the use of aerial photography, the high-water shoreline was measured using standard field surveying techniques (Shalowitz, 1964). Much care was taken to ensure accurate measurements representing this boundary, but these data were neither continuous nor synoptic due to time- and labor-intensive collection procedures. Monitoring the high-water—line position from aerial photographs is continuous and regionally synoptic, but interpretation of location is more subjective than direct measurement. Accurate delineation of the land-water interface depends on a thorough understanding of coastal processes and human activities, and their effects on the coastline. Compilation of shoreline change maps involves a variety of techniques and different data sources, which include maps, charts, aerial pho— tographs, and satellite imagery (Karo, 1961; Shalowitz, 1964; Morton, 1977, 1979; Dolan and Hayden, 1978; Dolan and others, 1979, 1980; Leatherman, 1983; Clow and Leatherman, 1984; Shabica and others, 1984; Ritchie and others, 1988; Byrnes and others, 1989; McBride, 1989a, b; Anders and Byrnes, 1991). Differing scales, datums, projec— tions, ellipsoids, and coordinate systems complicate the superimposition of these data. Furthermore, other potential errors are inherent to all shoreline mapping projects (table 1). Recognizing and minimizing these problems ensure more accurate shoreline change data. The following sections discuss the methods, materials, techniques, and sources of error associated with shoreline mapping along the Louisiana barrier shoreline. MATERIALS AND TECHNIQUES Shorelines compiled in this atlas were derived from either topographic or near—vertical aerial surveys conducted between 1853 and 1989 (table 2). The high-water line is used as the official shoreline on cartographic data (Shalowitz, 1964; Anders and Byrnes, 1991) and is interpreted and determined on near-vertical aerial photographs according to the location of the wet— and dry-beach contact or the high-water debris line. Because the upper foreshore represents the landward limit of influence by normal wave and current processes, the high-water line is the most appropriate reference for measuring change in shoreline position (Langfelder and others, 1968). Fortunately, it is also the steepest portion of the foreshore, and a small change in water elevation produces a relatively small horizontal displacement of the shoreline. Several primary data sources were used to establish a shoreline change data base for the barrier systems. Shoreline data compiled prior to 1951 were digitized directly from mylar-based topographic sheets (T—sheets) published by the US. Coast and Geodetic Survey, currently known as the National Ocean Service (NOS) within the National Oceanic and Atmo- TABLE l.——Potential errors associated with shoreline mapping (modified from Anders and Byrnes, 1991) ACCURACY PRECISION Maps and Charts Aerial Photographs scale interpretation of high-water line annotation of high-water line horizontal datum changes location of control points digitizing equipment temporal data consistency media consistency operator consistency shrink/stretch quality of control points surveying standards aircraft tilt and pitch publication standards altitude changes (scale) photogrammetric standards topographic relief projection negatives vs. contact prints datum ellipsoid 91°00' o , 39°30' 89°00’ 88°37'39" , ,, 30°07'30" 90,00 , 30 0730 l ’ North Chandeleur Islands Lake Pontchartrain : , .. .. l 30000! '— 30000, Lake Borgne ‘5' At Lake Salvador ‘ Breton Sound Little South Chandeleur , islands _29 30 f v Plaquemines l Caillou Caminada- 0 Bay Moreau Headland C and Grand Isle \ I 7L I _ Timbalier Islands { 29cm,“ Isles Dernieres ' —29°UU’ SCALE 1:500 000 5 5 10 15 20 25 MILES F l—l l-—-l l—l . - l‘ . l 5 5 10 15 20 25 30 35 KlLOMETERS U L H H r i . i ‘ 41 G l 2805730,, l , l l | 28°52’30” 91°00' 90°30 90°00’ 39°30' 89°00’ 88°37’30” FIGURE 1.—The four barrier island systems along Louisiana’s coastline: lsles Dernieres, Bayou Lafourche (Timbalier and East Timbalier islands, Caminada-Moreau Headland and Grand Isle), Plaquemines, and Chandeleur Islands (north and south). 36 TABLE 2.—Cartographic and aerial photography data sources used in this study. DATE 1853 1887 1 906 1 934 1 956 1 978 1/21/88 1 887 1 934 1956 1978 1/21/88 1 877 1 887 1934 1 956 1978 1/21/88 1 973 1/21/88 1 869 1 922 1951 1978 2/89 1 855 1 922 1951 1978 2/89 MAP NAME MAP NQ. PROJECTION SCALE PHOTOGRAPHY TYPE PHOTOGRAPHERS ISLES DERNIERES T-410 Polyconic 1210,000 H-442 Polyconic 1200.000 T-1691 Polyconic 120,000 T-1762 Polyconic 120,000 T—1763 Polyconic 120,000 T2752 Polyconic 120,000 T—5291 Polyconic 1 20,000 T-5295 Polyconic 120,000 West Derniere T-9878 Polyconic 120,000 Derniere T-9879 Polyconic 120,000 East Derniere T-9880 Polyconic 120,000 Cat Island Pass T-9881 Polyconic 120,000 Western Isles Dernieres 252-0 Polyconic 124,000 Central Isles Dernieres 252-d Polyconic 124,000 Eastern Isles Dernieres 253-0 Polyconic 124,000 Cat Island Pass 253-d Polyconic 124,000 -- 1215,000 9” x 9” Black & white Gulf Coast vertical aerial photography Aerial Mapping, Inc. BAYOU LAFOURCHE Timbalier Islands T-1764 Polyconic 120,000 T-1765 Polyconic 1 20,000 T-5295 Polyconic 120,000 T-5299 Polyconic 120,000 T-5303 Polyconic 120,000 Timbalier Island 254-c Polyconic 124,000 Calumet Island 254-d Polyconic 124,000 Belle Pass 255-c Polyconic 124,000 Timbalier Island 254—c Polyconic 124,000 Ca|umet |s|and 254‘0 Polyconic 124,000 Belle pass 255-c Polyconrc 124,000 -- 1:15,000 9" x 9” Black & white Gulf Coast vertical aerial photography Aerial Mapping, Inc. Caminada-Moreau Headland T-1468a Polyconic 120,000 T-1765 Polyconic 120,000 T-1766 Polyconic 120,000 T-5303 Polyconic 120,000 T-5302 Polyconic 120,000 T-5311 Polyconic 120,000 Leeville 255-a Polyconic 1 224,000 Caminada Pass 255-b Polyconic 124,000 Belle Pass 255-c Polyconic 124,000 Grand Isle 256-a Polyconic 124,000 Barataria Pass 242-0 Polyconic 124,000 Leeville 255-a Polyconic 1:24.000 Caminada Pass 255-b Polyconic 124,000 Belle Pass 255-c Polyconic 124,000 Grand Isle 256-a Lambert Conformal 124,000 Barataria Pass 242—0 Lambert Conformal 124,000 1215,000 9” x 9” Black & white Gulf Coast vertical aerial photography Aerial Mapping, Inc. PLAOUEMINES T 1468a Polyconic 120,000 T-1648 Polyconic 1 30,000 T-1658 Polyconic 120,000 T-5311 Polyconic 120,000 T-5432 Polyconic 120,000 T-5433 Polyconic 120,000 T-5402 Polyconic 120,000 Bay Ronquille 242-d Polyconic 1 24,000 Bastian Bay 241 -c Polyconic 124,000 Buras 241 -d Polyconic 124,000 Bay Coquette 257-b Polyconic 124,000 Pass Tante Phine 258-a Polyconic 124,000 Bay Ronquille 242-d Lambert Conformal 124,000 Bastian Bay 241-c Lambert Conformal 124,000 Buras 241-d Lambert Conformal 124,000 Bay Coquette 257—b Lambert Conformal 124,000 Pass Tante Phine 258—a Lambert Conformal 124,000 115,000 9” x 9” Black & white Gulf Coast vertical aerial photography Aerial Mapping, Inc. CHANDELEUR ISLANDS South Chandeleur Islands T-1092 Polyconic 120,000 T-1097 Polyconic 1 20,000 T—391 9 Polyconic 120,000 T-3920 Polyconic 120,000 T-3985 Polyconic 120,000 H-4223 Polyconic 1280,000 Grand Gosier Island 237—d Polyconic 124,000 Stake Islands 238-a Polyconic 124,000 Breton Island 239-a Polyconic 124,000 124,000 27“ x 27" Color infrared National Aeronautics & vertical aerial photography Space Administration (NASA) - 124,000 27" x 27" Color infrared ASA vertical aerial photography North Chandeleur Islands T-548 Polyconic 120,000 T—549 Polyconic 120,000 T-3917 Polyconic 120,000 T-3918 Polyconic 120,000 T-3919 Polyconic 120,000 T-3985 Polyconic 120,000 Chandeleur Light 195-d Lambert Conformal 1 24,000 North Islands 196-b Polyconic 124,000 Freemason Islands 196—c Polyconic 124,000 New Harbor Islands 196- Polyconic 124,000 124,000 27” x 27" Color infrared NASA vertical aerial photography — 124,000 27" x 27” Color infrared NASA vertical aerial photography spheric Administration (NOAA). Cartographic shorelines between 1951 and 1978 were recorded from NOS T—sheets and US. Geological Survey (USGS) 7 5-minute quadrangle maps. Aerial photography, dated January 1988 and taken at a scale of 1:15,000, was used to construct a shoreline west of the mouth of the Mississippi River from Raccoon Point to Sandy Point. To the east, the 1978 and 1989 Chandeleur Islands shorelines were compiled using National Aeronautic and Space Administration (NASA) high—altitude photography enlarged to scales of 1 :33,000 and 1 :24,000, respectively. Although aerial photography shorelines can be registered in several ways (Leatherman, 1 983), shoreline position for the delta plain was registered to USGS 75-minute quadrangle maps using a Bausch and Lomb Zoom Transfer Scope. These data together with cartographic shorelines were digitized by Intergraph’s VAX—based Interactive Graphics Design System (IGDS) or work station—based MicroStation software (Wright, 1989, 1990a, b) at a 1:1 scale according to original projection, ellipsoid, and North American Datums (NAD) (fig. 2). Intergraph’s World Mapping System (WMS) software can generate 21 map projections or coordinate systems; reference 20 ellipsoid types; convert coordinate systems, datums (NAD 27 and NAD 83 [Morgan, 1987; Wade, 1986; Shalowitz, 1964]), and associated data; and perform area, distance, and perimeter calculations. WMS software generates a latitude-longitude grid, or graticule, based on the same cartographic parameters as the map being digitized (Intergraph Corporation, 1987). This graticule is mathematically correct and free of any distortion that may be present on printed maps. At least four well- spaced primary control points on the map are registered to equivalent points on the graticule to provide a best fit between the map and the independently generated graticule. Maps digitized for this study are characterized by either Polyconic or Lambert Conformal projections (see Synder, 1987). Using WMS software, shoreline data for each year were converted to a common projection (Polyconic), coordinate system (lati— tude-longitude), datum (NAD 27), and ellipsoid (Clarke 1866) and su- perimposed for analysis (McBride, 1989a, b). Shoreline data were then converted to Universal Transverse Mercator (UTM) projection (Zones 15 and 16) for atlas production. SHORELINE CHANGE MAPPING STRATEGY DATA SOURCE DATA REVIEW DATA RENDERING DATA CAPTURE AERIAL PHOTOGRAPHY ZOOM TRANSFER SCOPE DIGITIZATION INTERPRET HIGH \ UGDSANB MS) L WATER LINE GEE-1%?JE: ’ CARTOGRAPHIC DATA T AND ERROR A HY (e.g., NOS T—SHEETS) > DA ACHECKING > (WMS OR PM) DIFFERENT CARTOGRAPHIC PARAMETERS PROJECTIONS V COORDINATE SYSTEMS DATA OVERLAY AND DATA RESULT END PRODUCT ANALYSIS TRANSFORMATION ACCURATE COMPUTATIONAL TRANSECT CONSTRUCTION COMMON SHORELINE SHORELINE CHANGE AND 4 CARTOGRAPHIC 4 CHANGE DATABASE SHORELINE CHANGE ‘ PARAMETERS ‘ DATA MEASUREMENT (WMS OR PM) COMPOSITE MAP OUTPUT DIGITAL & HARD COPY FIGURE 2.—Shoreline change mapping procedures and strategy at the Louisiana Geological Survey. To evaluate change in shoreline position, shore—normal transects were constructed at approximately 15-second intervals of longitude or latitude, depending on shoreline orientation. Isles Dernieres, Bayou Lafourche, and Plaquemines barrier systems (east-west shorelines) were analyzed using 15—second (about 404 m) intervals of longitude, while the Chandeleur Islands (north-south shorelines) were examined using 15-second (about 462 m) intervals of latitude. Also, information is provided about the location of transects near entrance areas (for example, tidal inlets, distributaries, etc.). Measurements of shoreline movement and change in island width were taken along transects perpendicular to the composite shoreline trend (fig. 3). A plus sign indicates progradation while a minus sign indicates recession (fig. 4). Average rates of movement and area change were calculated by dividing absolute measurements by elapsed time (year, month, and day—where available). For this study, shoreline change maps were produced to determine the spatial and temporal distribution of shoreline movement (magnitude, direction, and rate of change) and document geomorphologic evolution. SOURCES OF ERROR Errors are inherent to the compilation and analysis Of shoreline change maps and occur from 1) interpretation of the shoreline position, 2) resolution of source material, and 3) precision of digitizing equipment. Superimposing cartographic data and near—vertical aerial photography can cause large potential errors as a result of the different techniques used to delineate shoreline position. On early historical NOS T—sheets, the high- water line was mapped to within 10 m horizontally, but in many cases, these measurements were probably more accurate (Shalowitz, 1964). On aerial photography, the high—water line is determined by interpreting the wet- and dry-beach contact or the high—water debris line. This boundary will vary throughout the year depending on tide cycle, beach slope, sediment supply, wind direction, wave conditions, and human activities (Stafford, 1971; Morton, 1977). An aerial survey of an eroding shoreline could depict accretion simply from changes in wind direction at the time of the survey. Normal wind shifts can depress or elevate the water surface in several hours and cause the water line to move horizontally tens of meters. Therefore, to develop realistic cause-and-effect relationships, it is im- portant to understand the impact Of local processes on system response. Interpretation of shoreline position along the bay side poses some additional difficulties. Because emergent vegetation is mapped as land regardless Of actual water depth, a minimum density and size of individual stands of vegetation must be established and mapped consistently. There— fore, delineating the shoreline becomes subjective without extensive ground truthing when a mixture of vegetation, sand, and water exists, or when the water line is hidden by lush vegetation. Aerial video surveys, however, can provide an alternative to ground truthing (Penland and others, 1988, 1989b; McBride and others, 1989b). This low-Oblique color footage is taken at about 70 m and is viewed during air photo interpretation to aid in determining coastal habitats and delineating the high—water line along the gulf and bay sides. Although ground truthing is time consuming and expensive, it should be conducted in conjunction with any overflight. Pen—line width is another source of error during air photo interpreta- tion. A typical pen width of 0.25 mm results in a potential error of 2.5 m at 1: 10,000 scale, 6.0 m at 1:24,000 scale, or 16.3 m at 1:65,000 scale. A pen line 0.18 mm wide was used on the 1978 photography (133,000 scale) for the Chandeleur Islands, a potential error of 5.9 m. This is comparable to the potential error of 6.0 m on the 1989 photography (1:24,000 scale). In this study, a photo interpreter centered the pen line along the wetted boundary to delineate its position and subsequently digitized along the center of the pen line. The digitizer is precise and accurate to within 0.1 mm, a potential error Of 2.4 m at a scale of 1 : 24,000. Errors associated with the digitizing equipment are amplified by operator error. Loss of control points along a rapidly changing coastline also impedes accurately mapping shoreline change. Potential errors have been mini— mized by overlaying many different controlled shoreline data sources and by field checking when no other method was satisfactory. A controlled survey for the Chandeleur Islands was completed in 1951; however, considerable erosion and landward barrier island migration have occurred since then as a result of Hurricanes Betsy (1965), Camille (1969), Frederic (1979), Elena (1985), Juan (1985), and Florence (1988). These events removed all but a few control points along the southern half of the barrier chain (Penland and others, 1989b; McBride and others, 1989b). Grand Gosier, for example, has migrated about 1 km west since 1951. The 1978 and 1989 Chandeleur shorelines were constructed from NASA high-altitude, color—infrared aerial photography and interpreted at 1 :33,000 and 1 :24,000 scales, respectively. Because a limited number of control points were available, the Zoom Transfer Scope could not be used. Therefore, photomosaics of the 1978 and 1989 shorelines were con— structed and photographically scaled. To minimize error, the two shore— lines were overlaid with the most recent topographic maps, using the few available control points. Large oil platforms, visible on both sets of photographs, were used as additional control points. These positions were registered on 75-minute quadrangle maps by latitude and longitude acquired in the field using a Loran—C navigation system, calibrated to known points in the study area. The largest margin of mapping error along the Louisiana shoreline is found where lack of control points is common from the southern portion of Chandeleur Island to Breton Island. In these isolated areas of minimal control, shoreline position may be in error by as much as 50 m. Cartographic data sources for this study were digitized using a graticule digitizer setup. Intergraph mapping software provides an error calculation associated with the digitizer setup. The average error and maximum error of the digitizer setup are expressed as percentages. This represents the difference among control points placed on the digitizer table (map) using the cursor and corresponding points located in the graphics file coordinate system (latitude—longitude). If the coordinate system in the graphics file is identical to the coordinate system on the map, error is negligible. Larger setup errors can occur for a number of other reasons, including shrink and swell Of the original map (older mylar T-sheets are actually copies of original paper maps on a stable base); errors in plotted positions on the map; and errors in point placement during digitizer setup. For an Intergraph digitizer setup, a 0.0 1 percent error corresponds to 1 m of displacement in a distance of 10,000 m on the ground. Because NOS T—sheets are generally no larger than 1.2 m, a maximum distance of approximately 12,000 m is covered by a map at 1:10,000 scale. Thus, a 0.01 percent digitizer setup error would give a maximum error of 1.2 m on a 1:10,000 scale map. This error, however, will decrease with proximity to digitizer setup points, thus assuring that setup errors will be considerably less than this maximum. Digitizing errors associated with NOS T-sheets will be within National Map Accuracy standards (5 m at 1:10,000) (Ellis, 1978). In contrast, USGS 75—minute quadrangle maps measure approximately 20" X 23” (0.5 m X 0.6 m), and a maximum distance of approximately 14,400 m is covered by a map at 124,000 scale. Thus, a 0.01 percent digitizer setup error would give a maximum error of 1.44 m on a 124,000 scale map, and digitizing errors would be within National Map Accuracy standards (12.2 m at 124,000) for the location of the shoreline on USGS 75—minute quadrangle maps (Ellis, 1978). Although errors in map construction cannot be completely re— 2949' 2948' LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES moved, they can be quantified and minimized during this digitizer setup. A combined error of 0.01 percent (approximately 1 m of displacement at a 1:10,000 scale) or less is usually attained for NAD 27 maps. Errors of greater than 0.03 percent (about 3 m) are unacceptable on NAD 27 maps. For North American datum maps, setup errors of greater than 0.05 percent (about 5 m) are not allowed, and the criterion for pre—North American datum maps is no greater than 0.07 percent setup error (about 7 m). The majority of maps used have a digitizer setup error of 0.04 percent (about 4 m) or less. Other potential errors associated with factors listed in table 1 have been addressed in detail by Morton (1977, 1979), Tanner (1978), Anders and Leatherman (1982), and Anders and Byrnes (1991). These include photogrammetry problems, surveying standards, temporal data consis— tency, natural and human impacts of coastal processes, and others. These errors can be minimized by making sensible decisions about data sources (comparing data sources that are seasonally consistent) and interpretation techniques (using the center 2 inches of the photo and annotating with small pen line width). Because total potential error is a result of time—independent variables (data source, measurement technique, interpretation of high-water line, etc.) and the magnitude Of change is a time-dependent (1887 vs. 1934), long—term rates of shoreline movement will have the lowest rate of potential error, and short—term rates will have the highest. The maximum potential error for this study was $52 m, when quantifying the difference between shorelines, but one shoreline will have a potential error of $26 m. Root mean square of this value is i 13 m (see Merchant, 1987 for discussion of root mean square). The maximum value includes error associated with shoreline placement, line width, digitizer setup, operator inconsistencies, and equipment. Therefore, the maximum rate of potential error for long- term rates (>100 years) is i0.4 to i0.5 m/yr; short—term rates (10 to 15 years) are accurate to within i3.4 to i5.1 m/yr. Finally, shorelines published in this atlas are drafted representations of the original digital shorelines used for quantitative measurements. They have been subjected to the printing process, which involves hand scribing at a scale of 1: 100,000. They contain no gross errors, but these representations cannot approach the accuracy of the original computer— generated shorelines mapped at larger scale. 8851’ 8850' , . .. , . BAY SIDE 0 1000 2000 Feet I——-—F.J—~T——fi 0 200 600 Meters 8851’ 8850' 1855 - 1989 - 28 = Gulfside or Bayside Transect Numbers I—2150—A FIGURE 3.—Shore-normal transects used to measure linear distances between shoreline po- sitions. Transects were placed at 15-second intervals of latitude or longitude along the gulf and bay sides. CHANDELEUR SOUND Redilsh Point Bayside Shoreline Bayside Shoreline Movement Directions Gulfside Shoreline Chandeleur Island (1') Guliside Shoreline Movement Directions GULF OF MEXICO FIGURE 4.—-Explanation of shoreline retreat or advance along the bay or gulf side. 37 US. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY 90”?)9’ Isles Dernieres Barrier System—1853 to 1988 , Isles Dernieres is located about 100 km west of the mouth of the Mississippi River and about 120 km southwest of New Orleans (fig. 1). The island arc is 36 km long and extends from Raccoon Point to Wine Island Shoal (chapter 1, fig. 1 7). Tidal inlet development has fragmented the Isles Dernieres into an arc comprising five smaller islands: Raccoon, Whiskey, Trinity, and East islands and Wine Island Shoal. These islands range from 0.25 to 2 km wide and are separated by five tidal inlets: Coupe Colin, Whiskey Pass, Coupe Carmen, Coupe Juan, and Wine Island Pass. The inlets range from 0.3 to 6.0 km wide and are 2 to 16 m deep. The barrier shoreline is undergoing rapid geomorphologic change and severe coastal erosion (Peyronnin, 1962; Kwon, 1969; Neese, 1982; Penland and others, 1985, 1989a; McBride and others, 1989a; Ritchie and others, 1989; Dingler and Reiss, 1990). Maps presented in this section show morphologic changes along the Isles Dernieres for the years 1853, 1887, 1906, 1934, 1956, 1978, and 1988. All maps referenced in the text are labelled by date. Although the 1853 shoreline represents a reconnaissance of the area surveyed by the US. Coast and Geodetic Survey at a scale of 1 : 200,000, the map provides important morphologic information. This source of information, however, was not used for quantitative purposes. The gulf side was surveyed in 1 887, and the remaining bay side was finished in 1906. Because these surveys were incomplete, the 1887 and 1906 shorelines were combined and are referred to as the 1890’s shoreline. Linear, area, and width measurements were obtained, and rates of change were calculated to determine the extent of modification for the 134-year period. BARRIER SYSTEM MORPHOLOGY Isles Dernieres experienced significant erosion and fragmentation between 1853 and 1988. In 1853, the barrier island arc was a continuous shoreline except for Wine Island, which was located to the east of Wine Island Pass (1853 map). By 1887, an unnamed tidal inlet had developed 90°55’ 29°07’ 29°05’ ‘ Raccoon Point 1853 29°Ul’ l | I along the island’s west central portion. Meanwhile, submergence enlarged Lake Pelto to result in marsh deterioration (18905 map). By 1934, Whiskey Pass had formed in the center portion of Isles Dernieres, possibly in response to major hurricanes that struck the Louisiana coast in 1909, 1915, and 1926 (1934 map) (Neumann and others, 1985). Between 1934 and 1956, Coupe Colin developed to the west of the unnamed tidal inlet (1 956 map). Continued widening of existing tidal inlets and further deterioration of the interior marsh caused significant land loss and landscape change. As a result of Hurricane Carmen, Coupe Carmen formed on the eastern portion of the arc (1978 map). Along the western Isles Dernieres, the land area between Coupe Colin and the unnamed inlet became subaqueous, and most of Wine Island had become a shallow sandy shoal. The inlet referred to as Coupe Juan emerged when Hurricane Juan (1985) breached Isles Dernieres east of Coupe Carmen. By 1988, the once continuous barrier island had deteriorated into five narrow barrier islands separated by wide tidal inlets (1988 map). SHORELINE MOVEMENT The Isles Dernieres shoreline is one of the most rapidly deteriorating barrier shorelines in the United States. A comparison of shoreline positions is made for five periods: 1890’s vs. 1934, 1934 vs. 1956, 1956 vs. 1978, 1978 vs. 1988, and 1890’s vs. 1988. The magnitude of change, island width, and rate of change were obtained from 184 shore-normal transects at approximately 15-second intervals of longitude along both the gulf and bay shorelines (transects map, tables 3, 4, 5, 6, and 7). The average rate of bayside change was 0.8 m/yr between 1906 and 1934, while the average gulfside rate of change for Isles Dernieres between 1887 and 1934 was —11.7m/yr (tables 5 and 7). The gulfside rate decreased to -7.8 m/yr between 1934 and 1956, and the gulf and bay shorelines remained relatively constant through 1978. The gulfside rate, however, increased to -19.2 m/yr between 1978 and 1988, and the rate 0 Historic Shorelines 0 90°45’ of bay shoreline retreat increased to 5.2 m/yr, presumably in response to repeated hurricane impacts in 1985 (figs. 5 and 6) (see Penland and others, 1989a). The 1890’s vs. 1988 map illustrates land loss and summarizes cumulative quantitative changes along the gulf and bay shorelines. The gulf shoreline retreated between 1887 and 1988, except for the eastern end of East Island, and movement ranged from 3.4 to -23.2 m/yr to produce an average rate of —1 1.1 m/yr (table 7). Between 1906 and 1988, the rate of bay shoreline change ranged from 23.5 to -4.9 m/yr, with an average retreat rate of —O.6 m/yr (table 5). As a result, the gulf and bay shorelines are converging. AREA AND WIDTH CHANGE Changes in island area are a function of length and width adjustments in the barrier system. For the 18905 map, island width along the barrier arc ranged between 52 and 3,203 m (table 6). In general, the barrier island arc was narrower at both ends and widest in the middle, with an average width of 1,171 m. The average rate of land loss between the 1890’s and 1934 was 35.8 ha/yr (table 8). By 1934, the complex had narrowed to 8 15 m wide. Slow but steady deterioration of the system continued through 1978 when its average width decreased to 585 m. The average rate of land loss decreased to a low of 9.8 ha/ yr between 1956 and 1978. Island width decreased dramatically between 1978 and 1988 to result in an average width of 375 m and an increase in land loss to 47.2 ha/yr (fig. 7). This period of high rate of area loss included Hurricanes Danny and Juan in 1985. Erosion of the gulf and bay shorelines is causing the island to narrow. From the 1890’s to 1988, the barrier width decreased 796 m (figs. 8 and 9). This represents an average narrowing rate of 8.6 m/yr for approxi— mately the last century. Similarly, the area of Isles Dernieres decreased continuously from 3,532 ha in the 1890’s to 771 ha in 1988 (fig. 10). This is a land loss of 78 percent or 2,761 ha at an average rate of 28.2 ha/yr (table 8). 90°40’ 90°30’ 29°07’ — 29°05’ 29°Ul’ 90°59’ 38 90055, 90050! I 90°45’ I I 90°40’ 90°35’ 90°30’ LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A Isles Dernieres 90°59I o I o I 0 I o I 0 I 90°30, 29°07, 90 I55 90 50 90 45 ' 90‘40 90135 29007, %I ‘sz M I \ TERREBONNE BAY ’ A. C A ' Pelican Lake . / ~ " 7 Co; a (9/ I ( L 000'!) 0615‘ _ o I 29°05'- ( L T O WINE ISLAND . 29 05 0 Bay P E ‘ 0 Round ’ E . £806. V L A K ' x " (’42,) 020 ‘3’ M om CaiIlou Soon «7 P c O I RACCOON I E )4 ISLAND M TRINITY ISLAND S R E F ’ E R N E G U L F O 1890 s ’ S L E s D o I I I l I I o I 29 9310059! 90°55' 90050' 90°45’ 90°40' 90°35’ 900933 01 SCALE 1:100 000 EL H H 1 2 ? A W'LES 1H H F9 2 3 4 5 6 4 KILOMETERS o I o , o I o I o I o I 90030, 29009;], 59 90155 90 50 90 45 ${40 9035 29007, 7) I a)“ TERREBONNE BAY O K c; ‘ I C 4 .I/ I 66¢ / z . T O 9‘3» 29°05, — z E L WINE ISLAND mm _ 29009 O P 0 ’08, we ’20:?) “$232?" TRINITY . “iv RACCOON ISLAND C O \ WHISKEY ISLAND E w ‘ ‘39 \ u-n. /§§ E S E R F I R N \ O 1934 S L E S D E G u L F o I l o I 29 0910059, 90°|55' 900150: 90045: 900‘40’ 900235I 900% m 39 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY Isles Dernieres 90059’ o I o I o I o I O I 90030, 29007, 90155 90 50 90 45 9,040 9035 29007, ‘K I ‘ T E R R E B O N N E B A Y C 4 / £ Q» z WINE ISLAND ‘) > {fly 29°00 ~ 0 x 02% — 2005' 0 5‘6 9:, I20, *9 ’3 95 R $31.13“ 0 RACCOON I C ISLAND )K 00““ M E “w v, 0* F I . WHISKEY ISLAND O 1956 3L ES D E“ N‘ o I I | I I I o I 29 0910059: 90°55' 90°50 90°45' 90°40 90°30 9003209, 01 SCALE 1:100 000 1 0 1 2 3 4 5 MILES I—I I-—I I—I . - I———I I 11—1 H ._([) I 2 L 4 5 6 fl7 KILOMETERS 90°50 o , , , o , 90 55 90°50 90°40 90°40 o , 90°30 23 07 I a O. r j | 90135 29007! a 0 ~ ‘fi ' fi‘ 04 t ‘ r TERREBONNE BAY / . V PeIIcanLake v ‘ ( ’ I C‘ { :O %* ‘J ' f % WINE ISLAND 7 0’66 /' é 29005, ‘— 0 ‘ O ’bsé/ 01% __ 29005, 0,) “Jr 657 9% Rgcgoon A EAST ISLAND omt _ v 0 RACCOON ISLAND CaIIIou Boca 1 C \3 WH 7K 00““ ISKEY ISLAND (a) M E we V \e F 0° 0 1 978 I S L E G U L 29°00 I I I I I o , 90°59’ 90°55’ 90°50 90°40 90°40 90°30 9003209, 01 40 Isles Dernieres LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A 2905701059, 90055' 90°50 90°49 90°40' 90°35 gooazglonr I 7V ’ r I w | I 0- it. '3 " ‘ v ‘ n “" "‘ I. s , 3’11. ‘ TERREBONNE BAY C A f L r Pelican Lake I L i O ‘ i VWINEISLAND 0’! 0 l t ’ ’, A K E P E L T O wébo» 29005' ~ 3 L Wine ’%¢~ — 29°05’ 3/0” ‘5’ ’7 P Bay d Q, Round ‘F EAST ISLAND O Raccoon t, C230 C Point 090 (23¢ \ \ C . ‘ Q)‘ 6 RACCOON “II/011 Boca 5‘ $9”? ’6'? . 7k ISLAND WHISKEY a, TRINITY ISLAND °¢ E Cy . ISLAND Q09 IA I2; N O 03‘ ’ 63 AI“ 0 I “SS 3 O ‘2 S E o I I I I I I 29°01’ 29 0910059 90°59 90°50’ 90°49 90°40' 90°39 90°30' Average Rate (m/yr) Average Rate (m/yr) Area Change Rate (ha/yr) Average Width (m) z 1 o 1400*77 7**7 7*77 77777 7777* **~77**7~* o /\ 1200I~7* **7 77777 7 7*77 * * -* *7 7 7* \ —10 ‘ \ -5 B\ —1 \ \ 1000 i' \ ‘,¥ —\ _2 \ -20 / \ 80055 577777 N H I -10 / —3 \ _30 / 600 _15 -4 \ 400 -40 -5 I, \ 200 _20 I I I I _6 I I I I _50 | l I | O I I I 1875 1900 1925 1950 1975 2000 1875 1900 1925 1950 1975 2000 1875 1900 1925 1950 1975 2000 1850 1875 1900 1925 1950 1975 2000 Year Year Year Year FIGURE 5.—-Average gulfside rate of change along Isles Der- nieres between 1887 and 1988. FIGURE 6.—Average bayside rate of change along Isles Der- nieres between 1906 and 1988. FIGURE 7.—Rate of area change for Isles Dernieres between the 1890’s and 1988. FIGURE 8.—Average barrier width of Isles Dernieres between the 1890’s and 1988. 41 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY Isles Dernieres 0 Shoreline Change and Land Loss 0 90°59' 90°55! 90°49 90°40 90°39 90°30' 2907' I I I 2907' . W1 . . C / , TERREBONNE BAY 4 w j ' Pelican Lake \ .‘ ' z z 7/ 62),! % 29°05' — O I lgLIAIIVIED 00.9? —— 29009 O ’ - 99 $6.47 9»; R 63 ‘73 O 333?” 9 C ISLAND )K I ISLAND M E S O R E F 1890’ 1934 I R N ‘ E G U L 5 VS. 8 L E s D E o I I I | | I o I %10°59' 90°59 90°50' 90°45’ 90°40 90°39 90023IJ'U1 1890’s 1934 SCALE 1:100 000 I—l +—-« H I 2 3: 4 SMILES 1H H A) 1 2 3 4 5 6 I7 KILOMETERS 90°59 o , o , o , 90°30, 29007, 90:55 90 40 90135 29007, CA TERREBONNE BAY / z CO] { WINE ISLAND 9 4% ”0’ 29°09 — (<5?th — 29°09 0"? J {p 6,)? Raccoon «gm Point *9 C O RACCOON % I ISLAND E \ F 1934 1956 o E R N G U L VS. 8 L E s 0 I I I I l 0 I 29 [90°59 90°59 90°50’ 9045’ 90040' 90l°35' 9035901 1934 1956 42 Isles Dernieres LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A 90°59 o , o I o I o I o I 90°30' 29007, 90.55 P ‘ .- . 90 50 ‘ go 45 7' $0140 90135 29007, c ‘ ' V ‘ J ' "J 9 4, TERREBONNE BAY z ’ PelicanLake ‘ z ' o ‘ I " . C5, 0 I T O a WINE ISLAND 4‘4; ’2 29°05' — ‘ L @275. we; — may {9/ “Cr 65 Bay P E 0’29, 7 Round" L A K E 0% EAST Raccoon A w ISLAND C 0 Point I RACCOON IS CaI-IIou 30m - E X I , _ LAND WHISKEY ISLAND M , goes F s F R E l S L E s D E R N ‘ E G U L 1956 vs. 1978 o I | I I I I o I 29 0910059, 90°55' 90°50' 90°45' 90°40 90°35! 