C^o .cxitp n-o ( / - California Marine Boundary Proa ram *.-~-*.^- Cover designed by Kathy Ross State Lands Commission State of California CALIFORNIA MARINE BOUNDARY PROGRAM FINAL REPORT STATE OF CALIFORNIA/NATIONAL OCEAN SURVEY COOPERATIVE PROGRAM PREPARED BY THE TIDES AND WATER LEVELS DIVISION OFFICE OF OCEANOGRAPHY NATIONAL OCEAN SURVEY FOR THE STATE LANDS COMMISSION STATE OF CALIFORNIA 1982 ipiii Mention of a commerical company or product does not constitute an endorsement by the National Oceanic and Atmospheric Administration, National Ocean Survey. Use for publicity or advertising purposes of information from this report concerning proprietary products or the tests of such products is not authorized. TABLE OF CONTENTS Page I . INTRODUCTION 1 1 1 . BACKGROUND 1 III. FIELD ACQUISITION OF DATA 2 A. Introduction B. California Tide Party (CTP) C. Station Components/Instrumentation D. Station Installation E. Tide Station Operation and Maintenance F. Logistical Support 6. Operational Difficulties H. Recommendations I. Summary IV. DATA PROCESSING AND ANALYSIS 17 A. Introduction B. Processing C. Analysis V. TIDAL PARAMETERS 21 A. Introduction B. Tiajuana Estuary C. North San Diego County Lagoons D. El khorn Slough E. San Francisco Bay Estuarine System F. Humboldt Bay G. Comparison of Tidal Characteristics H. NGVD VI. PROGRAM ACCOMPLISHMENTS 35 A. Introduction B. Tide Stations C. Tidal Bench Marks D. Tidal Datums E. Bench Mark Publications F. Index Maps VII. RECOMMENDATIONS 38 A. Introduction B. Bench Mark Maintenance C. Future Tidal Surveys D. NGVCN E. Integrated Logistics Support (ILS) i LIST OF TABLES Table Page 1 i i Q a i o U i v c y lucq o i uili 2 Tidal 3 Tidal 4 Tidal 5 Tidal b Tidal 7 Tidal 8 Tidal 9 Tidal 10 Tidal 11 Tidal 12 Tidal 13 Tidal 14 Tidal Parameters for Tiajuana Estuary 22 Parameters for North San Diego County Lagoons 23 Parameters for Elkhorn Slough 24 Parameters for Gol den Gate 25 Parameters for San Francisco Bay (Proper) 25 Parameters for San Francisco Bay (Slough Regions) 26 Parameters for San Pablo Bay and Tributaries 27 Parameters for Carquinez Strait 27 Parameters for Suisun Bay and Tributaries 28 Parameters for San Joaquin River 28 Parameters for Sacramento River 29 Parameters for Lower Delta Region 29 Parameters for Humboldt Bay 30 i i LIST OF FIGURES Figure Page 1 Pier Installation - Conceptual Sketch . 7 2 Freestanding Pile Installation - Conceptual Sketch 8 3 Platform Gage Installation - Conceptual Sketch 9 4 Freestanding Platform Gage Installation - Conceptual Sketch 10 5 Illustration of Typical Bench Mark, Bedrock/Monument Bench Mark, Deep Rod Mark, and Installation of a Deep Rod Mark 14 6 Tidal Datums Related to NGVD Between 1930' s and 1970' s Tidal Series in San Francisco Bay Estuarine System 31 7 Monthly Mean Sea Level for San Francisco Bay for 1978 34 8 Tidal Datums Relative to NGVD for Some NTON Stations in Cal i form' a 35 m LIST OF ACRONYMS ADR Analog-to-Digital CMBP California Marine Boundary Program COE U.S. Army Corps of Engineers CTP California Tide Party DHQ Diurnal High Water Inequality DLQ Diurnal Low Water Inequality ILS Integrated Logistics Support MHW Mean High Water MHHW Mean Higher High Water MLW Mean Low Water MLLW Mean Lower Low Water Mn Mean Range MSL Mean Sea Level MTL Mean Tide Level NGS National Geodetic Survey NGVCN National Geodetic Vertical Control Network NGVD National Geodetic Vertical Datum NOAA National Oceanic and Atmospheric Administration NOS National Ocean Survey NTON National Tide Observation Network PMC Pacific Marine Center TV NATIONAL OCEAN SURVEY/CALIFORNIA MARINE BOUNDARY PROGRAM I. INTRODUCTION Prepared by A. K. Landsberqis and D. M. Martin The main objective of the National Ocean Survey (NOS) /California Marine Boundary Program (CMBP) is to utilize tidal data obtained from the established tide stations to determine tidal datums of sufficient accuracy to delineate marine boundaries