90053,“ 1956 1978 l Land Loss 900591 0 , o , o I o I 0 I 90030, 29007, 90 I55 v 90 50 970 I40 90 t35 29007, “3‘ C TERREBONNE BAY 4 ‘ f i p a. 001/ K F O VWINEISLAND 9 “"650, 29°05' — O T 5% 9% — norm 0 L 6/0 E P ”°’«o L A K 953, R <9 1°52?“ & 1 C O RACCOON '7 TRINITY ISLAND X O‘SQEIQéS‘ F , Q I U L F 1978 vs. 1988 G o I l I I I I o I' 29 0910059, 90°55 90°50' 90°49 90°40' 90°35' 900%?)[01 1978 1988 43 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY Isles Dernieres 4847 48 49 50 5T 52 53 54 55 5B 57 58 59 60 BI 52 B3 B4 65 66 B7 7071 72 73 74 75 7B 77 79 84 85 88 IRANSECTNUMBEH 4 5 3 7 3 3 10 11 1213 30 3132 33 34 35 33 37 33 33 40 41 30 2000 T 25 g _ 20 Lu (3 Z < — 15 I E 1000 o E 10 LU D g —— 5 Z ‘3 E 0 0 3 —'F'- D (7) , —5 >— < CD 7 -10 —1000 — -15 2900979059, 90°55’ 90°40 90035 3003205007, I .r I . w ‘- CA /\ ‘ 1"” TERREBONNE BAY I ' Pelican Lake Z A i a“ O VWINE ISLAND («‘54 o l {53/ 29 05 _ 0 9,? _29305, . Q’ A <9 0% 4, V (7 ISLAND 3% Raccoon 0 Point 6“" 1 C O RACCOON ISLAND 1 890’ 1 988 G u L 5 V5. 29001' g , I , I ' , I 29°UI’ 900594 90 55 30°50 30°45' 90°40 90°35’ 30°30 1890’s SCALE 1:100 000 1 0 1 5 MILES 1 O 1 2 3 4 5 6 7 KILOMETERS 1—1 1—1 1—1 fi 1—4 H I—I I— I I é. I 1988 134033010011333 3 4 5 3 7 3 3 10 11 23 27 23 23 30 31 32 33 34 35 33 37 33 33 40 41 43 4743 43 50 51 52 53 54 55 53 57 53 53 30 31 32 33 34 35 33 37 33 70 71 72 73 74 75 73 77 73 73 33 33 _2000 — _20 E — —15 LU <3 Z < —1000 _10 I U U. 0 Lu —5 D D I: Z (9 O 0 < 2 Lu 9 5 U) Ll. _I D o 1000 _ 1O _ 15 2000 44 BAYSIDE RATE OF CHANGE (m/yr) GULFSIDE RATE OF CHANGE (m/yr) SHORELINE 1 SHORELINE , I ADVANCE RETREAT ‘ SHORELINE ADVANCE I ( SHORELINE RETREAT LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A l D ’ Is es ermeres TABLE 3. —lsles Dernrares baysrde magnitude of change (meters) Transact# 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 Transact coordinate 90° 57' 45” 30" 15" 90° 57' 00" 45" 30" 15" 90° 56‘ 00" 45" 30" 15" 90° 55' oo" 45" 30" 15" 90° 54' 00" 45" so” 15" 90° 53' oo" 45" 30" 15" 90° 52' oo" 45" 30" 15" 90° 51' oo" 45" 30" 15" 90° 50' 00" 45" so" 15" 90° 49' 00" 45" 30" 15" 90° 48' oo" 45" so" 15" 90° 47' 00" 45" so" 15" 90° 4600” Y 1906—1934 n.a. n.a. -142 -172 -86 —186 —45 —2 —42 —110 —4 -59 -1o 6 n.a. n.a. n.a. n.a. n.a. n.a. 314 181 683 722 614 836 804 672 696 —115 —43 —74 —218 —284 -65 —58 —86 —63 —82 -96 —41 —61 -27 —39 n.a. -752 —90 —25 6 1934-1956 —86 -67 -48 —74 —11 -18 —215 -64 -12 —82 -30 -29 -42 n.a. n.a. n.a. n.a. n.a. n.a. n.a. 107 73 21 428 n.a. n.a. n.a. n.a. n.a. —6 —35 —24 2 207 4 ~23 -43 —34 -19 -71 32 —94 —26 -48 n.a. 525 -33 —73 3 1956-1978 145 -95 -137 —111 _199 -165 185 -68 —10 -4 —6 -14 4 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 255 n.a. n.a. n.a. n.a. n.a —10 —7 —7 -8 147 —8 —6 —4 4 —9 -11 —97 —39 —46 n.a. n.a. 159 —15 —3 r 1978-1988 223 314 M. 257 89 20 ~219 -6 -148 —42 —58 —61 -127 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 434 261 228 326 —65 —83 —55 108 219 -27 —65 —44 —75 -94 —190 -20 n.a n.a. n.a. n.a. 20 -136 -172 3 1906-1988 n.a. n.a. n.a. —100 —207 -349 —294 —140 —212 -238 —98 —163 —175 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 1879 1606 1303 1519 -196 468 —160 —116 289 —96 —152 -177 ~168 —204 —368 —126 n.a. n.a n.a. n.a. -48 —274 —273 Transact# 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 7O 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 Transact coordinate 45" 30" 15" 90° 45' 00" 45" 30” 15" 90° 44' 00" 45" 30" 15" 90° 43‘ oo" 45" 30" 15" 90° 42' 00" 45" 30" 15" 90° 41' 00" 45" 30" 15" 90° 40' 00" 45" 30" 15" 90° 39' oo" 45" 30" 15" 90° 38‘ 00" 45" 30" 15" 90° 37' 00" 45" so" 15" 90° 36' 00" 45” 30" 15" 90° 35' 00" Y 1906 - 1934 -85 -26 —26 -32 —33 —35 -45 —52 —37 —35 —20 -28 -71 —35 -26 -24 -41 —53 —49 -56 -47 —29 -57 —98 —80 —97 -93 —153 -401 na. —641 n.a. n.a. 74 74 112 186 227 469 389 689 753 948 n.a. a 1934 — 1956 —72 10 -6 -74 —4o —35 -29 3 -24 -27 —1o —24 —26 —57 —54 —54 -70 -46 —50 —57 —34 —35 —64 -53 —54 -55 ~58 —89 322 162 251 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. a 1956 - 1978 -73 —12 -27 —24 11 11 16 —8 —4 -5 —5 -3 —4 —3 21 9 22 n.a. 354 288 8 17 —9 17 29 22 29 234 37 57 -6 —12 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. r 1978- 1988 -149 —124 —201 —187 -73 —63 —48 —58 -168 -110 —243 -99 -114 —166 —21 -61 384 n.a. 33 n.a n.a —44 —161 —148 —242 —107 —66 —51 —53 -99 —3 1 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. S 1906 - 1988 -379 -152 —260 —317 —135 -122 —106 —115 —233 —177 —278 —154 —215 -261 —80 -130 295 324 288 n.a n.a —91 —291 —282 -347 —237 —188 —59 —95 n.a. -399 n.a. n.a. n.a. n.a. 1745 1838 n.a. n.a. 1931 n.a. n.a. n.a. n.a. Isles Dem/eras baysrde summary Years Sum Avg STD Total Range Count 1906 — 1934 -1655 —23.6 237.0 948 —752 70 1934 - 1956 -986 —15.9 104.1 525 -215 62 1956 - 1978 502 8.2 92.3 354 -199 61 1978 — 1988 -2878 -51.4 128.1 384 —243 56 1906 — 1988 —2894 —51.7 474.9 1931 -399 56 90059, O l o I 900 , 90035, 900301 29007, 90155 90 50 40 1 29007, I l Pelican Lake é C2,?! 0 0 “'5, ' 0' 29°05’ ~ ‘3‘,“ ~ 29°05’ «3 m Raccoon Point .1 3 4 RACCOON ISLAND ‘ " . 5 6 7 8 9 O 1 IO" C .7 ,8 1 1 4 49 G U L I ransects '9 20 2' 22232425 262728 29303132333435363733 3, 40 4. 42434 47 48 29°01, l I 1 I | 29001! 90059, 90°55’ 90°50’ 90°45’ 90°40’ 90°35’ 90°30! Gulfside Transects Bayside Transccts TABLE 4. ——ls/es Darn/eras gulfsrde magnitude of change (meters) Transact# . 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 4O 41 42 43 44 45 46 47 48 Transact coordinate 90° 57' 45" 30” 15" 90° 57' 00" 45" 30" 15” 90° 56’ 00" 45" 30" 15" 90° 55' 00" 45" 30" 15" 90° 54' 00" 45" so" 15" 90° 53' oo" 45" so" 15" 90° 52' 00" 45" 30" 15" 90° 51' 00" 45" 30" 15" 90° 50' 00" 45" 30" 15" 90° 49' 00" 45" 30" 15" 90° 48' oo" 45" 30" 15" 90° 47' 00" 45" 30" 15" 90° 46’ 00" Y 1887-1934 n.a. 433 215 6‘5 —72 —218 —370 —499 -585 —687 —732 -764 —843 n.a. n.a. n.a. n.a. n.a. n.a. n.a. —816 —745 -805 n.a. —630 —676 —692 -735 —812 —1299 —655 —674 —723 —578 -584 —552 —575 —643 n.a. n.a. —948 —1080 4280 n.a. n.a. -657 —600 -558 6 1934-1956 -30 -95 -184 -226 -250 -215 '152 -108 -42 -7 23 -7 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. -254 —424 —443 n.a. n.a. n.a. n.a. n.a. n.a. -61 -322 -339 —228 -510 —299 —267 —306 —203 n.a. n.a. -339 —418 -438 n.a. n.a. -380 -278 —221 a 1956—1978 -140 -65 -97 -94 -94 -111 -105 -140 -147 —150 —144 —316 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. ~321 n.a. n.a. n.a. n.a. n.a. -86 —254 -222 —239 -153 -311 —276 -241 —372 —379 -390 —407 -385 —339 n.a. n.a. —259 -310 -328 f 1978-1988 -340 n.a. '282 493 -154 455 459 —137 -145 -82 -125 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. -529 -318 —289 —274 —122 —167 —141 -116 -179 —172 —291 —365 —468 —563 -643 —182 n.a. n.a. n.a. n.a. —162 -153 -109 s 1887—1988 n.a. n.a. —348 -448 -570 -700 —796 -884 —919 -926 —978 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. —2019 4323 -1657 —1814 —1568 —1398 —1376 —1306 -1420 -1366 ~1386 —1487 —1686 -1925 -2222 —1876 n.a. n.a. n.a. n.a. -1452 —1341 —1211 Transactfi‘ ' 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 9O 91 92 Transact coordinate 45” 30" 15" 90° 45' 00" 45" 30" 15" 90° 44' 00" 45" 30" 15" 90° 43' oo" 45" 30" 15" 90° 42' oo" 45" so" 15" 90° 41' 00" 45" 30" 15" 90° 40' 00” 45" 30" 15" 90° 39' oo" 45" 30" 15" 90° 38' oo" 45" 30" 15" 90° 37' 00" 45" 30" 15" 90° 36’ 00" 45" 30" 15" 90° 35' 00" Y 1887-1934 -523 —492 -484 —561 —581 -618 -598 —s49 —556 —569 -578 —570 -574 —589 -594 ~625 -643 -633 —600 -605 —579 —582 —556 -501 —449 —442 —394 36 -63 54 592 n.a. n.a. n.a. n.a. n.a. n.a. —445 —487 —597 -670 -750 —825 n.a. 9 1934—1956 -223 -283 ~293 —185 -512 —118 ~123 —107 -122 -92 —101 -100 -97 -7o -83 —45 —19 -14 —35 —17 —11 13 23 22 3 —9 —15 -31 —110 —211 —311 —262 -182 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. a 1956—1978 —292 -280 -176 -210 109 -293 -292 -249 —182 —166 -135 —143 —137 -140 -126 -125 -136 —178 -172 n.a. -178 —116 —66 -74 —83 —69 —115 —119 -95 -3 59 139 108 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. f 1978-1988 -150 —120 —230 —115 —99 -133 -177 -186 -253 —167 —178 —176 -177 —221 —223 —230 —203 —197 —252 n.a. n.a. -173 -174 —153 -121 —102 —18 27 60 47 -28 ~199 -210 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. s 1887—1988 -1188 -1175 —1183 -1o71 —1083 -1162 —1190 —1091 -1113 —994 -992 —989 —985 —1020 —1026 -1025 —1001 —1022 —1059 -1083 n.a. -858 -773 —706 —650 -622 —542 -87 —203 —118 342 n.a. n.a. n.a. n.a. n.a. n.a. -2270 n.a. n.a. -2348 n.a. n.a. n.a. Isles Dem/eras gulfsrde summary Years Sum Avg STD Total Range Count 1887 — 1934 -39568 —549.6 309.9 592 —1299 72 1934 - 1956 —1o753 -170.7 144.2 23 —512 63 1956 - 1978 -1o730 —173.1 124.4 189 —407 62 1978 — 1988 -11547 -192.5 126.6 60 -643 60 1887 - 1988 -67195 -11199 527.5 842 —2348 60 See page 46 for explanation of numbers. 45 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY Isles Dernieres TABLE 5.—-ls/es Dernieres bayside rate of change (meters per year) Transect 11“ 1 2 3 4 5 6 7 8 9 1O 11 12 13 14 15 16 17 18 19 2O 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 Transect coordinate 90° 57' 45” 30” 15” 90° 57‘ 00” 45” 30” 15” 90° 56' 00” 45” 30” 15" 90° 55' 00” 45” 30” 15” 90° 54' 00” 45” 30" 15” 90° 53' 00” 45” 30" 15” 90° 52' 00” 45” 30” 15” 90° 51' 00” 45" 30” 15” 90° 50' 00” 45” 30” 15” 90° 49' 00” 45” 30” 15” 90° 48' 00” 45” 30" 15” 90° 47’ 00” 45” 30" 15” 90° 46' 00” Y 1906-1934 n.a. n.a. —5.1 -6.1 -3.1 —6.6 —1.6 —o.1 -1.5 -3.9 —o.1 -2.1 -0.4 0.2 n.a. n.a. n.a. n.a. n.a. n.a. 11.2 65 24.4 258 21.9 299 287 24.0 249 —4.1 —1.5 —2.6 —7.8 —1o.1 -2.3 -2.1 -3.1 —2.3 —2.9 -3.4 —1.5 —2.2 -1,0 —1.4 n.a. -26.9 —3.2 —o.9 e 1934—1956 -3.9 -3.0 -—2.2 -3.4 —0.5 —0.8 —9.8 -2.9 —0.5 —3.7 -1.4 —1.3 —1.9 n.a. n.a. n.a. n.a. n.a. n.a. n.a. 4.9 3'3 1'0 195 n.a. n.a. n.a. n.a. n.a. —O,3 —1.6 -1.1 01 9‘4 02 —1.0 —2.0 —1.5 —0.9 —3.2 1.5 —4.3 —1.2 —2.2 n.a. 23.9 —1.5 —3.3 a 1956-1978 55 —4.3 —8.5 -5.0 —9.0 —7.5 8.4 -3.1 —0.5 —0.2 —0.3 —O.6 0.2 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 11.6 n.a. n.a. n.a. n.a. n.a. —0,5 -O.3 -O.3 —0.4 6.7 —0.4 —O.3 —O.2 0.2 -0.4 —0.5 —4.4 -1.8 —2.1 n.a. n.a. 7.2 -0.7 —O.1 r 1978-1988 22.3 31.4 n.a. 25] 3.9 20 —21.9 —0.6 —14.8 —4.2 —5.8 —6.1 -12.7 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 434 26,1 223 32.6 —6.5 —8.3 —5.5 10.8 21.9 —2.7 —6.5 -44 —7,5 —9.4 -190 —2.0 n.a. n.a. n.a. n.a. 2.0 -13.6 —17.2 S 1906—1988 n.a. n.a. n.a. —1.2 -2.5 —4.3 —3.6 —1.7 —2.6 —2.9 —1.2 -2.0 -2.1 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 22.9 19.6 195 ,9] -24 .20 .910 -1.4 35 -12 -13 -22 .20 -25 -415 -15 n.a. n.a. n.a. n.a. -05 -33 _3,3 Transect 17‘ 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 8O 81 82 83 84 85 86 87 88 89 90 91 92 Transect coordinate 45" 30” 15” 90° 45' 00” 45” 30” 15” 90° 44' 00” 45” 30” 15" 90° 43‘ 00” 45” 30” 15” 90° 42' 00” 45" 30” 15” 90° 41' 00” 45” 30” 15” 90° 40' 00” 45” 30” 15” 90° 39' 00” 45" 30” 15” 90° 38' 00” 45" 30” 15” 90° 37' 00” 45” 30” 15” 90° 36' 00” 45” 30” 15” 90° 35' 00” Y 1906 _ 1934 —3.0 -o.9 -o.9 -1.1 —1.2 —1.3 —1.6 -1.9 -1.3 —1.3 —0.7 -1.0 —2.5 -1.3 -0.9 -0.9 -1.5 -1.9 -1.8 -2.0 -1.7 -1.0 —2.0 -3.5 —2.9 -3.5 —3.3 —5.5 -14.3 n.a. —22.9 n.a. n.a. 26 2.6 M 66 81 16,8 13.9 24.6 26.9 33.9 n.a. e 1934 _ 1956 —3.3 0_5 —0.3 -3.4 -1.8 —1.6 -1.3 0.1 —1.1 -1.2 —0.5 -1.1 -1.2 —2.6 —2.5 —2.5 —3.2 -2.1 —2.3 —2.6 —1.5 —1.6 —2.9 —2.4 —2.5 -2.5 —2.6 -4.0 14.6 714 ,114 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. a 1956 - 1978 —3.3 —0.5 —1.2 -1.1 0.5 05 0.7 -O.4 -O.2 —O.2 —0.2 —0.1 —0.2 —O.1 1.0 0.4 10 n.a. 16.1 73.1 0.4 0.8 —0,4 08 1‘3 1‘0 1.3 10.6 1] 2.6 —0.3 —0.5 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. I‘ 1978 -1988 -14.9 —12.4 —20.1 -18.7 -7.3 -6.3 —4.8 —5.8 —16.8 —11.0 -24.3 —9.9 -11.4 -16.6 —2.1 -6.1 38.4 n.a. 3‘3 n.a. n.a. -4.4 -16.1 —14.8 —24,2 —10.7 —6.6 —5.1 —5.3 —9.9 —0.3 0.1 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. s 1905 - 1988 -4.6 -1.9 —3.2 —3.9 —1.6 -1.5 —1.3 —1.4 —2.8 —2.2 —3.4 —1.9 —2.6 ~32 —1.0 -1.6 3.6 4.0 3.5 n.a. n.a. -1.1 —3.5 -3.4 -4.2 —2.9 —2.3 -o.7 -1.2 n.a. -4.9 n.a. n.a. n.a. n.a. 21.3 22.4 n.a. n.a. 23.5 n.a. n.a. n.a. n.a. Isles Dermeres baysrde summary Years Sum Avg STD Total Range Count 1906 - 1934 -59.1 -0.8 8.5 33.9 -26.9 70 1934 - 1956 -62.3 -1.0 3.7 14.6 —9.8 62 1956 — 1978 17.5 0.3 4.1 16.1 —9.0 61 1978 - 1988 —289.6 —5.2 12.8 38.4 —24.3 56 1906 — 1988 -35.3 —0.6 5.3 23.5 —4.9 56 TABLE 6. —/s/es Dermeres wrdth measurements (meters) Transect# 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 4O 41 42 43 44 45 46 47 48 Transect coordinate 90° 57‘ 45” 30” 15” 90° 57' 00” 45” 30" 15” 90° 56' 00” 45” 30” 15” 90° 55' 00” 45" 30” 15” 90° 54' 00” 45" 30” 15” 90° 53‘ 00” 45” 30” 15” 90° 52' 00” 45” 30” 15” 90° 51' 00” 45” 30” 15” 90° 50’ 00” 45” 30” 15” 90° 49' 00” 45" 30” 15” 90° 48' 00” 45” 30” 15” 90° 47' 00” 45” 30” 15” 90° 46‘ 00” Y 1890’s "-a- 239 561 677 1037 1261 1426 1334 1358 1482 1498 1305 1013 970 2080 607 669 373 302 331 706 746 616 325 439 170 179 112 263 2801 2677 2066 1520 1044 1738 3203 3084 717 548 536 335 560 620 495 n~a~ 767 1916 1854 9 1934 365 511 687 642 908 1051 848 844 610 784 738 548 199 "-a- "-3. "-3- ".a- "~a- "-3- ”-9 256 560 469 "~a- 422 368 335 58 129 1422 1869 1151 649 431 1055 2585 2467 67 "-6- "-8- 133 125 68 "-3- "-3- 883 1108 1214 a 1956 283 344 390 405 411 826 700 681 562 739 734 495 "-3- 257 510 455 344 261 168 88 75 88 26 113 "it "-3 n-a- "-a- "-a- 1333 1517 781 405 130 758 2301 2157 216 127 47 115 619 533 "-3- n-a- 495 786‘ 846 r 1978 50 104 122 135 205 490 537 518 419 595 579 173 "-a- "41 "-5- "-3- "-a- "-3- "-3- "-a- "-a- "-3- "-3- 38 137 128 100 121 172 1240 1228 543 195 123 439 2016 1896 148 99 179 297 145 114 "-3. "-3- 339 460 521 S 1988 25 "~64 33 74 78 308 369 286 221 473 392 "-3- "-3- "-3- ”-3- "J?- "-3- ”~a- "~a- "41 "-3- "-84 "‘a- "-a- "-8- 57 35 59 59 850 980 345 79 128 244 1663 1489 60 92 89 97 "-8 n-a- "-3- "-a- 153 191 260 Transactzi‘ 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 7O 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 Transact coordinate 45” 30” 15” 90° 45' 00” 45” 30” 15” 90° 44' 00” 45” 30” 15” 90° 43' 00” 45” 30" 15” 90° 42' 00” 45” 30” 15” 90° 41‘ 00” 45” 30” 15” 90° 40' 00” 45” 30” 15” 90° 39' 00” 45” 30” 15” 90° 38' 00” 45” 30” 15” 90° 37' 00” 45” 30” 15” 90° 36' 00” 45” 30” 15” 90° 35’ 00” Y 1890 s 2040 2121 2170 2672 2364 1838 1865 1811 2824 2134 2299 2090 2137 1899 2638 2289 1350 1193 1021 926 817 860 1054 1870 1686 1193 885 396 581 304 111 "-3- "-3- ”-5- 79 52 "-3. 419 437 439 537 292 245 189 e 1934 1394 1541 1656 2013 1747 1184 1213 1236 2204 1623 1624 1485 1506 1964 2010 1622 686 511 378 257 168 463 417 1306 1199 656 405 338 360 143 229 318 186 "-3- "-a- "-34 164 159 196 202 196 198 192 "-9 a 1956 1060 1185 1299 1540 743 1026 1052 1093 1940 1393 1497 1354 1403 1858 1831 1526 605 448 272 194 122 446 420 1257 992 463 348 247 130 167 185 179 226 "-3- "-a- "-3. "-a- "-8 "-a- "-3- "-38 "-3- ".a- 238 r 1978 756 457 817 1300 827 740 767 844 1779 1162 1356 1196 1264 1719 1709 1390 487 283 127 "-3- 250 342 360 1183 922 511 240 151 279 280 351 404 348 "-6- "-3- "-51- "-1 "-5 "-1 n‘a- "-a- "-3- ”-3- "-a' 3 1988 84 221 450 923 634 539 322 364 1137 863 1007 947 839 1435 1359 184 208 127 266 177 '13- 112 174 164 566 99 111 125 295 256 202 155 137 "-1 "-3- "-8- 121 23 "-8- "-9 185 "-a- "-3- "-8- lsles Dermeres wrdth summary Years Sum Avg STD Total Range Count 1890’s 100687 1170.8 826.2 3203 52 86 1934 61908 814.6 643.5 2585 58 76 1956 50860 687.3 559.0 2301 26 74 1978 39206 585.2 512.8 2016 38 67 1988 24000 375.0 401.0 1663 23 64 TABLE 7. —ls/es Dermeres gulfsrde rate of change (meters per year) Transect # 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 2O 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 4O 41 42 43 44 45 46 47 48 Transect coordinate 90° 57' 45” 30” 15” 90° 57' 00” 45” 80” 15” 90° 56' 00” 45” 30” 15” 90° 55' 00” 45” 30” 15” 90° 54' 00” 45” 30” 15” 90° 53' 00” 45” 30” 15” 90° 52‘ 00” 45” 30” 15" 90° 51' 00” 45” 30” 15” 90° 50‘ 00” 45” 30” 15” 90° 49‘ 00” 45” 30” 15” 90° 48‘ 00” 45” 30" 15” 90° 47' 00” 45” 30” 15” 90° 46‘ 00” Y 1887—1934 n.a. 9,2 415 114 —1.5 —4.6 -7.9 —10.6 -12.4 -14.6 -15.6 —16.3 —17.9 n.a. n.a. n.a. n.a. n.a. n.a. n.a. —17.4 —15.9 -17.1 n.a. —13.4 —14.4 —14.7 —15.6 —17.3 —27.6 —13.9 —14.3 —15.4 -12.3 —12.4 —11.7 -12.2 —13.7 n.a. n.a. -20.2 -23.0 —27.2 n.a. n.a. -13.9 —12.8 —11.9 e 1934—1956 -1.4 —4.3 —8.4 —10.3 —11.4 —9.8 —7.4 —4.9 —1.9 —0.3 10 —0.3 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. —11.5 —19.3 -20.1 n.a. n.a. n.a. n.a. n.a. n.a. —2.8 —14.6 -15.4 —10.4 —23.2 —13.6 —12.1 —13.9 —9.2 n.a. n.a. —15.4 -19.0 —19.9 n.a. n.a. -17.3 -12.6 -10.0 a 1956-1978 -6.4 —3.0 -4.4 —4.3 -4.3 —5.0 -4.8 —6.4 —6.7 -6.8 —6.5 -14.4 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. -14.6 n.a. n.a. n.a. n.a. n.a. -3.9 -11.5 —1o.1 —10.9 —7.0 —14.1 -12.5 -11.0 —16.9 -17.2 -17.7 -18.5 —17.5 —15.4 n.a. n.a. -11.8 -14.1 —14.7 r 1978—1988 —34.0 n.a. -28.2 —19.3 —15.4 —15.6 —15.9 —13.7 —14.5 —8.2 -12.5 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. ha. ha. n.a. —52.9 -31.8 —28.9 ~27.4 —12.2 -16.7 -14.1 -11.6 -17.9 ~17.2 -29.1 —36.5 —46.8 -56.3 -64.3 -18.2 n.a. n.a. n.a. n.a. -76,2 -15.3 -10.9 S 1887—1988 n.a. n.a. -3.4 —4.4 —5.6 —6.9 —7.9 —8.8 -9.1 -9.2 —9.7 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. —20.0 —18.0 —16.4 —18.0 —15.5 —13.8 -13.6 —12.9 ~14.1 —13.5 —13.7 —14.7 —16.7 -19.1 —22.0 -18.6 n.a. n.a. n.a. n.a. —14.4 -13.3 -12.0 Transect # 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 Transact coordinate 45” 30” 15” 90° 45' 00” 45” 30” 15” 90° 44‘ 00” 45” 30” 15” 90° 43' 00” 45” 30” 15” 90° 42' 00” 45” 30” 15” 90° 41' 00” 45” 30” 15” 90° 40’ 00” 45” 30” 15” 90° 39' 00” 45” 30” 15” 90° 38' 00” 45” 30” 15” 90° 37' 00” 45” 30” 15” 90° 36' 00” 45” 30” 15” 90° 35' 00” Y 1887—1934 -11.1 —10.5 —10.3 -11.9 -12.4 -13.1 -12.7 -11.7 -11.8 —12.1 —12.3 -12.1 —12.2 —12.5 —-12.6 -13.3 -13.7 -13.5 -12.8 —12.9 -12.3 -12.4 -11.8 —10.7 ~96 —9.4 -8.4 0.8 -1.3 1.1 126 n.a. n.a. n.a. n.a. n.a. n.a. —9.5 —1o.4 —12.7 -14.3 —16,0 -17.6 n.a. 6 1934—1956 -1o.1 —12.9 -13.3 —8.4 —23.3 -5.4 -5.6 -4.9 —5.5 —4.2 -4.6 -4.5 -4.4 -3.2 -3.8 -2.0 -o.9 —-O.6 -1.6 -0.8 —o.5 o_5 1.0 1.0 0.1 —0.4 -0.7 —1.4 —5.0 -9.6 -14.1 —11.9 -8.3 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 3 1956—1978 —13.3 —12.7 -8.0 -9.5 5_0 —13.3 -13.3 —11.3 —8.3 —7.5 —6.1 -6.5 —6.2 —6.4 -5.7 -5.7 -6.2 -8.1 —7.8 n.a. —8.1 -5.3 —3.0 -3.4 -3.8 —3.1 —5.2 -5.4 —4.3 —0.4 4.0 3.5 4_9 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. r 1978-1988 -15.0 —12.0 —23.0 -11.5 -9.9 —13.3 —17.7 —18.6 -25.8 -16.7 —17.8 —17.6 -17.7 —22.1 -22.3 —23.0 —20.3 -19.7 —25.2 n.a. n.a. -17.3 -17.4 -15.8 —12.1 —1o.2 -1.8 2.7 5.0 4.7 —2.8 -19.9 -21.0 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. S 1887—1988 —11.8 —11.6 —11.7 —10.6 -1o.7 -11.5 —11.8 —10.8 -11.0 -9.8 -9.8 -9.8 —9.8 -10.1 —1o.2 -1o.1 -9.9 -1o.1 -1o.5 -10.7 n.a. —8.5 -7.7 --7.0 —6.4 -6.2 —5.4 -o.9 —2.1 -1.2 34 ha. n.a. n.a. n.a. n.a. n.a. -22.5 n.a. n.a. —23.2 n.a. n.a. n.a. Isles Dermeres gulfsrde summary EXPLANATION Years Sum Avg STD Total Range Count 1887 - 1934 —841.9 —11.7 6.6 12.6 -27.6 72 Description of shoreline change data 1934 ' 1956 '483-8 77-8 6-5 1° '23-3 63 1439 Shoreline advance or island width as measured 1956 7 1978 '4877 '79 5-7 3-6 7135 62 at points subject to the influence of entrances 1978 - 1938 -1154.7 —19.2 12.7 6.0 —64.3 60 (e.g., tidal inlets, bayous, bays, etc.) 1887 ' 19 8 '665'3 '11'1 5'2 3'4 ‘23'2 6° 1 58 Shoreline advance or island width as measured at points not subject to the influence of entrances 0 Black zeroes, italicized or non-italicized, represent no shoreline movement —345 Shoreline retreat as measured at points not sub- ject to the influence of entrances -942 Shoreline retreat as measured at points subject to the influence of entrances Abbreviations in shoreline change data tables n.a. No shoreline data exist because of entrance location n.a. No bayside shoreline exists (e.g., headland areas) n.d. No survey exists or maps unavailable 46 Width (m) Isles Dernieres 3500 - 18905 Width 3000 1988 Width 2500 2000 1500 1000 500 III 0 West 16 24 32 Alongshore Position (km) East FIGURE 9.—Comparison of the 1890’s and 1988 barrier widths for Isles Dernieres. TABLE 8.—Area changes for Isles Dernieres from the 1890’s to 1988 Projected Date Date Area {ha} Change (ha! % Change Rate (ha/yr) of Disappearance 1890's 3,532 1934 1,958 -1,574 -45% —35.8 1989 1934 1,958 1956 1,458 -500 -26% -22.7 2020 1956 1,458 1978 1,243 -215 —15% -9.8 2105 1978 1,243 1988 771 -472 -38% —47.2 2004 1890’s 3,532 1988 771 -2,761 —78% -28.2 2015 Island Area (ha) 0 \ 3000 2000 1000 I I 0 1850 1875 1900 1925 Year 1950 1975 2000 FIGURE 10.—Area change for Isles Demieres between the 1890’s and 1988. LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A 47 US. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY Morphology The Timbalier Islands have experienced more lateral morphological change than any other island in Louisiana. In 1887, the barrier shoreline included Caillou, Timbalier, and East Timbalier islands (1 887 map). At that time, Caillou Pass separated Caillou and Timbalier islands. In 1934, Caillou Pass was partially blocked by the westward lateral migration of Timbalier Island; Little Pass Timbalier was much wider; and Raccoon Pass consisted of a series of breaches (1934 map). By 1956, Timbalier Island completely shielded Caillou Pass, and Caillou Pass evolved into a back— barrier channel (1956 map). Timbalier Island continued to migrate west while other areas only experienced land loss because of mangrove die-offs during the hard freezes of 1983 and 1985 (1978 and 1988 maps). Shoreline Movement Comparisons of shoreline position are made for the periods 1887 vs. 1934, 1934 vs. 1956, 1956 vs. 1978, 1978 vs. 1988, and 1887 vs. 1988. Shoreline position and barrier width were monitored at 164 shore- norrnal transects along the gulf and bay shorelines (transects map; tables 9, 10, 11, 12, and 13). Timbalier and East Timbalier islands were examined separately to provide a more accurate representation of barrier shoreline response to dominant coastal processes. Both islands formed as a result of lateral spit accretion and breaching; however, once formed, the mechanisms by which they migrated differed. Washover processes caused East Timbalier Island to rapidly migrate landward. In contrast, Timbalier Island continued migrating west in response to local processes (wind and waves). Therefore, the western end of the island grows laterally at the expense of erosion on the eastern end. Moreover, the dominance of lateral migration was enhanced by the width and elevation of the west—central portion of Timbalier Island, which inhibited washover processes from transporting sediment across the island to the bay shoreline. 29°09’ Bayou Lafourche Barrier System _ The Bayou Lafourche barrier system lies about 75 km west of the mouth of the Mississippi River and about 80 km south of New Orleans. The system encompasses Timbalier and East Timbalier islands, Caminada— Moreau Headland, and Grand Isle (fig. 1). The shoreline is approximately 65 km long and extends east from Cat Island Pass to Barataria Pass (chapter 1, fig. 11). Timbalier and East Timbalier islands, and Grand Isle are downdrift flanking barrier islands located to the west and east, respectively, of the Caminada-Moreau erosional headland. These islands range from 0.2 to 1.2 km wide. Cat Island Pass, Little Pass Timbalier, Raccoon Pass, Belle Pass, Caminada Pass, and Barataria Pass connect the Gulf of Mexico to Terrebonne, Timbalier, Caminada, and Barataria bays. Belle Pass represents the distal end of the abandoned Bayou Lafourche distributary system. The Bayou Lafourche barrier system is dominated by landward and lateral movement. Inadequate sediment supply, subsidence, and storm and human impacts are the major factors causing shoreline change in this region (Mossa and others, 1985; Penland and others, 1986; Ritchie and Penland, 1988; McBride, 1989b). The Bayou Lafourche shoreline is divided into two sections: the Timbalier Islands and the Caminada-Moreau Headland and Grand Isle. The Timbalier Islands extend east from Cat Island Pass to Belle Pass and consist of Timbalier and East Timbalier islands (Peyronnin, 1962; Kwon, 1969; Isacks, 1989). The Caminada-Moreau Headland and Grand Isle extend from Raccoon Pass to Barataria Pass (Kwon, 1969; Conaster, 1971; Harper, 1977; Gerdes, 1982; Shamban, 1982; Jeffrey, 1984; Combe and Soileau, 1987; Ritchie and Penland, 1990a, b). Maps presented show shoreline change for both sections in the years 1887, 1934, 1956, 1978, and 1988. From these maps, magnitude of shoreline movement, width, and island area measurements were obtained, and rates of change were calculated to determine the extent and rapidity of change to the barrier system. Timbalier Islands—1887 to 1988 90°35’ 90°35 l TERREBONNE Timbalier Island Along its gulf side, Timbalier Island generally exhibits a lower average rate of change because erosion on the east and accretion on the west cancel each other. More importantly, Timbalier Island is rapidly migrating west while its length slowly decreases (table 14). The average rate of change for Timbalier Island between 1 887 and 1 934 along the gulf shoreline was only —1.4 m/yr; the average bayside rate of change was -2.9 m/yr. (tables 11 and 13). This average gulfside rate of change decreased slightly to —1.2 m/ yr, while the average bayside rate of seaward—directed movement de— creased slightly to -2. 1 m/yr. Between 1956 and 1978, the gulf shoreline migrated landward at an increased average rate of -3.1 m/yr and then increased over twofold to -7.0 m/yr between 1978 and 1988 (fig. 1 1). For the period 1956 to 1978, the average bayside rate further decreased to -1.3 m/yr; however, between 1978 and 1988, the average rate escalated over tenfold to -14.1 m/yr (fig. 12). The rate of change along the bay indicates a net seaward movement, causing the gulf and bay sides to converge slowly. East Timbalier Island Rates of gulf and bayside movement are much higher along East Timbalier Island than Timbalier Island and, in fact, are the highest in the United States. The average gulfside rate of change for East Timbalier Island was —44.4 m/yr between 1887 and 1934 but decreased by about eightfold to —5.5 m/yr between 1934 and 1956 (table 13). Since 1956, the average rate of shoreline retreat has increased steadily to —16.2 m/ yr and —2 1.2 m/ yr for the periods 1956 vs. 1978 and 1978 vs. 1988, respectively (fig. 13). Along the bay side, the average rate of change decreased continuously from 45.1 to 18.3, 15.8, and -1.2 m/yr for the periods 1887 vs. 1934, 1934 vs. 1956, 1956 vs. 1978, and 1978 vs. 1988, respectively (fig. 14, table 1 1). This suggests a slow reversal in the natural and human processes along the back—barrier shoreline. Washover processes probably swept sand 90°30’ l BAY TERREBONNE Y across the island and caused the bay shoreline to migrate landward at a rate consistent with gulfside retreat. At some point, after the construction of seawalls on the island in the late 1950's, this natural process was terminated, and the bay shoreline experienced recession. Timbalier Islands Summary The average change rate along the gulf shoreline was —16.3 m/yr between 1887 and 1934, but decreased —3.8 m/yr between 1934 and 1956 (table 13). Migration increased steadily for the periods 1956 vs. 1978 and 1978 vs. 1988 (fig. 15). The rate of change along the bay shoreline was net progradational at 12.4 m/yr between 1887 and 1934 (table 1 1). This rate declined by half to 5.6 m/yr for the period 1934 vs. 1956 and raised slightly to 7.1 m/yr between 1956 and 1978. For the period 1978 to 1988, bayside change remained relatively constant at —7.8 m/yr; however, a reversal in direction resulted in extensive changes in back—barrier morphology (fig. 16). The 1887 vs. 1988 map presents cumulative shoreline position changes for the Timbalier Islands shoreline. The gulf shoreline of the Timbalier Islands experienced landward movement, except for the western end of Timbalier Island which exhibited lateral accretion. Gulfside change rates were highest along East Timbalier Island and the eastern end of Timbalier Island. The magnitude and direction of bay shoreline movement depends on island width and geomorphology, with low and narrow areas exhibiting the greatest change. The western end of Timbalier Island is undergoing lateral migration by spit-building processes at the expense of erosion along the eastern end. Between 1887 and 1988, the eastern and western ends of Timbalier Island migrated rapidly to the west (table 14). Area and Width Change Area change becomes more meaningful along the Timbalier Islands because of the dominance of lateral versus cross—shore sediment transport. 0 Historic Shorelines 0 90°25’ NO SURVEY FOR BDOZO’ ‘ 90015’ Extreme amounts of lateral migration characterize Timbalier Island; therefore, area and width measurements are probably better indicators of change than data derived from shore—normal transects. Timbalier Island In 1887, the average width of Timbalier Island was 1,341 m, and by 1934, the barrier island narrowed to 946 m (table 12). Between 1887 and 1 934, the rate of area change was —8.8 ha/yr (table 15). The average width of Timbalier Island decreased to 916 m by 1956. Between 1956 and 1978, the island grew at a rate of 3.8 ha/yr; however, island width decreased to 850 m by 1978. This land gain indicates that, while narrowing, Timbalier Island increased its length by spit processes. For the period 1978 to 1988, Timbalier Island experienced rapid land loss (fig. 1 7). During this period, island width decreased by over 50 percent to result in an average width of 415 m. This trend will eventually lead to fragmenta— tion because storms easily overwash and breach inlets across narrow islands. The average width of Timbalier Island decreased 926 In between 1887 and 1988, an average island narrowing rate of 9.2 m/yr (fig. 18). During the period, the area of Timbalier Island decreased from 1,485 to 542 ha (fig. 19, table 15). East Timbalier Island East Timbalier has experienced extreme changes in island area and width. In 1887, its width ranged from 80 to 649 m, with an average width of 283 m (table 12). The rate of area change between 1887 and 1934 was —2.1 ha/yr (fig. 20, table 16). By 1934, the width ranged between 94 and 441 m, with an average width that narrowed to 248 m. The rate of area change increased to 14.5 ha/yr between 1934 and 1956 to result in land gain. By 1956, average island width dramatically increased to 506 m with a range between 118 and 1,240 m. Land gain continued between 1956 THIS AREA and 1978 but slowed to 3.7 ha/yr. This land gain was reflected in a continual increase to 547 m wide by 1978. Island area showed a sharp decline between 1978 and 1988 with a loss of 257 ha, a 52 percent decrease at an average rate of -25.7 ha/yr. Average width along East Timbalier Island increased from 283 m in 1887 to 333 m in 1988 (fig. 21, table 12). This represents an average widening of 0.5 m/yr. Likewise, the island exhibited a slight area increase between 1887 and 1988, with major fluctuations (fig. 22). Overall, East Timbalier Island has conserved land area to show a slight land gain (table 16). Timbalier Islands Summary In 1887, island width along the Timbalier Islands ranged between 80 and 2,355 m, with an average width of 945 m (table 12). By 1 934, average width narrowed to between 94 and 1,906 m with an average width of 756 m. The average rate of area change for this period was -10.9 ha/yr (table 17). The average rate of area change reversed from land loss to land gain between 1934 and 1956 to 7.5 ha/yr, stabilized at 7.6 ha/yr between 1956 and 1978 but dramatically increased —7 1.5 ha/yr between 1978 and 1988 (fig. 23). The average width of the barrier islands decreased continuously from 1956 to 1988 (fig. 24). Although barrier width narrowed between 1934 and 1978, the islands experienced land gain because rapid lateral spit accretion is capable of depositing sediment faster than the narrowing process can remove it. High land loss rates occurred between 1978 and 1988 primarily because Hurricanes Danny and Juan struck the area in 1 985 (Case, 1986). During this short time, 7 15 ha were lost. Combined area of the Timbalier Islands has decreased 897 ha from 1887 to 1988 (fig. 24, table 17). Shoreline changes between 1887 and 1988 along the gulf and bay shorelines caused the Timbalier Islands to narrow 5.6 m/yr (fig. 25, table 12). Barrier island widths for 1887 and 1988 are shown in figure 26. ISLAND 095 b9 CAILLOU ISLAND 29° WINE c; lSLAND c 29005, “ _ 29005! G is 00 \a UL F TIMBALIER ISLAND ago/2’6 OF v 00:1" X] ”"a— 1 887 . C O ego EAST TIMBALIER ISLAND 29°02' l l I i l o , 90035' 90°39 90°30’ 90°25' 90020. 90°15 9002192'[J2 48 LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A Timbalier Islands 90036, 90035, 90030, 90025, I 900201 90015! 9001210 I 29°99 I I I i I I 29 09 DeviIs Point " TERREBONNE BAY AL 1 E R TERREBONNE T I M B 8’ ISLAND V ‘ A PELICAN CASSE TETE J’ ‘ ISLANDS" 'SLAND 9 v » CALUMET ISLAND ‘ CAILLOU ISLAND BUSH 'SLAND ‘5 Q09 $00000 290051 A WINE ISLAND 00b. Cg”, ’7 A ' —290051 I 9} cu pass EAST TIMBALIER ISLAND 0% N ‘ Do TIMBALIER ISLAND / - O ‘ g 7L 2; 9% VIE “35‘ 2; ”It; 1934 a . O F O , I I I I I 29092' 29 [920039 90°35: 90°39 90°29 90°20 90°I5' 90°I2’ SCALE 1:100 000 1 0 1 2 3 4 5 MILES |:--I I—I I—I I——I a I 1 O 1 2 3 4 5 6 7 KILOMETERS H H H F *I 99°39 90°39 90039 99025' 99029' 90°15' 90151309, 29°99 I I I I . , Devils Point * d TERREBONNE BAY R TERREBONNE B A L I E ISLAND T I M B r A Y PEL'CAN CASSE TETE ISLANDS ISLAND 3 v CALUMET ISLAND 5" 0 Q0 006 I CAILLOU ISLAND BUSH 'SLA'R‘ 439% 1 WINE ISLAND xe‘ . 0“ V O S \V ' o , 29005'~ 0 s C , — 29 05 all/Du P I“ ass TIMBALIER ISLAND 29°92' I I I I I 29092' 90035, 90°35] 90°39 99°25' 90°2U’ 90°I5’ 99012' 49 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY Timbalier Islands 90036, D I o I o l o I 90015’ 90012, 29009, 90'35 90130 90'25 90’20 x 29009, Devils Point ’ d TERREBONNE BAY ER , I TERREBONNE T I M B A L I B ISLAND , ,4 . I” PELI A [ELENDS CASSE TETE ISLAND 3 # CALUMET ISLAND cf? u‘ ' 6‘20 BUSH ISLAND ¢ of“ CAILLOU ISLAND a WINEISLAND f”) 29°05’_ 0017/0“ Pas —29°U5I S \ EAST TIMBALIER ISLAND TIMBALIER ISLAND ‘. C O ‘ ‘,>' ‘5 \ .a 7L, ‘I ”e * \3 D 0‘98 K“ «I ‘ IA 7})??6 J 04$ 0 ? go I I I I I I o I 2 [33200351 90°39 90°30! 90°29 90°20! 90°19 90°12' SCALE 1:100 000 1 2 3 4 SMILES P—-| F—I I—I . . J 1 0 1 2 3 4 5 6 7K|LOMETERS I—II—II—I I J 90°36’ 90°35' 90°30' 90°25' 90020' 90°15' 90%? 29°09: I , . , I 29°09' ‘ Devils Point ( TERREBONNE BAY [ER 824 B A L I’ T I M g CASSETETE ISLAND ‘_ u 1” CALUMET ISLAND I3" 0 Q0 \006 B ’ (I?) “‘5’ CAILLOU ISLAND USH'SfiAND’ 0000 3 ()0 p. e", V évQ 29005, '“ ‘ 4 Ow ¥ 290051 00/7/ m Ou Pas ‘ S , \ TIMBALIER ISLAND EAST THYIBALIER ISLAND C 0 fit ,. I A 4 / J' Q \J Wins» 6 74 E9 7%] (y‘fla‘ IA 6% E 29°02’ I , I I I I 29°02' 90°35! 90°35 90°30' 90025' 90°20’ 90°15’ 90°12' Average Rate (m/yr) 0 _2 ”/”\ \ 1875 1900 1925 1950 1975 2000 Year FIGURE 11,—Average gulfside rate of change between 1887 and 1988 along Timbalier Island. Average Rate (m/yr) O _5 /\ _10 \ '15 / _20 1 1 1 1 1875 1900 1925 1950 1975 2000 Year FIGURE 15.—Average gulfside rate of change between 1887 and 1988 along the Timbalier Islands shoreline. Island Area (ha) 1600 1400 \ 1200 \\ 1000 \/\ 800 \ 600 \ 400 200 o 1 | 1 | l 1850 1875 1900 1925 1950 1975 2000 Year FIGURE l9.—Area changes of Timbalier Island between 1887 and 1988. Timbalier Islands Average Rate (m/yr) 0 ‘2 /\ I: \ \. —14 '16 1 1 1 1 1875 1900 1925 1950 1975 2000 Year FIGURE 12.—Average bayside rate of change between 1887 and 1988 along Timbalier Island. Average Rate (m/yr) 5 .0 \ _ 10 1 1 1 1 1875 1900 1925 1950 1975 2000 Year FIGURE l6.—-Average bayside rate of change between 1887 and 1988 along the Timbalier islands shoreline. Area Change Rate (ha/yr) 1O -10 \ _30 1 1 1 1 1875 1900 1925 1950 1975 2000 Year FIGURE 20,—Rate of area change between 1887 and 1988 for East Timbalier Island. -10 -20 -30 -40 -50 Average Rate (m/yr) /\ \ 1 1 1 1 1875 1900 1925 1950 1975 2000 10 -10 -20 -30 ~40 -50 Year FIGURE l3.—Average gulfside rate of change between 1887 and 1988 along East Timbalier Island. Area Change Rate (ha/yr) 1 | 1 1 1875 1900 1925 1950 1975 2000 600 500 400 300 200 100 0 Year FIGURE l7.—Rate of area change between 1887 and 1988 of Timbalier Island. Average Width (m) | 1 1 1 | 1850 1875 1900 1925 1950 1975 2000 Year FIGURE 21.—Average barrier width between 1887 and 1988 for East Timbalier Island. LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A Average Rate (m/yr) 0 40 \ 30 20 \fl 10 0 x __ 10 1 1 1 1 1875 1900 1925 1950 1975 2000 Year FIGURE l4.-—-Average bayside rate of change between 1887 and 1988 along East Timbalier Island. Average Width (m) 1400 1200 \ 1000 \ 800 \ 600 \ 400 200 o | | | 1850 1875 1900 1925 1950 1975 2000 Year FIGURE 18.—Average barrier width between 1887 and 1988 of Timbalier Island. Island Area (ha) 0 500 300 / \ 200 / 100 \N/ 0 1 1 1 1 1 1850 1875 1900 1925 1950 1975 2000 Year FIGURE 22.—Area changes of East Timbalier Island between 1887 and 1988. 51 US. DEPARTMENT OF THE INTERIOR US GEOLOGICAL SURVEY Timbalier Islands 0 Shoreline Change and Land Loss 0 gooasl o , 90030! D , 29°09 90 ,35 90l 25 TERREBONNE ISLAND ‘ TERREBONNE PELICAN‘ ISLANDS.‘ our“ BUSH ISLAND CASSE TETE ISLAND CAILLOU ISLAND / , WINE ISLAND 29°05' ~ Caillou Pass TIMBALIER ISLAND 1887 vs. 1934 EAST TIMBALIER ISLAND ’ Devils Point 90°12’ 29°02' I I I I 90°35! 90°35' 90°30 90°25' 90°20’ 90°19 90° 1887 1934 SCALE 1:100 000 1 0 I 2 3 4 SMILES I—I I—I I—I ‘ % . I I 1 0 1 2 3 4 5 6 7KILOMETERS I—II—II—I l I “V39 90°35’ 90030' 90°25 90°20' 90°15’ 29 09 I I I I I Devils Point L I E R TERREBONNE BAY TIMBA TERREBONNE A y ISLAND s. F’ELICAN§ CASSETETE $ ISLANDS\ ISLAND «v M 055 ‘., {2 CAILLOUISLAND BUSH'SLAEE . 1 29° \ 1 .. ~ - ...... .~ WINEISLAND \ ~ ‘ 29°05' “ DO ‘ Caillou Pass TIMBALIER ISLAND \ ”0% W l 93 4 VS . l 9 5 6 2900926035, 90:35' 90!?30' 900125, 90120, 90:15, 900 1934 1956 52 29°09’ — 29°05’ 29°02 12’ ~ 29°05’ 29°02’ 12’ Timbalier Islands LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A 90°36’ 90°35' 90°30' 90°29 90°20' 90°19 90°I2’o, wow I I , I , J9 09 Devils Point T R R E B N N E B A Y E O TERREBONNE T I M B A L I E R ISLAND a- ‘ B PELICAN . _ ,q ISLANDS CASSE TETE ‘ J2 ISLAND Q a“ 0 CALUMET ISLAND 6) 5 00 b ”6 CAILLOU ISLAND . COO QWINEISLAND $9“ BUSHV'SLANDg" 06‘ 29°05'— C V L #29005, Oil/IOU Pass v.57 EAST TIMBALIER ISLAND TIMBALIER ISLAND «g." _ o -» 41476, X I C O 05‘s _ E [0260/- 99 [Er do F O I: 1956 vs. 1978 . U L o I I I I G1 | 29002! 90°35I 90°35’ 90°30’ 90°25’ 90°20’ 90°15’ 90012' 1956 1978 - Land Land Loss 90°39 o I a I o I o I 9001' 90°12' 29009, [9035 . 90l30 90125 90120 29009, TERREBONNE BAY MBALIER T I 3 A ’ Y CASSE TETE ISLAND V J CALUMET ISLAND Qae‘v’ w: $002) CAILLOU ISLAND BUSH ISLAND ‘9 x " 00 29°05’ — I 00,7, — 29°05' OH 10083 TIMBALIER ISLAND 9 (it‘ll 9 P038 . E X I C O Tlmbd/iér F M 1978 vs. 1988 G U L 29002! I I I I I I 29002! 90036! 90°35, 90°30] 90°25, 90°20 90°15, 90012’ 1978 1988 53 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY 54 Timbalier Islands THANSECT NUMBER 19 20 21 22 23 24 25 2B 27 28 29 39 31 32 55 56 57 58 59 80 B1 62 B3 64 65 BB 87 58 B9 75 7B 77 78 79 4000 3000 — 30 E LL] L9 <2: I 2000 A7— 20 0 LL 0 “5 3 1000 7 10 t Z (9 < 2 LL] 0 L 0 9 (I) >. < CD —1000 —10 -2000 90°35' a , o , o , o , 90°12' 29°09, 90,35 90‘ 30 90‘25 90{20 ‘ 29009, x Devils Point TERREBONNE BAY R " I E T I M B A L CASSE TETE Y ISLAND fl .‘ s? 6“ / BUSH ISLAND. Q .- O , G CAILLOU ISLAND 20°05 N ~29°05' 0° TIMBALIER ISLAND AST TIMBALIER ISLAND 1887 vs. 1988 1 1 90°35' I 90°30 90°25' 90°20 90°15' 900ml SCALE 1:100 000 1 0 1 2 3 4 5 MILES 1 0 1 2 3 4 5 6 7 KILOMETERS H H I—I , . I—_I 1 I—I I—I I—I I—-I I . I————-I J 18 19 29 21 22 23 24 25 25 27 28 29 39 31 55 5B 57 58 59 80 B1 B2 83 54 55 BB 87 58 89 70 75 7B 77 78 79 80 81 82 83 84 85 2900? 90°39 TRANSECT NUMBER _4000 E _3000 Lu (9 Z < I U LL 0 —2000 LIJ D :3 t Z ‘53 —1000 2 Lu 9 U) LL _l D o 0 1000 I 1 2900? BAYSIDE RATE OF CHANGE (m/yr) GULFSIDE RATE OF CHANGE (m/yr) -————————a-1 HOREUNE ADVANCE S ___L_________ HOREUNE RETREAT ”_’L 1887 1988 SHOREUNE L RETREAT SHOREUNE ADVANCE LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A . C Timbaher Islands TABLE 9.—Timballer Islands baysrde magnitude of change (meters) Transect# 1 2 3 4 5 6 7 8 9 1O 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 3O 31 32 33 34 35 36 37 38 39* 40* 41 * 42* 43* 44* 45* 46* 47* 48* Transact coordinates 90° 33' 00" 45" 30” 15" 90° 32' 00” 45” 30" 15" 90° 31' 00" 45” 30" 15" 90° 30' 00” 45” 30” 15” 90° 29' 00” 45” 30” 15” 90° 28' 00” 45” 30” 15" 90° 27' 00" 45” 30” 15" 90° 26' 00” 45” 30” 15” 90° 25' 00" 45" 30” 15" 90° 24' 00” 45" 30" 15” 90° 23' 00” 45” 30” 15" 90° 22' 00” 45" 30" 15" Y 1887 - 1934 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. -270 -328 —84 -31 —163 —106 —120 —100 —196 —40 24 —203 —52 —216 —10 —178 —169 —174 —136 —101 —204 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 8 1934 — 1956 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. -127 —134 —58 —55 -106 —46 —49 —14 —54 -73 —16 —50 —33 —17 -10 12 54 —1 —23 —6 —7 -—249 5 —4 n.a. 52 —186 —60 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. a 1956 _ 1978 n.a. n.a. 132 320 586 n.a. 343 30 269 58 43 —4 12 5 —6 —4 —10 -8 —194 —11 —208 —170 —136 —162 -12 -13 -331 -13 -507 -165 -401 -547 19 140 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 72 577 434 769 968 r 1978 — 1988 n.a. n.a. —76 —116 —402 -230 —170 34 —476 -130 -146 ~368 ~52 -7 —20 —15 —25 —238 —9 —-190 —158 —1227 —363 —81 —2 —39 —118 —143 —8 10 27 522 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 41, 268 353 n.a. n.a. n.a. n.a. S 1887 — 1988 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a n.a. —527 —602 —466 -1478 —695 —366 -144 -140 —591 —197 —514 —364 —433 —490 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. Transect 11‘ 49* 50* 51 * 52* 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 7O 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 Transect coordinates 90° 21' 00” 45" 30” 15” 90° 20' 00” 45" 30” 15” 90° 19' 00” 45" 30” 15” 90" 18' 00” 45" 30" 15” 90° 17' 00" 45" 30” 15" 90° 16' 00" 45” 30” 15" 90° 15' 00” 45" 30" 15” 90° 14' 00” 45” 30" 15" 90° 13' 00” 45" 30” 15” 90° 12' 00" Y 1887 - 1934 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 2132 2119 2089 2188 2026 1981 2019 2267 2236 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a 1557 1475 —43 n.a. n.a. n.a. n.a. n.a. n.a. e 1934 — 1956 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 57 —41 11 170 381 454 783 763 785 n.a. n.a. n.a. n.a. n.a. 571 n.a. n.a. 959 1124 27 n.a. n.a. n.a. n.a. n.a. n.a. a 1956 — 1978 n a. n.a. n.a. 1012 745 311 -76 495 -5 166 ~62 242 —6 17 -109 —12 4 —41 7 324 n.a. 652 825 715 898 116 710 322 172 388 57 "~61 “-39 “-61- ML '13- ”-a- f 1978 — 1988 n.a. n.a. n.a. n.a. -133 —42 -66 —613 —85 —117 —10 —31 -16 -16 —38 —231 —37 —12 —16 —347 —3 n.a. n.a. n.a. 232 231 —25 —10 3 20 23 n.a. n.a. n.a. n.a. n.a. n.a. S 1887 - 1988 n.a. n.a. ”.3. n.a. n.a. n.a 1768 2239 2092 2210 1.954 2400 2056 2101 2130 2164 2402 2749 3021 2998 3302 "~51- n.a. n35. n.a. ”33- 2908 2753 2806 3007 64 ”13- ”'31- n.a. n‘a' n-a' n'a' Timbalier Island bayside summary East TImbalIer Island baysrde summary T/mba/Ier Islands baysrde summary Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count 1887 — 1934 —2857 —136.0 85.7 24 —828 21 1887 — 1934 19057 2117.4 93.7 2267 1981 9 1887 — 1934 19289 584.5 1024.3 2267 —328 33 1934 - 1956 —1244 —46.1 66.5 62 -249 27 1934 — 1956 4034 403.4 319.3 785 —41 10 1934 - 1956 4910 122.8 332.6 1124 —249 40 1956 - 1978 -894 —28.8 232.7 586 -547 31 1956 - 1978 10064 347.0 358.9 1012 —109 29 1956 - 1978 9787 155.3 347.2 1012 -547 68 1978 — 1988 ~4216 —140.5 257.5 522 —1227 so 1978 — 1988 -298 —12.2 214.2 411 —613 24 1978 - 1988 —4458 —78.2 247.7 522 -1227 57 1887 - 1988 —7007 -500.5 316.7 -140 -1478 14 1887 - 1988 41247 2426.3 429.9 3302 1768 17 1887 - 1988 40117 1179.9 1511.9 3302 -1478 34 0 I 290099990 90°35' 90°30 90°25' 90°20’ 9" '229°09' I I I I ‘ EXPLANATION T I M B A L I E R ’ (Timbalier Islands only) 8 Description of shoreline change data T E R R E B O N N E B A Y (4 1439 Shoreline advance or island width as measured at points subject to the influence of entrances (e.g.. tidal inlets. bayous. bays. etc.) CASSE TETE 1 58 Shoreline advance or island width as measured ISLAND at points not subject to the influence of entrances 0 Black zeroes. italicized or non»italicized. represent no shoreline movement ~ -345 Shoreline retreat as measured at points not sub- .” CALUMET ISLAND ject to the influence of entrances -942 Shoreline retreat as measured at points subject “ to the influence of entrances BUSH ISLAND .1. Portions of the same transect used to represent CAI 0U ISLAND .- _. different islands as a result of rapid lateral 5, ‘ island migration 6 7 i o I a—1887 throu h 1934 ulfside and width 290051 _ .1 g a 910 E T TIMBALIER ISLAND 29 “5 measuremefz'rsonry g K“ It [2 l3 M b—l956 through 1988 gulfside and width \ ‘ \ measurements only . c—1887 through 1934 bayside measure- ments only d—1956 through 1988 bayside measurements only Abbreviations in shoreline change data tables n.a. No shoreline data exist because of entrance 3 location mo n.a. No bayside shoreline exists (e.g.. headland areas) Tr 8 ts n.d. No survey exists or maps unavailable 29°02 I I l ' , 29°02 90°39 90°35’ 90°30’ 90°25 90°20 90°15 90°12 Gulfside Transects Bayside Transects TABLE 10.—T/mbal1er Islands gulfsrde magnitude of change (meters) Transact # 1 2 3 4 5 6 7 8 9 1O 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39* 40* 41 * 42* 43* 44* 45* 46" 47* 48* TranseCl' coordinates 90° 33' 00" 45" 30" 15” 90° 32' 00" 45" 30” 15" 90° 31' 00" 45" 30” 15" 90° 30 00” 45” 30" 15” 90° 29' 00” 45" 30" 15" 90° 28' 00" 45” 30" 15” 90° 27' 00" 45" 30" 15” 90° 26' 00” 45” 30" 15” 90° 25' 00" 45” 30" 15" 90° 24' 00" 45" 30" 15" 90° 23' 00" 45" 30" 15" 90° 22' 00" 45” 30" 15" Y 1887 — 1934 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 353 535 515 517 331 284 192 141 44 —71 —119 —202 —308 —395 —444 —494 -479 -426‘ —430 —389 -521 —866 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. e 1934 — 1956 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 758 421 822 266 210 139 105 107 59 —19 —84 -77 —94 —180 —212 -250 -280 —289 —272 —253 -321 —156 -90 —30 -183 —316 n.a_ n.a. n.a. n.a. n.a_ n.a. n.3, 11a, n.a_ n.a. n.a. n.a. a 1956 — 1978 11a, na, 12 15 20 n.a. 1g 7g 73 76 58 4o 6 6 12 e 4 14 7 14 1e —31 -77 —85 —105 -131 —155 —164 -221 -173 —52 —237 —352 —836 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. —531 n.a. —623 —336 n.2, r 1978 _ 1988 My ”1,1 275 ,34 109 115 97 112 120 33 so 23 1 —63 —110 —120 -145 —165 -157 —205 —227 —227 —188 —159 —140 —122 —72 —80 —129 -323 -540 n.a. n.a. n a. n.a. n.a. n.a. n.a. n.a. n.a. ~845 —663 -6‘49 —480 n.a. n.a. n.a. n.a. S 1887 — 1988 n.a. n.a n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 809 604 404 222 46 -75 -182 -316 -459 -578 -652 ~824 -1057 —1308 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. Transect # 49* 50" 51 * 52* 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 7O 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 Transact coordinates 90° 21' 00" 45” 30" 15” 90° 20' 00" 45" 30” 15” 90° 19' 00” 45" 30" 15” 90° 18' 00” 45" 30” 15” 90° 17' 00” 45" 30” 15” 90° 16' 00” 45" 30'" 15” 90° 15' 00” 45" 30" 15” 90° 14' 00” 45" 30" 15" 90° 13' 00" 45” 30” 15” 90° 12' 00' Y 1887 —1934 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. -2021 —1972 —2055 —2124 -2133 —2120 —2138 -2119 —2103 n.a. n.a. n.a. n.a. n.a. n.a. n.a. —2011 -1928 —1883 -1808 —1568 —1437 -1206 —1942 —2150 e 1934 — 1956 n.a. n.a. n.a. n.a. n.a. n.a. n.a n.a. n.a. n.a. n.a. n.a. 57 —47 —43 —79 -123 -158 -139 —305 —243 n.a. n.a. n.a. n.a. -133 n.a. n.a. —368 —593 —446 —311 —291 —401 —616 158 362 a 1956 _ 1978 —1014 —531 -133 —196 —220 —208 —200 —222 -250 -253 —256 —232 -221 -203 —118 -107 —123 -94 -198 —91 —197 —335 —463 —1148 —720 —513 -527 —280 —243 —107 —256 —320 -14 —36 -79 -125 —115 r 1978 _ 1988 n_a. n.a_ —272 -142 —98 -19 —65 —74 -1 25 33 46 25 15 —40 —44 —71 —17 35 -106 -336 —765 n.a. n,a, n.a. ~846 —106 —279 —243 —157 —80 ~76 -12 -36 —28 —41 —61 S 1887 - 1988 Ha. n.a. n.a. n.a. n.a. n.a. -1647 -1826 -1850 —1883 —1949 -2017 —2159 —2207 -2256 —2354 —2450 —2384 —2440 —2621 -2879 -3368 n.a. n.a. n.a. n.a. -2876 -2326 —2865 —2785 —2665 —2515 —1885 —1910 -1929 —1950 —1964 Timballer Island gulfSIde summary East TImbalIer Island gulfsrde summary Tlmballer Islands gulfsrde summary Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count 1887 — 1934 —1432 -65.1 455.0 853 —866 22 1887 — 1934 —18785 —2087.2 54.8 -1972 —2138 9 1887 - 1934 -36150 —903.8 1002.0 853 —2150 40 1934 - 1956 -659 -25.3 256.9 758 -321 26 1934 — 1956 —1208 —120.8 97.6 57 —305 10 1934 — 1956 -4373 —97.2 263.0 758 —616 45 1956 - 1978 —2144 -69.2 173.2 78 -836 31 1956 - 1978 -11043 -356.2 268.6 ~91 -1148 31 1956 - 1978 -14482 —204.0 253.7 78 —1148 71 1978 - 1988 -2088 —7o.3 165.2 276 —540 29 1978 — 1988 —5733 -212.3 287.5 46 —846 27 1978 — 1988 —8505 —130.8 227.8 276 —846 65 1887 - 1988 -3366 ~240.4 600.0 809 —1308 14 1887 - 1988 —41992 -2332.9 439.8 —1647 —3368 18 1887 - 1988 -65826 —1605.5 1099.7 809 -3368 41 55 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY TABLE 11.—Timba/ier Islands bayside rate of change (meters per year) Transect # 1 2 3 4 5 6 7 8 9 10 11 12 13 Timbalier Islands 14 15 16 17 18 19 2O 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39* 40* 41* 42* 43* 44* 45* 46* 47* 48* Transect coordinates 90°33'00" 45” 30” 15” 90°32'00" 45” 30" 15" 90°31'00" 45" so" 15” 90°30'00" 45" 30" 15" 90°29’00” 45" 30” 15” 90°28’00” 45” 30” 15” 90°27'00” 45” 30” 15” 90°26'00" 45” 30” 15” 90°25'00” 45” 30" 15" 90°24'00” 45” 30”” 15" 90°23'00” 45” 30” 15” 90°22'00” 45” 30” 15” Y 1887-1934 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. '57 '7-0 ’1-8 ‘0‘7 '3-5 '2-3 ‘25 '2-1 ‘42 ‘0-9 0.5 —4.3 ‘191 '4‘5 ‘0-2 -3.8 7315 —3-7 -2-9 -2-1 -4.3 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. e 1934 _ 1956 “a, n_a_ "a. na' na. na n.a. n.a. n_a. "(a -5.8 -6.1 —2.6 —2.5 —4.8 —2.1 -2.2 -0.6 —2.5 —3.3 —0.7 —2.3 —1.5 —0.8 -O.5 0'5 25 O —1.0 —0.3 —0.3 -11,3 03 —0.2 n.a. 2.8 —8.5 -2.7 n,a_ n.a, n_a, n,a_ n.a. n,a. n.a. ”,3. n3, n.a. 6 1956-1978 n.a. n.a. 8.3 14.5 26.6 n.a. 15.6 1.4 12.2 2.6 2.0 -0-2 0.5 0.3 '03 '0-2 '0'5 '0-4 '8-8 ’0-5 '9'5 ‘7-7 ’5-2 '7-4 ‘05 '0-6 ‘15-0 '0-5 '23-0 '7-5 713-2 '24~9 0.9 6.4 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 3.3 250 19.7 35.0 44.0 r 1978—1988 M, M, -7.6 -11.6 —40.2 -23.0 —17.0 3.4 —47.6 —13.0 —14.6 —36.8 —5.2 —0.7 -2.0 —1.5 —2.5 —23.8 -0.9 —19.0 —15.8 -122.7 —36.3 —8.1 —0.2 —3.9 -11.8 —14.3 —0.8 1'0 27 52.2 n.a. ”a, n.a. n.a. M. M, "A ,m n.a. 41.1 26.8 363 M. ,,_a_ n.a. “I S 1887— 1988 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. '52 7590 *446 -14-5 -6.9 -3.6 '44 -1,4 -5.9 -240 -5-1 '35 -4.3 -4.9 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. Transect # 49* 50* 51* 52* 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 8O 81 82 83 84 85 Transact coordinates 90° 21' 00” 45” 30” 15” 90° 20' 00” 45” 30” 15” 90° 19‘ oo" 45" 30" 15" 90° 18' 00” 45" 30” 15” 90° 17' 00” 45” 30” 15” 90° 16' 00" 45" 30” 15” 90° 15' 00” 45" 30” 15” 90° 14' 00" 45” 30” 15” 90° 13' 00” 45” 30” 15" 90° 12' 00” Y 1887 - 1934 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 45.4 45.1 44.4 46.6 43.1 42.1 43.0 48.2 47.6 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 35.3 31.4 -0-9 n.a. n.a. n.a. n.a. n.a. n.a. 8 1934 — 1956 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 2.6 ‘19 0.5 7.7 17.3 20.6 35.6 34.7 35.7 n.a. n.a. n.a. n.a. n.a. 30.5 n.a. n.a. 44.0 51.1 1.2 n.a. n.a. n.a. n.a. n.a. n.a. a 1956 — 1978 n.a. n.a. n.a. 46.0 33.9 14.1 -3‘5 22.5 -0-2 7.5 -2.8 11.0 -0‘3 0.8 -5-0 -0-5 0.2 -149 0.3 14.7 n.a. 29.6 37.5 32.5 40.8 5.3 32.3 14.6 7.8 17.6 2.6 n.a. n.a. n.a. n.a. n.a. n.a. f 1978 — 1988 n.a. n.a. n.a. n.a. '73-3 '4-2 ‘55 761-3 78-5 ‘11'7 ‘1-0 ‘3-1 ‘1-6 '1-5 '3-8 7231 '3-7 ‘1-2 -1-5 '34-7 '0-3 n.a. n.a. n.a. 23.2 28.1 "2-5 '1-0 0.8 2.0 2.3 n.a. n.a. n.a. n.a. n.a. n.a. S 1887 — 1988 n.a. n.a. n.a. n.a. n.a. n.a. 17.5 22.2 20.7 21.9 19.3 23.8 20.4 20.8 21.1 21.4 23.8 27.2 29.9 29.7 32.7 n.a. n.a. n.a. n.a. n.a. 28.8 27.3 27.8 29.8 0.6 n.a. n.a. n.a. n.a. n.a. n.a. Timbalier Island bay6ide summary East Timbalier Island bayside summary Timbalier Islands baySIde summary Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count 1887 — 1934 —60.8 -2.9 1.8 0.5 —7.0 21 1887 — 1934 405.5 45.1 2.0 48.2 42.1 9 1887 - 1934 410.4 12.4 21.8 48.2 —7.0 33 1934 — 1956 -56.5 —2.1 3.0 2.8 —11.3 27 1934 - 1956 183.4 18.3 14.5 35.7 —1.9 10 1934 — 1956 223.2 5.6 15.1 51.1 -11.8 40 1956 - 1978 —40.6 -1.3 10.6 26.6 —24.9 31 1956 — 1978 457.5 15.8 16.3 46.0 —5.0 29 1956 — 1978 444.9 7.1 15.8 46.0 —24.9 63 1978 — 1988 —421.6 —14.1 26.7 52.2 —122.7 30 1978 — 1988 —29.3 —1.2 21.4 41.1 —61.3 24 1978 - 1988 -445.8 —7.8 24.8 52.2 —122.7 57 1887 — 1988 —69.4 —5.0 3.1 —1.4 —14.6 14 1887 — 1988 408.4 24.0 4.3 32.7 17.5 17 1887 - 1988 397.2 11.7 15.0 32.7 —14.6 34 TABLE 12.—Timbalier Islands Width measurements (meters) * * * . k ‘k * Transect# 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 2O 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39* 40* 41* 42 43 44 45 46 47 48 Transect coordinates 90°33'00" 45” 30” 15” 90°82'00” 45” 80" 15” 90°31'00” 45” so” 15” 90°30'00” 45" 30" 15” 90° 29' 00” 45" 30” 15” 90°28'00” 45” so” 15" 90°27'00” 45” 30" 15” 90°26'00” 45” 30” 15” 90°25'00" 45” 30” 15" 90°24'00” 45” 30" 15” 90°23'00" 45” 30” 15” 90°22'00” 45” 30” 15" Y 1887 n.a. n.a. n.a. na. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 652 914 977 949 1696 2217 2355 1672 1859 1560 1579 1796 1844 1683 1464 2026 1807 1286 1826 1532 1190 1315 970 675 462 913 1297 1335 1519 1384 1334 e 1934 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 122 567 615 664 671 803 1051 1187 1390 1562 1739 1906 1719 1682 1729 1718 1445 1315 1398 1345 1145 1012 469 296 119 393 233 283 338 na- na- Ira. ri-a- ".4 "-8. 179 239 M- a 1956 n.a. n.a. 7 103 n.a. n.a. 297 464 420 586 630 748 860 779 846 830 1073 1210 1365 1496 1478 1773 2246 2065 1456 1525 1160 1014 1116 943 795 588 404 845 52 139 n.a. na. "‘4. n.a. "-4 na- "-61- 617 232 250 118 184 r 1978 n.a. n.a. 579 428 604 653 671 704 354 733 722 777 874 788 852 876 1059 979 1363 1365 1546 1593 1435 1451 1146 1089 1000 574 707 434 366 456 674 356 n.a. n.a. n.a. m. 102 81 152 685 423 170 "-a- 292 16 ”-5- s 1988— 63 78 196 444 338 377 440 663 632 657 726 713 781 716 491 730 714 560 811 237 94 60 92 476 94 131 132 382 507 150 383 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 2o 32 37 41 60 "9 "~a- ’79 Transect# 49* 50* 51* 52* 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 Transect coordinates 90° 21' 00” 45" 30" 15" 90° 20' 00” 45" 30” 15” 90° 19' 00” 45” 30” 15” 90° 18’ 00” 45” so” 15” 90° 17' 00” 45" so” 15” 90° 16' 00” 45” so” 15'” 90° 15' 00” 45” 30” 15” 90° 14' 00” 45” 30” 15” 90° 13' 00” 45” 30" 15” 90° 12' 00” Y 1887 1150 866 664 163 n.a. n.a. 649 269 329 243 379 239 399 241 126 362 363 400 179 374 213 168 94 na. 80 n.a. 145 412 621 766 854 ML n-a- n-a- 08- M- "-9- e 1934 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 385 441 256 255 213 275 233 173 n.a. g4 n.a. n.a. n.a. n.a. 159 n.a. n.a. 194 305 924 n.a. n.a. n.a. n.a. n.a. n.a. a 1956 130 241 217 1017 800 1161 1132 500 1240 702 506 464 364 314 328 476 197 928 813 n.a. 257 286 470 504 344 269 480 605 663 388 489 n.a. n‘a. n.a. na- na- “-9- r 1978 199 438 606 795 933 875 1431 1353 1001 793 331 198 125 134 261 351 341 699 1059 1054 1133 965 544 58 321 705 331 734 844 309 315 Mt na- n.a. 06- 08- “-61. s 1988 n.a. n.a. 120 606 619 106 788 706 1114 506 632 420 202 125 79 40 26 189 523 766 819 326 n.a. n.a. 24 75 202 461 724 248 251 na- n-ar n.a. n.a. 09- n.a. Timbalier Island Width summary East Timbalier Island Width summary Timbalier Islands Width summaiy Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range COUHt 1887 46931 1340.9 495.8 2355 163 35 1887 5664 283.2 135.1 649 80 20 1887 54836 945.4 634.6 2355 80 58 1934 29384 946.3 581.7 1906 119 31 1934 2484 248.4 97.8 441 94 10 1934 83242 755.5 580.6 1906 94 44 1956 29308 915.9 555.6 2246 7 32 1956 16196 506.1 310.1 1240 118 32 1956 47044 702.1 485.5 2246 7 67 1978 27207 850.2 358.9 1593 354 32 1978 19689 546.9 386.7 1431 16 36 1978 48364 681.2 400.1 1593 16 71 1988 12868 415.1 251.3 811 60 31 1988 9664 333.2 308.1 1114 20 29 1988 23755 377.1 280.7 1114 20 63 TABLE 13.——Timba/ier Islands gquSide rate of change (meters per year) Transect# 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39* 40* 41* 42* 43* 44* 45* 46* 47* 48* Transect coordinates 90° 33' 00” 45” 30” 15" 90°32'00" 45" 80" 15” 90°31'00” 45" 30” 15” 90°30'00” 45” so” 15” 90°29'00” 45” 30” 15” 90°28'00" 45” 30” 15” 90°27'00" 45" 30" 15” 90°26’00" 45” 30" 15” 90°25'00” 45” so” 15” 90°24'00" 45” 30” 15” 90°23'00" 45" 30” 15” 90°22'00” 45” 30” 15” Y 1887-1934 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 13.1 14,5 13.1 110 8.1 5,0 4.1 3,0 0,9 —1.5 —2.5 -4,3 —6.6 —8.4 —9.4 —10.5 —10.2 —9.1 —9.1 —8.3 -11.1 —18.4 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 9 1934—1956 "-a- ’16- ”-6 "-a- ”-a- "ra- "-4 "-6 ””a- "-a- 34.5 19.1 14.6 12.1 9.5 6.3 4.8 4.9 3.1 —o.9 -3.8 -3.5 -4,3 -5.9 —9.6 —11.4 —12.7 —13.1 —12.4 —11.5 —14.6 —7.1 —4.1 -1.4 —8.3 —14.4 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. a 1956—1978 "'a- "~a- 0.5 0.7 0.9 "-61” 0.8 3.5 3.3 3.5 2.6 1.8 0.3 0.3 0.5 0.3 0.2 0.6 0.3 0.6 0.7 —1.4 —3.5 —3.9 —4.8 —6.0 —7.0 —7.5 —10.0 —7.9 —2.4 —10.8 -16.0 —38.0 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. —24.1 n.a. ~28.3 —38.0 n.a. r 1978—1988 "-9 "-a- 27.6 13.4 10.9 11.5 9.7 11.2 12.0 8.3 6.0 2.8 0.1 —6.3 —11.0 —12.0 —14.5 —16.5 —15.7 —20.6 -22.7 -22.7 —18.8 —15.9 —14.0 —12.2 —7.2 —8.0 —12,9 —32.3 —54.0 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. -84.5 —66.3 -64.9 —48.0 n.a. n.a. n.a. n.a. S 1887—1988 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a n.a. n.a. 3.0 50 4'0 2‘2 0'5 -o,7 _1,3~ -3.1 _4,5 _5,7 -e.5 —8.2 -105 -130 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. Transect # 49 * 50 * 51* 52 * 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 7O 71 72 73 74 75 76 77 78 79 8O 81 82 83 84 85 Transect coordinates 90° 21' 00” 45” 30” 15” 90° 20' 00” 45” 30” 15" 90° 19' 00” 45” so” 15” 90° 18' 00” 45” 30” 15” 90° 17' 00” 45” 30” 15" 90° 16’ 00” 45”” 30” 15” 90° 15' 00” 45” 30" 15” 90° 14' 00" 45” 30” 15” 90° 13' 00” 45” 30” 15" 90° 12' 00” Y 1887-1934 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. -43_o -42_o _43‘7 -452 -45_4 -45_1 -45.5 -45.1 -44_7 n.a. n.a. n.a. n.a. n.a. n.a. n.a. —42.8 —41.0 —40,1 —38,5 —33.4 —30,6 —25.7 —41.3 —45.7 8 1934 - 1956 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 2.6 _2.1 -24) _3‘5 -5_5 -7.0 -e_3 -139 -71.0 n.a. n.a. n.a. n.a. ~60 n.a. n.a. -16.7 —27.0 —2o.3 —14,1 —13.2 —18.2 —28.0 72 16.5 8 1956-1978 -46.1 -24.1 —6.0 —8.9 —1o.o —9.5 —9.1 —10.1 —11.4 —11.5 —11.6 -10.5 -10.0 —9.2 —5.4 —4.9 —5.6 —4.3 —9.0 —4.1 -9.0 -15.2 -21.0 -52.2 —32.7 —23.3 -24.0 —12.7 —11.0 —4.9 —11.6 —14.5 —0.6 —1.6 —3.6 —5.7 —5.2 r 1973-1988 "9 "~a- -27.2 -14.2 —9.8 -1.9 —6.5 —7.4 —0.1 2.5 3.8 4.6 2.6 1,5 —4.0 —4.4 -7.1 —1,7 3.5 —10.6 ~33.6 —76.5 n.a. n.a. n.a. —84.6 —10.6 —27.9 -24.3 —15.7 —8.0 -7.6 —1.2 —3.6 -2.8 —4.1 —6.1 3 1887-1988 "va- "-34 ”-51- M- "~a- "-6- -16.3 -18.1 -18.3 -18.6 -19.3 -2o.0 -21.4 —21.9 -22.3 -23.3 —24.3 —23.6 -24.2 —26.0 -28.5 -33.3 n.a. n.a. n.a. nva. -28.5 -28.0 -28.4 —27.6 —26.4 —24.9 -18,7 -18.9 -19,1 —19.3 —19.4 Timbalier Island gquSide summary East Timbalier Island gu/ISide summaiy Timbalier Islands gulfs/de summary Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count 1887 - 1934 —30.5 —1.4 9.7 18.1 ~18.4 22 1887 — 1934 —399.7 —44.4 1.2 -42.0 —45.5 9 1887 — 1934 —769.1 -16.3 21.7 18.1 —45.7 40 1934 - 1956 -30.0 —1.2 11.7 34.5 —14.6 26 1934 — 1956 -54.9 —5.5 4.4 2.6 -13.9 10 1934 - 1956 —198.8 —3.8 11.2 34.5 -28.0 45 1956 — 1978 —97.5 -3.1 7.9 3.5 —38.0 31 1956 - 1978 —502.0 -16.2 12.2 -4.1 —52.2 31 1956 — 1978 -658.3 —9.6 11.9 3.5 —52.2 71 1978 — 1988 —203.8 —7.0 16.5 27.6 —54.0 29 1978 — 1988 —573.3 —21.2 28.7 4.6 -84.6 27 1978 — 1988 -850.5 -14.0 23.7 27.6 —84.6 65 1887 — 1988 -33.3 -2.4 5.9 8.0 —13.0 14 1887 — 1988 —415.8 —23.1 4.4 —16.3 -33.3 18 1887 — 1988 —651.7 -15.2 11.6 8.0 —33.3 41 56 See page 55 for explanation of numbers. Area Change Rate (ha/yr) ~20 -40 -60 -80 1875 1900 1925 Year 1950 1975 2000 FIGURE 23.—Rate of area change between 1887 and 1988 for the Timbalier Islands. 2500 2000 1500 1000 500 Width (m) Timbalier Islands Average Width (m) 1000 800 600 \ 400 L 200 o I I I | i 1850 1875 1900 1925 1950 1975 Year FIGURE 24.—Average barrier width between 1887 and 1988 for the Timbalier Islands shoreline. TABLE l4.—-Lateral and length change of Timbalier Island LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES Island Area (ha) \ 1500 1000 \ 500 o I I I i I 1850 1875 1900 1925 1950 1975 Year FIGURE 25.—Area changes between 1887 and 1988 for the Timbalier Islands. 2000 I—2150—A - 1887 Width Lateral Migration 7% 1988 Width ,5 Dates (Number of Years) West End(m) Rate(m/vr) East End(m) Rate(m/vr) 1887—1934 (47) 2,843 60.5 5,207 110.8 1934-1956 (22) 3,715 168.9 743 33.8 1956-1978 (22) 83 3.8 1,232 56.0 1978—1988 (10) 1,154 115.4 1,063 106.3 1887-1988 (101) 7,795 77.2 8,245 81.6 Length of Island West ii iii iirlli _ _ 12 16 I 20 Alongshore Position (km) FIGURE 26.—Comparison of barrier widths between 1887 and 1988 for the Timbalier Islands shoreline. TABLE 15.—-Area changes for Timbalier Island from 1887 to 1988 Projected Date Date Area (ha) Chanqe (ha) % Chanqe Rate (ha/yr) of Disaggearance 1887 1,485 1934 1,071 -414 -28% —8.8 2056 1934 1,071 1956 915 -156 -15% —7.1 2085 1956 915 1978 999 84 9% 3.8 N.A. 1978 999 1988 542 —457 -46% -45.7 2000 1887 1,485 1988 542 -943 -64% -9.3 2046 Date Lengthjm) Changejm) - 1887 13,952 N.A. 24 28 1934 11,651 -2,301 1956 14,646 2,995 East 1978 13,477 -1,169 1988 13,569 -92 1887-1988 -383 Rate of Changejm/yr) N.A. -49.0 136.1 -53.1 -9.2 -3.8 TABLE 16. —Area changes for East Timbalier Island from 1887 to 1988 Projected Date Date Area (ha) Change (ha) % Change Ratejha/yr) of Disaggearance 1887 193 1934 93 -100 —52% -2.1 1978 1934 93 1956 413 320 344% 14.5 N.A. 1956 413 1978 495 82 20% 3.7 N.A. 1978 495 1988 238 -257 —52% 25.7 1997 1887 193 1988 238 45 23% 0.4 N.A. TABLE l7.—Area changes for the Timbalier Islands from 1887 to 1988 Date 1887 1934 1934 1956 1956 1978 1978 1988 1887 1988 Area (ha) 1,677 1,164 1,164 1,328 1,328 1,495 1,495 780 1,677 780 Change (ha) -513 16 167 -715 —897 % Change -31% 14% 13% -48% -53% Rate (ha/yr) -10.9 7.5 7.6 -71.5 -8.9 Projected Date of Disappearance 2041 N.A. N.A. 1999 2076 57 US. DEPARTMENT OF THE US. GEOLOGICAL SURVEY 0'5; 58 INTERIOR Caminada-Moreau Headland and Grand Isle—1887 to 1988 CAMINADA-MORFJKU HEADLAND AND GRAND ISLE Morphology In 1887, several tidal inlets and former distributaries segmented Caminada—Moreau Headland and Grand Isle. Raccoon Pass formed the western boundary and has been open continuously from pre-1887 to present (1887 map). No major changes in morphology had occurred by 1934, except for the barriers fronting Bay Marchand, which were mapped as intertidal features and therefore do not appear on the 1934 map. Belle Pass, Pass Fourchon, and Bayou Moreau segment the central headland area. Caminada Pass lies between the large, well—developed Caminada spit (locally known as Elmer’s Island) to the west and Grand Isle to the east. Grand Isle is a classic drumstick-shaped barrier island with a narrow western end that widens to the east and becomes bulbous on the eastern end. It is the only barrier island in Louisiana commercially and residentially developed (Meyer-Arendt, 1 987). Barataria Pass, the deepest tidal inlet along the Louisiana coastline (>40 m in 1989), forms the eastern boundary and is the primary tidal inlet that connects Barataria Bay to the Gulf of Mexico. By 1956, the land area fronting Lake Champagne was breached as the shoreline retreated (1956 map). Bay Marchand decreased over 70 percent in response to shoreline retreat. Moreover, the downdrift offset west of Belle Pass began to develop. The 1978 shoreline depicts the widening of Bayou Lafourche and Pass Fourchon, while the downdrift offset is more acute (1978 map). Shoreline retreat has reduced Bay Marchand to a small pond and intercepted Bayou Moreau to segment the distributary. By 1988, shoreline retreat had removed large quantities of sediment from the central headland area. This sediment was transported downdrift to Grand Isle but blocked from reaching the Timbalier Islands by . the Belle Pass jetties, causing the magnitude of downdrift offset to increase west of Belle Pass. Bay Champagne experienced extensive size reductions, while Bay Marchand is close to complete disappearance. Bayou Moreau now intersects the shoreline in three different locations, and numerous dredge canals dissect the coastal landscape. Shoreline Movement Shoreline change was measured at 91 shore—normal transects along the gulf and bay shorelines (transects map; tables 18, 19, 20, 2 1, and 22). Shoreline change measurements were taken along the gulf shoreline, but bayside measurements were possible only along Caminada spit because no bay shoreline exists to the west. Caminada-Moreau Headland The Caminada-Moreau Headland has experienced some of the highest rates of shoreline movement along the Louisiana coastline. Between 1887 and 1934, the average gulfside rate of change was -15.8 m/yr, but this rate gradually decreased to —1 1.5 m/yr and —9.5 m/yr for the periods 1934 to 1956 and 1956 to 1978, respectively (fig. 27, table 22). The average rate of coastal retreat increased to —13.6 m/yr between 1978 and 1988. The rapid landward movement of the shoreline along the Caminada-Moreau Headland has caused large quantities of sediment to be eroded from this segment. Most of the sediment is transported laterally or offshore, and a smaller percentage has moved landward by overwash processes. In contrast to barrier island shorelines, the Caminada-Moreau Headland consists predominately of cohesive deltaic sediment and a large, sandy beach ridge plain with no back-barrier lagoon or bay, except for a small water body behind Caminada spit. The average rate of bayside movement slowed along Caminada spit from shoreline advance to more stable conditions (fig. 28, table 20). Grand Isle Grand Isle is characterized by shoreline retreat and advance along the gulf side, which balances migration directions. The average rate of gulfside change was -0.9 m/yr between 1887 and 1934, with stable or slightly increasing shoreline advance rates of 0.0 m/yr, 2.5 m/yr, and 5.2 m/yr for the periods 1934 to 1956, 1956 to 1978, and 1978 to 1988, respectively (fig. 29, table 22). For 101 years, the gulf shoreline has experienced retreat along its western end while remaining relatively stationary at its midsection and accreting seaward on its eastern end. These trends show that Grand Isle is slowly rotating clockwise around a stable midpoint, a result of net longshore sediment transport that becomes captured by Barataria Pass. The Barataria Pass tidal inlet system is a large sediment sink storing most of its sand as a large ebb-tidal delta. Shoreline advance at the eastern end of Grand Isle is directly related to this ebb-tidal delta (Shamban, 1982). Average bayside rates of change showed slowly increasing rates of shoreline retreat between 1887 and 1988 (fig. 30, table 20). The bay shoreline experienced the greatest erosion to the west and slowly decreased to the east with stable conditions at the eastern end. Caminada-Moreau Headland and Grand Isle Summary The average rate of gulfside change between 1887 and 1934 was -10. 1 m/yr (table 22). The average rate decreased to -7.2 m/yr between 1934 and 1956 and to —4.9 m/yr between 1956 and 1978. This trend was interrupted when the average gulfside rate increased to -6.5 m/yr between 0 Historic Shorelines 0 \ 0%” o? 1978 and 1988 (fig. 31). These rates reveal shoreline retreat of the gulf side except on the eastern end of Grand Isle, which exhibits seaward progradation. The average bayside rate of change for the periods 1887 vs. 1934, 1934 vs. 1956, and 1956 vs. 1978 indicates that only migration direction has changed (fig. 32, table 20). Between 1934 and 1956, average shoreline movement along the bay reversed direction from landward to seaward. The rate of change slowly increased seaward to -3.0 m/yr between 1978 and 1988. The 1887 vs. 1988 map illustrates land loss and summarizes the cumulative measured changes along the gulf and bay shorelines. The rate of change between 1887 and 1988 along the gulf side of the Caminada- Moreau Headland and Grand Isle ranged from 6.2 to -20 m/yr, with an average change rate of -7.9 m/yr (table 22). The rate of change along the bay between 1887 and 1988 ranged from 7.0 to-13.0 m/yr with an average change rate of 0.1 m/yr (table 20). Area and Width Change at Grand Isle In 1887, Grand Isle ranged from 301 to 1,451 m wide, with an average width of 882 m (table 21). The average rate of land loss between 1887 and 1934 was 2.3 ha/yr (table 23). By 1934, the island had narrowed to an average width of 841 m; widths ranged between 302 and 1,186 In Between 1934 and 1956, the average rate of area change underwent land loss but slowed slightly to 1.6 ha/yr. Similarly, the average width continued to decrease to 82 1 m by 1956. Between 1956 and 1978, land loss reversed at an average rate of 1.0 ha/yr, and by 1978, the average width increased to 851 m. Land gain continued at a rate of 1.1 ha/yr between 1978 and 1988 (fig. 33). Numerous coastal engineering activities (beach restoration and replenishment projects) began along Grand Isle in the mid-1950’s, and changes in island area and width possibly reflect these human alterations, especially the extensive 1984 dune restoration project conducted by the US. Army Corps of Engineers (Adams and others, 1976; Combe and Soileau, 1987). Overall, Grand Isle experienced only a slight decrease in area from 1,059 to 960 ha between 1887 and 1988 (fig. 34). Compared with other barrier islands along the Louisiana coast, the area of Grand Isle has remained relatively stable. For the period 1887 to 1 988, the average width of Grand Isle is essentially stable, ranging between 821 and 882 in (fig. 35, table 21). Barrier widths for the Grand Isle area between 1887 and 1988 are shown in figure 36. Timbalier Bay Bay . ' Champagne Bay Marchand NO SURVEY FOR THIS AREA r Bay des Ilettes FIFI ’S ISLAND 1) MENDICANT . ISLAND Barataria Bay J ll .. Q ' MOREAU HEADLAND 9%. CAMiNADA ' M E X F I 1887 G U L F O C O o§$ 990% 95‘) 2670’“ e§§ «€365: {0°49 Caminada - Moreau Headland and Grand Isle LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES 8 2900‘; 90y K MENDICANT \ ‘ ' a, ISLAND 0%” 45° ‘ 0:» § fl 4 .- ‘ Barataria Bay 0 ’— 06) '1 w; '/ / ’y" °~* ‘ ’/ I; l / “V ‘1‘ ‘I ‘ BayMarchand ' Ch Bay :\’\X\// \jk ‘ A ampagne "} f?» X GRAND TERRE ISLAND ”a / \‘ CAMINADA — MOREAU HEADLAND § 1 ® €90 g9: {90 § 63: 390 o a , o / 0 0 / o? v” o? 0’ 0? o3: 0” SCALE 1:100 000 1 2 3 4 5 MILES L—I I—I I-—I fi. , | 1 o 1 2 3 4 5 6 7 KILOMETERS 1—1 1—1 1—1 H 1———1 . . 1 <9: 3 Q ‘93 % \ o '\ § 2 o 0% 8 0/9 69°05, 3’3! 0 $60 a? ‘9 Lake I Laurier $09 Bay des Ilettes “ ’ K\ $060 ‘ \ Q ‘ 0% 0 §MENDICANT 8°03} . / FIFI's ISLAND °°°° ML 4 -- , M f ISLAND 4‘: Barataria Bay {5; fig—’7 41 ‘ ‘ I r 5&3? ‘ Wiggne’tm 9,; «x »- s Caminada spIt %o. 1:63 GRAND TERRE ISLAND CAMINADA — MOREAU HEADLAND «<19 1 9 5 6 G U L O \ 2 o \ \ \ §\ 905’ °§é° 890/0, °§§ (8.39:3 {90/5, I—2150—A 59 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY Caminada - Moreau Headland and Grand Isle x3, é’ /y, 05 ’\J 3° {0° Lake Laurier ELI-£1180 ISLAN D Barataria Bay ' ‘ ~u. & GRAND TERRE ISLAND CAMINADA - MOREAU HEADLAND ‘OF MEXICO 4/1 1978 GULF § {9 «‘3 89 § «3 {90 0\ 00 0% 0/ 0% o“3 / o? 5’ o? 0’ 0? 9g: 5 SCALE 1:100 000 0 1 2 3 4 5 MILES . . . 1 l 1 O 1 2 3 4 5 6 7 KILOMETERS H . . , . J Lake Laufler ! E; ‘\ do E509 / Baydes Ilettes ' ' ‘A * (6‘90 w‘. (‘3 0‘6 ' ’MENDICANT (go ’ FIFI’S .. ISLAND ’ .KISEND” Baratan’a Bay 3&3 ' . Bay Champagne CAMINADA _ MOREAU HEADLAND Caminadaspit GRANDTERREISLAND 1988 GULF /o, 39’ O 05, (3’ 0 60 LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A Caminada - Moreau Headland and Grand Isle Average Rate (m/yr) Average Rate (m/yr) 6 Average Rate (m/yr) 8 \ 5 , 6 4 4 _2 I I I I _1 1875 1900 1925 1950 1975 2000 1875 1900 1925 1950 1975 2000 1875 1900 1925 1950 1975 2000 Year Year Year FIGURE 27.—Average gulfside rate of change along the FIGURE 28.—Average bayside rate of change along the FIGURE 29,—Average gulfside rate of change along Grand Caminada-Moreau Headland between 1887 and 1988. Caminada-Moreau Headland between 1887 and 1988. Isle between 1887 and 1988. 0 Average Rate (m/yr) 0 Average Rate (m/yr) Average Rate (m/yr) _' \ —e \ \ 2 _8 / _2 \\ , _3 \ -3 \ _35 I I I I _ 12 I I I I _4 I | I I 1875 1900 1925 1950 1975 2000 1875 1900 1925 1950 1975 2000 1875 1900 1925 1950 1975 2000 Year Year Year FIGURE 30.—Average bayside rate of change along Grand FIGURE 31.—Average gulfside rate of change between 5186;;“2 3:.1—9As\78e;agethba\émde rjteMof Chasgedlbetjweeg Isle between 1887 and 1988. 1887 and 1988 for the Caminada-Moreau Headland and an or e amma a oreau ea an an . Grand Isle shoreline. Grand Isle shorelme. Area Change Rate (ha/yr) 1.5 _25 I I I I 1875 1900 1925 1950 1975 2000 Year FIGURE 33.—Rate of area change between 1887 and 1988 of Grand Isle. 61 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY Caminada - Moreau Headland and Grand Isle 0 Shoreline Change and Land Loss 0 05, NO SURVEY FOR THIS AREA IN 1934 Lake Laurier MENDICANT ISLAND I 0;) " 93: q § ENDICANT Q ISLAND :90 Barataria Bay h; I $1. 8 .U' Marcal'sxjand Q09? .Q. . I ‘\ . , oV" ISLAND °§<23 I HEADLAND CAMINADA — MOREAU F M E X I 1 1887 vs. 1934 e U L S 2‘90 Q‘ 2I90 § (0‘ 2.90 O 0 , ° 0 o / , 1887 °°Q ‘9 SQ ’0’ S (g, a 1934 SCALE 1:100 000 1|: H H L g 3L 4 .5 MILES LI—H ._(‘) 1; 2 3 4 5 6 I7 KILOMETERS «s 2 § c, NO SURVEY FOR § 2 °\ ‘90 °\ 0% 2n90 0% £90 9%, 0? x0, , o? 0? 4; THIS AREA IN 1934 o? 49, Lake k I, Laurier 9 s 0Q; Bay ‘ Champagne ‘ I: Barataria Bay a g GRAND TERRE ISLAND - a £3 CAMINADA - MOREAU HEADLAND ‘b M E X 1 1 U 1934 vs. 1956 G S 20 x o I \ o 1934 °§ 905’ °§% 2‘9 ’0’ «ST cg?” 8%, 1956 62 LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A Caminada - Moreau Headland and Grand Isle 29°05 '33 {o S $5 96’ ® {979’ Laurier V 06> 08° g MENDICANT ISLAND Barataria Bay 0 L» . - 6 > _ >L,_ _ ,. aminadaspi %°6 415$ GRAND TERRE ISLAND \ CAMINADA — MOREAU HEADLAND "3% % o\ 03% I U L F o F M E X 1 C o 4» 1956 vs. 1978 G '\\ 2«9o %\ (29° § \ 2‘90 o 0, ° 0% é” 1956 o? 5 ® ’0’ o? E 25, 1978 I - Land Loss °§% {90/29, 'lllr g ”\ y 3 B d 11 ~ ‘ $ 0;) es ettes ‘ q 6:0 % HHS ’MENDICANT W y ISLAND Barataria Bay %. Q; .9 § GR QC}? . AND TERRE ISLAND 1978 vs. 1988 i G u L F 1978 /0, ’b §° 0 Q5; ’\a 3° 00, ‘3’ 0 1988 63 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY Caminada - Moreau Headland and Grand Isle TBANSECTNUMBER 75 7B 77 78 78 34 35 38 37 38 39 40 41 42 43 44 45 46 47 48 48 50 51 52 53 54 55 5B 57 58 58 BI] 81 82 * 30 E A LIJ E E 8 2 m I Lu 2"” U 2000 20 co 3% u. Z LIJ< O < 92> _ I OD “a U M LL (I) D o l: 1000 _ 10 Lu 2 '2: ‘2 m 2 LIJ L” O D _. c7) 0 0 g 2 m SHORELINE m RETREAT _1000 —10 Q3 § NO SURVEY FOR % 990 \ THIS AREA IN 1887 $9 9190/ 05/ o: 57/ U Lake Laurier Bay des Ilettes MENDICANT » £3 0 ISLAND o FIFI’S 18> ISLAND Barataria Bay CAMINADA — MOREAU {5; 1887 vs. 1988 § {9 2«.90 § “\5 '\ 0 § § § ”5' ° “5 o? , _m, im —— 1988 IlllllLandlnss SCALE 1:100 000 1 0 1 2 3 4 5 MILES I——-I I——I I——I . . . 1 I 1 O 1 2 3 4 5 6 7 KILOMETERS H H H T—I I ' I—I I TRANSECTNUMBER 78 75 7B 77 78 78 88 818283 84 1 2 3 4 5 S 7 8 8 1811 12 13 14 15 18 17 18 1820 21 22 23 24 25 28 27 2B 28 38 31 32 33 34 35 38 37 38 41] 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 5E 57 58 58 88 131 62 ) | 00 O O O —2000 1 I I (A) o SHORELINE ’1 RETREAT GULFSIDE MAGNITUDE OF CHANGE (m GULFSIDE RATE OF CHANGE (m/yr) —1ooo —10 0 o SHORELINE A ADVANCE 1000 ‘ 10 64 LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A Cammada - Moreau Headland and Grand Isle TABLE 18.—Caminada-Moreau head/and and Grand Isle bayside magnitude of change (meters) Transectfl‘ 1 2 3 4 5 6 7 8 9 1O 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 ' 40 41 42 43 Transect coordinate 90° 12' 00" 45" 30" 15" 90° 11’ 00" 45" 30” 15" 90° 10' 00" 45" 30” 15" 90° 09' 00" 45" 30" 15" 90° 08’ oo" 45" 30” 15° 90° 07' 00" 45" 30” 15" 90° 06' 00" 45" 30” 15" 90° 05' 00" 45" 30" 15" 90° 04' 00" 45" 30" 15" 90° 03’ 00" 45" 30” 15" 90° 02' 00" 45" 80" Y 1887 — 1934 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 203 420 399 353 247 490 38 -41 35 -115 e 1934 - 1956 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a n.a. —20 5 -2 n.a. —8 —190 —97 19 -56 -35 a 1956 - 1978 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 26 0 153 n.a. —9 —72 54 —76 -92 —11 I' 1978 - 1988 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 4 -8 -19 -28 -37 55 -9 —26 -39 -69 s 1887 — 1988 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 218 417 531 707 193 233 —4 -124 -152 -230 Transect # 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 Transect coordinate 15" 90° 01' 00" 45" 30" 15" 90° 00' 00" 45" 30" 15" 89° 59' 00" 45" 30” 15" 89° 58' 00" 45" 30" 15" 89° 57' 00" 45" Y 1887 - 1934 —134 -229 —45 —123 -79 —9 —79 —127 —54 -88 -24 -19 12 —11 -11 3 1 -8 -170 e 1934 - 1956 -31 63 -10 29 -4 24 34 7o —74 -157 ~28 14 -16 1g 15 22 174 -20 —107 a 1956 - 1978 -17 -9 -26 -5 -18 3 —14 —80 -18 14 -145 -17 -21 —14 —89 -80 -28 -80 ,4 r 1978 — 1988 —92 —112 -180 -95 —46 -115 -10 —8 -7 —88 —8 -18 2 —6 3 0 -5 —82 24 s 1887 - 1988 —274 -287 —211 -194 —142 —97 —59 -145 —153 —214 -205 -85 -28 -21 -26 —5 147 -90 -239 Caminada—Moreau head/and bayside summary Grand Isle bayside summary Caminada—Moreau head/and and Grand Isle bayside summary Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count 1887 — 1934 1627 325.4 83.7 420 208 5 1887 — 1934 —732 —30.5 126.8 490 —229 24 1887 - 1934 895 80.9 180.5 490 —229 29 1934 — 1956 —25 —6.8 9.2 5 —2o 4 1934 — 1956 -850 -14.6 74.2 174 ~19o 24 1934 - 1956 —375 —13.4 68.8 174 -190 28 1956 — 1978 170 42.5 65.1 153 —9 4 1956 - 1978 —657 —27.4 40.8 64 ~145 24 1956 — 1978 —487 —17.4 51.8 153 —145 28 1978 — 1988 -88 -17.6 14.5 4 —37 5 1978 — 1988 -771 —32.1 46.2 55 —130 24 1978 — 1988 —859 -29.6 42.8 55 —130 29 1887 — 1988 2066 418.2 193.3 707 198 5 1887 - 1988 —2500 -1o4.2 130.0 283 —287 24 1887 — 1988 -484 —15.0 242.1 707 -287 29 Q1) \ NO SURVEY FOR \ \ 2.9 g 8.90 68 THIS AREA IN 1887 06> 82., O9“ 280 005, Q.) l / / Q 70 'II 72 7_ . . 1 ‘ _ Bay cles [lattes . . 1" ' _ . . 1 , , MENDICANT ‘ 8 , . W ' ' . ., OISLAND 83% 7 . 1 . , . .1 FlFl’S ‘ 1 .. .. . >\ . . . .. 1, 1 . .1 ISLAND BaratanaBay 70 7 71 72 ‘1: 73 74 ‘ .-" .4 ‘6 “S14?” “-'m,u~ 39 40 41 42 43 44 45 46 47 48 49 50 SI 52 53 545 8I ' V V 34 35 37 38 GRAND ISLE 82 83 84 . 25 26 27 23 29 30 31 32 33 36 2 3 4 5 ' 19 20 2| 22 23 24 Caminada spit \ 5789I0II1213I4I5I8I7 '8 o'\ D 8 CAMINADA— MOREAU HEADLAN F O 1: M E X I C O Iransects G U L (>8 9% 0%“) 2"", 08% 083 29$ 03% 6" 03% a, 0? Q2) 6‘5 Gulfside Transects Bayside Transects TABLE 19.—Caminada-Moreau headland and Grand Isle gulfside magnitude of change (meters) Transect# . 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 2O 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 Transect coordinate 90° 12' 00" 45" 30" 15" 90° 11' 00" 45" 30" 15" 90° 10' 00" 45" 80" 15" 90° 09' 00" 45" 30” 15" 90° 08‘ 00" 45" 30” 15" 90° 07' 00" 45" 30" 15" 90° 06‘ 00" 45" 30" 15" 90° 05' 00" 45" 80" 15" 90° 04' 00" 45" 30” 15" 90° 03' 00" 45" 30” 15" 90° 02' 00" 45" 30” Y 1887 - 1934 -2119 -2128 —1866 -1208 —1o14 -1047 -912 —929 -936 —889 -896 —861 ~815 —848 —855 —818 —806 -748 —659 -538 —528 -490 —488 —428 -386 -405 —386 -352 -379 -410 -895 -461 -433 -428 —439 —898 —378 -265 -682 -287 —288 -415 —396 e 1934 — 1956 850 880 200 -334 —441 —521 -501 —495 —444 -428 -497 —418 —727 -546 -582 —873 —367 —332 —287 -278 —243 —201 -187 —165 -292 —246 —228 -175 -306 -293 -125 —94 —85 -111 —87 -82 -62 0 n.a. 169 155 137 39 a 1956 — 1978 —138 —117 -154 —170 -849 -889 -385 -444 —452 —471 —486 —528 -194 -254 -167 -272 -249 —284 -237 —218 —212 —258 -250 -263 -122 -164 -187 -212 -77 -80 —169 —133 —96 —28 35 15 4o 4 n.a. —99 —196 —61 40 r 1978 - 1988 -62 -97 -92 —130 -102 -114 —182 —157 —188 -186 —151 -128 —151 -215 -288 -254 —253 —420 —213 —190 -189 —167 -164 —150 -139 —144 —120 —117 —79 -81 —52 —52 -50 —63 -52 —28 —28 -35 n.a. 11 81 —2 —12 s 1887 — 1988 -1969 -1962 -1912 —1887 —1906 -2021 -1930 —2025 -2020 -1969 -1980 —1985 —1887 —1863 —1887 —1717 -1675 -1734 -1396 —1219 —1172 -1111 -1034 -1001 -989 —959 —921 —856 —841 —814 -741 —740 —664 -625 -548 -498 -428 -296 n.a. —206 —828 —341 —329 Transact # 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 Transeot coordinate 15" 90° 01' 00" 45" 30" 15" 90° 00 00" 45" 30" 15" 89° 59’ 00" 45" 30” 15" 89° 58' oo" 45" 30” 15" 89° 57' 00" 45" Y 1887 - 1934 —320 -304 -270 -247 -138 -67 -12 55 90 152 193 212 258 821 826 287 228 163 91 e 1934 _ 1955 —22 -57 -52 1 -84 -20 35 35 -21 —86 —81 —51 —93 —61 -3 —5 91 -18 -158 a 1956 — 1978 38 7o 64 65 75 46 —4 -9 —6 2 -10 —1 7 65 74 189 133 332 475 r 1978 — 1988 8 49 141 2 77 -5 —18 —25 80 40 42 76 117 88 118 145 167 107 10 s 1887 - 1988 —306 -242 -117 -179 -20 —46 1 56 63 158 194 287 284 418 510 616 624 584 418 Caminada-Moreau head/and gulfside summary Grand Isle gulfside summary Caminada-Moreau head/and and Grand Isle gulfside summary Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count 1887 — 1934 —28271 —744.0 451.4 —265 ~2128 38 1887 — 1934 -1055 —44.0 275.7 826 -682 24 1887 — 1934 —29826 —473.0 520.2 826 —2128 62 1934 — 1956 —9618 —253.1 284.2 380 -727 38 1934 - 1956 0 0.0 76.5 169 -158 28 1934 - 1956 -9618 —157.7 226.8 380 —727 61 1956 — 1978 —7905 —208.0 142.2 40 -—528 88 1956 — 1978 1289 56.0 182.5 475 ~196 28 1956 - 1978 -6616 —108.5 188.7 475 -528 61 1978 — 1988 -5178 —186.8 77.6 —28 —420 38 1978 - 1988 1187 51.6 56.7 167 -25 23 1978 - 1988 —3991 —65.4 115.1 167 -420 61 1887 - 1988 -50972 —1841.4 569.4 —296 -2025 88 1887 — 1988 2044 88.9 317.3 624 -341 28 1887 — 1988 —98479 —321.8 544.6 624 -2128 61 See page 46 for explanation of numbers. 65 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY Caminada - Moreau Headland and Grand Isle TABLE 20.—Caminada-Moreau head/and and Grand Isle bayside rate of change (meters per year) Transact # 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 4O 41 42 43 Transact coordinate 90° 12' 00" 45" 30" 15" 90° 11' 00" 45" 30" 15" 90° 10' 00" 45" 30" 15" 90° 09' 00" 45" 30" 15" 90° 08’ 00" 45" 30" 15" 90° 07' 00" 45" 30" 15" 90° 06’ 00" 45" 30" 15" 90° 05' 00" 45" 30" 15" 90° 04' 00" 45" 30" 15" 90° 03' 00" 45" 30" 15" 90° 02' 00" 45" 30” Y 1887 — 1934 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 4.4 8.9 8.5 7.5 5.3 10.4 0.8 -0.9 0.7 -2.4 a 1934 - 1956 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. —0.9 0.2 -0.1 n.a. -0.4 -8.6 —4.4 0.9 —2.5 —1.6 a 1956 - 1978 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 1.2 0 7.0 n.a. —0.4 —3.3 2.9 —3.5 -4.2 -O.5 f 1978 - 1988 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 0.4 —0.8 —1.9 —2.8 —3.7 5.5 —0.9 —2.6 —3.9 —6.9 S 1887 - 1988 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 2.2 4.1 5.3 7.0 1.9 2.8 0 -1.2 -1.5 -2.3 Transact # _ 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 Transact coordinate 15" 90° 01' 00" 45" 30" 15" 90° 00' 00" 45" 30" 15" 89° 59' 00" 45" 30" 15" 89° 58' 00" 45" 30" 15" 89° 57' 00" 45" Y 1887 - 1934 —2.9 -4.9 -1.0 —2.6 -1.7 —0.2 —1.7 —2.7 —1.1 -0.7 0.5 —0.4 0.3 -0.2 -o.2 0.1 0 —0.2 —3.6 a 1934 — 1956 -1.4 2.9 -0.5 1.3 —0.2 1.1 1.5 3.2 —3.4 —7.1 —1.3 0.6 —0.7 0.5 0.7 1.0 7.9 -0.9 ~49 a 1956 - 1978 —0.8 -0.4 -1.2 -0.2 -0.6 0.1 -o.6 -3.6 —0.8 0.6 -6.6 —0.8 —1.0 -0.6 -1.8 —1.4 -1.0 -1.4 0.6 r 1978 - 1988 -9.2 —11.2 -13.0 -9.5 -4.6 —11.5 —1.0 -0.8 —o.7 -3.8 —0.8 —1.3 0.2 —0.6 0.8 o -o.5 —3.2 2.4 s 1887 - 1988 -2.7 -2.8 -2.1 -1.9 -1.4 -1.0 —O.6 -1.4 —1.5 —2.1 —2.0 -0.3 —0.2 -o.2 —0.3 0 1.5 —o.9 —2.4 Caminada-Moreau headland bayside summary Grand Isle bayside summary Caminada-Moreau headland and Grand Isle bayside summary Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count 1887 — 1934 34.6 6.9 1.8 8.9 4.4 5 1887 - 1934 —15.6 —0.6 2.7 10.4 —4.9 24 1887 — 1934 19.0 0.7 3.8 10.4 -4.9 29 1934 — 1956 —1.1 —0.3 0.4 0.2 —0.9 4 1934 — 1956 —15.9 —o.7 3.4 7.9 —8.6 24 1934 — 1956 -17.0 —0.6 3.1 7.9 —8.6 28 1956 - 1978 7.7 1.9 3.0 7.0 —0.4 4 1956 — 1978 —29.9 —1.2 1.9 2.9 —6.6 24 1956 — 1978 -22.1 -O.8 2.3 7.0 —6.6 28 1978 - 1988 —8.8 —1.8 1.4 0.4 —3.7 5 1978 — 1988 —77.1 —3.2 4.6 5.5 -13.0 24 1978 - 1988 —85.9 -3.0 4.3 5.5 —13.0 29 1887 — 1988 20.5 4.1 1.9 7.0 1.9 5 1887 — 1988 -24.8 -1.0 1.3 2.8 —2.8 24 1887 - 1988 -4.3 -0.1 2.4 7.0 —13.0 29 TABLE 21 .—-Caminada-Moreau head/and and Grand Isle Width measurements (meters) Transact # _ 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 2O 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 Transact coordinate 90° 12' 00” 45" 30” 15” 90° 11’ 00” 45" 30" 15" 90° 10' 00" 45" 30" 15" 90° 09' 00" 45” 30" 15" 90° 08‘ 00" 45" 30" 15" 90° 07' 00" 45" 30" 15" 90° 06‘ 00" 45" 30" 15" 90° 05' 00" 45" 30" 15" 90° 04' 00" 45" 30" 15" 90° 03' 00" 45" 30" 15" 90° 02' 00" 45" 30" Y 1887 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 461 260 174 145 224 301 553 698 686 870 e 1934 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 248 242 161 122 201 n.a. 302 358 378 343 a 1956 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 120 159 64 101 193 n.a. 315 537 420 358 r 1978 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 118 170 212 380 189 n.a. 342 283 278 328 S 1988 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 59 110 201 314 117 n.a. .344 272 238 306 Transact # _ 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 Transact coordinate 15" 90° 01' 00" 45" 30" 15" 90° 00' 00" 45" 30" 15" 89° 59’ 00" 45" 30" 15” 89° 58' 00" 45" 30" 15" 89° 57' oo" 45" Y 1887 1080 1171 1323 1451 1160 1301 1244 1011 895 1006 938 826 855 642 563 550 416 771 866 a 1934 550 724 980 1088 941 1186 1149 1013 982 1126 1105 1021 1125 950 876 843 643 896 772 a 1956 545 650 911 1116 900 1094 1223 1033 928 933 1046 983 1011 901 892 856 910 828 491 r 1978 549 701 967 1176 967 1166 1204 953 911 949 890 964 1001 951 926 992 1024 1115 939 s 1988 428 643 971 1085 998 1141 1172 917 928 956 926 1027 1118 1030 1050 1145 1185 1209 982 Caminada-Moreau headland width summary Grand Isle width summary Caminada-Moreau headland and Grand Isle width summary Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count 1887 1264 252.8 111.4 461 145 5 1887 21177 882.4 294.5 1451 301 24 1887 22441 773.8 361.2 1451 145 29 1934 974 194.8 48.0 248 122 5 1934 19351 841.3 276.8 1186 302 23 1934 20325 725.9 353.1 1186 122 28 1956 637 127.4 44.9 193 64 5 1956 18881 820.9 252.5 1223 315 23 1956 19518 697.1 351.1 1223 64 28 1978 1069 213.8 88.7 380 118 5 1978 19576 851.1 284.1 1204 278 23 1978 20645 737.3 356.8 1204 118 28 1988 801 160.2 89.4 314 59 5 1988 20071 872.7 316.1 1209 238 23 1988 20872 745.4 397.5 1451 59 28 TABLE 22.—Camrnada-Moreau headland and Grand Isle gulfsrde rate of change (meters per year) Transact # . 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 4O 41 42 43 Transact coordinate 90° 12' 00" 45" 30" 15" 90° 11’ 00" 45" 30" 15" 90° 10' 00" 45" 30" 15" 90° 09’ 00" 45" 30" 15" 90° 08' 00" 45" 30" 15" 90° 07' 00" 45" 30" 15" 90° 06’ 00" 45" 30" 15" 90° 05' 00" 45" 30" 15" 90° 04' 00" 45" 30" 15" 90° 03' 00" 45" 30" 15" 90° 02‘ 00" 45" 30” Y 1887 - 1934 -45.1 —45.3 —39.7 -25.6 -21.6 —22.3 -19.4 —19.8 —19.9 —18.9 -19.1 -18.3 —17.3 —18.0 —18.2 -17.4 -17.1 -15.9 —14.0 —11.4 -112 —10.4 —9.2 —9.0 —8.2 —8.6 -a.2 -7.5 —8.1 -8.7 —8.4 —9.8 -9.2 —9.0 —9.3 -8.5 —8.0 -5.6 -14.5 -6.1 —6.1 —8.8 —8.4 a 1934 — 1956 15.9 17.3 9.1 —15.2 —20.0 —23.7 -22.8 —22.5 —2o.2 -19.2 —22.6 —19.0 —33.0 —24.8 —26.5 -17.0 —16.7 -15.1 —13.0 —12.6 -11.0 -9.1 —8.5 -7.5 -13.3 -11.2 -1o.4 —8.0 —13.9 —13.3 —5.7 -4.3 —3.9 —5.0 —4.0 -3.7 —2.8 o n.a. 7,7 7,0 6,2 13 a 1956 — 1978 -63 _5.3 —7.0 -7.7 —15.9 —15.4 -17.5 —20.2 —20.5 -21.4 —19.8 —24.0 —8.8 —11.5 -7.6 -12.4 -11.3 —10.6 —10.8 —9.7 -9.6 —11.5 —11.4 —12.0 —5.5 —7.5 —8.5 -9.6 —3.5 —1.4 -7.7 —6.0 —4.4 -1.3 1.6 0.7 1.8 0.2 n.a. —4.5 -8.9 —2.8 1,3 r 1978 — 1988 —6.2 —9.7 —9.2 —13.0 -10.2 —11.4 —13.2 —15.7 -18.8 —18.6 -15.1 —12.8 —15.1 -21.5 —23.3 -25.4 -25.3 -42.0 -21.3 -19.0 —18.9 —16.7 —16.4 —15.0 —13.9 -14.4 —12.0 —11.7 —7.9 —8.1 -5.2 —5.2 —5.0 —6.3 —5.2 —2.8 —2.8 —3.5 n.a. 1.1 3.1 -0.2 —1.2 S 1887 — 1988 -19.5 —19.4 —18.9 -18.2 —18.9 —20.0 -19.1 —20.0 —20.0 —19.5 -19.6 -19.2 —18.7 —18.4 -18.2 -17.0 —16.6 —17.2 -13.8 -12.1 —11.6 -11.0 —10.2 —9.9 —9.3 —9.5 -9.1 —8.5 -8.3 -8.1 —7.3 -7.3 -6.6 -6.2 -5.4 —4.9 —4.2 -2.9 n.a. -2.0 —3.2 —3.4 —3.3 Transact # ' 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 Transact coordrnata 15" 90° 01' 00" 45" 30" 15" 90° 00' 00" 45" 30" 15" 89° 59' 00” 45" 3o" 15" 89° 58’ 00" 45" 30" 15" 89° 57' 00" 45" Y 1887 - 1934 -6.8 -6.5 —5.7 -5.3 -2.9 -1.4 —0.3 1.2 1.9 3.2 4.1 4.5 5.4 6.8 6.9 6.1 4.9 3.5 1.9 a 1934 - 1956 —1.0 -2.6 —2.4 0 —1.5 -0.9 1.6 1.6 -1.0 —1.6 —1.4 —2.3 —4.2 —2.8 -o.1 -0.2 4.1 —0.8 —7.2 a 1956 - 1978 1.5 3.2 2.9 3.0 3.4 2.1 —0.2 —0.4 —0.3 0.1 —o.5 o 0.3 3.0 3.4 8.6 6.3 15.1 21.6 r 1978 — 1988 0.3 4.9 14.1 0.2 7.7 -0.5 -1.8 —2.5 3.0 4.0 4.2 7.6 11.7 8.8 11.3 14.5 16.7 10.7 1.0 S 1887 — 1988 —3.0 —2.4 —1.2 -1.8 -0.2 -0.5 0 0.6 0.6 1.6 1.9 2.3 2.8 4.1 5.0 6.1 6.2 5.8 4.1 Caminada-Moreau head/and gulfside summary Grand Isle gulfside summary Caminada-Moreau headland and Grand Isle gulfside summary Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count 1887 — 1934 —601.5 —15.8 9.6 -5.6 —45.3 38 1887 - 1934 -22.4 —0.9 5.9 6.9 —14.5 24 1887 — 1934 -624.0 -1o.1 11.1 6.9 —45.3 62 1934 — 1956 —437.2 —11.5 10.6 17.3 —33.0 38 1934 - 1956 0.0 0.0 3.5 7.7 —7.2 23 1934 — 1956 —437.2 —7.2 10.3 17.3 —33.0 61 1956 — 1978 —359.3 —9.5 6.5 1.8 —24.0 38 1956 — 1978 58.6 2.5 6.0 21.6 —8.9 23 1956 — 1978 —3oo.7 —4.9 8.6 21.6 —24.0 61 1978 - 1988 —-517.8 -13.6 7.8 —2.8 —42.0 38 1978 — 1988 118.7 5.2 5.7 16.7 -2.5 23 1978 — 1988 —399.1 -6.5 11.5 16.7 -42.0 61 1887 — 1988 —5o4.7 —13.3 5.6 —2.9 —20.0 38 1887 - 1988 20.2 0.9 3.1 6.2 —3.4 23 1887 — 1988 —484.4 -7.9 8.4 6.2 -2o.o 61 66 See page 46 for explanation of numbers. LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A Caminada - Moreau Headland and Grand Isle Island Area (ha/yr) Average Width (in) 1200 1000 \ \\// 1000 V 300 800 600 600 400 400 200 200 o I I I I I 0 | I I I I 1850 1875 1900 1925 1950 1975 2000 1850 1875 1900 1925 1950 1975 2000 Year Year FIGURE 34.-—-Area changes between 1887 and 1988 of FIGURE 35.—Average barrier width of Grand lsle between Grand Isle. 1887 and 1988. Width (m) 2000 - 1887 Width 7% 1988 Width 1500 1000 500 o I I I I I I «-- . - 0 4 8 12 16 20 24 28 32 36 4O 44 West Alongshore Position (km) East FIGURE 36.—Comparison of barrier widths for 1887 and 1988 for the Caminada-Moreau Headland and Grand lsle shoreline. TABLE 23,-Area changes for Grand Isle from 1887 to 1988 Projected Date Date Area (ha) Chanqe (ha) % Chanqe Rate(ha/vr) of Disagpearance 1887 1934 1934 1956 1956 1978 1978 1988 1887 1988 1,059 950 950 915 915 936 936 960 1,059 960 —109 —35 21 24 -99 -10% 4% 2% 3 % -9% —2.3 >1.6 1.0 1.1 —1.0 2347 2528 N.A. N.A. 2948 67 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY 68 The Plaquemines barrier shoreline lies about 45 km northwest of the mouth of the Mississippi River and about 80 km south-southeast of New Orleans (fig. 1). The arcuate barrier system is approximately 48 km long, forms the eastern flank of Barataria Bight, and extends from Grand Terre Islands to Sandy Point (chapter 1, fig. 14). The Plaquemines barrier shoreline consists of the Grand Terre Islands (west, central, and east), Cheniere Ronquille, the Bay La Mer area, Bay Joe Wise spit, Bastian Island, Shell Island, Pelican Island, and Sandy Point. These islands and spits range from 0.02 to 0.9 km wide. Barataria Pass, Pass Abel, Quatre Bayoux Pass, Pass Ronquille, Pass La Mer, Chaland Pass, Grand Bayou Pass, Coupe Bob, Fontanelle Pass, Scofield Bayou, and Dry Cypress Bayou Pass are some of the numerous tidal inlets and bayous that segment the shoreline. In addition, an extensive network of pipeline canals fragment the shoreline’s landscape. The Plaquemines shoreline has undergone severe coastal erosion and land loss, primarily from a lack of sediment supply, rapid subsidence, and storm and human impacts (Adams, 1970; Adams and others, 1976; Howard, 1982; Mossa and others, 1985; Penland and Suter, 1988; Levin, 1990; Ritchie and others, 1990). Maps presented depict changes along the shoreline during the years 1884, 1932, 1956, 1973, and 1988. From these maps, linear, area, and width measurements were obtained, and rates of change were calculated to determine the amount and rapidity of change that has occurred. MORPHOLOGY In 1884, Plaquemines’ morphology was influenced by several tidal inlets and passes, such as Barataria Pass, Quatre Bayoux Pass, Pass La Mer, Chaland Pass, Grand Bayou Pass, and two unnamed passes at both ends of Lanaux Island (1884 map). Grand Terre Island was a large and continuous barrier island that extended from Barataria Pass to Quatre Bayoux Pass. The remainder of the shoreline was dominated by deltaic headlands associated with Robinson Bayou, Grand Bayou, and Dry Cypress Bayou and flanking barrier islands and spits. Lanaux Island was a long and narrow barrier island with bulbous ends, which suggests long- shore sediment transport at both ends and an erosional center portion. By 1932, Grand Terre Island was breached, and Pass Ronquille opened east Plaquemines Barrier System—1884 to 1988 _ of Quatre Bayoux Pass (1932 map). Chaland Pass had widened substan- tially, and Lanaux Island was breached by an unnamed tidal inlet as its eastern end welded to the mainland shoreline. Moreover, an opening developed west of Sandy Point to form Sandy Point Island. By 1956, the Grand Terre area had deteriorated and separated into three smaller barriers (1956 map). Lanaux Island, currently known as Shell Island, welded onto the mainland shoreline and evolved into a long, narrow spit. Fontanelle Pass was dredged, and Scofield Bayou developed naturally, forming two new entrances along the shoreline. By 1973, Grand Terre Island was reduced to less than half its original size with only fragmentary island remnants remaining between Pass Abel and Quatre Bayoux Pass (1973 map). This fragmentary nature of the shoreline had developed between Pass Abel and Chaland Pass. Jetties at Fontanelle Pass (known as Empire jetties) blocked longshore sediment transport to the west-northwest, and a downdrift offset occurred. Large volumes of sand deposited against the updrift jetty to the east caused seaward advance, while the area to the west experienced inadequate sediment supply and shoreline recession. The Plaquemines shoreline appears to be reaching a complete breakdown in the coastal system (1988 map). The Grand Terre Islands no longer form a protective barrier for Barataria Bay. Submergence, a decreasing sediment supply, and human impacts have caused large areas of back-barrier marsh to be converted to open water (Britsch and Kemp, 1990). In 1979, Hurricane Bob breached Shell Island (Coupe Bob), and the island further deteriorated (see Neumann and others, 1985). SHORELINE MOVEMENT Magnitude and rate of change, as well as island width for the Plaquemines coast, were derived from 149 shore—normal transects along the gulf and bay shorelines (transects map; tables 24, 25, 26, 27, and 28). Comparisons of shoreline position are made for the periods 1884 vs. 1932, 1932 vs. 1956, 1956 vs. 1973, 1973 vs. 1988, and 1884 vs. 1988. Proximity of the shore-normal transects to entrances (tidal inlets) is also provided. The average rate of change between 1884 and 1932 along the gulf shoreline was -5.5 m/yr. This average rate decreased to —4. 1 and -3.2 m/ yr for the periods 1932 and 1956, and 1956 and 1973, respectively. However, the rate increased threefold to -9.9 m/yr between 1973 and 1988 (fig. 37, table 28). This period coincides with the occurrence of Hurricanes Bob (1979) and Juan (1985). The impacts of these hurricanes on the fragile Plaquemines shoreline probably contributed to the increased rate of retreat of the gulf shoreline over the last 15 years. The bayside rate of change between 1884 and 1932 averaged 2.2 m/ yr (table 26). From 1932 to 1956, the shoreline continued to migrate landward at a slower rate of 0.2 m/yr and reversed directions to increase to —2.3 m/ yr between 1956 and 1973. Bayside movement reversed again to migrate landward at 3.7 m/yr between 1973 and 1988 (fig. 38). A sudden reverse of the bay shoreline landward suggests storm impacts (hurricanes or cold fronts). Elevated water levels associated with storms carry sediment across islands and deposit it as washover along the bay shoreline to result in shoreline progradation. Hurricanes Bob and Juan directly impacted the Plaquemines shoreline and produced washover deposits (Neumann and others, 1985; Case, 1986; Penland and others, 1987, 1989c; Ritchie and others, 1990). The 1884 vs. 1988 map illustrates land loss and quantitative changes for the Plaquemines barrier system. The rate of gulfside change along ~ individualtransects ranged from 1.9 to -15.6 m/yr (table 28). Three locations exhibited stable or accretionary trends: west Grand Terre Island, west Shell Island, and the land east of Fontanelle Pass. Grand Terre and Shell islands experienced accretion from spit processes, but the land east of Fontanelle Pass is on the updrift side of the Empire jetties, which capture sediment in the longshore transport system. The average gulfside rate of change was -5.5 m/yr (table 28), and the bayside rate of change ranged from 12.5 to —4.7 m/yr, with an average rate of 0.4 m/yr (table 26). The average width narrowed from 487 to 263 m between 1884 and 1988 (fig. 39, table 27) because the gulf shoreline migrated landward about five times faster than the bay shoreline (—5.5 m/yr vs. 0.4 m/yr, respectively). Barrier widths for 1884 and 1988 are shown in figure 40. 0 Historic Shorelines 0 AREA AND WIDTH CHANGE Coalescing deltaic headlands with numerous spits dominate the Plaquemines shoreline. Therefore Grand Terre and Shell islands are the only locations along the Plaquemines coast where true area calculations could be obtained. Grand Terre In 1884, the area of Grand Terre was 1,699 ha with an average width of 909 m (tables 27 and 29). By 1932, both area and width decreased to 1,058 ha and 701 m, respectively. The average rate of land loss between 1884 and 1932 was 13.4 ha/yr, a 38 percent decrease in island area. By 1956, the area of Grand Terre was 901 ha and the average width 670 m. As width decreases in response to gulf and bayside erosion, area decreases. Between 1932 and 1956, the average rate of change decreased 15 percent to —6.5 ha/yr. By 1973, area had contracted further to 675 ha, while island width decreased to 608 m. Between 1956 and 1973, area decreased by 25 percent, or an average rate of 13.3 ha/yr. Between 1973 and 1988, the rate of land loss slowed slightly to —10.8 ha/yr (fig. 41). Overall, the area of Grand Terre Island decreased 1,186 ha at a rate of 11.4 ha/yr between 1884 and 1988 (fig. 42, table 29). Island width decreased from 909 to 530 m, an average island narrowing rate of 3.6 m/yr (fig. 43). Shell Island In 1884, the area of Shell Island was 127 ha with an average width of 136 m (tables 27 and 30). By 1932, area and width increased to 175 ha and 247 m as the island grew in size at a rate of 1.0 ha/yr (fig. 44). Between 1932 and'1956, the rate of change slowed to 0.1 ha/yr. Area remained relatively stable at 178 ha, while the width showed an increase to 269 m. By 1973, the size of the island decreased to 144 ha at a rate of 2.0 ha/yr. Similarly, island width narrowed to 207 m. The land loss rate further increased to —5.0 ha/yr between 1973 and 1988 as both area and width experienced nearly a 50 percent decrease to 69 ha and 105 m, respectively. Shell Island decreased 46 percent between 1884 and 1988 (fig. 45, table 30). Its width decreased 55 m to represent an average narrowing rate of 0.5 m/yr for the last 104 years (fig. 46). I 89°57’ o , 89 , 89° , 89°40’ ° ' ° ’ 29°19'38" 89,55 50 45 ‘ 89 35 — 89 30 29°19'30" ' Bay. Bastian Bay Barataria Joe Wise Bay CHENIERE RONOUILLE m 8 “- GRAND TERRE <17qu ISLAND ob Shell Island Bay 6° 6;. LANAUX 8% ISLAND <9 A 0%. 29°15,_ ' 29°15’ Bay Coquette s°° 1 8 8 4 SANDY POINT 29°12' I , o , l , I , 1 29°12' 89057, 89 55 89 50 89°45 89°40 89°35’ 89°30’ 99°29 r4 1" ’75: 2‘) Q‘ ’ .g I LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A 89°28’ 29°19’30” 89°30’ 89°35' Plaquemines 89°4U’ 89°45’ NO SURVEY FOR THIS AREA Bay Joe Wise 89°57’ 89°55’ 29°19'39" I ‘ I p. , I Ronquille Barataria Bay Bay Melville 05,3582 ‘3 v— :3 .9. g: E CHENIERE RONOUILLE s 08 ‘ Q E" \o ‘9 0 A S 0: «o D a; 06’ 3‘ (5" Q $8 GRAND TERRE :9 Q 0“ C, ISLANDS a“ 0‘3 O? Qffi 8 0 08° 63% 28% (006‘s 29°15’ A 29°I5' M E X I C Bay Coquette .\5 L F O F O 8001‘?“ O 0 Bay Jaque 1 93 2 SANDY POINT 29°12' I I I | I I , 29°12' 89°57, 89°55’ 89°50’ 89°45’ 89°40’ 89°35’ 89°39 89023! SCALE 1:100 000 1 0 1 2 3 4 5 MILES t—«I I—I I—I fl - . I 1 0 1 2 3 4 5 6 7 KILOMETERS I—I H H I . I———I ' I 39°57 89°50’ 89°45' 89°40’ 89°35' °3 ' 39°29 29°19'39" I ' I , - ‘ I 89I 0 29°19'39" Bay ’_ 4 « '| 'l' . A ) Ronqwlle )4“ , Ba t ' Ba ‘ ra and y Bay 53’ RE? Bastian Bay Bay Melville ‘ Dispute cf 3‘” CHENIERE RONQUILLE $3 ’ e, y . § 419 Q a? / 515-469 ‘ng é” g? Q0 9“ 9 8° Q 8 f g ‘ NO SURVEY FOR THIS AREA GRAND TERRE § v5 8 ~ 3 ISLANDS 0' 0 <1: Shell Island Bay (3: LANAUX 0*“ ISLAND Ge: 98 ’o «0 04:? 29°15' — — 29°I5’ G U L C O ((0 Coquette \ : <5 29012! I I I I I 29012] 89°55’ 89°50’ 89°45’ 89°40’ 89°35’ 89°30’ 89°28, 89°57’ US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY Plaquemines 89°45’ 29°19'380EIIE7I 89°55] 89°50’ I ”tit—8:; Bay )’ -I I 1‘! 3.3:. Ronquifie I“ J v '63.; ‘ I” ~—_._.. 89°35’ 89°28' 89°30’ 29019’30” ‘0 ~2) Barataria Bay p0 w a” g Q9 RONQUILLE 3 Q5, “”8469 A 9” a“: S a 9‘ I ‘I Q ‘I \‘5 NO SURVEY FOR THIS AREA V GRAND TERRE 8* 6° 63, ISLANDS c§ :1 O (6% Shell Island (3} Bay 60 ISLAND <90 2010,70 M E Pass 0 F X I C 0 29°15'— G U 29°I5' \ \ Bay Jaque 1 9 7 3 SANDY POINT 29°12' | | I I I I , 29012, 89057’ 89°55“ 89°50’ 89°45’ 89°40’ 89°35' 89°30 89°28’ SCALE 1:100 000 1 O 1 2 3 4 5 M|LES I———-I I—I I—I . fi = 4 1 O 1 2 3 4 5 6 7 KILOMETERS r—I I—I I—I I——-—I I——% 89057, O I O I O I O I O I O I 89028, 2901930,, 99'55 \ 89‘50' 89 45 89 40 89'35 89 [30 2901930,, “ow—— Bay ‘ ’ 7 . N g; t9 “Va: Bay MerIHe ’ 4)? § CHENIERE é Baratarla Bay Pas. § 39 RONOUILLE we, “5? Qt? RTHIS ARE GRAND TERRE 528) NO SURVEY F0 A ISLANDS d ’ <99 [274%‘0 °° F o F 29°I5' — G 29015, I? a, Q V0 01’ Bay (40“ \SQ‘ L-v“ Coquette 9 -I2: cf§ ‘ I ‘ V Bay Jaque 1 98 8 SANDY POINT a 29°12' I I I I (I) , '0 , 29°12’ 89057, 99°59 89°50’ 89°45’ 89°49 99 35 89 30 89°28’ 70 Average Rate (m/yr) -10 _12 I I I I 1875 1900 1925 1950 1975 Year 2000 FIGURE 37.—Average gulfside rate of change along the Plaquemines shoreline between 1884 and 1988. 2000 1500 1000 500 Plaquemines Average Rate (m/yr) 4 3 2 "\ _ 3 I I I | 1875 1900 1925 1950 1975 Year 2000 FIGURE 38,—Average bayside rate of change along the Plaquemines shoreline between 1884 and 1988 Average Width (m) - 1884 Width 7% 1988 Width West 8 12 16 20 24 2 Alongshore Position (km) 8 32 36 40 4 4 East FIGURE 40.—Comparison of the 1884 and 1988 barrier widths along the Plaquemines shoreline. Area Change Rate (ha/yr) 0 -10 / -12 z/// — 14 1875 1900 1925 1950 Year \/ 1975 Island Area (ha) LOUISIANA BARRIER ISLAND EROSION STUDY I—2150—A ATLAS OF SHORELINE CHANGES Average Width (m) 600 500 400 \ 300 200 100 I o I | I I 1850 1875 1900 1925 1950 Year 1975 2000 FIGURE 39.—Average barrier width of the Plaquemines shoreline between 1884 and 1988. 1500 \ 2000 FIGURE 4l.—Rate of area change for the Grand Terre Islands between 1884 and 1988. 1000 500 O I I I I I 1850 1875 1900 1925 1950 1975 Year 2000 FIGURE 42.—Area changes for the Grand Terre Islands be- tween 1884 and 1988. US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY Plaquemines 0 Shoreline Change and Land Loss 0 89°57’ 3 o , 89°45’ 29°19'30" 9155 Ba RonquiIIe , '/’ I , > -» _ . » We Buy ' R‘aHNEgEEE GRAND TERRE ISLANDS LANAUX R Shel! IsIand Bay 89°28’ 29°19’30” 89°35’ 8903’0’ eorq’onb p083 29015/_ 1 29015! 1887 vs 1932 0 29°12’ I , I , I , OI , I , I , 29°12' 89°57’ 89 55 89 50 89 45 89 40 89 35 89 30 89028, 1887 1932 SCALE 1:100 000 0 1 2 3 4 SMILES I—-I I—I I—I - - I | 1 0 1 2 3 4 5 6 7K|LOMETERS FI’I—I I—I : . I . - | 89°57, 89055! 890501 89045! 890401 89035, 89030, 89028! 29°19'30“ I ,v .. . , , I 29°19'30" ' CHENIERE I RONOUILLE Q) E U N) (a to o? GRAND TERRE ISLANDS ‘0 ‘0 Q? 3 Q 4r? LANAUX E: (5° Bastian Bay NO SURVEY FOR THIS AREA NO SURVEY FOR THIS AREA IN 1956 NO SURVEY FOR THIS AREA IN 1956 29°15'— O F M E 1932 vs. 1956 89°57, 89°55’ 89°50’ 89°45’ . 89°40’ 89°35’ 89°30’ 1932 1956 72 89°28’ 89°57’ 29°19’30" 89055’ Baratan'a Bay .0 0% Bay Melville 4‘59,» ' GRAND TERRE ISLANDS ‘ v CHENIERE RONOUILLE Plaquemines 89400] SHELL LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES 89°35’ 89°30’ Bastian Bay ISLAND NO SURVEY FOR THIS AREA NO SURVEY FOR THIS AREA IN 1956 NO SURVEY FOR THIS AREA IN 1956 [~2150—A 89°28’ 29°I9’30” - 29°45' 29°I5’—- I Q t' 9‘00 A O F M Q0 . ' 3 Bay Coquette 0 9o . Bay Jaque ‘ . 1973 SANDYPOINT I 1956 vs. 29°42’ I I , I I I 29°42' 89°57, 89°55’ 89°58 89°45’ 89°40' 89°35’ 89°30’ 89028, 1956 1973 89°57’ o I o I o l o I 89°28’ 2901930,, 89155 89 4 89 35 89 30 2901930,, Baratan’a Bay ' GRAND TERRE ISLANDS CHENIERE RONOUILLE V0- 9 ‘3 Q0 ’7 Bay Joe Wise Bastian Bay ' Shell Island Bay NO SURVEY FOR THIS AREA 29°15’ — 29°15’ SANDY POINT 1 9 7 3 vs . 1 98 8 29012! I I I I I I I 290121 89057, 89°55 89°50’ 89°45’ 89°40’ 39039 89030! 89028, 1973 1988 73 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY Plaquemmes TRANSEETNUMBER 1 2 3 4 5 5 7 a 9 10 13 57 58 59 EU 61 62 63 70 71 73 74 75 105 107 500 — 4 SHORELINE , ADVANCE A O 0 .71.. L5, 5 L E \ <2: E I k —4 Lu 0 O < I-I-I — I o o D u. I: _ —8 O L“ 2 Lu E: (D 1— -'m < —1000 < 30: E ' * 9: ob: u.1 ”DJ in: D —12 '- — U) W >- 2 < 00 __ m —1500 — -16 —2000 88°57’ I I o I o I o I c I 88°28I 8°5 ° 88 40 88 35 88 30 0 , ,, 28°18’30” 8 l 5 89 150 89 45 V . _ H , ., _ , _ , . ,. ,_ , , 29 1930 Bay ' Ronquille ' - Bastian Bay 1884 Bay Melville Barataria Bay CHENIERE RONQUILLE 1988 ‘0 yoga: Q , GRAND TERRE 09‘ $0900 SHELL ISLANDS 0:018 'SLAND <. .Shelllsland Bay 0 28°15’ 28°15I Coquette 118’ $00 I SCALE 1:100 000 Land 1 0 1 2 3 4 5 MILES H H H ' ‘ ' ‘ ' Land Loss 1 o 1 2 3 4 5 6 7 KILOMETERS H H H l ‘ ' I I . | 1884 vs. 1988 29°12’ 1 , g , 3 , ' 1 1 29°12’ 89°57’ 89°55 89 50 89 45 89°40’ 89035’ 39°30! 89°28’ THANSECT NUMBER 1 2 3 4 5 8 7 B 8 10 11 17 18 18 20 21 23 24 25 28 27 28 31 32 33 34 85 38 37 38 38 40 41 42 43 44 45 48 47 4B 48 50 51 54 55 58 57 58 58 80 B1 82 83 84 70 71 74 75 78 77 78 78 80 81 82 83 84 85 88 87 88 88 90 81 82 83 84 85 88 87 8888100101102 103 105 107 111 —2000 7 —16 A —1500 g _ L” ’2‘ 3 12 3 E g m 0 8 a: _ '— z __1 5 1000 <1: 3:436 LIJ I OE g “‘ ‘8 :3 In: I: o ‘0 Z 11‘ (D _ . g —500 g 7 —4 3 E 5 i 5 D D (3 O O . _ 0 -— — SHORELINE ADVANCE L 4 500 LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A Pl ' aquemmes TABLE 24 —Plaquem/nes baysrde magnitude of change (meters) Transact 11‘ 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 4O 41 42 43 44 45 46 47 48 49 Transact Coordinate 89° 56' 45” 30” 15" 89° 56' 00" 45” 30" 15" 89° 55' 00” 45” 30" 15" 89° 54' 00" 45” 30" 15” 89° 53' 00” 45" 30" 15" 89° 52' 00” 45" 30" 15" 89° 51' OO” 45" 30" 15” 89° 50' 00" 45" 30" 15” 89° 49' 00” 45” 30" 15” 89° 48' 00" 45" 30” 15” 89° 47' 00" 45" 30" 15” 89° 46' 00” 45” 30” 15” 89° 45' 00” 45” Y 1884 — 1932 ~77 ~218 -140 -171 ~213 ~34 ~62 ~131 ~33 ~17 n.a. ~43 n.a. 926 0 ~55 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. e 1932 — 1956 ~16 ~54 ~74 ~37 ~26 ~59 ~75 ~45 ~66 ~45 n.a. ~53 n.a. ~45 ~84 ~115 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. a 1956 - 1973 120 ~75 ~52 ~61 ~124 ~97 ~75 ~37 ~28 ~48 n.a. n.a. n.a. 16 n.a. 35 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. l' 1973 ~ 1988 75 ~31 ~63 ~78 ~113 ~102 ~72 ~64 ~45 253 n.a. n.a. n.a. n.a. n.a. 33 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. S 1884 ~ 1988 103 -378 -329 -347 -476 ~292 -304 —277 -174 14g n.a. n.a. n.a. n.a. n.a. ~101 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. Tran390t# 50 51 52 53 54 55 56 . 57 58 59 60 61 62 63 64 65 66 67 68 69 7O 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 '88 89 90 91 92 93 94 95 96 97 98 Transact coordinate 30" 15” 89° 44' 00" 45” 30" 15" 89° 43' 00" 45” 30" 15” 89° 42' 00" 45” 30” 15” 89° 41' 00" 45” 30” 15" 89° 40' 00” 45" 30” 15" 89° 39' 00” 45" 30” 15" 89° 38' 00" 45" 30" 15” 89° 37' 00" 45” 30” 15" 89° 36' 00" 45” 30" 15" 89° 35' 00” 45" 30" 15” 89° 34' 00" 45” 30" 15" 89° 33' 00” 45" 30” Y 1884 - 1932 n.a. n.a. n.a. n.a. n.a. n.a. n.a. 257 219 83 59 ~185 139 95 n.a. n.a. n.a. n.a. n.a. n.a. 294 ~60 25 533 428 223 n.a. 618 683 453 346 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 6’ 1932 — 1956 n.a. n.a. n.a. n.a. n.a. n.a. n.a. ~14 ~27 25 3 2 ~27 12 n.a. n.a. n.a. n.a. 25 ~13 21 38 4 18 ~56 564 n.a. 403 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. a 1956 — 1973 n.a. n.a. n.a. n.a. n.a. n.a. n.a. ~15 9 ~10 ~31 ~12 ~5 ~33 n.a. n.a. n.a. ~49 ~43 ~65 ~46 ~41 ~27 ~43 16 ~46 ~36 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. I’ 1973 — 1988 n.a. n.a. n.a. n.a. n.a. n.a. n.a. 4 ~17 ~39 ~297 ~57 ~48 ~83 n.a. n.a. n.a. 30 -2 -11 ~17 991 n.a. n.a. 757 551 172 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. S 1884 — 1988 n.a. n.a. n.a. n.a. n.a. n.a. n.a. 232 184 59 ~266 ~232 59 -8 n.a. n.a. n.a. n.a. n.a. n.a. 252 908 n.a. 503 1145 1297 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. Transect # 99 100 101 102 103 104 105 106 107 108 109 110 111 112 Grand Ter re lSlaNdS Dal/Side summary Shell Island baySIde summary Plaquemmes bays/d9 summary Transect coordinate 15" 89° 32' oo" 45" so" 15" 89° 31' oo" 45" so" 15" 89° 30' oo" 45" so" 15" 89° 29' 00" Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count Y 1884 — 1932 n.a. n.a. n.a. n.a. n.a. n.a. -219 -113 98 -283 n.a. 112 297 n.a. 1884 — 1932 —288 —2o.6 271.3 926 —218 14 1884 - 1932 3528 352.8 232.7 683 -80 10 1884 — 1932 3820 103.2 278.0 926 ~283 37 e 1932 - 1956 n.a. n.a. n.a. n.a. n.a. n.a. 73 33 -126 n.d. n.d. n.d. n.d. n.d. 1932 - 1956 —796 -56.9 24.4 ~16 -115 14 1932 - 1956 601 75.1 147.7 564 ~56 8 1932 - 1956 172 5.2 131.3 564 -126 33 a 1956 - 1973 n.a. n.a. n.a. n.a. n.a. n.a. -145 -130 -100 n.d. n.d. n.d. n.d. n.d. 1956 — 1973 —425 ~35.4 63.1 120 ~124 12 1956 - 1973 —380 —38.0 136.8 16 ~65 10 1956 - 1973 -1277 —39.9 50.3 120 -145 32 r 1973 — 1988 n.a. n.a. n.a. n.a. n.a. n.a. -27 n.a. ~188 n.a. n.a. n.a. ~15 n.a. 1978 — 1988 —2o1 —18.3 102.4 258 —113 11 1973 — 1988 2471 308.9 213.1 991 —17 8 1973 - 1988 1503 51.8 267.1 991 -297 29 s 1884 — 1988 n.a. n.a. n.a. n.a. n.a. n.a. -31B n.a. -316 n.a. n.a. n.a. n.a. n.a. 1884 - 1988 —2427 —220.6 188.3 148 ~476 11 1884 - 1988 4110 822.0 310.3 1297 252 5 1884 — 1988 1077 43.1 466.4 1297 -476 25 89057, 0 I o I o I O I 8 o I 89028, 29°19,30,, 89 [55 89 45 88 40 88‘ 35 9’ 30 2901930,, Bay Bastian Ba g Melville y Baratan‘a Bay 7 9 3 ’ 35 3 39 4 5 1 67 8 , '. Shell Island 7 Note: Bayslde and gultside transects 57-63, M 67-80. and 105-111 are identical. 29015' ~ G U ‘- 29°15 29°12 l l l l 2901 2' 89°57’ 89°55’ 89°50’ 89°45’ 89°40’ 89°35’ 39°30! 89°28, Gulfside Transects Bayside Transects TABLE 25 —P/aquem/nes gulfsrde magnitude of change (meters) Transact 71‘ 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 3O 31 32 33 34 35 36 37 38 39 4O 41 42 43 44 45 46 47 48 49 Transeot coordinate 89° 56' 45” 30” 15” 89° 56' 00" 45” 30” 15" 89° 55' 00” 45” 30” 15” 89° 54' 00" 45" 30" 15" 89° 53' 00" 45” 30” 15" 89° 52' 00" 45” 30” 15” 89° 51' 00” 45” 30” 15” 89° 50' 00" 45” 30” 15” 89° 49' 00” 45” 30" 15” 89° 48' 00" 45" 30” 15” 89° 47' 00” 45” 30" 15” 89° 46' 00” 45" 30” 15” 89° 45' 00" 45" Y 1 884 - 1 932 ~356 ~213 135 51 ~48 ~106 ~160 ~191 ~263 ~304 ~354 n.a. ~830 n.a. ~474 ~390 ~367 ~314 -280 -282 -330 ~93 ~28 ~907 ~917 ~712 ~747 ~933 ~520 ~443 ~48 ~$68 ~489 ~488 ~514 ~518 ~549 ~623 ~812 ~572 ~524 ~360 ~319 ~292 ~286 ~263 -307 -298 ~304 9 1932 ~ 1956 55 169 174 108 95 119 134 117 1 10 148 105 n.a. ~79 n.a. ~163 ~213 ~135 ~214 ~202 ~257 n.a. ~292 ~277 ~208 ~23! ~465 ~312 ~213 ~498 ~386 ~276 ~234 ~177 -186 -129 ~154 ~134 ~103 105 ~148 ~97 ~250 ~171 ~184 ~119 ~136 ~84 ~44 ~43 a 1956 — 1973 82 -1 -168 ~62 ~12 23 14 34 10 ~62 ~214 n.a. n.a, ~287 ~459 n.a. -218 -452 ~155 n.a. n.a. ~102 ~139 ~98 ~120 ~118 ~116 ~114 n.a. ~120 ~127 ~103 ~77 ~93 ~134 ~561 ~138 ~187 ~58 ~195 ~125 ~27 ~136 ~113 ~111 ~73 ~81 ~61 ~55 r 1973 — 1988 44 75 -128 -153 ~111 ~134 ~118 ~140 ~141 ~169 ~207 n.a. n.a. n.a. n.a. n.a. -234 88 -218 n.a. ~138 n.a. ~221 ~40? ~332 ~310 ~315 ~177 n.a. n.a. ~252 ~226 ~251 ~234 ~1B1 224 ~185 ~92 ~223 ~24 ~126 ~90 ~76 ~100 ~147 ~133 ~79 ~81 ~102 S 1884 - 1988 -175 30 13 ~56 ~76 ~98 ~130 ~180 ~284 ~407 ~670 n.a. n.a. n.a. n.a. n.a. ~954 ~892 -855 -795 -817 n.a. ~665 ~1620 ~1807 ~1605 ~1490 ~1437 n.a. n.a. ~705 ~951 ~994 ~981 ~958 ~1009 -1006 -1005 -988 ~939 ~874 ~727 -702 -689 ~665 ~625 ~551 ~504 ~504 Transect # ' 50 51 52 53‘ 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 Transact COO/'d/nafe 30” 15" 89° 44' 00” 45" 30” 15” 89° 43' 00" 45" 30" 15" 89° 42' 00” 45” 30" 15" 89° 41' 00” 45" 30” 15” 89° 40' 00” 45” 30" 15" 89° 39' 00" 45" 30” 15” 89° 38' 00” 45” 30" 15" 89° 37' 00" 45” 30” 15" 89° 36' 00" 45” 30” 15" 89° 35' 00" 45" 30” 15” 89° 34' 00" 45” 30" 15" 89° 33' 00” 45" 30” Y ' 1884 - 1932 -344 ~354 n.a. n.a. ~342 ~272 ~240 ~200 ~171 ~152 ~72 ~81 ~90 -7 121 n.a. ~53 26 118 n.a. 114 ~20 ~73 ~32 ~46 ~194 n.a. ~637 ~680 ~508 ~361 —234 261 278 371 342 282 265 158 63 -10 -109 471 -155 -305 -353 -454 -539 -594 e 1932 - 1956 ~14 ~20 n.a. 518 93 15 16 11 29 37 38 60 82 86 95 n.a. -93 134 233 21 ~80 ~85 ~141 ~217 ~256 ~317 n.a. ~278 ~251 ~286 ~302 ~240 ~282 ~151 -183 -168 ~141 ~132 ~54 ~7 50 723 357 ~94 ~28 -9 ~13 ~80 -131 a 1956 — 1973 -24 ~64 ~290 —73 ~14 -7 ~14 —19 ~10 -17 -12 ~17 ~26 4 -5 -30 188 27 -7 -35 -57 -71 -55 -52 -53 -27 -53 —a4 —32 -97 -57 -142 192 7 35 8 -5 4 -23 o 14 17 10 137 47 105 76 88 -7 r 1973 — 1988 '97 -13 185 ~61 ~80 ~82 ~81 ~64 ~64 ~63 ~49 ~52 ~32 ~38 ~93 n.a. ~54 ~156 ~209 ~232 ~257 ~1051 n.a. n.a. ~731 -691 433 ~301 -228 -192 ~274 ~275 ~87 ~115 ~96 ~52 ~73 ~115 ~95 ~145 ~150 ~144 ~163 3 47 24 -6 0 57 S 1884 - 1988 ~479 ~451 n.a. n.a. -343 -346 ~319 ~272 -216 -195 ~95 ~90 ~66 45 118 n.a. n.a. n.a. n.a. n.a. ~260 ~1227 n.a. n.a. ~1098 -1229 ~1229 ~1300 ~1241 ~1085 ~994 ~891 34 19 127 130 52 22 ~14 ~89 ~96 ~113 ~267 ~119 ~24O ~233 ~407 ~531 ~675 Transact ,4 99 100 101 102 103 104 105 106 107 108 109 110 111 112 Grand Terre Islands gulfsrde summary Shell Island gulfsrde summary Plaquemmes gulfsrde summary Transect coordinate 15" 89° 32‘ oo" 45" 30" 15" 89° 31' 00" 45" so" 15" 89° 30' 00" 45" so" 15" 89° 29' on" Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count Y 1384 _ 1932 -765 -857 —343 -268 ~358 -239 ~167 -181 -158 -171 n.a. -250 -210 n.a. 1884 — 1932 ~4817 —229.4 197.0 315 —630 21 1884 - 1932 —2580 —184.3 255.3 118 —680 14 1884 — 1932 -27600 ~265.4 279.7 371 —933 104 e 1932 _ 1956 -253 -208 -306 -332 -325 -287 -277 -240 -236 n.d. n.d. n.d. n.d. n.d. 1932 - 1956 —498 -24.9 169.1 174 —292 20 1932 - 1956 -2142 -142.8 161.7 233 —317 15 1932 — 1956 -9867 -97.7 173.1 518 —498 101 a 1956 - 1973 95 71 27 65 119 1 44 47 33 n.d. n.d. n.d. n.d. n.d. 1956 — 1973 -2188 —121.6 153.9 82 —459 18 1956 - 1973 —698 —41.1 67.7 188 -142 17 1956 — 1973 —5429 —53.8 115.9 192 —561 101 r 1973 _ 1988 -141 -94 -147 -147 -171 n.a. ~160 n.a. ~226 n.a. n.a. n.a. -105 n.a. 1973 — 1988 —1905 —119.1 98.0 88 —234 16 1973 — 1988 ~5084 ~363.1 264.4 -54 -1051 14 1973 — 1988 -13955 —148.5 166.5 224 —1051 94 s 1884 — 1988 -1064 -918 ~769 —682 —735 n.a. ~560 n.a. ~587 n.a. n.a. n.a. -528 n.a. 1884 — 1988 ~6831 —4o1.8 365.1 193 —954 17 1884 - 1988 —10554 —1055.4 291.6 ~260 -1300 10 1884 — 1988 -51411 -571.2 464.5 193 —1620 90 See page 46 for explanation of numbers. 75 US. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY O Plaquemmes TABLE 26.—Plaquem1nes bays1de rate of change (meters per year) Transect # 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 4O 41 42 43 44 45 46 47 48 49 Transact coordinate 89° 56' 45" 30" 15" 89° 56' 00" 45" 30" 15" 89° 55' 00" 45" 30" 15" 89° 54' oo" 45" 30" 15" 89° 53' 00" 45" 30" 15" 89° 52' oo" 45" 30" 15" 89° 51' 00" 45" 30" 15" 89° 50' 00" 45" 30" 15" 89° 49' 00" 45" 30" 15” 89° 48‘ 00" 45" 30" 15" 89° 47' 00" 45" 30" 15" 89° 46' 00" 45" 30" 15" 89° 45' 00" 45" Y 1884 - 1932 —1.6 —4.5 —2.9 -3.6 —4.4 —0.7 -1.7 —2.7 -0.7 —0.4 n.a. -O.9 n.a. 19.3 0 —1.1 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 6’ 1932 — 1956 —0.7 -2.3 -3.1 —1.5 —1.1 —2.5 —3.1 -1.9 -2.8 —1.9 n.a. -2.2 n.a. -1.9 -3.5 —4.8 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. a 1956 — 1973 7.1 —4.4 —3.1 —3.6 -7.3 —5.7 —4.4 -2.2 —1.6 —2.8 n.a. n.a. n.a. 0.9 n.a. 2.1 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. r 1973 — 1988 5.1 -2.1 —4.2 —5.2 —7.5 —6.8 -4.8 —4.3 —3.0 17.2 n.a. n.a. n.a. n.a. n.a. 2.2 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. S 1884 — 1988 1.0 —3.7 —3.3 -3.4 —4.7 —2.9 —3.0 —2.7 -1.7 1.5 n.a. n.a. n.a. n.a. n.a. —1.0 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. Transact # 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 Transect coordinate 30" 15" 89° 44' 00" 45" 30" 15" 89° 43' 00" 45" 30" 15" 89° 42' 00" 45" 30" 15" 89° 41' 00" 45" 30" 15" 89° 40' oo" 45" 30” 15" 89° 39' 00" 45" 30" 15" 89° 38' oo" 45" 30" 15" 89° 37' 00" 45" 30" 15" 89° 36' 00" 45" 30" 15" 89° 35' 00" 45" 30" 15" 89° 34' 00" 45" 30" 15" 89° 33' 00" 45" 30" Y 1884 — 1932 n.a. n.a. n.a. n.a. n.a. n.a. n.a. 5.4 4.6 1.7 1.2 —3.4 2.9 2.0 n.a. n.a. n.a. n.a. n.a. n.a. 6.1 -1] 05 11.1 8.9 43 n.a. 129 142 9.4 7_2 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n,a. n.a. n a. n.a. n.a. n.a. e 1932 - 1956 n.a. n.a. n.a. n.a. n.a. n.a. n.a. -0.6 -1.1 1.0 0.1 0.1 —1.1 0.5 n.a. n.a. n.a. n.a. 1.0 —o.5 0.9 1.6 0.2 0.8 —2.3 23.5 n.a. 17.0 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. a 1956 - 1973 n.a. n.a. n.a. n.a. n.a. n.a. n.a. -0.9 0.5 -O.6 -1.8 -0.7 -0.3 —1.9 n.a. n.a. n.a. -29 _2_5 _3_3 -2.7 _2_4 —1,5 —2,5 0.9 —2,7 -2.1 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. r 1973 — 1988 n.a. n.a. n.a. n.a. n.a. n.a. n.a. 0.3 ~1.1 —2.6 -19.8 -3.8 —3.2 —5.5 n.a. n.a. n.a. 2.0 -O.1 —0.7 —1.1 66.1 n.a. n.a. 50,5 36.7 11,5 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. S 1884 - 1988 n.a. n.a. n a, n.a. n.a. n.a. n.a. 2.2 1.8 0.6 -2.6 —2.2 0.6 —O.1 n.a. n.a. n.a. n.a. n.a. n.a. 2.4 8.7 n.a. 4.9 11.0 12.5 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. Transect# 99 100 101 102 103 104 105 106 107 108 109 110 111 112 Grand Terr 8 Islands baySIde summary Shall Island baySIda summary Plaquemmes baysrda summary Transect coordinate 15" 89° 32' 00" 45" 30" 15" 89° 31' oo" 45" 30" 15" 89° 30' 00" 45" 30" 15" 89° 29' 00" Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count Y 1884 — 1932 n.a. n.a. n.a. n.a. n.a. n.a. —4.6 —2.4 2.0 -5.9 n.a. 2.3 6.2 n.a. 1884 - 1932 —6.0 -o.4 5.7 19.3 —4.5 14 1884 — 1932 73.5 7.4 4.8 14.2 —1.7 10 1884 - 1932 79.6 2.2 5.8 19.3 —5.9 37 a 1932 - 1956 n.a. n.a. n.a. n.a. n.a. n.a. 3.0 1.6 —5,3 n.d. n.d. n.d. n.d. n.d. 1932 — 1956 —33.2 —2.4 1.0 —o.7 —4.8 14 1932 — 1956 25.0 3.1 3.9 23.5 -2.3 8 1932 — 1956 7.2 0.2 5.5 23.5 -5.3 33 a 1956 - 1973 n.a. n.a. n.a. n.a. n.a. n.a. —8.5 -7.6 -5,9 n.d. n.d. n.d. n.d. n.d. 1956 — 1973 -25.0 —2.1 3.7 7.1 —7.3 12 1956 — 1973 -22.4 —2.2 4.3 0.9 —3.8 10 1956 — 1973 -75.1 —2.3 3.0 7.1 —8.5 32 r 1973 - 1988 n.a. n.a. n.a. n.a. n.a. n.a. —1.8 n.a. —12.5 n.a. n.a. n.a. —1.0 n.a. 1973 — 1988 —13.4 -1.2 6.8 17.2 —7.5 11 1973 — 1988 164.7 20.6 12.4 66.1 —1.1 8 1973 - 1988 100.2 3.5 17.8 66.1 —19.8 29 s 1884 — 1988 n.a. n.a. n.a. n.a. n.a. n.a. -3.1 n.a. —3.0 n.a. n.a. nta. n.a. n.a. 1884 — 1988 —24.0 -2.2 1.9 1.5 —4.7 11 1884 — 1988 39.5 7.9 12.0 12.5 2.4 5 1884 — 1988 9.7 0.4 4.5 12.5 -4.7 25 TABLE 27.—-—P/aquem1nes Width measurements (meters) Transact fl‘ 1 2 3 4 5 6 7 8 9 1O 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 Transact coordinata 89° 56' 45" 30" 15" 89° 56' 00" 45" 30” 15" 89° 55' 00" 45" 3o" 15" 89° 54' 00" 45" 30" 15" 89° 53' 00" 45" 30" 15" 89° 52' 00" 45" 30" 15" 89° 51' oo" 45" 30" 15" 89° 50' 00" 45" 30" 15" 89° 49' 00" 45" 30" 15" 89° 48‘ 00" 45" 30" 15" 89° 47' 00" 45" 30" 15” 89° 46' 00" 45" 30” 15" 89° 45' oo" 45" Y 1884 n.a. 740 893 1199 1383 1390 1145 891 738 1080 n.a. 578 993 393 389 915 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. e 1932 n.a. 329 964 1058 1168 1109 752 487 371 686 n.a. n.a. 321 n.a. 678 494 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. a 1956 n.a. 345 908 1081 1171 1146 870 586 454 617 n.a. n.a. 268 591 478 195 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. l' 1973 n.a. 342 660 934 1094 1012 803 555 424 461 n.a. n.a. n.a. 319 83 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. S 1988 n.a. 397 700 656 824 880 479 346 241 251 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. Transact # 50 51 52 53 54 55 56 57 58 59 6O 61 62 63 64 65 66 67 68 69 7O 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 Transact coordinate 30" 15" 89° 44' 00" 45" 30" 15" 89° 43‘ 00” 45" 30" 15" 89° 42' 00" 45" 30" 15" 89° 41' 00" 45" 30" 15" 89° 40' oo" 45" 30" 15" 89° 39' 00" 45" 30" 15" 89° 38' 00" 45" 30" 15" 89° 37' 00" 45" 30" 15" 89° 36' 00" 45" 30” 15" 89° 35' 00" 45" 30" 15" 89° 34' 00" 45" 30" 15" 89° 33' 00" 45" 30" Y 1884 n.a. n.a. n.a. n.a. n.a. n.a. n.a. 136 119 208 577 449 210 195 n.at 86 200 259 331 17.3 34 351 377 52 79 69 402 55 49 93 70 293 “~a- "-a- “~a- "-a- “-a- ”-a- “-a~ ”-a- "-a- "-a- “-a~ "-9 "‘a- ”-a~ "-a- “-a' ”-a- 8 1932 n.a. n.a. n.a. n.a. n.a. n.a. n.a. 193 167 139 565 202 261 285 n.a. n.a. 11g 257 251 505 442 251 331 552 462 100 ynja. 36 53 39 56 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. a 1956 n.a. n.a. n.a. n.a. n.a. n.a. n.a. 192 169 201 605 264 314 380 n.a. n.a. 34 199 175 510 402 204 195 355 157 348 384 168 08- "fit "-3. '19- n-a- n-a- "-83 n-a- ”~a- “13‘ “-a- “a "-a- ”-a- "~a- “-a~ ”-a- "-5“ "~a- ”-a' ”~31 I' 1973 n.a. n.a. n.a. n.a. n.a. n.a. n.a. 160 170 138 560 234 285 351 n.a. n.a. 111 17g 145 410 297 91 110 261 101 275 296 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. S 1988 n.a. n.a. ”.3. n.a. fl.a. n.a. n.a. 99 87 72 214 125 204 230 n.a. 234 64 53 120 166 23 29 n.a. n.a. 123 147 36 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. Transect# 99 100 101 102 103 104 105 106 107 108 109 110 111 112 Grand Terre Islands Width summary Shell Island WIdth summary Plaquemmes w1dth summary Transect coordinate 15" 89° 32' oo" 45" 30" 15" 89° 31' oo" 45" 30" 15" 89° 30' 00" 45" 30" 15" 89° 29' 00" Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count Y 1884 n.a. n.a. n.a. n.a. n.a. n.a. 980 908 968 575 166 412 626 n.a. 1884 12727 909.1 809.0 1390 389 14 1884 2183 136.4 111.7 377 34 16 1884 21439 487.3 407.1 1390 34 44 a 1932 n.a. n.a. n.a. n.a. n.a. n.a. 667 648 945 124 n.a. 274 708 n.a. 1932 8417 701.4 297.9 1168 321 12 1932 3458 247.0 179.1 552 36 14 1932 17053 437.3 310.5 1168 36 39 a 1956 n.a. n.a. n.a. n.a. n.a. n.a. 430 419 736 n.d. n.d. n.d. n.d. n.d. 1956 8710 670.0 320.5 1171 195 13 1956 2963 269.4 132.7 510 34 11 1956 15551 444.3 291.2 1171 34 35 r 1973 n.a. n.a. n.a. n.a. n.a. n.a. 353 359 663 n.a. n.a. 80 551 n.a. 1973 6687 607.9 306.7 1094 83 11 1973 2276 206.9 101.2 410 91 11 1973 12867 378.4 269.2 1094 80 34 s 1988 n.a. n.a. n.a. n.a. n.a. n.a. 166 n.a. 251 n.a. n.a. n.a. 372 n.a. 1988 4774 530.4 228.3 880 241 9 1988 1045 104.5 77.3 284 23 10 1988 7639 263.4 282.4 880 23 29 TABLE 28.——P/aquem1nes gu/fside rate of change (meters per year) Transect 11‘ 1 2 3 4 5 6 7 8 9 1O 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 3O 31 32 33 34 35 36 37 38 39 4O 41 42 43 44 45 46 47 48 49 Transect coordinate 89° 56' 45" 30" 15" 89° 56' 00" 45" 30" 15" 89° 55' oo” 45" 30" 15" 89° 54' 00" 45" 30" 15" 89° 53' 00" 45" 30" 15" 89° 52' oo" 45" 30" 15" 89° 51' oo" 45" 30" 15" 89° 50' 00" 45" 30" 15" 89° 49' 00" 45" 30" 15" 89° 48’ oo" 45” 30" 15" 89° 47' 00" 45" 30" 15" 89° 46‘ 00" 45" 30" 15" 89° 45' oo” 45" Y 1884 - 1932 -7.4 -4.4 2.8 1.1 -1.0 —2.2 —3.3 -4.0 —5.5 —6.3 —7.4 ",2 —13.1 n.a. —9.9 -8.1 —7.6 -6.5 —5.8 —5.9 —6.9 —1.9 —0.6 -18.9 -19.1 -14.8 —15.6 —19.4 —10.8 -9.2 -1.0 -8.1 -10.2 -1o.2 -1o.7 —10.8 -11.4 -13.0 -16.9 -11.9 —1o.9 —7.5 -6.6 —6.1 —6.0 -5.9 —6.4 —6.2 -6.3 a 1932 — 1956 2.3 7.0 7.3 4.5 4.0 5.0 5.6 4.9 4.6 6.2 4.4 n.a. —3.3 n,a_ —6.8 -8.9 —5.6 —8.9 —8.4 -10.7 n.a. -12.2 —11.5 -8.7 -9.9 —19.4 -13.0 -8.9 —20.8 —16.1 —11.6 -9.8 -7.4 -6.9 -5.4 -6.4 —5.6 —4.3 4,4 -6.2 —4.0 —10.4 —7.1 -7.7 —5.0 —5.7 ~35 -1.8 —1.8 a 1956 — 1973 4.8 —0,1 -9.9 -3.6 -o.7 1.4 0.8 2.0 0.6 -4.8 -12.6 n,a_ M, -16.9 -27.0 "a, -12.8 -26.6 -9.1 "A n.a. -6.0 -8.2 -5.8 -7.1 —6.9 -6.8 -6.7 n.a. —7.1 —7.5 —6.1 —4.5 —5.5 —7.9 -33.0 -8.1 —11.0 -3.4 ~11.5 —7.4 —1.6 —8.0 -6.6 -6.5 —4.3 -4.8 —4.8 —3.2 r 1973 - 1988 2.9 5.0 —8.5 —1o.2 —7.4 —8.9 —7.9 —9.3 —9.4 -11.3 -13.8 "Ia n_a_ n_a_ n.a. M, -15.6 5.9 —14.5 n.a. —9.2 n_a_ ~14? —27.1 -22.1 -20.7 —21.0 —11.8 n.a. n.a. -16.8 -15.1 -16.7 -15.6 —12.1 14.9 -12.3 —6.1 -14.9 —1.6 —8.5 -6.0 —5.1 —6.7 -9.8 —8.9 —5.3 -5.4 —6.8 s 1884 _ 1988 -1.7 0.3 0.1 —o.5 -o.7 —0.9 —1.3 —1.7 —2.7 —3,9 —6.4 n.a. n.a. n.a_ n_a, n.a. —9.2 -8.6 -8.2 -7.6 -7.9 n_a_ —6.4 —15.6 -15.5 —15.4 -14.3 -13.8 n.a_ M, -6.8 —9.1 —9.6 —9.4 —9.2 —9.7 -9.7 —9.7 -9.5 -9.0 —8.4 -7.0 -6.8 —6.6 —6.4 —6.0 —5.3 —4.8 —4.8 Transact # 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 8O 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 Transact coordlnata 30" 15" 89° 44’ oo" 45" 30" 15" 89° 43' oo" 45" 30" 15" 89° 42' 00" 45" 30" 15" 89° 41‘ 00" 45" 30" 15" 89° 40' 00” 45" 30" 15" 89° 39' oo" 45" 30” 15" 89° 38' 00" 45" 30" 15" 89° 37' 00" 45" 30" 15" 89° 36' 00" 45" 30" 15" 89° 35' 00" 45" 30" 15" 89° 34' oo" 45" 30" 15" 89° 33' 00" 45" 30" Y 1884 - 1932 -7.2 -7.4 n.a. o -7.1 —5.7 -5.0 -4.2 —3.6 -3.2 —1.5 —1.7 —1.9 -0.1 2.5 n.a, —1.1 0.5 2.5 n.a. 2.4 —0.4 —1.5 —0.7 —1.0 -4.0 ”.5 —13.3 —14.2 —10.6 —7.5 —4.9 5,4 5,3 7_7 7.1 5.9 5.5 3,3 1,3 -0.2 —2.3 —9.8 -3.4 —6.4 —7.4 —9.7 -11.2 —12.4 e 1932 _ 1955 —0.6 -0.8 n.a. 21.6 3.9 0.6 0.7 0.5 1.2 1.5 1.6 2.5 3.4 3.6 4.0 n.a. -3.9 5.6 9.7 0.9 -2.5 —3.5 —5.9 —9.0 —10.8 -13.2 M. -11.6 -1o.5 -12.0 —12.6 —1o.o —11.8 —6.3 -7.6 -7.0 —5.9 -5.5 -2.3 -o.3 2,1 51 1419 —3.9 —1.2 -0.4 —0.5 —3.3 —5.5 a 1956 - 1973 -1.4 -3.8 -17.1 —4.3 -O.8 -o.4 —0.8 —1.1 -o.6 —1.0 —0.7 —1.0 -1.5 0.2 —o.3 -1.8 11.1 1.6 —o.4 —2.1 -3.4 -4.2 —3.3 —3.1 -3.7 -1.6 —3.1 —4.9 —4.8 -5.7 —3.4 -8.4 113 0,4 2,1 0.5 —0.4 02 —1.4 o 0.8 1.0 0,5 3.1 2.3 6,2 4.5 5,2 -0.4 r 1973 - 1988 —6.5 —o.9 12.3 —4.1 —5.3 —5.5 -5.4 -4.3 ~43 —4.2 -3.3 —3.5 -2.1 —2.5 -6.2 n.a. —3.6‘ —1o.4 —13.9 —15.5 -17.1 —70.1 M, "a, -48.7 -46.1 —28.9 —20.1 —15.2 —12.8 -18.3 —18.3 -5.8 —7.7 —6.4 -3.5 —4.9 -7.7 —6.3 —9.7 -10.0 —9.6 —10.9 02 3.1 1,5 —o.4 0 3,3 8 1884 — 1988 -4.6 --43 n.a. o -3.3 -3.3 —3.1 —2.6 —2.1 —1.9 —0.9 —0.9 —0.6 0.4 1.1 n.5, n_a, ”a, n.a_ ”a, —2.5 —11.8 n.a. n,a_ —10.6 —11.8 -11.8 -12.5 —11.9 —1o.4 —9.6 —8.6 0.3 02 1.2 1_3 0.6 0,2 —o.1 —o.9 —0.9 —1.1 —2.6 —1.1 -2.3 —2.2 -3.9 -5.1 -6.5 Transect# 99 100 101 102 103 104 105 106 107 108 109 110 111 112 Grand Terra Islands gulfsrde summary Shell Island gulfsrde summary Plaquemmes gulfSIde summary Transect coordinate 15" 89° 32' 00" 45" 30" 15" 89° 31' 00" 45" 30" 15" 89° 30' 00" 45" 30" 15" 89° 29' 00-" Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count Y 1884 - 1932 -15-9 -143 -7-1 -5-6 -7-5 -6-0 -3.5 -3-8 -3.3 -3-6 n.a. -52 -45 n.a. 1884 — 1932 —1oo.4 -4.8 4.1 6.6 —13.1 21 1884 - 1932 -53.8 -8.8 5.3 2.5 —14.2 14 1884 - 1932 -575.0 -5.5 5.8 7.7 -19.4 104 e 1932 — 1956 —10.5 —8.7 —12,8 -13.8 -13.5 -12.0 -11.5 —10.0 —9.8 n.d. n.d. n.d. n.d. n.d. 1932 - 1956 —2o.8 —1.0 7.0 7.3 —12.2 20 1932 - 1956 —89.3 —6.0 6.7 9.7 -13.2 15 1932 - 1956 -411.1 —4.1 7.2 21.6 —20.8 101 a 1956 - 1973 5.6 4‘2 1.6 3.8 7.0 0.1 2.6 2.8 1.9 n.d. n.d. n.d. n.d. n.d. 1956 — 1973 -128.7 —7.2 9.1 4.8 -27.0 18 1956 — 1973 —41.1 —2.4 4.0 11.1 -8.4 17 1956 — 1973 ~319.4 —3.2 6.8 11.3 ~33.o 101 f 1973 — 1988 -9.4 —6.3 -9.8 —9.8 -11.4 n.a. -10.7 n.a. —15.1 n.a. n.a. n.a. -11.0 n.a. 1973 — 1988 —127.0 —7.9 6.5 5.9 —15.6 16 1973 — 1988 —338.9 —24.2 17.6 —3.6 —70.1 14 1973 - 1988 -930.3 -9.9 11.1 14.9 —70.1 94 S 1884 - 1988 -10-2 -8-8 ~74 -6-6 -7-1 n.a. -5-4 n.a. -56 n.a. n.a. n.a. -591 n.a. 1884 — 1988 —65.7 —3.9 3.5 1.9 —9.2 17 1884 — 1988 -1o1.5 —10.1 2.8 —2.5 —12.5 10 1884 - 1988 -494.3 —5.5 4.5 1.9 —15.6 90 76 See page 46 for explanation of numbers. Average Width (m) 1000 \ 800 600 400 200 1 1 1 O 1850 1875 1900 1925 YEar 1950 1975 2000 FIGURE 43.—Average barrier width of the Grand Terre Islands between 1884 and 1988. Island Area (ha) 200 150 / 100 50 1 1 O 1850 FIGURE 45.—Area changes of Shell Island between 1884 1875 and 1 988. TABLE 29.-—Area changes for Grand Terre Island 1900 1925 Year from 1884 to 1988 1950 1975 2000 Projected Date Date Area {hat Change (ha) 00 Change Rategha/yrl of Disappearance 1884 1932 1932 1956 1956 1973 1973 1988 1884 1988 1,699 1,058 1,058 901 901 675 675 513 1,699 513 —641 -157 —226 —162 -1,186 -38% —15% -25% -24% —70% —13.4 -6.5 -13.3 -10.8 -11.4 2011 2095 2024 2036 2033 Plaquemines Area Change Rate (ha/yr) \ \ \ -6 1875 1900 1 1925 Year 1950 1 1975 2000 FIGURE 44.—Rate of area change of Shell Island between 1884 and 1988. Average Width (m) 300 250 200 150 100 50 J I 1 0 1850 1875 1900 1925 Year 1950 1975 2000 FIGURE 46.—Average barrier width of Shell Island between 1884 and 1988. TABLE 30.—Area Changes for the Shell Island from 1884 to 1988 Date 1884 1932 1932 1956 1956 1973 1973 1988 1884 1988 Area 1ha1 127 175 175 178 178 144 114 69 127 69 Projected Date Rate (ha/vr) of Disappearance Change (ha) % Chanqe 48 38% 3 0% -34 -19% -75 -52% -58 -46% 1.0 0.1 —2.0 -5.0 N.A. N.A. 2045 2002 2103 LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A 77 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY 78 Morphology The South Chandeleur Islands are fragmented into three groups of small ephemeral islands and shallow shoals that are separated by wide tidal inlets. In 1869, the barrier islands included Breton Island, Errol Island, and Curlew Island (1869 map). Grand Gosier, which currently lies between Breton Island and Curlew Island, was not mapped on the NOS T—sheet for this area. Either field surveyors accidently missed the island, or the island did not exist at that time. Breton Island displayed a typical horseshoe shape that characterizes the island today, which suggests antecedent topographic control that anchors both ends. By 1922, all of the islands except Breton were reduced to small islands and shoals (1922 map). Additionally, Breton Island was breached, and two small shoals appeared between Breton and Errol islands. These features later corresponded to the north and south ends of Grand Gosier Island. By 1951, Grand Gosier had evolved into a substantial barrier island apparently from two much smaller shoals (1951 map). Also, Errol Island was not present, leaving Curlew Island and the southern half of Stake Island to the north. The 1978 map depicts Breton and Grand Gosier islands as breached. The resistant ends of Breton Island are evident and tend to anchor the island. Grand Gosier Island evolved into two smaller islands known as north and south Grand Gosier islands, and Curlew Island was the single remaining barrier island to the north. By 1989, these three groups of islands had remained relatively intact (1989 map). The central portion of Breton Island remained susceptible to breaching, and the northern end of south Grand Gosier formed a unique recurved spit directed offshore. A large fetch is available across Breton and Chandeleur sounds capable of producing enough wave energy to form well—developed, barred beaches along the bay shorelines of south and north Grand Gosier islands and Curlew Island. On the northern end of south Grand Gosier, bayside wave energy may be more dominant than gulfside wave energy, thus producing the recurved spit. Chandeleur Islands Barrier System — The Chandeleur Islands barrier system lies about 25 km north— northeast of the mouth of the Mississippi River and about 120 km east of New Orleans (fig. 1). This system extends south to north from Breton Island to Hewes Point (chapter 1, fig. 18). The Chandeleur Islands are the largest barrier island system along the Mississippi River delta plain and provide the seaward protective boundary for St. Bernard Parish (Kwon, 1969; Kahn, 1980; Nummedal and others, 1980; Kahn and Roberts, 1982; Penland and others, 1985; Suter and others, 1988; Ritchie and others, 1991). Three tidal inlets, Breton Island Pass, Grand Gosier Pass, and Curlew Island Pass, connect the Gulf of Mexico to Breton and Chandeleur sounds. For the purposes of this atlas, the Chandeleur Islands barrier system is divided into two sections: South Chandeleur Islands (Breton, Grand Gosier, and Curlew islands) and North Chandeleur Islands (New Harbor, North, and Freemason islands, and Chandeleur Island). The South Chandeleur Islands extend north from Breton Island to Curlew Island, and the North Chandeleur Islands extend from Curlew Island Pass to Hewes Point. Shoreline position, island width, and rate of change data were compiled for the South Chandeleur Islands from the years 1869, 1922, 1951, 1978, and 1989; the North Chandeleur Islands include the years 1855, 1922, 1951, 1978, and 1989. South Chandeleur Islands—1869 to 1989 Shoreline Movement Shoreline change maps were constructed for the South Chandeleur Islands area. Shoreline movement and island width were derived from 120 shore-normal transects along the gulf and bay shorelines (transects map, tables 31, 32, 33, 34, and 35). Comparisons of shoreline position are made for the periods 1869 vs. 1922, 1922 vs. 1951, 1951 vs. 1978, 1978 vs. 1989, and 1869 vs. 1989. The average rate of gulfside change for the South Chandeleur Islands between 1869 and 1922 was —11.3 m/yr (fig. 47, table 35). This rate decreased twofold to —5.7 m/yr between 1922 and 1951. Between 1951 and 1978, the rate increased to —16.6 m/yr and increased further to -19.7 m/yr between 1978 and 1989. Along the bay shoreline, the average rate of change was 8.8 m/yr between 1869 and 1922 and decreased to 5.9 m/yr between 1922 and 1951 (fig. 48, table 33). The rate increased to 9.8 and 19.8 m/yr for the periods 1951 to 1978 and 1978 to 1989, respectively. The South Chandeleur Islands are migrating landward along the gulf and bay shorelines because a good sediment supply exists, and the islands are narrow and low enough for this sediment to be transported across the island by washover processes. The 1869 vs. 1989 map illustrates land loss and summarizes changes along the gulf and bay shorelines. Between 1869 and 1989, the average rate of change along the gulf shoreline ranged from 5.9 to -2 1.1 m/yr with an average rate of -11.6 m/yr (table 35). The gulf shoreline of the South Chandeleur Islands has undergone retreat over the last 120 years, except for the southern end of Breton Island, which experienced accretion. The bay—side rate of change ranged from 22.6 to —7.7 m/yr, with an average rate of 10.7 m/yr (table 33). The gulf shoreline is migrating landward about 1.0 m/yr faster than the bay shoreline (-1 1.6 m/yr vs. 10.7 m/yr), causing the barrier width to narrow as the islands retreat (fig. 49, table 34). Area and Width Change Breton Island In 1869, the average width of Breton Island was 396 m, and the area was 332 ha (tables 34, and 36). This area decreased by 18 percent to 271 ha over the next 53 years, with a similar decrease in width to 320 m. The average rate of change between 1869 and 1922 was —1.2 ha/yr. However, by 1951, island area expanded to 291 ha at a rate of 0.7 ha/ yr, but island width continued to narrow (292 m). During the period 1951 to 1978, Breton Island experienced the greatest amount of area loss. Island area was reduced by 52 percent, with a loss of 150 ha at a rate of 5.4 ha/yr, and the average island width narrowed to 268 m. Because its center area was breached, the island lost its unconsolidated and highly mobile central portion to leave two resistant ends that did not experience much change. Between 1978 and 1989, Breton Island slowly recovered and actually experienced a 23—ha increase in area to 164 ha, reversing from land loss to land gain at a rate of 2.2 ha/yr. Interestingly, average width continued to decrease (199 m) even though area was increasing. This was possible because the breached central portion of Breton Island almost completely recovered to cause area gain. Average island width did not increase, however, because the recovered central portion had always been narrower than the resistant ends. Therefore, when the resistant ends suffered concurrent erosion, an overall decrease in width occurred. Breton Island’s area decreased between 1869 and 1989 from 332 to 164 ha (fig. 50, table 36). The average rates of area change fluctuated between —5.4 and 2.2 ha/yr, which indicate reversing periods between land loss and gain in response to the breaching and healing process along the central island portion (fig. 51). In contrast, the average width of Breton Island experienced a continuous decrease from 1869 to 1989 (fig. 52). 0 Historic Shorelines 0 08° v39 Grand Gosier and Curlew Islands These barrier islands experienced extreme changes in configuration over the last 120 years, causing large fluctuations in average width and island area. In 1869, the average width was 423 m, and the area of Grand Gosier and Curlew islands was 453 ha (tables 34 and 37). By 1922, island area decreased dramatically to only 29 ha at an average rate of —8.0 ha/ yr, and average island width was only 90 m (fig. 53). Tremendous land gain occurred by 1951 with island area expanding to 330 ha, a 1,038 percent increase at a rate of 10.4 ha/yr. Similarly, average width jumped 186 m to 276 m. Between 1951 and 1978, total area fell to 162 ha at a rate of 6.0 ha/yr. Changes in land area reversed again between 1978 and 1989, increasing 71 percent to 277 ha with a similar increase in island width to 249 m. For this period, Grand Gosier and Curlew islands experienced land gain at an average rate of 1 1.1 ha/ yr. Overall, the area of the islands declined between 1869 and 1989 from 453 to 277 ha (fig. 54). This is a total land loss of 39 percent at an average rate of -1.5 ha/ yr (table 37). The rate of area change fluctuated between -8.0 to 11.1 ha/yr from 1869 to 1989, resulting in periods of land gain and loss similar to that of Breton Island (fig. 51). Likewise, average barrier width decreased from 423 m in 1869 to 249 m in 1989 (fig. 55). This signifies an average island narrowing rate of 1.5 m/yr between 1869 and 1989. South Chandeleur Islands Summary The area of the South Chandeleur Islands has shown an overall decline in area from 784 ha in 1869 to 441 ha in 1989 with fluctuations in the intervening years (fig. 56). A total loss of 343 ha, at an average loss rate of —2.9 ha/yr, has been determined (table 38). Interestingly, the average rate of area change fluctuated between —1 1.5 and 13.3 ha/yr from 1869 to 1989, showing cyclic periods of land gain during an overall trend of land loss (fig. 57). The barriers decreased in average width from 384 m in 1869 to 232 m in 1989. A comparison of barrier widths for 1869 and 1989 is shown in figure 58. CHANDELEuR ERROL ISLAND ‘0 ‘9 {2° .l \ a, Q ‘30 0 if" G U L F .s 392,, .s .s 990,, 08° ’ 08> 08° LOUISIANA BARRIER ISLAND EROSION STUDY South Chandeleur Islands ATLAS OF SHORELINE CHANGES I-2150-A I S «s \ «a <§® 693%, cg); {9395’ 033% §3@ {90%, £29) 1922 NDELEUR SOUND «a B R E T O C H A " 09 N 8 O U CURLEW Jr- S N D ISLANDS ERROL .’ ’ BRETON ISLANDS :2 'SLAND V] V 0? fl‘ 1 b g 4/ 6590 ‘ a G U L F O F M E X I C O {9%0 20 (0 $ 90 0S ’ (bog'S 9070’ (82% 5% '95 $9) «a S \ \ «3 es? {932, S? 89325, S“ S?“ 9% S“ 1951 ANDELEUR SOUND B C H \ 03> R E T O N \§ wg‘b‘fl 98° ,3 {a CURLEW ~ ’ 0 U N D Qé° ISLANDS ”‘3 Egg?) g Ks «AI-n...“ <15? 0° 1 S S w S0 GRAND GOSIER ISLAND -L 0 0 «750 ‘6 _‘ G U L F O F M E X I C O {57%0 OS 990 0&3 0% 890 0S ’ 9:3 070/ °§° SCALE 1:100 000 (g? 03’ Cégb 1% H J 1 2 i 4 EISMILES 1M H F9 1 2 3 4:- :3 Z KILOMETERS 03> 20 OS A S “3 a? (930’ c? 23:95 030? 033% 29% «133% 1978 C H A N D E L E U R S (}U N D \ B 083$ R E T O N CURLEWISLANDS ’ S O U N D 09;) - I ,3} BRETON ISLANDS % <26) 4’ (20" 006 . . b A m 90“ GRAND GOSIER ISLANDS 0 O Q U (7)0 ‘S 04’” G U L F o 1: M E X I c 0 {90¢& ® 90 <33 20 \ ’ S3 902/ (g? 0:?“ 9 0,, egg 0'3) 2&9 0 0® {90 0&5 o§ 8‘90 09:3 S» a, «D «a; 0:: £3 m S0 1989 CHANDELEUR SOUND ‘ R «€53 E T O N ‘ CURLEWISLAND S 0 U N D 05:? I .g BRETON ISLANDS 5°?” 4, 040 b0 ,. - 0on GRAND GOSIER ISLANDS Go“ ‘- I \9 a 6&00 Is - G U L F O F M E X I C O (290 \ ¢0’ o® {02> 0%“ CS 390 S3 (g) O’ S83 93> 5/ 933 79 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY -10 -15 -20 -25 1875 1900 1925 1950 1975 2000 350 300 250 200 150 100 50 O 1850 1875 1900 1925 1950 1975 2000 80 Average Rate (m/yr) 0 \ I l Year FIGURE 47.—Average gulfside rate of change between 1869 and 1989 along the South Chandeleur Islands shoreline. Island Area (ha) ’\ V\ I I I I I Year FIGURE 50.—Area changes of Breton Island between 1869 and 1989. South Chandeleur Islands Average Rate (m/yr) 5 2O / 15 10\/ o | I I 1875 1900 1925 1950 Year 1975 2000 FIGURE 48.—Average bayside rate of change between 1869 and 1989 along the South Chandeleur Islands shoreline. Area Change Rate (ha/yr) 4 _ 5 I I I 1875 1900 1925 1950 Year FIGURE 51.—-Rate of area change between 1869 and 1989 for Breton Island. 5 Area Change Rate (ha/yr) I 1975 2000 10 " 5 \ o/\/ _5 V '10 I I 1 1875 1900 1925 1950 Year I 1975 2000 FIGURE 53.—Rate of area change between 1869 and 1989 for Grand Gosier and Curlew islands. Average Width (m) 400 300 200 100 I o I I I I 1850 1875 1900 1925 1950 1975 Ybar 2000 FIGURE 49.—Average barrier width between 1869 and 1989 of the South Chandeleur Islands shoreline. Average Width (m) 500 300 \\ 200 100 o I l | I 1850 1875 1900 1925 1950 1975 Ybar 2000 FIGURE 52.—Average barrier width of Breton Island between 1869 and 1989. South Chandeleur Islands LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A «s «s 8 «3 £0? 29370 980? 237535, c8? «£0? {9%, egg) 1869 vs. 1922 0343 L E u R % N S O U N D N D E H A ERROL C ISLAND 8055 €00 - 00 <8”) w 690 \8 <90 g § 890 Q; {’0’ 1869 cg? 30/ cg: 0g: ”3” 93% 1922 0 Shoreline Change and Land Loss 0 “3 2 ‘ ‘ S «‘3 8 0g"? 9% 8“ 8°? 3% 8” 1922 vs. 1951 R s . 035 E L E U ‘{ \\13‘b 8° 3 O U N D H A N D CURLEW ISLANDS H“. 3M5 C d,» ISLAND \s «thaw V \J I GRAND GOSIER ISLAND -. 8°59 4, -D G $0 U L F O F , 6 M E x I c o (290 (Ag {92? $25 § 29:)? «(3‘3 ¢a 1922 93’ & £03 SCALE 1:100 000 (g: 5’ 9:: 1951 I_I H ,_? 1 2 3 4 JSMILES 1% A) 1 2 3 4 5 6 Z KILOMETERS «s 8 <23 8 «a ‘5? {9090/ 08‘? 39°35, 9‘5? 5% 29%, £ng 1951 vs. 1978 0&3 0.: co B R E T o N s 0 U N D 23°99 GRAND GOSIER ISLANDS 38%" G 1 $0 00;, U L F 4/ ,9“ D O F 8°” 6° M E X I C O 390 $ {9° $23 § (:90 9‘33 ¢0, 1951 8:3 “’0 cg? g; “’5’ g: 1978 03) 290 DC 390 £3 § 89 «5‘ 93° «90’ 98’ 0°00 <§° e§> 0% 923 1978 vs 1989 s 0 U N D ‘ R Q ' U N D L E U CURLEWISLAND 5’ £2 E T O N S 0 D E ‘u ., B R H A N ‘ I C Q0963 ..... w BRETON ISLANDS gas} 0 ' 82°55 5’0 .1. Cr ; «A <2“ G U LF OF MEXICO 03 \ 2190 OS 2‘92; 83 S {00 £3 ¢0’ 1978 cg) 0’ (8: £0) 6" 93% 1989 81 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY TRANSECT NUMBER South Chandeleur Islands 40 4I 42 43 44 45 48 47 48 49 50 BI 52 53 3000 E m 2000 (D Z < I 0 LL 0 1000 Lu 0 D t E < 0 E LIJ 9 U) > _1000 < m -2000 <35 ‘ Q: S ‘ o\ {90 o\ {90 0% 0% (:9 0“) £3 ”90/ £3 “95’ £3 £3 0%, ng 1 869 vs. 1989 Q S 0 £3 R E T 0 N U N D B a) BRETON ISLANDS Q0” ‘\ a “0 Q" 0" \ g GRAND GOSIER ISLANDS 03,0 M‘ -’ \ (O at ‘J a O \ o\ D (5° %( $ 990 «3 § 0\ 09/ 0% 0% 1869 cg» 0 083 ago 1989 SCALE 1:100 000 1 I 2 4 5 MILES I—I I—I I—I I-—--—-I - | ‘I O I 2 3 4 5 6 7 KILOMETERS I—-I I—I I-I l I I I IRANSECT NUMBER I 2 4 5 B 7 8 9 II] II I2 38 39 40 4I 44 45 4B 47 48 49 50 5I 52 53 _3000 E m —2000 (D Z < I U LI. 0 _1000 Lu D :3 fl. t Z (D < 0 E LL] 9 E3 4 1000 :3 (D 2000 82 25 20 BAY$DE RATEOFCHANGE(m/yw I ( SHORELINE I SHORELINE ) I RETREAT ADVANCE GULF$DE RATEOFCHANGE(m/yw I SHORELINE E I RETREAT SHORELINE ADVANCE I<- LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A South Chandeleur Islands TABLE 31 . ——South Chandeleur Islands bayside magnitude of change (meters) Transact # 1 2 3 4 5 6 7 8 9 1O 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 Transect coordinate 29° 27' 15" 30" 45" 29° 28' oo" 15" 30" 45" 29° 29' oo" 15" 30" 45" 29° 30' oo" 15” 30" 45" 29° 31' 00" 15" 30" 45" 29° 32' oo" 15" 30" 45" 29° 33' oo" 15" 30" 45" 29° 34' oo" 15" 30" 45" 29° 35' oo" 15" 30" 45” 29° 36' oo" 15" 30" 45" 29° 37' oo" 15" 30" 45" 29° 38' oo" 15" 30" 45" 29° 39' 00" Y 1869 - 1922 n.a. n.a. —143 —80 —122 128 437 662 847 795 202 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 557 590 492 n.a. n.a. n.a. n.a. n.a. 875 n.a. —113 e 1922 — 1951 n.a. n.a. 54 45 —72 175 156 140 n.a. 228 -193 142 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 65 n.a. 573 a 1951 - 1978 n.a. n.a. —797 —154 n.a. n.a. n.a. n.a. n.a. 110 —31 120 n.a. n.a. n.a. n.a. 205 551 534 455 209 n.a. n.a. n.a. n.a. 95 154 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 621 379 240 523 591 304 r 1978 - 1989 ' n.a. n.a. —31 —38 n.a. n.a. n.a. n.a. 58 —27 —11 —27 n.a. n.a. n.a. n.a. 215 253 296 362 249 n.a. n.a. n.a. n.a. 57 -85 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. —93 69 216 213 277 559 s 1869 — 1989 n.a. n.a. -922 -226 280 793 805 1170 1202 1106 -33 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 2222 1848 2150 1539 1537 1527 1676 1857 1328 Transect 71‘ 49 50 51 52 53 54 55 56 57 58 59 60 Transact coordinate 15" so" 45" 29° 40' oo" 15" 30" 45" 29° 41' oo" 15" so" 45" 29° 42' 00" Y 1869 — 1922 466 650 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 982 1140 9 1922 - 1951 n.a. n.a. n.a. n.a. n.a. n.a. n.a. 552 467 n.a. 155 61 a 1951 - 1978 n.a. n.a. n.a. 448 661 486 n.a. n.a. n.a. n.a. n.a. n.a. f 1978 - 1989 625 520 498 307 482 n.a. n.a. n.a. n.a. n.a. n.a. n.a. S 1869 — 1989 1497 1657 1916 1811 2712 n.a. n.a. n.a. n.a. n.a. n.a. n.a. Breton Island baysrde summary Grand Gosier and Curlew Islands baySIde summary South Chandeleur Islands baysrde summary Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count 1869 - 1922 2721 302.3 373.6 847 —148 9 1869 - 1922 3517 502.4 280.7 875 -113 7 1869 - 1922 8360 464.4 392.9 1140 —148 18 1922 — 1951 676 75.1 126.2 223 —193 9 1922 - 1951 643 321.5 256.5 578 65 2 1922 - 1951 2554 170.3 207.9 578 -193 15 1951 - 1978 -752 -150.4 338.6 120 -797 5 1951 - 1978 6457 403.6 174.0 661 96 16 1951 - 1978 5705 271.7 325.6 661 -797 21 1978 - 1989 -76 -12.7 32.6 58 —38 6 1978 - 1989 5020 278.9 201.6 625 -93 18 1978 - 1989 4944 206.0 216.1 625 -93 24 1869 - 1989 4175 463.9 695.8 1202 -922 9 1869 — 1989 25277 1805.5 349.8 2712 1328 14 1869 — 1989 29452 1280.5 832.3 2712 -922 23 (:3 \ \ \ x o\ {90 o\ {90 0%“) 0% 8‘9 0(‘5 93° <90, «8° v31, 42: 93> °0, 83o Transects BRETON ISLANDS a (920° GRAND GOSIER ISLANDS 26 27 0 \1'3‘0 '9 20 2' § . . \V 6 <0“ '6 17 13/ 19 20 20 <23 . 330/ oiQ Gulfsnde Transects ‘3 Bayside Transects TABLE 32. —-—South Chandeleur Islands gulfside magnitude of change (meters) TranseCt# 1 2 3 4 5 6 7 8 9 1O 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 Transectcoordlnate 29°27‘15" 30" 45" 29°28'00” 15" 30" 45" 29°29'00" 15" 3o" 45” 29°30'00" 15" 30" 45" 29°31'00" 15" 30" 45" 29°32'00” 15" 30" 45" 29°33'00" 15" 30" 45" 29°34'00" 15" 30” 45" 29°35'00” 15" 30" 45" 29°36’00" 15" 30" 45" 29°37'00" 15" 30" 45" 29°38'00” 15" 30" 45" 29°39'00" Y 1869-1922 —31 —102 —65 —327 -350 —436 —559 —668 —687 —648 -630 -72 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. -663 -610 n.a. n.a. n.a. n.a. n.a. n.a. -104s n.a. -495 -1023 —1168 6 1922—1951 -78 302 71 ‘ 9 ~120 —179 -237 -293 n.a. —356 -268 —143 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. -45 n.a. —455 n.a. n.a. a 1951—1978 n.a. 169 —457 n.a. n.a. n.a. n.a. n.a. n.a. -70 -196 —319 n.a. n.a. n.a. ~13? —460 -611 -685 —689 n.a. n.a. n.a. n.a. n.a. 21 2 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. —610 n.a. —372 -426 —467 —500 ha. n.a. r 1978-1989 n.a. ~246 n.a. n.a. n.a. n.a. n.a. n.a. 39 28 71 -45 n.a. n.a. n.a. —324 —218 —221 —203 n.a. n.a. n.a. n.a. n.a. n.a. 27 -188 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 72 -2 -113 —232 —266 —364 —416 —429 s 1869—1989 702 123 n.a. —590 —912 -949 —1042 —1103 -1085 -1046 —1083 —579 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a.-2084 -1961 -1916 -1884 n.a. n.a. -1751 -733 -1314 -1906 -1981 Transect 11‘ 49 50 51 52 53 54 55 56 57 58 59 60 Transactcoordinate 15" 30" 45" 29°40'00" 15" 30" 45" 29°41'00" 15" 30" 45" 29°42'00" 1” 1869-1922 -1212 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a.-1048 -755 -617 6 1922-1951 n.a. n.a. n.a. n.a. n.a. n.a. -399 -211 n.a. 53 —300 -310 a 1951 — 1978 n.a. n.a. -660 —995 —1253 ~1001 n.a. n.a. n.a. n.a. n.a. n.a. I‘ 1978—1989 ~419 -397 -403 -263 —356 n.a. n.a. n.a. n.a. n.a. n.a. n.a. s 1869 - 1989 —1995 —2094 -2223 -2381 -2533 n.a. n.a. n.a. n.a. n.a. n.a. n.a. Breton Island gulfsrde summary Grand Gosier and Curlew Island gu/fSIde summary South Chandeleur Islands gulfside summary Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count 1869 — 1922 -4575 —381.3 248.9 —31 —687 12 1869 - 1922 -6219 -888.4 269.8 -495 —1212 7 1869 - 1922 —13214 —600.6 346.1 -31 -1212 22 1922 ~ 1951 —1292 —117.5 180.4 302 -356 11 1922 — 1951 —899 —299.7 181.5 —45 —455 3 1922 — 1951 —2959 -164.4 186.4 302 -455 18 1951 - 1978 —873 -174.6 214.5 169 -457 5 1951 — 1978 —8843 -552.7 337.1 21 —1253 16 1951 - 1978 -9716 -462.7 351.4 169 -1253 21 1978 — 1989 —213 -42.6 105.7 39 -246 5 1978 — 1989 -4715 —248.2 150.8 72 —429 19 1978 — 1989 -4928 -205.3 165.2 72 -429 24 1869 — 1989 -7563 —687.5 561.5 702 -1103 11 1869 — 1989 -27256 —1946.9 395.4 —733 —2533 14 1869 - 1989 -34819 -1892.8 785.5 702 —2533 25 See page 46 for explanation of numbers. 83 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY South Chandeleur Islands TABLE 33.—South Chandeleur Islands bayside rate of change (meters per year) Transect 11‘ 1 2 3 4 5 6 7 8 9 1O 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 Transeot coordinate 29° 27' 15" 30" 45” 29° 28' 00" 15" 30" 45" 29° 29' 00" 15" 30" 45" 29° 30' 00" 15” 30" 45" 29° 31' 00" 15" 30" 45" 29° 32' 00” 15" 30" 45” 29° 33' 00” 15” 30” 45" 29° 34' 00" 15" 30” 45” 29° 35' 00" 15" 30” 45" 29° 36' 00” 15” 30” 45” 29° 37' 00” 15" 30” 45” 29° 38' 00" 15” 30" 45" 29° 39' 00" Y 1869 - 1922 n.a. n.a. —2.8 -1.5 —2.3 2.4 3.2 12.5 16.0 15.0 3.3 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 1o_5 11,1 9,3 n.a. n.a. n.a. n.a. n.a. 15,5 n.a. —2.1 e 1922 — 1951 ha. n.a. 1_9 1.6 —2.5 5,1 5,4 49 n.a. 7,9 —6.7 4,9 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 23 n.a. 2011 a 1951 — 1978 n.a. n.a. —28.7 —5.5 n.a. n.a. n.a. n.a. n.a. 40 -1.1 43 n.a. n.a. n.a. n.a. 7,4 19_g 19.2 164 75 n.a. n.a. n.a. n.a. 3.5 5.5 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 223 135 8.6 13.3 21.3 10.9 f 1978 — 1989 n.a. n.a. -3.0 —3.7 n.a. n.a. n.a. n.a. 5.6 —2.6 -1.1 —2.6 n.a. n.a. n.a. n.a. 20.7 24,3 235 34.3 23.9 n.a. n.a. n.a. n.a. 5,5 —8.2 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. -8.9 55 20.8 20.5 26.6 53.8 S 1869 — 1989 n.a. n.a. -7.7 -1.9 2,3 6.6 6.7 9,3 10,0 92 -0.3 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 13.5 1514 179 12.3 12.3 12.7 14.0 15.5 11_1 Transact # 49 50 51 52 53 54 55 56 57 58 59 60 Transect coordinate 15" 30" 45" 29° 40' 00" 15" 30" 45" 29° 41' 00" 15" 30” 45" 29° 42' 00" Y 1869 — 1922 8.8 12.3 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 18.5 21.5 e 1922 - 1951 n.a. n.a. n.a. n.a. n.a. n.a. n.a. 192 152 n.a. 54 21 a 1951 — 1978 n.a. n.a. n.a. 16.1 23.8 17,5 n.a. n.a. n.a. n.a. n.a. n.a. r 1978 — 1989 60.1 50.0 47.9 29.5 46.3 n.a. n.a. n.a. n.a. n.a. n.a. n.a. s 1869 - 1989 12.5 13.8 16.0 15.1 22.6 n.a. n.a. n.a. n.a. n.a. n a. n.a. Breton Island baysrde summary Grand Gosrer and Curlew Islands baysrde summary South Chandeleur Islands baysrde summary Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count 1869 - 1922 51.3 5.7 7.0 16.0 —2.8 9 1869 — 1922 66.4 9.5 5.3 16.5 -2.1 7 1869 — 1922 157.7 8.8 7.4 21.5 —2.8 18 1922 - 1951 23.5 2.6 4.4 7.9 —6.7 9 1922 — 1951 22.3 11.2 8.9 20.1 2.3 2 1922 - 1951 88.7 5.9 7.2 20.1 —6.7 15 1951 — 1978 —27.1 —5.4 12.2 4.3 -28.7 5 1951 - 1978 232.3 14.5 6.3 23.8 3.5 16 1951 — 1978 205.2 9.8 11.7 23.8 -28.7 21 1978 - 1989 —7.3 —1.2 3.1 5.6 —3.7 6 1978 — 1989 482.7 26.8 19.4 60.1 -8.9 18 1978 - 1989 475.4 19.8 20.8 60.1 —8.9 24 1869 - 1989 34.8 3.9 5.8 10.0 —7.7 9 1869 - 1989 210.6 15.0 2.9 22.6 11.1 14 1869 - 1989 245.4 10.7 6.9 22.6 -7.7 23 TABLE 34. ——South Chandeleur Islands Width measurements (meters) Transect# 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 2O 21 22 23 24 25 26 27 28 29 3O 31 32 33 34 35 36 37 38 39 4O 41 42 43 44 45 46 47 48 Transect coordinate 29° 27‘ 15" 30" 45" 29° 28' 00" 15" 30" 45" 29° 29' 00" 15" 30" 45" 29° 3000" 15" 30” 45" 29° 31' oo" 15" 30" 45" 29° 32' oo" 15" 30" 45" 29° 33' oo" 15" 30" 45" 29° 3400" 15" 30" 45" 29° 35' oo" 15" 30" 45" 29° 3600" 15" 30" 45” 29° 3700” 15" 30" 45" 29° 38‘ oo" 15" 30" 45" 29° 3900" Y 1869 257 754 571 273 224 237 137 72 126 67 1240 793 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 453 361 351 299 270 243 222 524 n.a. n.a. 290 711 733 723 644 e 1922 94 590 550 101 169 179 209 269 286 223 24g 913 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 243 185 n.a. n.a. n.a. n.a. n.a. n.a. 10 n.a. 1g 99 62 a 1951 147 917 562 260 208 126 100 31 n.a. 92 192 578 n.a. n.a. n.a. 177 239 352 384 443 549 407 254 202 122 142 594 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 230 49 n.a. 166 194 100 102 n.a. n.a. r 1978 n.a. 957 43 n.a. n.a. n.a. n.a. n.a. 126 129 102 248 n.a. n.a. 82 245 214 180 231 47 n.a. n.a. n.a. n.a. n.a. 337 845 na. n.a. n.a. n.a. n.a. n.a. n.a. n.a. na- "-61. ML n-a. "-4 56 332 112 189 223 161 56 82 s 1989 128 688 10 226 217 47 249 157 224 133 119 192 n.a. n.a. n.a. 135 258 283 299 n.a. n.a. n.a. n.a. n.a. 220 342 571 na. n.a. n.a. n.a. n.a. n.a. n.a- n-a- na- 30 26 410 329 230 303 186 174 214 279 189 242 Transect 11“ 49 50 51 52 53 54 55 56 57 58 59 60 Transect coordinate 15" so" 45" 29° 40' 00" 15" 30" 45" 29° 41' 00" 15" 30" 45" 29° 42' 00" Y 1869 613 442 487 143 86 n.a. n.a. n.a. n.a. 191 83 38 6‘ 1922 54 n.a. n.a. n.a. n.a. n.a. 50 90 n.a. 68 448 282 a 1951 n.a. n.a. 266 301 731 .91 197 350 527 275 211 230 f 1978 171 166 151 170 141 213 n.a. n.a. n.a. n.a. n.a. n.a. S 1989 273 271 208 n.a. 259 n.a. n.a. n.a. n.a. n.a. n.a. n.a. Breton Island Width summary Grand Gosrer and Curlew Islands wrdth summary South Chandeleur Islands width summary Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count 1869 4751 395.9 350,1 124o e7 12 1869 7615 423.1 197.1 733 86 18 1869 12678 384.2 272.3 1240 38 33 1922 3836 319.7 233.8 918 94 12 1922 721 90.1 77.3 243 10 8 1922 5445 226.9 209.4 918 10 24 1951 3213 292.1 262,3 917 31 11 1951 6342 275.7 171.5 731 49 23 1951 11148 285.8 196.6 917 31 39 1978 1605 267.5 314,3 957 43 6 1978 4322 205.8 162.2 845 47 21 1978 6009 214.6 205.4 957 43 28 1989 2390 199.2 1632 688 10 12 1989 5731 249.2 110.6 571 26 23 1989 8121 232.0 133.2 688 10 35 TABLE 35.—South Chandeleur Islands gqu3/de rate of change (meters per year) Transect# 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 3O 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 Transact coordinate 29° 27' 15” 30” 45" 29° 28' 00" 15" 30” 45" 29° 29' 00” 15" 30" 45" 29° 30' 00” 15” 30” 45” 29° 31' 00" 15" 30” 45" 29° 32' 00” 15" 30” 45” 29° 33' 00” 15" 30" 45” 29° 34' 00" 15" 30” 45" 29° 35' 00” 15" 30” 45” 29° 36' 00” 15" 30” 45" 29° 37' 00” 15” 30" 45" 29° 38' 00” 15” 30” 45” 29° 39' 00" Y 1869 — 1922 -o.6 -1.9 -1,2 -6.2 —6.6 —8.2 —10.5 —12.6 —13.0 —12.2 —11.9 —1.4 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. -12.5 -11.5 n.a. n.a. n.a. n.a. n.a. n.a. -19.8 n.a. -9.3 -19.3 -22.0 e 1922 - 1951 —2.7 10,5 2,5 0,3 —4.2 —6.2 ~82 —10.2 n.a. ~12.4 —9.3 -5.0 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. -1.6 n.a. —15.8 n.a. n.a. a 1951 - 1978 n.a. 6.1 —16.4 n.a. n.a. n.a. n.a. n.a. n.a. -2.5 —7.1 -11.5 n.a. n.a. n.a. —4.9 —16.5 —22.0 —24.6 -24.8 n.a. n.a. n.a. n.a. n.a. 0.8 0.1 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. -21.9 n.a. -13.4 -15.3 —16.8 -18.0 n.a. n.a. f 1978 — 1989 n.a. -23.7 n.a. n.a. n.a. n.a. n.a. n.a. 3.8 2.7 1.1 -4-3 n.a. n.a. n.a. =31.2 -21.0 -21.3 -19.5 n.a. n.a. n.a. n.a. n.a. n.a. 2.6 —18.1 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 6.9 -0,2 -10,9 —22.3 —25.6 -35.0 -40.0 —41.3 S 1869 — 1989 5.9 1.0 n.a. -4.9 -7.6 -7.9 ~87 -92 --90 ~87 —9.0 ~48 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. -17.4 -16.3 —16.0 —15.7 n.a. n.a. -14.6 -6.1 -15.1 -15.9 —16.5 Transect 11“ 49 50 51 52 53 54 55 56 57 58 59 60 Transect coordinate 15” 30” 45" 29° 40' 00" 15" 30" 45” 29° 41' 00" 15" 30" 45" 29° 42' 00" Y 1869 - 1922 ~22.9 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. -19.8 —14.2 —11.6 e 1922 — 1951 n.a. n.a. n.a. n.a. n.a. n.a. -13.9 -7.3 n.a. 1.8 -10.4 —10.8 a 1951 — 1978 n.a. n.a. —23.7 —35.8 —45.1 -36.0 n.a. n.a. n.a. n.a. n.a. n.a. l' 1978 — 1989 -40.3 ~38.2 —38.8 —25.3 —34.2 n.a. n.a. n.a. n.a. n.a. n.a. n.a. S 1869 — 1989 —16.6 —17.5 -13.5 -19.8 —21.1 n.a. n.a. n.a. n.a. n.a. n.a. n.a. Breton Island gulfsrde summary Grand Gos:er and Curlew Islands gulfsrde summary South Chandeleur Islands gulfsrde summary Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count Years Sum Avg STD Total Range Count 1869 - 1922 —86.3 —7.2 4.7 -o.6 -13.0 12 1869 — 1922 -117.3 —16.8 5.1 -9.3 -22.9 7 1869 — 1922 —249.3 —11.3 6.5 —0.6 —22.9 22 1922 - 1951 —44.9 —4.1 6.3 10.5 -12.4 11 1922 - 1951 —31.2 -1o.4 . 6.3 —1.6 -15.8 3 1922 — 1951 -102.7 ~57 6.5 10.5 —15.8 13 1951 - 1978 —31.4 —6.3 7.7 6.1 —16.4 5 1951 - 1978 —318.1 -19.9 12.1 0.8 -45.1 16 1951 - 1978 -349.5 —16.6 12.6 6.1 -45.1 21 1978 - 1989 —2o.5 —4.1 10.2 3.8 —23.7 5 1978 — 1989 —453.4 —23.9 14.5 6.9 —41.3 19 1978 — 1989 —473.8 ~19.7 15.9 6.9 —41.3 24 1869 - 1989 —63.0 —5.7 4.7 5.9 -9.2 11 1869 - 1989 -227.1 -16.2 3.3 —6.1 -21.1 14 1869 - 1989 -290.2 -11.6 6.5 5.9 -21.1 25 See page 46 for explanation of numbers. 84 Island Area (ha) South Chandeleur Islands Average Width (m) LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES Island Area (hai 800 \ 600 A 400 V V/ 200 o I I I i | 1850 1875 1900 1925 1950 1975 2000 Year FIGURE 56.—Area changes between 1869 and 1989 of the South Chandeleur Islands. - 1869 Width 7% 1989 Width 500 400 \ 400 \ 300 //\ 300 200 / V/ 200 /\/ 100 V 100 - o I I l I | o I I I | I 1850 1875 1900 1925 1950 1975 2000 1850 1875 1900 1925 1950 1975 2000 Year Year FIGURE 54.—Area changes of Grand Gosier and Curlew is- FIGURE 55.—Average barrier width of Grand Gosier and lands between 1869 and 1989. Curlew islands between 1869 and 1989. Width (m) 2000 Area Change Rate (ha/yr) 15 1500 1° A\ / 5 \\\ // 1000 ° \ / I '5 //// \\\ // 500 ' ‘10 V _ 15 | I | I 1875 1900 1925 1950 1975 2000 Year FIGURE 57.—Rate of area change between 1869 and 1989 for South Chandeleur Islands. TABLE 36.—Area changes for Breton Island from 1869 to 1989 Projected Date Date Area jhaj Change Ihaj % Change Ratejha/yrj of Disaggearance 1869 332 1922 271 -61 -18% —12 2051 1922 271 1951 291 20 7% 07 IVA. 1951 291 1978 141 -150 —52% -54 2004 1978 141 , 1989 164 23 16% 2.2 N.A. 1869 332 1989 164 469 —51% —L4 2106 TABLE 37.—Area changes of the Grand Gosier and Curlew islands from 1869 to 1989 South Aiongshore Position (km) 20 24 Nonh FIGURE 58.—Comparison of the 1869 and 1989 barrier widths along the South Chandeleur Islands shoreline. Projected Date Date Area jhaj Change jhaj % Change Ratejha/yrj of Disaggearance 1869 453 1922 29 -424 —94% —80 1926 1922 29 1951 330 301 L038% 104 NJ\ 1951 330 1978 162 -168 -5196 —6I) 2005 1978 162 1989 277 115 71% 11.1 N.A. 1869 453 1989 277 -176 -39% 4.5 2174 TABLE 38.—Area changes of South Chandeleur Islands from 1869 to 1989 Date 1869 1922 1922 1951 1951 1978 1978 1989 1869 1989 Projected Date Area jhaj Change jhaj % Chanqe Rate (ha/yr) of Disappearance 784 300 —484 —62% —9.1 1955 300 624 324 108% 11.3 N.A. 624 303 -321 —51% —11.5 2003 303 441 138 46% 13.3 N.A. 784 441 -343 —44% -2.9 2199 I—2150—A 85 US.DEPARTMENT(M:THEINTBHOR US.GEOLOGKDM_SURVEY North Chandeleur Islands—1855 to 1989 Morphology The North Chandeleur Islands are dominated by a large, arcuate- shaped barrier island that protects three groups of smaller, irregular— shaped islands that lie to the west. In 1855, Chandeleur Island was a fairly continuous barrier island except for breaches along the north-central portion of the shoreline (1885 map). One of the major breaches was known as Schooners Pass; its name indicates how the pass was utilized at the time. At the northern end lies Hewes Point, a large recurved spit complex, and the terminus of longshore sediment transport for the northern half of the barrier island arc. The gulf shoreline forms a smooth arc, but the bay shoreline is crenulate and dominated by washover fans and ebb—tidal deltas. In addition, two other prominent morphological features along the bay shoreline include Redfish Point and Monkey Bayou, interpreted as possible relict distributary systems of the St. Bernard delta. In 1922, several breaches along the north central island shoreline closed, except for three or four, the most prominent of which is still Schooners Pass (1922 map). At this point, the island arc was narrowest at both ends and widest in the central portion. Since then the southern end also has developed some surge channels. A detailed description of surge channels and other related storm impact features is provided by Boothroyd and others (1985). The back-barrier islands (North, New Harbor, and Freema— son islands) are moving and deteriorating, especially Freemason Islands, which consist predominately of reworked oyster shells and are therefore, highly mobile. By 1951, Schooners Pass had closed, but to the north an unnamed inlet remained opened (1951 map). The southern tip of the arc became detached to form Stake Island. Chandeleur Island suffered a devastating hurricane impact by Camille in 1969, which fragmented the arc into nu- merous smaller islands. However, by 1978, the arc had recovered, and all breaches healed. To the south, Stake and Palos islands disappeared, and the back—barrier islands underwent a major contraction. The 1988 map shows that Chandeleur Island has maintained its overall arcuate shape, smooth gulf shoreline, and highly irregular bay shoreline. Although the back-barrier islands remained, their shapes were very different and sizes greatly reduced. Shoreline Movement Comparisons of shoreline position along the North Chandeleur Islands are made for the periods 1855 vs. 1922, 1922 vs. 1951, 1951 vs. 1978, 1978 vs. 1989, and 1855 vs. 1989. Shoreline change is presented in terms of direction, magnitude, and rate of change, as well as island width. These were obtained from 172 shore—normal transects along the gulf and bay shorelines (transects map, tables 39, 40, 41, 42, and 43). The average gulfside rate of change between 1855 and 1922 was -5.3 m/yr (table 43). This average rate slightly increased to —5.6 m/yr between 1922 and 1951 and increased nearly twofold to -10.0 m/yr between 1951 and 1978 (fig. 59). This doubling of the gulfside rate of change between 1951 and 1978 includes the impact of Hurricane Camille, a category 5 hurricane that made landfall in 1969 at Pass Christian, Miss, after crossing the Chandeleur Islands (Neumann and others, 1 985). This large storm severely weakened the overall morpholog- ical structure of the Chandeleur Island system, making the arc more susceptible to subsequent storm events. For the period 1978 to 1989, the high average rate of gulfside movement was maintained and even in— creased to —12.2 m/yr (fig. 59). Contributing to this high rate of shoreline retreat were the impacts of Hurricane Frederic (1979) and Hurricanes Elena and Juan (1985) (Neumann and others, 1985; Case, 1986). The bay shoreline also was migrating landward. For the period between 1855 and 1922, the average rate of change was 2.2 m/yr (fig. 60, table 41). This average rate increased over twofold to 5.4 m/yr between 1922 and 1951 but decreased to 3.3 m/yr for the period 1951 through 1978. Between 1978 and 1989, the average rate increased to 5.3 m/yr (fig. 60). For the past 134 years, the bay shoreline migrated landward primarily in response to washover deposition associated with extratropical and tropical storms. The 1855 vs. 1989 map illustrates land loss for the North Chandeleur Islands and presents a quantitative summary of changes along the gulf and bay shorelines. The rate of change between 1855 and 1 989 along the gulf shoreline ranged from —O.2 to —17.6 m/ yr, with an average change rate of —6.5 m/yr (table 43). The rate of bayside change for the same period ranged between 15.0 and —2.0 m/yr with an average change rate of 2.9 m/yr (table 41). The gulf and bay shorelines are rapidly migrating 0 Historic Shorelines 0 landward, but the gulf shoreline is migrating twice as fast (-6.5 m/yr vs. 2.9 m/yr), causing net deterioration of the islands. Area and Width Change To better understand area changes, comparisons are made to general trends in barrier width (tables 42 and 44). In 1855, Chandeleur Island contained 2,763 ha of land with an average width of 941 in. By 1922, total area further decreased to 2,485 ha, while average width decreased to 670 m. During the period 1855 to 1922, the rate of area change was —4. 1 ha/yr (fig. 61). However, by 1951, the island are increased in area to 2,588 ha. This was consistent with an increase in average width to 678 m. For the period 1922 to 1951, the average rate of area change was 3.6 ha/yr, indicating a reverse from land loss to land gain. Not surprisingly, Chandeleur Island lost the most area between 1951 and 1978, which coincides with the impact of Hurricane Camille in 1969. The island arc lost 31 percent, or 792 ha, of its land area at a rate of —28.5 ha/yr. Correspondingly, average barrier width decreased to 506 m. By 1989, both area and width only slightly decreased to 1,749 ha and 475 m, respectively, and the rate of area change slowed to —4.5 ha/yr (fig. 61). Over the last 134 years, Chandeleur Island has experienced a decrease in area from 2,763 to 1,749 ha (fig. 62, table 44), at an average loss rate of 7.6 ha/yr. This represents a 37 percent decrease in island area, most of which occurred between 1951 and 1978. Compared with other barrier islands along the Louisiana coast, the area of Chandeleur Island has decreased at a slower rate. Between 1855 and 1989, both the gulf and bay shorelines migrated landward. However, the gulf shoreline migrated land— ward more than twice as fast as the bay shoreline (—6.5 m/yr vs. 2.9 m/yr, respectively), causing island width to narrow (fig. 63, table 42). The barrier island decreased in average width from 941 m in 1855 to 475 m in 1989, representing an average narrowing rate of 3.5 m/yr for the past 134 years (fig. 63). Barrier widths for 1855 and 1989 are shown in figure 64. Meanwhile, area changes decreased for North and Freemason islands but remained stable for New Harbor Islands (tables 45, 46, and 47). 29°55' 30°00’ 30°04’ 88°59’ Hewes Point w 88°55’ — 88°50’ 88°48’ war 0 I l 880:3,41 29145 \\ M w 1855 "““ v \, FREEMASON ISLANDS \bv ‘5 C ”’ A '7"). N o \ 38°55'4 E l y 45‘ 1' o R J/ 4 NORTH .5 ISLANDS (,0 ~ 4. 90" a “(.29 3° NEW HARBOR‘ ISLANDS ° ““ ébnack Channel Redfish Point 88°50'4 D L‘ GULF OF MEXICO EUR 88°48’ I I 29°41' 29°49 29°50, 86 29°55' 30°00’ 30°04’ North Chandeleur Islands LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A 29f50' 88°559°4V 29745 I "%fi I 29155, 30700, 30 0848059, FREEMASON ISLANDS v 2 > C‘ o I 88°55’ & I A 88 55 \ 6' 4 7". *4 \ 0 NORTH ’ . 5 L ISLANDSgB’ ' E U Q, N D ’ R .. ’ S O U Hewes Point w 00 ‘6“ NEW HARBOR $035” ISLANDS ~. ‘q s 0‘? mac/c Channel $213 00°01 0 k ‘Redfish Point 290 ow 9 fi . ~‘ 9' 88°5U’ A o ‘1 — 88°50' D GULF OF MEXICO E 03 L E U R I S L A N 88°48’ I I I I o , 29°41’ 29045, 29050, SCALE 1:100 000 29°55] 30000, 300802’48 0 I 2 3 4 5 MILES 1H H F9 1 2 3 4 5 6 7 KILOMETERS 29°50' 29°41’ o I I o , O , 30004, 88059, 29 {45 N L 29 I55 30 ‘00 88059, 1 9 5 l ,r‘ ‘ FREEMASON ISLANDS Z > C‘ a 6' ’ \\ 3 4 88°55’A e' 4’ ~88°55’ \ 0 g \ 0‘. 0 NORTH ‘g ‘ 5’ ISLANDS % o‘ N D . fie] ,. 00 ’ ~u S O U Hewes POInt ‘3 W W S!“ $59 NEW HARBOR\. Q' 'Qo ISLANDS ’3 d ('< \ Smack Q; ‘ Channel C?3 ‘ . Vb Redfish Point $5 9-" L \ 00' ‘ [I o I ‘5' O .‘ I. o I 8850— ’ )I ‘t i 1" H I .‘0 .."J,5~" 43850 C H ‘ ‘ \ f. . . Q I x A N 5 \flI .. _' GULF OF MEXICO D E L N 05 E U R I S L A o I I I I o I 88 459041, 29°45] 29°50, 29°55’ 30‘100' 30008: 48 87 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY North Chandeleur Islands 29°50' 290411 290451 J I I 29055, 30000, 30°04, 88°59! l \ i I 88059, 1 978 ; FREEMASON ISLANDS Z > C‘ 6' 4 1V D 6 88°55’ — l \ # 88°55’ 8 U z.» 32» NORTH ISLANDS " AMI’ S O U N D Hewes Point W \ ‘3‘ .Qqu NEW HARBOR ISLANDS ° .A‘ S T“ . Smack Channel I ‘ 000% n ‘. \Redfish Point 000$. ' v . C o , I» S ‘ z. ’ _ o , 88 50 »— ‘ I o) _ ‘I ' 88 50 C ‘ r " ‘ . Q 5 _ H \ ‘ ‘ ‘I -’ o ‘ ‘ A N ‘ I \ ‘ I D E D L E A N GULF OF MEXICO U R I S L o I I I I I o I 88 439°41’ 29°45’ 29°50' 29055: 30000, 3000848, 48 SCALE 1:100 000 1 '_9 1 2 3 4 S MILES 1H H A) 1 2 3 4 5 6 I7 KILOMETERS 29°50' I 29041, 29°45" o , o , 30004’ 88°59 ; \ A 29155 30‘00 88°59’ l 989 / FREEMASON ISLANDS 2 >- C‘ _ J“, H 4 Q A g; . 'm 88°55’ ~ \4 4, ‘. W 88055, ' D I 6 l 6 0 JR R NORTH ISLANDS 3‘ U N D Q- S O Hewes Point W0 \ ‘Bfi' " ON» NEW HARBOR ISLANDS ' \I‘ .9" ‘ S u male Channel 00 . . 00 . ' Redfish Point 0Q} \ . ‘il‘ w§9 ' ’, " 88°50’ — > I I . ‘0‘“ " t \ ~ ~ —88°50’ C H ‘ O ‘ ‘ \ n b ‘ S A \ I I D ’V D E L L A N GULF OF MEXICO EU R .s o l I I I I 048, 88 439°4I’ 29°45’ 29°50! 29°55, 30°00, 88 30°04’ 88 LOUISIANA BARRIER ISLAND EROSION STUDY North Chandeleur Islands ATLAS OF SHORELINE CHANGES I—2150—A 28058' 8805929°4" 29:45’ I ”Q I I 29755' 30700, 3000:8059 FREEMASON ISLANDS 1 Z > £53». 0 O I 8 a I —‘ ‘88 55 8 55 \ 6' as; 4 III I 294 \ 0 NORTH ‘ ,' E L E ISLANDsg’E D k! U R . . 5 S O U N Hewes Point O I 5°90 NEW HARBOR $0889 ISLANDS ~. Q. a 0'5.) 8’77 aCk Channel {3J3 0°00 Redfish Point 00 05 ‘9 V S90? -' ‘ ~‘ 9" 88°50’ 88°50’7 * ° * I: ‘M v A N ‘3 D GULF OF MEXICO E Ds . L E U R I S L A N 88°48’ I i I I o , 29°41’ 29°45, 29°50, SCALE 1:100 000 29°55 30000, 300%3’48 I—I I——I E_SJ 1 2 3 4 E) MILES Id L—I H0 1 2 3 4 5 6 I7 KILOMETERS 29°50’ 29°41' o I I o I o I 30°D4’ 88059, 28 '45 I N 29 ‘55 38 ‘00 88059, 1 9 5 l ,r‘ ‘ FREEMASON ISLANDS Z > O 1 6’ ' 4 \s o i" I 4» 88 55 a 88°55’ \ 0 5 \ l l g (V k ’5 0 NORTH 'g t 5’ ISLANDS 4‘ N D ‘6, * 0 ’ .fl 8 O U Hewes Point ‘4'“ *8; NEW HARBOR\. " "$00 ISLANDS ’ u‘ ‘ r ' < X S ‘ mac/f Channel ‘QOQQ’ .1]. Vb Redfish Point é” L 0' l (I I 5 88°50’ — I I . \ 8350 o . In" ’ ‘I‘ " VBB°50’ I, I I I. l «- .. ‘ . ~. 2 - C \ \ ‘0 . L 3 H A N \ s b \fl. . h .. ’ D ‘ I GULF OF MEXICO E L E N 05 U R I S L A O I I I I o I 88 4289841, 29045' 29°50’ 29°55’ 30:00’ 88 48 30°04’ 87 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY 29050' 29°4I' o , I o , O , 30°04, 88°59’ 29145 I \ I 29 [55 30 '00 88059, 1 9 7 8 /‘ FREEMASON ISLANDS 2 > C 6' 4 A, 0 88°55’—— 5 l \ —88°55’ E (I e 32» NORTH ISLANDS ’. AM.’ 8 O U N D Hewes Point 99°“ \ \3‘ 'qu NEW HARBOR ISLANDS " ‘ .A \ O’ I . Smack ChanneI I 000% Q ‘ Redfish Point 006 . ‘ ' W \ $0 3' '0 v / I 99°59'— \ 4 039 '- - ~ —88°50 C ‘ , ‘- o H A 4 ‘ .. ‘ ‘ | ‘ I N I ’ D E L N D GULF OF MEXICO E U I s L O I I I I I o I 88 439041, 290452 29050, 29055, 30000, 3000849 48 SCALE 1:100 000 1:! H J 1 .2 L 4 ‘SMILES 1H H A) 1 4 L 6 7 KILOMETERS 29°59 I 29°41, 29°45 o , o , 30°04' 99°59 E '\ 29 [55 39109 88059, 1989 \/ 2 >* C I 8- . 0" ‘ ~i ' 88055,” \4 A 4’ m‘- —33°55’ ' 0 6‘ 9 l 5 u 22.x R NORTH ISLANDS '3‘ N 0 *v S O U Hewes Point 9°?“ \ ‘5' r 0366‘) NEW HARBOR ISLANDS ' 9 5" ‘ S n ”700k Channel 0% 0° 9 Redfish Point 0Q} ‘ ‘ \ woo. ' ' 88°50’ - > I I _ Co“ ‘ b » ~ 48°59 C ‘ Y) H A ’ D ‘ l \ b D 5 N D E L N GULF OF MEXICO E U ‘SL 0 I I I I I o , 88 43901“, 29045, 29°50, 29055, 30000! 3000848, 48 88 North Chandeleur Islands LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A North Chandeleur Islands Average Rate (m/yr) 0 Average Rate (m/yr) Area Change Rate (ha/yr) 5 -2 5 /\ / O //\\ -4 ‘5 '6 V " 10 -8 / - 15 2 \ / - 10 ' 20 \ / — 12 x, 1 -25 V _14 I I I I O I I I I _30 I I I I 1875 1900 1925 1950 1975 2000 1875 1900 1925 1950 1975 2000 1875 1900 1925 1950 1975 2000 Year Year Year FIGURE 59.--Average gulfside rate of change between 1855 and 1989 along Chandeleur Island. Island Area (ha) FIGURE 60.—Average bayside rate of change between 1855 and 1989 along Chandeleur Island. 1989 of Chandeleur Island. 3000 000 Average Width (m) 1 \ j /\ 2500 —.— K\\\\\\\\\\\ 800 2000 \\ 600 1500 \ 1000 400 500 200 o I I I | L 1850 1875 1900 1925 1950 1975 2000 0 ‘ I ‘ ‘ I Year 1850 1875 1900 1925 1950 1975 2000 Year FIGURE 62.—Area changes between 1855 and 1989 of Chandeleur Island. 3000 2500 2000 1500 1000 500 0 Width (m) FIGURE 63.—Average barrier width between 1855 and 1989 along Chandeleur Island. - 1855 Width 7% 1989 Width IIIEEEEIII South E III II II 12 16 20 I 36 Nonh FIGURE 61.—Rate of area change between 1855 and Alongshore Position (km) FIGURE 64.—Comparison of 1855 and 1989 barrier widths along Chandeleur Island. 89 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY North Chandeleur Islands 29°50' I 29041, c I o I o I O I 88059, 29[45 29155 salon 30 [$059, 1855 vs. 1922 Z > FREEMASON ISLANDS ‘ C 6' 4 4; 0 5 88°55’ l 5 —88°55’ U I? b: S O U N D Hewes Point NEW HARBOR‘ ISLANDS ‘- Snmck Channel (204$ % QT 0 Redfish Point 88°50’ — _ 88°50’ D E ' ' N D GULF OF MEXICO LEUR ISLA O I I I I I o I 88 439041’ 29°45, 29°50’ 29°55I 30000, 3000?; 48 1855 . 0 Shorelme Chan 2 and Land Loss 0 1922 29°50' 29°41’ ’ o , I o , o , o , 88°59’ 29 I45 I 29'55 30100 30 038059 1922 vs. 1951 3/ FREEMASON ISLANDS SCALE1z100000 1 0 1 2 3 4 SMILES g I—I H F9 1 2 3 4 5 6 I7 KILOMETERS 2» C‘ I,“ O 6’ 4 88055 J\ e [V ~88°55’ 0 E a, l E U R NORTH ISLANDS 4" S O U N D Hewes oint 9090” NEW HARBOE‘ ISLANDS . Smack Channel Redfish Point 88°50’ — J — 88°50’ D E D N GULF OF MEXICO LEUR IsLA o I I I I I o I 88 45239041, 29045, 29050! 29°55’ 30000I ' 3000848, 48 1922 1951 90 LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES North Chandeleur Islands I—2150—A 28°58 29041’ c , I o , 29 45 29°55’ ° , -30°04’ 88 59 I - ‘ I I BUIUU 88°58 1951 vs 1978 g} ° ' FREEMASON ISLANDS Z P C‘ o 6' 4 $5 88°55’ N D \ —88°55' 6‘ l E 0 I? “,9 H P 'nt 0 U N D ewes 0| 6on NEW HARBOR «1 ISLANDS “‘ p‘ Smack Channe! Redfish Point I‘ ‘8 88°58 v ‘°-~\‘“\»\: - 88°58 GUL D EL I L AN F OF MEXICO E U R I 3 88°48’ I I I I ° ’ 29041, 28°48 28°58 28°58 30°00’ 30°0848’ 48 1951 - Land 1978 29050, I Land Loss , I 0 29,0“ 29°49 28°55’ am 1 30°04’ 88 58 ‘ \ - I I 0 88059, 1978 vs 1989 / O 2 > .0 ..'°. . \l o ' 88°58 — V C H A 06.". —88°55' ' 1v \ ISLANDS D E l E U I? s, a. D \ ‘ S O U N Hewes Point 6090 NEW HARBOR , / '- x Q’ 8°“qu ISLANDS o q 8 I, ‘NH 6‘ Smack Channel Q) . ‘ I 00° \ 77-1- ‘ L Redfish Point 031'? ‘ k \ ‘3 I I O 0 ¢ V " 88°58 — ' S I a I - ...... , ”I ‘ ‘ " I — 88°58 ~ ’ “I I V ‘ ' K C H ......... \ IIIII ,\ L r” (l ”mu \ y x ., A N .. rrrrrr D D N GULF OF MEXICO E LE S LA U R I 88°48 I I I I o , 28°4I' 29°45’ 28°58 28°55' 30°88 38°II48I 48 1978 1989 91 US. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY North Chandeleur Islands 11 12131415161718 19 2D 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 3637 38 39 404142 4344 45 46 49 50 51 52 53 54 55 56 57 59 60 61 62 63 64 65 66 67 68 69 70 71 73 74 75 76 77 76 79 8081 82 83 84 85 1114113331 NUMBER :3 2000 LL! (9 Z < I O 3 1000 Lu 0 3 t (Z: < 0 E LIJ 9 _ _5 (I) >— < —1000 no — —10 29°41’ o , 29°53 30°33 30°U4’ 33°53 29145 1 1 33053' 1 85 5 vs 1 989 FREEMASON . ISLANDS 1 2 3 4 5 MILES 1——1 1—-—-1 1—1 1 - I 1855 1 0 1 2 3 4 5 3 7 KILOMETERS 1—1 1-—1 H J 1 I 1989 38°55’—‘ -88°59 Hewes Point NEW HARBOR‘ $13“ ISLANDS "’ - Land W- i p _ Land Loss M H A E ’V D E ' X L D S l C O E U R 1 s L A N 33°43 I I 1 1 33°43 29°41: 29°45’ 29°50’ 29°55’ 30°00' 30°04’ TRANSECTNUMBER 3 3 10 11 12 13 14 15 13 17 13 13 23 21 22 23 24 25 23 27 28 29 33 31 32 33 34 35 33 3733 33 43 41 42 43 44 43 43 47 53 51 52 53 55 53 53 33 31 32 34 35 33 33 33 73 71 7374 75 73 77 73 73 33 31 32 33 34 35 g —2000 -15 LIJ (9 Z ‘1‘ U i —10 '5 —1000 LL] 0 7 —5 D t E < O — 0 E Lu 0 (7, — 5 5 3 1000 (9 ~ 10 92 BAYSIDE RATE OF CHANGE (m/yr) GULFSIDE RATE OF CHANGE (m /yr) SHORELINE ADVANCE SHOREUNE RETREAT SHORELINE RETREAT SHORELINE ADVANCE LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A North Chandeleur Islands 29°50’ 29°41' o 1 o 1 30°00: 30°04 88°59' 29145 29 ‘55 ‘ 88059, 2 > C «9 a 9‘ 4 " °‘ ° w 1 a 5 88°55’ ~ IV D E m“\ — 88°55’ _ L NEW HARBOR ISLANDS 86 880501 _ ~ 88050, G U L F o F 35 36 37 38 56 57 5 39 40 4' 42 43 44 45 46 4748 49 so 5' 52 53 54 55 88°48’ I I 1 1 88048, 28°41' 29°45’ 29°50 29°55 30°00’ 30°04' Gulfside Transects Bayside Transects TABLE 39.—North Chandeleur Islands bayside magnitude of change (meters) Transectfi‘ 1 2 3 4 5 6 7 8 9 1O 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 4O 41 42 43 44 45 46 47 48 Transectcoord/nate 29°42'15" 30" 45" 29°43‘00" 15" 3o" 45" 29°44'00" 15" 30" 45" 29°45'00" 15" 3o" 45" 29°46'00” 15" 3o" 45" 29°47'00" 15" 30" 45" 29°48’00” 15" 30" 45" 29°49'00" 15" 30" 45" 29°50'00" 15" 3o" 45" 29°51'00" 15" 30" 45" 29°52'00" 15" 30" 45” 29°53'00" 15" 30" 45" 29°54‘00” Y 1855—1922 n.d_ n.d. n_d‘ n.d. n_d. m1. n.d. n‘a_ n_a_ M, 726 277 1286 119 226 546 1360 732 362 69 196 215 5 257 359 72 ~410 ~251 ~99 ~21 ~330 69 624 56 161 107 ~91 556 22 37 65 82 506 26 94 895 n.a. n.a. 9 1922-1951 52 n_a_ na. n.a. 281 n.a_ 470 39 496 709 610 480 5 31 ~46 272 ~152 251 224 14 39 ~20 ~11 ~177 —56 40 439 471 506 91 382 57 24 ~33 ~6 ~93 19 ~15 ~245 36 ~12 35 ~18 27 —78 ~91 ~12 ~7 a 1951—1978 "‘3, n_a_ n.a. n‘a. n.3, na. 1351 1276 727 337 302 467 713 611 270 -8 ~35 -84 ~165 ~23 ~30 ~15 ~33 ~9 ~6 ~5 ~17 ~2 129 ~29 51o ~27 ~24 ~27 ~7 ~19 ~21 ~32 234 ~44 ~14 ~8 ~53 ~19 142 36 ~20 ~9 r 1978—1989 n.a. n.a. n.a. n.a. n.a. n.a. 479 384 424 332 223 58 4 14 400 ~1 1 4 124 1 ~7 ~7 1 3 ~2 ~14 1 14 279 ~5 ~4 ~8 ~16 -5 217 9 ~9 3 ~81 ~3 o ~2 5 366 334 60 ~19 ~10 s 1855—1989 n_d_ mi nu. nd, ”d, n,d. M. “a, n.a., "3,1861 1282 2008 775 850 809 1174 903 545 61 198 173 ~38 74 295 93 13 232 815 36 558 91 608 ~9 365 4 ~102 512 2 26 39 110 440 400 492 900 n.a. n.a. Transect# 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 7O 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 Transect coordinate 15” 30" 45" 29° 55‘ 00" 15" 30" 45" 29° 56’ oo" 15" 30" 45" 29° 57' 00" 15" 30" 45" 29° 58' 00" 15" 30" 45" 29° 59' oo" 15" 30" 45" 30° 00' oo" 15" 30" 45" 30° 01' 00" 15" 30" 45" 30° 02' 00" 15" 30" 45” 30° 03‘ 00" 15" 30" Y 1855-1922 371 110 332 ~44 ~40 na, 25 71 ~13 ma, 118 319 83 799 463 ~44 ~42 ~336 ~354 ~235 234 232 443 n.a. 753 ~145 n.a. 136 142 81 ~64 ~217 ~83 ~271 ~637 ~225 ~312 ~99 9 1922—1951 276 20 77 105 86 416 151 50 -58 n,a_ ~3 148 235 ~83 63 ~60 ~92 467 764 684 184 218 382 165 138 1099 n.a. 257 230 258 —68 369 445 204 273 22 53 ~76 a 1951 —1978 -8 3 1 0 ~14 97 32 3 ~17 ~10 ~75 ~85 ~83 20 ~8 -8 2 26 18 ~89 185 ~17 32 49 402 ~46 —60 116 229 94 ~52 4 30 ~15 86 ~4 ~3 105 r 1978—1989 -2 271 1 7 4 11 ~15 —8 2 ~11 ~9 82 ~13 ~15 ~9 ~5 ~15 ~9 ~10 ~6 ~35 3 12 4 16 -9 ~14 ~52 11 118 225 ~12 ~3 11 14 103 104 n.a. S 1855-1989 637 404 411 68 36 524 193 116 ~86 M. 31 464 222 721 509 ~117 ~147 148 418 354 568 436 869 n.a. 1309 899 644 457 612 551 41 144 389 ~71 ~264 ~1o4 ~158 n.a. Chande/eur Island bayside summary Years Sum Avg STD Total Range Count 1855—1922 10456 149.4 363.0 1360 —637 70 1922—1951 12430 155.4 242.3 1099 ~245 80 1951 ~1978 7260 90.8 260.9 1351 ~165 80 1978—1989 4366 55.3 123.4 479 ~52 79 1855-1989 27823 391.9 443.5 2008 ~264 71 See page 46 for explanation of numbers. 93 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY TABLE 40.—North Chandeleur Islands gulfside magnitude of change (meters) North Chandeleur Islands 94 Transact# 1 2 3 4 5 6 7 8 9 1O 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 Transactcoord/nate 29°42'15” 30” 45" 29°43‘00” 15” 30” 45” 29°44‘00” 15” 30” 45” 29°45'00” 15” 30” 45” 29°46'00" 15” 30” 45” 29°47‘00” 15" 30” 45” 29°48'00” 15” 30” 45” 29°49'00" 15” 30" 45” 29°50'00” 15” 30” 45” 29°51'00” 15" 30” 45” 29°52'00” 15” 30” 45" 29°53'00” 15" 30” 45” 29°54'00” Y 1855-1922 n.d. n.d. n.d. n.d. n.d. n.d. n.d. —992 —1003 -977 -860 —836 —822 —840 —849 -790 —733 -710 -667 —642 -655 —616 -556 —534 —493 —502 —470 —465 —442 —361 —329 —341 -321 —295 -310 -13 -351 —323 —333 -320 —330 —351 -64 —285 —191 -221 31 n.a. (-3 1922—1951 —411 n.a. -451 n.a. —311 —283 -314 —342 —460 -293 —275 -273 —285 —242 —227 —247 —264 —242 -283 -272 -267 -265 —256 —250 —237 —192 —175 —139 —139 —146 —140 —105 -132 -129 -121 -147 -147 -146 —130 -148 -150 —132 -127 —112 —95 —90 —88 —82 a 1951—1978 n.a. n.a. —1459 n.a. —1261 —1107 —982 -775 —606 -721 —659 —599 —563 —536 —465 —416 -381 -357 —°02 —263 -238 -255 —251 —248 —241 —230 -243 —259 —285 —275 —267 —286 -281 -281 -279 —256 -250 -260 ~239 —218 -245 —255 —242 -246 —248 —239 —221 -227 r 1978—1989 n.a. n.a. —276 —286 —229 -254 -266 —259 —250 -238 -205 —216 —218 —223 —244 -231 -218 -225 —234 —256 —237 —226 —214 —175 —193 —146 —125 —108 —92 —98 —112 -103 —86 —98 —101 —101 —104 -102 —157 —119 -106 —93 -92 -91 -81 —68 —94 -101 s 1855—1989 n.d. n.d. n.d n.d. n.d. n.d. n.d. —2368 -2319 —2229 —1999 —1924 —1888 —1841 —1785 -1684 —1596 —1534 —1486 —1433 —1397 —1362 —1277 —1207 —1164 —1o70 —1013 -971 —958 -880 —848 —835 —820 —803 —811 -517 —852 —831 —859 -805 —831 —831 —525 -734 —615 —618 -372 n.a. Transectrl‘ 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 7O 71 72 73 74 75 76 77 78 79 8O 81 82 83 84 85 86 Transact coordinate 15” 30” 45”” 29° 55' 00” 15” 30” 45” 29° 56’ 00” 15” 30” 45” 29° 57' 00” 15" 30” 45” 29° 58' 00" 15”” 30” 45” 29° 59' 00” 15” 30” 45” 30° 00' 00” 15” 30” 45” 30° 01' 00” 15” 30” 45” 30° 02' 00" 15" 30" 45" 30° 03’ 00" 15" 30” Y 1855-1922 n.a. -191 —140 —92 394 n.a. 50 32 n.a. n.a. n.a. —7 5 —61 n.a. —91 —73 —85 n.a n.a. —1 10 -250 -323 n.a. -377 -387 n.a. —417 —345 -172 —221 -298 —368 -336 -241 —148 —77 58 8 1922—1951 -106 -95 —144 -171 —184 —172 —-128 -104 —95 n.a. -71 -32 —53 —1 6 —31 —72 —88 —85 n.a. n.a. -60 —46 —3 n.a. 27 —51 n.a. —138 —234 —254 —220 -123 —90 —94 —90 —51 49 85 a 1951—1978 —214 —208 —171 -174 -151 —143 —157 —164 —141 -134 —123 —125 —92 —89 —95 —109 —117 -112 —109 ~91 ~79 —75 —102 -106 —107 —119 —106 —54 -19 -29 —71 —84 —81 ~100 —171 —194 -213 -123 r 1978—1989 —92 —99 —91 ~83 -81 -78 —68 —51 —53 —55 —60 —60 —56 —49 —45 —54 —69 -71 -53 —61 —79 —106 —89 -82 -82 -58 -51 —38 —68 —90 —1 10 —125 —1 16 —91 —53 —79 -126 n.a. 3 1855—1989 n.a. -593 -546 -520 -22 n.a. —303 -287 n.a. -300 n.6 —224 -196 —21 5 n.a —326 —34 7 -353 n.a. —355 ~328 —477 —51 7 n.a. —539 —61 5 —688 —647 —666 -545 -622 —630 -655 -621 —555 —472 -367 na- Chandeleur Island gulfs1de summary Years Sum Avg STD Total Range Count 1855-1922 -24433 —359.3 291.1 394 —1003 68 1922—1951 —12702 —160.8 106.1 85 -460 79 1951—1978 -23069 -277.9 260.3 —19 —1459 83 1978—1989 —10523 —126.8 70.8 -38 —286 83 1855—1989 —61423 —877.5 553.8 -22 —2368 70 TABLE 41 .——North Chandeleur Islands baysrde rate of change (meters per year) Transect# 1 2 3 4 5 6 7 8 9 1O 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 Transactcoordinate 29°42'15” 30” 45” 29°43'00” 15” 30” 45” 29°44'00” 15” 30” 45” 29°45'00” 15" 30” 45” 29°46'00” 15” 30” 45” 29°47'00” 15” 30" 45” 29°48’00" 15” 30” 45” 29°49'00” 15” 30” 45” 29°50'00” 15” 30” 45” 29°51'00” 15” 30” 45” 29°52'00” 15” 30” 45” 29°53'00” 15” 30” 45” 29°54'00” Y 1855-1922 n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.a. n.a. n.a. 10.8 4.1 19.1 1.8 3.4 8.1 20.2 10.9 5.4 1.0 2,9 3.2 0.1 3.8 5.3 1.1 —6.1 -3.7 -1.5 -0.3 —4.9 1.0 9.3 0.8 2.4 1.6 —1.4 8.3 0.3 0.5 1.0 1.2 7.5 0.4 1.4 13.3 n.a. n.a. 6 1922—1951 1.3 n.a. n.a. n.a. 9.8 n.a. 16.3 1.4 172 24.6 21.2 16.7 0.2 1.1 —1.6 9.4 —5.3 8.7 7.8 0.5 1.4 —0.7 —0.4 —6.1 —1.9 1.4 15.2 16.4 17.6 3.2 13.3 2.0 0.8 —1.1 —0.2 —3.2 0.7 —o.5 —8.5 1.3 —o.4 1.3 —0.6 0.9 —2.7 -3.2 -0.4 —o.2 a 1951—1978 n.a. n.a. n.a. n.a. n.a. n.a. 48.6 45,9 252 121 10.9 15.3 25,5 22.0 9.7 —O.3 -1.3 —3.0 —5.9 —0.8 —1.1 —0.5 —1.2 —O.3 —0.2 —0.2 —0.6 —O.1 4.6 —1.0 18.3 —1.0 —0.9 —1.0 -O.3 -0.7 —0.8 —1.2 8.4 -1.6 -O.5 —0.3 -1.9 —O.7 5.1 1.3 —0.7 -0.3 r 1978—1989 n.a. n.a. n.a. n.a. n.a. n.a. 46.1 36.9 40.8 31.9 21.4 5.6 0.4 1.3 38.5 —O.1 0.1 0.4 11.9 0.1 —o.7 —0.7 0.1 0.3 —0.2 -1.3 0.1 1.3 26.8 —o.5 —0.4 -0.8 —1.5 —0.5 20.9 0.9 —0.9 0.3 -0.9 —o.3 0 -o.2 0.5 35.2 32.1 5.8 -1.8 —1.0 s 1855—1989 n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.a. n.a. n.a. 13.9 9.5 15.0 5.8 6.3 6.0 8.7 6.7 4.1 0.5 1.5 1.3 —0.3 0.6 2.2 0.7 0.1 1.7 6.1 0.3 4.2 0.7 4.5 —o.1 2.7 0 -O.8 3.8 o 0.2 0.3 0.8 3.3 3.0 3,7 5.7 n.a_ n.a. Transact # 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 7O 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 Transact coordinate 15” 30” 45” 29° 55’ 00” 15” 30" 45” 29° 56’ 00” 15” 30” 45" 29° 57‘ 00” 15” 30” 45” 29° 58' 00” 15” 30” 45” 29° 59' 00” 15” 30” 45” 30° 00' 00” 15” 30” 45” 30° 01‘ 00” 15” 30” 45” 30° 02' 00” 15” 30” 45” 30° 03' 00” 15” 30” Y 1855—1922 5.5 1.6 4.9 —0.7 —0.6 n.a. 0.4 1.1 -0.2 n.a. 1.8 4.7 1.2 11.9 6.9 —0.7 —0.6 -5.0 —5.3 -3.5 3.5 3.4 6.6 n.a. 11.2 -2.2 n.a. 2.0 2.1 1.2 -1.0 —3.2 —1.2 —4.0 —9.5 -3.3 —4.6 —1.5 9 1922—1951 9.6 0.7 2.7 3.6 3.0 14.4 5.2 1.7 -2.0 n.a. —o.1 5.1 8.2 —2.9 2.2 —2.1 —3.2 16.2 26.5 23.8 6.4 7.6 13.3 5.7 4.8 38.2 n.a. 8.9 8.0 9.0 -2.4 12.8 15.5 7.1 9,5 0.8 1.8 —2.6 6 1951—1978 —0.3 0.1 o 0 -o.5 3‘5 1_2 0,1 -0.6 —o.4 —2.7 —3.1 —3.0 0.7 —0.3 —o.3 0.1 0.9 0.6 —3.2 6.7 —0.6 1.2 1.8 14.5 -1.7 —2.2 4.2 8.2 3.4 -1.9 0.1 1.1 -0.5 3.1 —0.1 —o.1 3.8 r 1978—1989 —0.2 251 0.1 0.7 0.4 1,1 —1.4 —0.8 0,2 —1.1 -0.9 7.9 -1.3 -1.4 -o.9 —0.5 —1.4 —0.9 ~1.0 —O.6 —3.4 0.3 1.2 0.4 1.5 —o.9 —1.3 -5.0 1.1 11.3 21.6 —1.2 —o.3 1.1 1.3 9.9 10.0 n.a. 5 1855—1989 47 3,0 3_1 0.5 0,3 3.9 1.4 0.9 —o.6 n.a. 0.2 3.5 1.7 5.4 3.8 -0.9 —1.1 1.1 3.1 2.6 4.2 3.2 6.5 n.a. 9.7 6.7 4.8 3.4 4.6 4.1 0.3 1.1 2.9 —o.5 —2.0 -0.8 -1.2 n.a. Chandeleur Island baysrde summary Years Sum Avg STD Total Range Count 1855—1922 155.4 2.2 5.4 20.2 —9.5 70 1922-1951 431.6 5.4 8.4 38.2 —8.5 80 1951—1978 261.2 3.3 9.4 48.6 —5.9 80 1978—1989 419.8 5.3 11.9 46.1 -5.0 79 1855—1989 207.2 2.9 3.3 15.0 —2.0 71 TABLE 42.—North Chandeleur Islands wrdth measurements (meters) Transect# 1 2 3 4 5 6 7 8 9 1O 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 4O 41 42 43 44 45 46 47 48 Transactcoordinate 29°42'15” 30” 45” 29°43‘00” 15” 30” 45” 29°44'00" 15" 30” 45” 29°45'00” 15” 30” 45” 29°46'00” 15” 30” 45” 29°47'00” 15” 30” 45” 29°48'00” 15” 30” 45” 29°49'00” 15” 30” 45” 29°50'00" 15” 30” 45” 29°51‘00" 15” 30" 45” 29°52'00” 15" 30” 45” 29°53‘00" 15” 30” 45” 29°54'00” Y 1855 n.d. n.d. n.d. n.d. n.d. n.d. n.d. 268 510 1323 63 1389 1301 1564 1466 1207 1402 1201 1938 2653 2366 1810 1504 1257 1963 1856 1108 726 638 1388 940 1204 1011 1119 1630 1109 961 959 1012 1619 1611 1280 600 1026 743 775 675 n.a. e 1922 553 357 527 208 333 156 297 481 399 473 215 793 803 710 907 1464 971 625 1342 2163 1978 1192 1154 1093 1534 1034 447 385 41 1080 328 969 292 872 1268 1061 629 733 710 892 1403 847 956 768 506 465 833 958 a 1951 252 n.a. 153 n.a. 107 557 412 467 491 538 492 470 246 572 924 1090 1091 690 1068 1844 1687 914 780 765 1368 1211 299 388 556 937 570 886 528 685 1163 956 609 600 358 942 1170 761 871 684 410 572 675 985 r 1978 n.a. n.a. 21 21 100 95 204 156 200 361 326 302 437 82 416 632 602 210 769 1587 1429 622 515 510 1104 958 517 133 441 642 300 581 594 404 733 678 296 340 289 709 916 485 568 423 178 341 472 712 s 1989 20 24 227 226 373 374 281 204 198 175 161 319 289 285 170 404 375 130 512 1300 1181 398 295 310 923 841 417 171 380 551 695 469 565 457 701 563 490 232 175 576 801 389 485 697 518 568 360 602 Transact # 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 Transact coordinate 15" 30” 45” 29° 55' oo” 15” 30” 45” 29° 56' 00” 15” 30” 45” 29° 57' 00” 15” 30” 45” 29° 58' 00" 15” 30” 45” 29° 59' 00” 15” 30” 45” 30° 00' 00” 15” 30” 45” 30° 01' 00” 15” 30” 45” 30° 02' 00” 15” 30” 45” 30° 03' 00” 15” 30” Y 1855 240 825 667 903 554 n.a. 965 1170 278 957 596 1690 770 817 81 716 920 790 334 512 24 544 743 n.a. 57 363 196 227 624 142 307 1087 840 606 875 850 646 394 e 1922 764 377 388 296 252 429 1023 1245 968 n.a. 1519 1580 884 767 284 1152 933 326 n.a. n.a. 75 79 204 n.a. 185 53 n.a. 61 65 120 135 246 205 262 364 435 215 186 a 1951 938 646 262 270 744 665 1053 1224 678 879 1521 1609 800 759 1528 1137 942 396 561 359 317 102 694 545 259 488 712 147 180 318 180 307 503 97 428 370 275 272 r 1978 719 455 435 316 568 610 920 1060 262 750 1403 1498 646 662 1451 1021 824 307 243 252 346 234 554 326 257 495 662 281 250 238 201 417 424 529 105 119 105 126 s 1989 624 629 543 398 488 560 832 995 342 674 1331 1419 581 597 919 960 755 625 676 414 158 174 465 341 455 351 618 130 305 172 196 387 313 440 276 225 134 n.a. Chandeleur Island wrdth summary Years Sum Avg STD Total Range Count 1855 71485 940.6 542.8 2653 24 76 1922 54282 670.1 468.2 2163 41 81 1951 56959 678.1 387.8 1844 97 84 1978 42482 505.7 346.8 1587 21 84 1989 40359 474.8 286.7 1419 20 85 See page 46 for explanation of numbers. LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150-A TABLE 43.—North Chande/eur Islands gulfsrde rate of change (meters per year) Transect# 1 2 3 4 5 6 7 8 9 1O 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 3O 31 32 33 34 35 36 37 38 39 4O 41 42 43 44 45 46 47 48 Transect coordinate 29°42'15” 30" 45" 29° 43' 00" 15" 30" 45" 29° 44' oo" 15" 30" 45" 29° 45' oo" 15" 30” 45" 29° 46’ oo" 15" 30" 45" 29° 47' oo" 15" 30" 45" 29° 48‘00” 15" 30" 45" 29° 49' oo" 15" 30" 45" 29° 50' oo" 15" 30" 45" 29° 51'00" 15" 30" 45" 29° 5200" 15" 30" 45" 29° 53' oo" 15" 30" 45" 29° 54' 00" Y 1855—1922 n.d. n.d. n.d. n.d. n.d. n.d. n.d. —14.7 -14.9 -14.5 —12.8 —12.4 —12.2 —12.5 —12.6 —11,7 —1o.9 —1o.5 ~99 —9.5 —9.7 -9.2 —s.3 —7.9 —7.3 -7.5 -7.0 —6.9 —6.6 —5.4 —4.9 -5.1 —4.8 —4.4 —4.6 —o.2 —5.2 —4.8 —4.9 —4.3 —4.9 -5.2 -1.0 —4.2 —2.8 —3.3 0.5 n.a. 9 1922—1951 -14.3 n.a. —15.7 n.a. -10.3 —9.8 —10.9 —11.9 -16.0 -10.2 -9.5 —9.5 —9.9 —8.4 —7.9 —8.6 —9.2 —8.4 —9.3 —9.4 —9.3 —9.2 —8.9 —a.7 —8.2 —6.7 —6.1 —4.8 —4.3 —5.1 —4.9 —3.6 —4.6 —4.5 -4.2 -5.1 —5.1 -5.1 —4.5 —5.1 —5.2 —4.6 —4.4 —3.9 —3.3 —3,1 —3.1 —2.8 a 1951—1978 n.a. n.a. —52,5 n.a. —45.4 —3e.a -35.3 -27.9 -21.8 -25.9 —23.7 -21.5 —20.3 —19.3 —16.7 ~15.o —13.7 —12.8 —10.9 ~95 —8.6 —9.2 —9.0 —8.9 —9.7 —s.3 —3.7 —9.3 —10.3 —9.9 —9.6 —1o.3 —1o.1 —10.1 —10.0 -9.2 —9.0 —9.4 —8.6 —78 —8.8 -92 —8.7 —8.8 —8.9 —8.6 —7.9 —8.2 r 1978—1989 n.a. n.a. —26.5 —275 -22.0 —24.4 -25.6 —24.9 —24.0 ~22.9 -19.7 -2o.s -21.0 —21.4 -23.5 —22.2 -21.0 —21.6 —22,5 —24.6 —22.8 —21.7 —20.6 —16.8 —18.6 —14.0 —12.0 —10.4 —8.8 —9.4 -1o,8 —9.9 —8.3 —9.4 -9.7 -9.7 —10.0 —9.8 —15.1 —11.4 —1o.2 —8.9 —8.8 —8.8 —7.8 —6.5 —9.0 —9.7 s 1855—1989 n.d. n.d. n.d. n.d. n.d. n.d. n.d. —17.5 —17,3 —16.6 ~14.9 _14.3 —14.1 —13.7 —13.3 —12.5 -11.9 -11.4 —11.1 —10,7 —1o.4 —1o.1 —9.5 —9.0 —8.7 —8.0 —7.5 —7,2 —7.1 —6,6 —6.3 —6.2 —6.1 —6.0 -6.0 —3.8 —6.3 —6.2 —6.4 —6.0 —6.2 —6.2 —3.9 —5.5 —4.6 —4.6 —2.8 n.a. Transect # 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 7O 71 72 73 74 75 76 77 78 79 8O 81 82 83 84 85 86 Transect coordinate 15" 30" 45" 29° 55‘ oo" 15" 30" 45" 29° 56‘ oo" 15” so” 45" 29° 57' oo" 15" 30" 45" 29° 58’ oo" 15" 30" 45" 29° 59' oo" 15” 3o" 45" 30° 00' oo" 15" 30" 45" 30° 01' 00" 15" 30" 45" 30° 02' oo" 15" 30" 45" 30° 03' oo" 15" 30" Y 1855—1922 n.a. —2.8 -2.1 -1.4 5.9 n.a. 0.7 0.5 n.a. n.a. n.a. —o.1 0.1 —o.9 n.a. —1.4 —1.1 —1.3 n.a. n.a. —1.6 —3.7 —4.9 n.a. —5.6 —5.8 n.a. —6.2 —5.1 —2.6‘ —3.3 —4.4 —5.5 —5.0 —3.6 —2.2 —1.1 0.9 9 1922-1951 —3.7 —3.3 —5.0 —5.9 —6.4 —6.0 —4.4 -3.6 -33 n.a. —2.5 —1.1 —1,8 —O.6 —1.1 —2.5 —3.1 —3.0 n.a. n.a. —2.1 —1.6 —o.1 n.a. 0.9 —1.8 n.a. —4.8 —8.1 -8.8 -7.6 —4.3 —3.1 —3.3 —3.1 —1.8 1.7 3.0 a 1951 —1978 —7.7 —7.5 —6.2 —6.3 -5.4 —5.1 —5.6 -5.9 -5.1 —4.8 —4.4 —4.5 —3.3 —3.2 -3.4 -3.9 -4.2 -4.0 —3.9 —3.3 -2.8 —2.7 —3.7 —3.3 —3.8 —4.3 —3.8 -1.9 -0.7 —1.0 —2.6 —3.0 —2.9 —3.6 —6.2 —7,0 -7.7 —4.4 r 1978—1989 —8.8 —9.5 —8.8 —8.0 —7.8 —7.5 —5.5 —4.9 -5.1 -5.3 —5.8 —5.8 ~54 —4.7 —4.3 —5.2 —6.6 —6.8 —5.1 —5.9 —7.6 —1o.2 —8.6 —7.9 —7.9 —5.6 —4.9 —3.7 —6.5 —8.7 —10.6 —12.0 —11.2 —8.8 —5,1 —7.6 —12.1 n.a. s 1855—1989 n.a. —4.4 —4.1 -3,9 -0.2 n.a. —2.3 -2.1 n.a. —2.2 n.a. —1.7 —1.5 —1.6 n.a. -2.4 —2.6 —2.6 n.a. —2.6 -2.4 —3.6 -—3.8 n.a. —4,0 —4.6 —5.1 —4.8 -5.0 -4.1 -4.6 —4.7 —4.9 —4.6 —4.1 —3.5 -2. 7 n.a. Chande/eur Island gu/fside summary Years Sum Avg STD Total Range Count 1855—1922 ~363.0 —5.3 4.3 5.9 -14.9 68 1922-1951 —441.0 —5.6 3.7 3.0 -16.0 79 1951-1978 -829.8 —1o.o 9.4 —o.7 —52.5 83 1978—1989 -1011.8 -12.2 6.8 —3.7 —27.5 83 1855—1989 —457.4 —6.5 4.1 -o.2 -17.6 70 TABLE 44.—Area changes for Chandeleur Island from 1855 to 1989 Date Area jhaj Change jhaj % Change 1855 2,763 1922 2,485 -278 -10% 1922 2,485 1951 2,588 103 4% 1951 2,588 1978 1,796 —792 -31% 1978 1,796 1989 1,749 —47 -3% 1855 2,763 1989 1,749 -1,014 -37% Projected Date Rate (ha/vr) of Disappearance —4J 3.6 -28.5 -7.6 2528 N.A. 2041 2360 2218 TABLE 46.—Area Changes of the New Harbor Islands from 1855 to 1989 Date 1855 72 1922 94 22 1922 94 1951 70 -24 1951 70 1978 63 -7 1978 63 1989 75 12 1855 72 1989 75 3 31% —25% -10% 19% 4% 0.3 -0.8 —O.3 1.2 .02 Projected Date Area jhaj Change jhaj % Change Ratejha/yrj of Disappearance N.A. 2039 2188 N.A. N.A. TABLE 45.-—Area changes of North Islands from 1855 to 1989 J22: 1855 589 1922 391 1922 391 1951 280 1951 280 1978 110 1978 110 1989 109 1855 589 1989 109 -198 -111 —170 -480 -34% -28% -61% —1% —81% Area jhaj Change jhaj % Change Ratejha/yrj -2.9 -3.9 -6.1 -0.1 —3.6 Projected Date of Disappearance 2057 2023 1996 3079 2019 TABLE 47.—Area changes of the Freemason Islands from 1855 to 1989 Date 1855 1922 1922 1951 1951 1978 1978 1989 1855 1989 Area jhaj 218 100 100 52 52 21 21 12 218 12 Change jhaj —118 -48 -31 -206 % Change -54% —48% -60% —43% —94% Rate jha/yrj of Disappearance -1.8 1978 -1.7 1982 -1.1 1997 -0.9 2002 -1.5 1997 Projected Date See page 46 for explanation of numbers. 95 US. DEPARTMENT OF THE INTERIOR US. GEOLOGICAL SURVEY CLASSIFICATION OF SHORELINE CHANGE Classification of the distribution and rate of change along Louisiana’s barrier shoreline has been compiled and presented in past studies (Morgan and Larimore, 1957; Adams and others, 1978; Penland and Boyd, 1981; Morgan and Morgan, 1983; Dolan and others, 1985; Britsch and Kemp, 1990). These studies, however, were compiled using various methodologies, techniques, time periods, scales, and accuracy standards, which may have led to inconsistencies. Furthermore, they neither use rectified aerial photography nor discuss total potential error in detail. This study differs from previous work because it is based on approximately 880 shore—normal transects derived from digital shorelines compiled from large— scale data sources (1:33,000 or larger) using the most advanced computer mapping technology available. Moreover, temporal data were comprehensive from the 1850’s to 1989, providing both long—term and short—term rates of change, and spatial consistency was maintained among data sources (table 48). Shoreline movement along Louisiana’s barrier shoreline was divided into three broad categories based on direction and rate (m/yr) of change: shoreline advance, stability, and retreat (summary map). For this study, the terms advance and retreat were used to describe shoreline movement in contrast to the terms erosion and accretion, which imply volumetric changes. For example, retreating barrier islands can preserve volume when migrating landward (both the gulf and bay shorelines) and therefore, are not eroding but merely migrating. Based on the adopted classification scheme, the summary map illustrates that the majority of Louisiana’s barrier shoreline is suffering from high rates of coastal retreat. The Timbalier Islands section of the Bayou Lafourche barrier shoreline experienced the highest average rate of landward migration. The Plaquemines barrier system, however, experi- enced the lowest average rate of shoreline change at -5.5 m/yr between 1884 and 1988. Only six small areas had stable or advancing shorelines: the western portions of Timbalier, Grand Terre (Barataria Pass area), and Shell islands; the eastern portion of Grand Isle; the area east of Fontanelle Pass; and the southern portion of Breton Island. These stable or accre— tionary areas are related to spit processes in conjunction with an adjacent tidal entrance, except the area east of Fontanelle Pass, which is related to the capture of longshore sediment transport by jetties. CONCLUSIONS Louisiana’s barrier island systems have undergone landward migra- tion, area loss, and island narrowing as a result of a complex interaction among subsidence, sea level rise, wave processes, inadequate sediment supply, and intense human disturbance. Consequently, the structural continuity of the barrier shoreline weakens as the barrier islands narrow, fragment, and finally disappear. In the past 100 years, total barrier island area in Louisiana has declined 55% at a rate of 63 ha/ yr. This deterioration will continue to destroy Louisiana’s coastline until coastal restoration techniques that complement natural processes are implemented to restore and fortify the shoreline The Isles Dernieres barrier system experienced retreat rates along the gulf shoreline that averaged 1 1.1 m/yr between 1887 and 1988, while the bayside rate of change averaged -0.6 m/yr between 1906 and 1988. Erosion of the gulf and bay shorelines caused island width to narrow from 1,171 m in the 1890’s to 375 m in 1988. Consequently, gulf and bay shorelines are converging to cause the core of the barrier island arc to remain essentially stationary through time. Moreover, the area of Isles Dernieres decreased from 3,532 ha in 1890's to 771 ha in 1988, which is a loss of 2,761 ha at a rate of 28.2 ha/yr. The 2,761—ha loss represents a 78 percent decrease in island area since the 18905. If this rate of loss continues, Isles Dernieres is projected to disappear and evolve into a subaqueous, inner-shelf shoal by the year 2015. The Timbalier Islands experienced landward migration along the gulf and bay shorelines at average rates of -15.2 m/yr and 11.7 m/yr, respectively. However, Timbalier and East Timbalier islands must be examined separately to provide a more accurate representation of shore- line movement in response to dominant coastal processes. Between 1887 and 1988, the gulf shoreline of Timbalier Island retreated landward at 5.0 m/yr while the bay shoreline migrated seaward at 2.4 m/yr. But more importantly, Timbalier Island migrated laterally by spit processes over 6.5 km to the west. Also, island width narrowed from 1,293 m in 1887 to 415 min 1988. The area of Timbalier Island decreased from 1,485 ha in 1887 to 542 ha in 1988, which is a loss of 64 percent, or 943 ha, at a rate of 9.3 ha/yr. At this rate, Timbalier Island is not projected to disappear until the year 2046, but short—term rates indicate a more serious problem, with a projected disappearance date by the year 2000. East Timbalier Island experienced the highest gulfside retreat rate (—23. 1 m/yr) for any barrier island shoreline, not only in Louisiana but in the country. Correspondingly, the bay shoreline raced landward as well, averaging 24.0 m/ yr. Initially, the rapid rate of landward migration of the gulf and bay shorelines was caused TABLE 48.—Summary of Louisiana’s barrier island shoreline change statistics. by washover processes, but extensive seawall construction beginning in the late 1950’s terminated this process. Interestingly, width and area for East Timbalier Island increased between 1887 and 1988. Average island width increased from 264 to 333 m and area expanded from 193 ha in 1887 to 238 ha in 1988, which is a gain of 23 percent, or 45 ha, at a rate of 0.4 ha/yr. Caminada-Moreau Headland and Grand Isle experienced shoreline retreat at an average gulfside rate of —7.9 m/yr between 1887 and 1988, while at the same time, the bay shoreline was essentially stable. However, for shoreline change analysis, this coastal segment was further divided into the Caminada-Moreau Headland and Grand Isle. The gulf shoreline of the Caminada-Moreau Headland averaged 13.3 m/yr of shoreline retreat between 1887 and 1988, while the bay shoreline advanced 4.1 m/yr for the same period. In contrast, the average gulfside rate of shoreline change along Grand Isle advanced 0.9 m/ yr, while the bay shoreline retreated at an average rate of 1.0 m/ yr. The average area of Grand Isle decreased only slightly from 1,059 to 960 ha between 1887 and 1988, which is a loss of only 9 percent at a rate of 1.0 ha/yr. At this rate, Grand Isle is projected to disappear in the year 2948. Average width for Grand Isle also showed stability, remaining constant at approximately 690 m. The eastern end of Grand Isle was the only portion along this barrier shoreline to experience shoreline advance. Beach replenishment probably contributed to Grand Isle’s stability over the years. The Plaquemines barrier system experienced the lowest rate of gulfside retreat, averaging 5.5 m/yr with a bayside rate of 0.4 m/yr between 1884 and 1988. Two islands along the Plaquemines shoreline were examined individually: Grand Terre and Shell. Grand Terre Islands migrated landward along the gulf shoreline at -3.9 m/yr for the period 1884 and 1988, while the bay shoreline migrated seaward at 2.2 m/yr. Therefore, the core of the island was stationary, causing the width to narrow from 909 to 530 m and the area to diminish from 1,699 ha in 1884 to 513 ha in 1988; this is a loss of 70 percent at a rate of 11.4 ha/yr. If this rate of land loss continues, Grand Terre Islands are projected to disappear by the year 2033. Shell Island migrated landward along the gulf shoreline more rapidly than Grand Terre Islands, averaging 6.0 m/ yr. But, the bay shoreline also migrated landward at 3.4 m/yr, causing the entire island to migrate landward instead of maintaining a stationary position. The width of Shell Island narrowed from 177 to 122 m between 1884 and 1988 with a similar decrease in area from 127 to 69 ha. This is a loss of 46 percent at a rate of 0.6 ha/yr. If this long—term rate of land loss continues, Shell Island will not disappear until the early twenty—second century. However, the short-term rate loss of 5.0 ha/yr between 1973 and 1988 projects a disappearance date of 2002. The South Chandeleur Islands underwent the second highest average rate of gulfside retreat between 1869 and 1989 at 1 1.6 m/ yr, with the bay shoreline migrating landward also at a high rate of 10.7 m/yr. During rapid landward migration, average barrier width decreased from 384 to 232 m. Area decreased from 784 to 441 ha, representing a land loss of 44 percent, at a rate of 2.9 ha/yr. Individually, Breton Island migrated landward along the gulf and bay shorelines between 1869 and 1989 at —5.7 and 3.9 m/yr, respectively. Similarly, area was reduced from 332 to 164 ha, which is a 51 percent loss at an average rate of 1.4 ha/yr. For the same period, Grand Gosier and Curlew islands migrated landward at even higher rates along the gulf and bay shorelines at 16.2 and 15.0 m/yr, respectively. Area decreased from 453 to 277 ha, which is a 39 percent loss at an average rate of 1.5 ha/yr. Overall, the South Chandeleur Islands are narrowing as they rapidly migrate landward. This type of migration is similar to East Timbalier and Shell islands. The North Chandeleur Islands are characterized by an average retreat rate of 6.5 m/yr along the gulf shoreline between 1855 and 1988. The bay shoreline migrated landward also but was twice as slow as the gulf shoreline at 2.9 m/ yr. As a result, average island width narrowed by about 50 percent from 941 m in 1855 to 473 m in 1989, with a 37 percent decrease in island area from 2,763 to 1,749 ha. The total loss was 1,014 ha at an average rate of 7.6 ha/yr. Once again, the North Chandeleur Islands display a narrowing trend as they rapidly migrate landward similar to East Timbalier, Shell, and South Chandeleur islands. Finally, the Louisiana barrier shoreline is dominated by two types of island evolution: landward rollover and iii—place breakup. Landward rollover is dominated by washover processes capable of eroding and transporting sediment from the gulf shoreline, across the barrier island, and depositing this sediment along the bay shoreline; both the gulf and bay shorelines migrate landward. This appears to be associated with barrier islands having sufficient sediment to migrate landward under relative sea level rise (East Timbalier Island, 1887 to 1956; Chandeleur Island). When in—place breakup occurs, sediment is not transported across the entire barrier because there is an inadequate sediment supply and/ or the barrier island is too wide to be completely overwashed. Seaward migration along the bayside shoreline occurs in response to wave activity (erosion) and subsidence. This type of evolution is associated with barrier island systems that are rapidly deteriorating and have short life expectancies (Isles Dernieres, Grand Terre Islands). Systems where in-place breakup occurs are the most critical areas of barrier island land loss and need the greatest attention. GULFSIDE SHORELINE CHANGE RATES (m/yr) Long Term* Short Term** Long Term* ISLAND AREA CHANGE RATES (ha/yr) Short Term* * Long Term* PROJECTED DATE OF DISAPPEARANCE (yr) Short Term* * Long Term* BAYSIDE SHORELINE CHANGE RATES (m/yr) Short Term** BARRIER SYSTEM ISLAND/BEACH Avg. STD Total Range Avg. STD Total Range Avg. STD Total Range Avg. STD Total Range 1. Isles Dernieres —11.1 5.2 3.4 / —23.2 —19.2 12.7 6.0 /—64.3 —28.2 —47.2 2015 2004 —0.6 5.8 23.5 / —4.9 —2.7 15.5 43.4 / —24.3 Raccoon —7.2 2.1 —3.4 / —9.7 —17.7 7.3 —8.2 /—34.0 —7.7 —6.8 1999 2000 —2.4 0.9 —1.2 / —4.3 2.0 16.1 31.4 / —21.9 Whiskey —16.3 2.6 —12.9 / —22.0 —30.1 16.3 —11.6 /—64.3 —3.7 —12.7 2042 2007 —1.7 1.8 3.5 / —4.5 5.4 17.7 43.4 / —19.0 Trinity —11.0 1.2 —9.8 / -14.4 —17.8 4.5 —9.9 /—25.3 ——— —18.9 ——— 2007 -1.6 2.3 4.0 / —4.6 —8.4 12.5 38.4 / —24.3 East —4.8 3.9 3.4 / —10.7 —8.7 9.5 6.0 /—21.0 ——— —9.0 ——— 1998 —2.7 1.4 —0.7 / —4.9 —8.8 7.0 0.1 / —24.2 Wine —22.9 0.4 —22.5 / —23.2 ——— ——— ___ ___ —1.5 ——— 1995 ——— 22.4 0.9 23.5 / 21.3 ——— ——— ——— ——— 2. Bayou Lafourche Timbalier Islands —15.2 11.6 8.0 / —33.3 —14.0 23.7 27.6 /—84.6 —8.9 —71.5 2076 1999 11.7 15.0 32.7 / —14.6 —7.8 24.8 52.2 /—122.7 Timbalier —2.4 5.9 8.0 / —13.0 —7.0 16.5 27.6 /—54.0 —9.3 —45.7 2046 2000 -5.0 3.1 -1.0 / -15.0 —14.1 26.7 52.2 /-122.7 East Timbalier —23.1 4.4 —16.3 / —33.3 —21.2 28.7 4.6 /—84.6 0.4 —25.7 ——— 1997 24.0 4.3 33.0 / 18.0 —1.2 21.4 41.1 / —61.3 Caminada—Moreau Headland and Grand Isle —7.9 8.4 6.2 / —2o.o —6.5 11.5 16.7 /_42.0 ___ -__ ___ _— _o.1 2.4 7.0 / —2.8 -3.0 4.3 5.5 / —13-0 Caminada—Moreau Headland -13.3 5.6 —2.9 / —2o.o —13.6 7.8 —2.8 /—42.0 -__ ___ ___ ___ 4.1 1.9 7.0 / 1.9 —1.8 1.4 0.4 / —3.7 Grand Isle 0.9 3.1 6.2 / —3.4 5.2 5.7 16.7 / —2.5 -1.0 1 1 2948 ——— —1.0 1.3 2.8 / —2.8 —3.2 4.6 5.5 / —13.0 3. Plaquemines —5.5 4.5 1.9 / —15.6 —9.9 11.1 14.9 /—70.1 ___ -__ ___ ___ 0.4 4.5 12.5 / —4.7 3.7 17.8 66.1 / —19.8 Grand Terre —3.9 3.5 1.9 / —9.2 —7.9 6.5 5.9 /-15.6 —11.4 —10.8 2033 2036 —2.2 1.9 1.5 / —4.7 —1.2 6.8 17.2 / —7.5 Shell —10.1 2.8 —2.5 / —12.5 —24.2 17.6 ~3.6 /—70.1 —0.6 —50 2103 2002 7.9 12.0 12.5 / 2.4 20.6 12.4 66.1 / —1.1 4. Chandeleur Islands South Chandeleur Islands —11.6 6.5 5.9 / —21.1 —19.7 15.9 6.9 /—41.3 -2.9 13.3 2199 ——— 10.7 6.9 22.6 / —7.7 19.8 20.8 60.1 / —8.9 Breton —5.7 4.7 5.9 / —9.2 —4.1 10.2 3.8 /—23.7 —1.4 2.2 2106 ——— 3.9 5.8 10.0 / —7.7 —1.2 3.1 5.6 / —3.7 Grand Gosier/ Curlew —16.2 3.3 —6.1 / —21.1 —23.9 14.5 6.9 /—41.3 —1.5 11.1 2174 ——— 15.0 2.9 22.6 / 11.1 26.8 19.4 60.1 / —8.9 North Chandeleur Islands Chandeleur —6.5 4.1 —O.2 / —17.6 —12.2 6.8 —3.7 /—27.5 —7.6 —4.5 2218 2360 2.9 3.3 15.0 / —2.0 5.3 11.9 46.1 / —5.0 North --- --— ——— ——— ——— ——— ——— —3.6 —0.1 2019 3079 ___ ——— -—— -—— -—— ——— -—— ——— New Harbor ——— ——— ——— ___ ___ ___ ___ 0,0 1.2 ___ ___ ___ ___ ——— ——— ——— ——— -—— ——— Freemason --- -—— ——— ——— ——— ——— ——— —1.5 —0.9 1997 2002 ___ ——- ——— ——— ——— ——— ——— ——- * Long Term = Shoreline record covering more than 100 years. (except long-term island area rate for Whiskey Island —— 54 years) ** Short Term = Shoreline record for the last 10 — 15 years. 96 Summary Map LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A o , 91°” 0 , 88°37’30” so 07 30 89 ‘00 30°07'30" Lake Pontchartrain ”c3 ‘1‘ — 30°oo' Lake Borgne '3 w 0 ‘C «a» Q» 9.) g E Change Period in, «a § . . . a) Isles Dernieres, Timbalier Islands, '2 . Caminada - Moreau Headland g Sho'e'me A 1887—1988 0 B 1934—1988 .r: Advance 0 1956—1988 a g D 1978—1988 0 Z Plaquemines A 1884—1988 . B 1932—1988 Stable Shoreline C 1955—1988 a :— D 1973—1988 South Chandeleur Islands A 1869—1989 Shoreline B 1922—1989 Breton C 1951—1989 Retreat D 1978—1939 Sound North Chandeleur Islands A 1855—1989 B 1922—1989 __ 290 , —-—— C 1951—1989 30 No Data B 1978—1989 This Summary Map concentrates on classifying long-term (>100 years) shoreline change rates that have the lowest potential error and are the best indicators for future predictions of actual shoreline change. Gray tone indicates “no data” because one or more of the historical shorelines did not exist; white areas indicate that shorter-term data do exist and can be found in the shoreline change tables presented previously in this chapter. i ’ fie r "'9 - X Timbalrer Bay 29°OU’ —- 29°00’ Isl ' . . U I. F O F 28°52'30" es Dernieres IT'mbalrer Islands l ‘ 91°00’ 90°30’ 90°00’ o I o , 28°52’30” 5 0 5 10 15 2O 20 25 MILES I *1 25 30 35 KILOMETERS l-——i *1 Recommended citation for this chapter: McBride, R. A., Penland, Shea, Hiland M. W., Williams, S. J., Westphal, K. A., Jaffe, B. E., and Sallenger, A H., Jr., 1992, Analysis of barrier shoreline change in Louisiana from 1853 to 1989, in Williams, S. J., Penland, Shea, and Sallenger, A. H., Jr, eds, Louisiana barrier island erosion study—atlas of barrier shoreline changes in Louisiana from 1853 to 1989: US. Geological Survey Miscellaneous Investigations Series I-2150-A, p. 36-97. 97 US.DEPARTMENT(M:THEINTBflOR llS.GEOLOGK}U_SURVEY YEAR 1711 1722 1723 1772 1776 1778 1779 1780 1781 1793 1794 1794 1 800 1811 1812 1812 " 1819 1821 1822 1831 1837 1 846 1 848 1855 1 856 1 860 1865 98 AppendixA Louisiana’s Hurricane History 8 TORM A major three-day storm was reported in early September just south of Lake Pontchartrain. The first recorded great hurricane in Louisiana history occurred in September. On September 11 a hurricane struck New Orleans and destroyed nearly all homes and buildings. A storm disrupted shipping along the Mississippi River in late August and early September. A minor storm did minimal damage to the buildings in New Orleans. A storm between October 7— 10 destroyed Balize. On August 12 a severe storm battered New Orleans and the sur- rounding region, destroying homes, ships and other human-made features. An August 24 storm struck the Louisiana coast and sunk every ship anchored in the Mississippi. A mid-August storm passed near New Orleans. A mid-August storm passed near New Orleans, destroying crops and devastating rural areas. A mid-August storm devastated rural areas near New Orleans. A storm struck the Louisiana coast in August. A mid-August storm passed near New Orleans. A mid-August storm passed near New Orleans. A violent mid-August hurricane struck New Orleans. On August 19 a great hurricane struck the New Orleans area, destroyed the city’s levees and ships, and resulted in a number of deaths. Although primarily centered on Bay St. Louis, Mississippi, a July storm was also felt in east Louisiana, with a small amount of damage recorded in New Orleans. Little damage was recorded in New Orleans from a September storm. In early July, a hurricane battered the shoreline between Mobile and New Orleans. This storm, described as the Barbados to Louisiana Hurricane, was one of the great hurricanes of the century. It moved east of New Orleans, destroying homes and sinking ships. The death toll was estimated at 1,500. On the Isle of Barataria (believed to be Grand Isle) the storm’s winds and a 2m storm surge destroyed a fishing village and killed 150 people. A storm called the “Racer’s Hurricane” left a path of destruction over 3,000 km long in the northern Gulf of Mexico. In the inun- dated areas of New Orleans, six people died, and marine interests suffered considerable losses around Lake Pontchartrain. A rare April storm battered the mouth of the Mississippi River at Balize. Three hurricanes made landfall in the northern Gulf of Mexico. In early August, one storm moved up the Mississippi damaging crops, but property losses were apparently minimal. A September 15 storm destroyed the Gulf coast from Lake Pont- chartrain to Gulf Shores. On Sunday, August 10, the Isles Dernieres storm decimated Loui- siana’s coast. The resort community at Isles Dernieres was destroyed, and approximately 400 people died. Three hurricanes struck the middle Gulf Coast in late summer and early fall. One of them inundated property adjacent to Lake Pont- chartrain and was responsible for 13 deaths. A September storm concentrated its energy between Orange, Texas, and Cameron, Louisiana. 1867 1872 1875 1877 1879 1882 1885 1 886 1887 1888 1889 1 892 1893 1897 1898 1900 1901 1 904 1 905 1 906 1 909 1915 1916 Galveston, Texas, and western Louisiana were devastated by this storm, but damage to south Louisiana’s coastal communities was minor. A July storm affected the area east of the Mississippi Delta. A September storm came ashore in Texas and turned east through the middle of Louisiana; it had no direct effect on Louisiana’s coast. A September hurricane paralleled the Louisiana coast from Isles Dernieres to the mouth of the river—a track that caused consider- able shoreline change. Making landfall near Vermilion and Atchafalaya bays, a late-August, early-September hurricane did little damage along Louisiana’s coast. A September hurricane affected the entire Gulf of Mexico. Winds at Port Eads, Louisiana, were recorded at over 145 km/hr. Three hurricanes brushed Louisiana’s coastal margins between August 29 and October 2. An October storm struck the Louisiana-Texas border. Fifty people were killed in Cameron Parish, and a 1-m storm surge was recorded at Cheniere Caminada. Seventeen hurricanes were recorded in the United States in 1887. One October storm made landfall in Louisiana and damaged New Orleans considerably. The city’s levees were breached, and exten- sive flooding occurred. An August hurricane crossed the Louisiana coast near Vermilion Bay with winds measured at 145 km/hr near New Orleans. A storm crossed Mexico’s Yucatan Peninsula, turned north, and crossed the Gulf of Mexico, nicking the Mississippi Delta on September 22. A small hurricane hit southeast Louisiana. A storm made landfall near Barataria Bay without warning, allow- ing no time for evacuation. From 1,000 to 2,000 people were killed from the storm’s two-day rampage. Communities at Cheniere Caminada and Grand Isle were hit hard. At least 150 fishing vessels were sunk and numerous shrimp-drying platforms and associated settlements were destroyed. Fort Livingston was also severely damaged. A September hurricane came through the Florida Keys and took aim at Louisiana, crossing the coast near Vermilion Bay on September 12. A small hurricane hit Louisiana’s coast. Six thousand people died on September 8 when a hurricane inun~ dated Galveston Island, Texas, with a 6-m storm surge. Minimal damage occurred in coastal Louisiana, but the water rose over a meter in 10 minutes at Pilottown. Almost all of New Orleans’ east bank was under water. Levees were breached, and water poured into the Crescent City. A small hurricane did minimal damage in Louisiana, but there was considerable loss of life east of Bay St. Louis, Mississippi. A small November storm swept pass the Mississippi Delta. A small hurricane came ashore in Louisiana on September 29. An estimated 350 people were killed in a Louisiana-Mississippi storm. About 350 people died in September when a storm flooded most of the Louisiana coast with wind speeds of over 200 km/hr and a 5-m storm surge at Timbalier Island and the hamlet of Sea Breeze. The community at Manila Village was nearly demolished. Two hundred seventy-five people died when a hurricane struck the Mississippi Delta on September 29. In New Orleans, 25,000 struc- tures with an estimated value of $13 million were damaged or destroyed. A 4-m storm surge was reported. Grand Isle’s storm surge was estimated at three meters; nearly the entire island was under water. A small October storm affected the area east of the Mississippi Delta, but did minimal damage. 1918 1 920 1923 1926 1931 1 932 1934 1936 1937 1938 1939 1940 1 947 1 948 1949 1 954 1955 1 956 1957 1 960 1961 1964 An extreme storm killed 34 people and did $5 million in damage to the communities in western Louisiana. A small September hurricane crossed Louisiana’s coast near Last Island. One person was killed, and damages were estimated at $1,450,000. A tropical depression from the eastern Pacific crossed Mexico and became a Gulf of Mexico hurricane. It crossed Louisiana’s coast near Isles Dernieres on October 15. A hurricane crossed the Louisiana coast near Timbalier Island on August 26 with a 3-m storm surge. Twenty-five people were killed, and damages were estimated at $4 million. A small July hurricane did minor damage to Louisiana’s coast. A small hurricane made landfall at Morgan City, Louisiana, on September 19. Another storm in October along the Louisiana and Mississippi Gulf coasts did minor damage. A small storm crossed the Louisiana coast near Isles Dernieres on June 16 and was responsible for six deaths and $2,605,000 in damages at Morgan City, Louisiana. A small July hurricane did minor damage to Louisiana’s coast. A small September hurricane did minor damage to Louisiana’s coast, but dropped 42 cm of precipitation on New Orleans. Hurricane-force winds battered the Louisiana and Texas coasts on August 14. Damage was estimated at $243,000. An estimated $1.7 million in damages were assessed from New Orleans east as a result of a September 26 hurricane. On August 7 and 8, the Louisiana and Texas coasts were lashed by hurricane winds and a 1-m storm surge. Over 2.5 m of water flooded New Orleans from a September hur- ricane that tracked directly over New Orleans. It generated a surge that easily overtopped the region’s protective levees. Thirty-four people were killed, and over $100 million in damages were assessed. A September 4 hurricane made landfall near Grand Isle, Louisiana recorded nearly $900,000 in damages. A minor storm crossed Louisiana’s coast on September 4. A minor storm crossed Vermilion Bay on July 29. A minor storm killed two people on August 1 along the Louisiana- Mississippi border. Another storm on August 27 killed four people in Louisiana. Hurricane Flossy struck Grand Island and Eugene Island in September, putting over two meters of water outside the levees protecting New Orleans’ eastern boundary. Two and one half meters of water flowed over areas of Grand Isle. Eight people were killed, and property damages were estimated at $22 million. Hurricane Audrey’s 4—m storm surge hit the coast near Calcasieu Pass on June 27. Many people refused to evacuate and over 500 died. Property damages were estimated at $150 million. Hurricane Ethel passed near the Mississippi Delta. Hurricane Carla, one of the most severe Gulf hurricanes, caused high tides and inundated many of the low-lying communities along Louisiana’s coast with from 1-2 m of water. Hurricane Hilda hit Louisiana’s coast in late September and early October. Hilda caused considerable damage to offshore and coastal oil installations and generated a surge height of 1.5 m at Grand Isle. The storm caused considerable damage to the beach at Grand Isle and cut through the western end of the island and Cheniere Caminada. 1965 1 969 1971 1974 1977 1979 1985 1 988 Hurricane Betsy roared into southern Florida and Louisiana on September 8 with winds over 250 km/hr. Grand Isle was inundated with nearly a 3-m surge height. The entire island was covered, and nearly all buildings were swept away, demolished, or severely damaged. In southeast Louisiana, 81 people were killed, 17,600 injured, and 250,000 evacuated. The storm was responsible for over $1.4 billion in damages within an inundated area that exceeded 1.2 million hectares. On August 17 Hurricane Camille—one of the most violent storms ever to hit the US. mainland—killed over 300 people. A 6-m storm surge was recorded near New Orleans. Hurricane Edith crossed the Louisiana coast near Cameron on September 16. Louisiana citizens from Eugene Island to Lake Charles were affected by Hurricane Carmen. Hurricane Babe crossed Louisiana’s coast near Point-Au-Fer. Hurricane Frederic ravaged southern Alabama, and Hurricane Bob hit Grand Isle. Six hurricanes made landfall in the United States. Danny, Elena, and Juan battered the Louisiana coast. These storms were respon- sible for at least $4 billion in property damages. Three million coastal residents were evacuated. Hurricane Florence crossed the Mississippi Delta on September 8 and brought high water to Mississippi. Eight days later, Hurricane Gilbert hit Mexico with 300 km/hr winds. Its waves severely eroded Louisiana’s barrier islands. 1’ These accounts may refer to the same storm, but the historical material is inconclusive. Appendix B Coastal Erosion and Wetlands Loss Tables TABLE Bl.—Rate of shoreline change for US. coastal states and regions [Symbol used: —, no data] TABLE BZ.—Distribution of coastal wetlands in the United States [Symbol used: —, data not available] TABLE B3.—Distribution of US. coastal wetlands in the Gulf of Mexico [Symbol used.- —, data not available] Wetland Area (hectares) Mean Standard Region (m/yr)1 Deviation Total Range N2 Atlantic Coast -0.8 3.2 25.5 to 24.6 510 Maine -0.4 0.6 1.9 to -0.5 16 New Hampshire 0.0 __ -0.5 to -0.5 4 Massachusetts 09 1.9 4.5 to -4.5 48 Rhode Island -0.5 0.1 -0.3 to -0.7 17 New York 0.1 3.2 18.8 to -2.2 42 New Jersey -1.0 5.4 25.5 to -15.0 39 Delaware 0.1 2.4 5.0 to -2.3 7 Maryland -1.5 3.0 1.3 to —8.8 9 Virginia -4.2 5.5 0.9 to -24.6 34 North Carolina 06 2.1 9.4 to -6.0 101 South Carolina 20 3.8 5.9 to -17.7 57 Georgia 0.7 2.8 5.0 to -4.0 31 Florida 01 1.2 5.0 to -2.9 105 Gulf of Mexico -1.8 2.7 8.8 to -15.3 358 Florida 04 1.6 8.8 to -4.5 118 Alabama -1.1 0.6 0.8 to -3.1 16 Mississippi -0.6 2.0 0.6 to -6.4 12 Louisiana -4.2 3.3 3.4 to -15.3 106 Texas -1.2 1.4 0.8 to -5.0 106 Pacific Coast 0.0 1.5 10.0 to -5.0 305 California -0.1 1.3 10.0 to -4.2 164 Oregon 01 1.4 5.0 to -5.0 86 Washington -0.5 2.2 5.0 to -3.9 46 Alaska 24 2.0 2.9 to -6.0 69 1Negative values indicate erosion; positive values indicate accretion. 2Total number of 3-minute grid cells over which the statistics are calculated. (Data from US. Geological Survey, 1988.) Total 1,800,752 (% of total) (39) Region and State Salt Marsh Fresh Marsh Tidal Flats Swamp Total Maine 6,723 10,409 23,612 10,125 50,868 New Hampshire 3,038 — — — 3,038 Massachusetts 19,481 6,116 16,808 10,085 52,488 Rhode Island 3,200 0 0 23,126 26,325 Connecticut 6,723 — — — 6,723 New York 10,814 1,377 — — 12,191 Pennsylvania 0 324 0 0 324 New Jersey 88,047 8,789 19,683 191,282 307,800 Delaware 31,631 2,876 4,577 49,977 89,060 Maryland 66,258 10,368 729 7,857 85,212 Virginia 61,682 8,100 — — 69,782 Subtotal 297,594 48,357 65,408 292,451 703,809 North Carolina 64,314 37,260 — 853,538 955,112 South Carolina 149,648 26,123 — — 175,770 Georgia 151,592 12,758 3,848 115,830 284,027 Florida (Atlantic) 38,840 155,277 — 104,895 299,012 Subtotal 404,393 231,417 3,848 1,074,263 1,713,920 Gulf of Mexico Florida (Gulf) 174,677 31,388 — 393,134 599,198 Alabama 5,913 4,293 — 61,277 71,483 Mississippi 25,920 1,620 — 30,780 58,320 Louisiana 708,183 278,964 — 177,066 1,164,213 Texas 158,112 31,874 — 16,322 206,307 Subtotal 1,072,805 348,138 0 678,578 2,099,520 West Coast California 8,748 1,782 5,427 1,377 17,334 Oregon 7,614 2,552 10,206 — 20,372 Washington 9,599 7,128 891 11,826 29,444 Subtotal 25,961 11,462 16,524 13,203 67,149 639,374 85,779 2,058,494 4,584,398 (14) (2) (45) (100) Data converted to metric units from Alexander and others (1986, p. 6). Sums of some columns or rows may not exactly equal totals shown because of the conversion procedure and subsequent rounding. Region and State Gulf of Mexico Florida Alabama Mississippi Louisiana Texas Total Gulf of Mexico County Salt Marsh Fresh Marsh Bay 2,683 Charlotte 4,927 Citrus 12,410 Collier 16,902 Dixie 9,530 Escambia 1,102 Franklin 8,310 Gulf 256 Hernando 4,564 Hillsborough 993 Jefferson 1,848 Lee 5,751 Levy 15,881 Manatee 438 Monroe 64,613 Okaloos 264 Pasco 1,501 Pinellas — Santa Rosa 3,217 Sarasota 362 Taylor 9,686 Wakulla 7,936 Walton 1,488 Subtotal 174,663 Baldwin 1,601 Mobile 4,328 Subtotal 5,928 Hancock 8,910 Harrison 3,240 Jackson 13,770 Subtotal 25,920 Assumption 0 Cameron 147,070 Iberia 37,463 Jefferson 28,553 Lafourche 86,063 Livingston 0 Orleans 17,415 Plaquemines 117,045 St. Bernard 86,873 St. Charles 8,100 St. James 0 St. John Bap. 2,633 St. Mary 7,898 St. Tammany 12,960 Tangipahoa 0 Terrebonne 121,095 Vermilion 35,033 Subtotal 708,197 Aransas 3,629 Brasoria 17,107 Calhoun 9,331 Chambers 25,142 Galveston 17,885 Harris 778 Jackson 1,296 Jefferson 54,691 Kleberg — Matagorda 13,219 Nueces —— Orange 10,368 Refugio 1,555 San Patricio 2,333 Victoria 778 Subtotal 158,112 1,072,820 111 26,304 723 31,398 2,859 1,430 4,289 608 203 810 1,620 0 115,139 4,253 7,493 9,518 0 608 18,428 0 6,885 0 1,823 39,083 5,468 5,063 63,383 1,823 278,962 1,814 2,333 6,221 59 1,296 4,406 4,666 1,037 1,037 3,629 1,555 2,592 1,037 31,882 348,149 Wetland Area (hectares) Flats Swamp Total — 17,358 20,373 — 6,838 11,765 — 6,233 18,644 — 33,180 50,082 — 16,568 26,098 — 5,376 6,477 — 58,602 67,842 — 47,999 50,917 —- 9,784 14,349 — 3,740 4,966 — 7,063 8,911 — 17,485 23,236 — 5,318 21,285 — 2,415 2,965 —- 89,895 180,812 — 10,881 11,145 — 1,347 2,848 — 2,421 2,421 — 16,099 19,333 — 380 743 — 18,626 28,312 — 3,455 12,114 — 12,065 13,553 0 393,130 599,190 —— 42,489 46,948 — 18,786 24,543 0 61,275 71,492 — 7,290 16,808 — 2,228 5,670 — 21,263 35,843 0 30,780 58,320 — 0 0 — 83 262,292 — 2,228 43,943 — 11,543 47,588 — 6,885 102,465 — 608 608 — 3,240 21,263 — 10,125 145,598 —— 4,050 90,923 — 7,290 22,275 —— 17,415 17,415 — 25,718 30,173 — 36,855 83,835 — 8,303 26,730 — 22,275 27,338 — 17,820 202,298 — 2,633 39,488 0 177,068 1,164,227 — — 5,443 — 1,296 20,736 — — 15,552 —— 259 25,402 — — 17,885 — 4,666 5,702 — —— 2,592 — 1,555 60,653 — -——- 4,666 — 778 15,034 — — 1,037 — 7,258 21,254 — — 3,110 — — 4,925 —— 518 2,333 0 16,330 206,323 0 678,583 2,099,552 Data converted to metric units from Alexander and others (1986, p. B4). Sums of some columns or rows may not exactly equal totals shown because of the conversion procedure and subsequent rounding. LOUISIANA BARRIER ISLAND EROSION STUDY ATLAS OF SHORELINE CHANGES I—2150—A 99 Acknowledgments The authors would like to thank Mark R. Byrnes, Randall Detro, George F. Hart, Philip B. Larimore, Klaus Meyer-Arendt, and Robert A. Morton for their technical reviews and comments of vari- ous chapters. Historic maps presented in Chapter 2, and some of the historic maps digitized for Chapter 4, were provided by the Cartographic Information Center of the Department of Geography and Anthro— pology at Louisiana State University, and the assistance of Joyce N. Rolston, Map Librarian, is appreciated. Historic photographs were provided by the Louisiana Collection of the State Library, the Louisiana Department of Wildlife and Fisheries, the Biloxi Public Library, the Historic New Orleans Collection, the National Archives, the Smithsonian Institution, and Fonville Winans. Special thanks are extended to Mr. Bernard Davis and Mrs. William W. McMichael, who opened their family collections of photographs of events hitherto recorded only in written literature. The authors thank the knowledgeable and accommodating staffs of Hill Memorial Library and the Business Administration/Documents Department of Mid- dleton Library, both of Louisiana State University; the Biloxi Public Library; the Historic New Orleans Collection; the National Archives; and the Smithsonian Institution for help in locating photographs, charts, maps, and textual and miscellaneous material related to the settlement history of Louisiana’s coastal zone. Computer support, including the invaluable technical advice of Farrell W. Jones, Systems Manager, was provided by the CADGIS Research Laboratory of Louisiana State University. We thank Mark R. Byrnes and Karen E. Ramsey for technical support and advice on personal-computer—based applications. Claudia C. Holland provided editorial assistance on early drafts of Chapter 4. Numerous student assistants at the Louisiana Geological Survey contributed to production. Chris Copley, Rhonda Brewer, and Brian Savell assisted in digitizing and plotting coastal data in Chapter 4. Word processing for the atlas was done by Annetta Taylor, Eella Yokum, and Vanessa Burford. Cartographic assistance was pro- vided by Matthew Morris, Peter Dufrene, Maria Marcello, and Lacey Picou, and editorial assistance by Paul Hebert. References INTRODUCTION Gagliano, S. M., Meyer-Arendt, K. J., and Wicker, K. M., 1981, Landloss in the Mississippi River deltaic plain: Transactions of the Gulf Coast Association of Geological Societies, v. 31, p. 295—300. McBride, R. A., Penland, Shea, Jaffe, B. E., Williams, S. J., Sallenger, A. J., Jr., and Westphal, K. 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Appendix A Daily Comet, 1985, Seven hurricanes formed in 1985: Thibodaux, Lafourche Parish, Louisiana, November 29, v. 98, no. 176, p. 1A. Dunn, G. E., and Miller, B. I., 1964, Atlantic hurricanes: Baton Rouge, Louisiana State University Press, 377 p. Louisiana Office of Emergency Preparedness, 1985, Southeast Louisiana storm surge atlas: Baton Rouge, Office of Emergency Preparedness, Department of Public Safety Service, State of Louisiana, 53 p. Ludlum, D. M., 1963, Early American hurricanes, 1492-1870: Boston: American Meteorological Society. National Oceanic and Atmospheric Administration, 1988, Storm Data: Asheville, North Carolina, National Climatic Data Center, v. 30, no. 9, 55 p. Neumann, C. J., Cry, G. W., Caso, E. L., and Jarvinen, B. R., 1985, Tropical Cyclones of the North Atlantic Ocean, 1871-1980: Washington DC, U.S. Government Printing Office, 174 p. Simpson, R. H., and Riehl, Herbert, 1981, The hurricane and its impact: Oxford, England, Basil Blackwell Publishers Limited and Baton Rouge, Louisiana State University, 398 p. U.S. Army Corps of Engineers, 1972, Grand Isle and vicinity Louisiana, review report: Beach erosion and hurricane protection: New Orleans, U.S. Army Corps of Engineers, New Orleans District. Ward, Fred, 1980, Dominica, effects of Hurricane David: National Geo— graphic, v. 158(3), p. 354-359. Williams, Joel, 1988, Gilbert pounds Mexico, Texas: Morning Advocate, September 17, 64th year, no. 79, p. 1A. CONVERSION FACTORS Measurements appearing in the text of the Atlas are generally given in metric units. Many of the illustrations and tables in the Atlas, however, are reprinted or only somewhat modified (with permission) from other published sources, some of which are copyrighted; therefore measurements in the cited material are presented in their original form. The following conversion table is provided to aid the reader in making conversions from metric to U.S. customary units and from U.S. customary to metric, as needed. U.S. customary to metric units Multiply By To obtain inch (in) 2.54 centimeter (cm) toot (ft 0.3048 meter (m) yard (yd) 0.9144 meter (m) mile (mi) 1.609 kilometer (km) square mile (sq mi 2.59 square kilometers (sq km or miz) or km?) acre 4,047 square meter (sq m or m2) acre 2.471 hectare (ha) (ha=10,000 m2’ pound (lb) 453.592 grams (9) ton 0.9072 metric tonne (t) (t=1,000 kg) quart (qt) 0.9464 liter (L) gallon (gal) 3.785 liter (L) bushel (bu) 35.238 liter (L) degree Fahrenheit (’) degree Celsius (°C) (°F) Metric to U.S. customary units centimeter (cm) 0.3937 inch (in) meter (m) 3.28 toot (ft) meter (m) 1.094 yard (yd) kilometer (km) 0.6214 mile (mi) square kilometer 0.3861 square mile (sq km or m2) (sq mi or miz) square meter (sq m 10.764 square foot or m2) (sq ft or ttz) hectare (ha) 0.4047 acre (a) (ha: 10,000 m2) metric tonne (t) 1.102 ton liter (L) 1.057 quart (qt) liter (L) 0.264 gallon (gal) liter (L) 0.284 bushel (bu) degree Celsius (°C) (2) degree Fahrenheit (°F) ‘ Temp °F=1.8 K—459.67. 2 Temp °F=1.8 temp+32, 103 JUL37 v mm“..__w~ Rec’d UCB EART 1995 ~wmn RETURN EARTH SCIENCES LIBRARY T0 V 230 McCone HOII 642-2997 LOAN PERIOD 1 2 3 7 DAYS 4 5 6 DUE AS STAMPED BELOW FORM NO‘ DDS UNIVERSITY OF CALIFORNIA, BERKELEY BERKELEY, CA 94720 U C. BERKELEY LIBRARIES IIIIIIIII \IIIII . 9T}: 36/5 N UERARE‘E'E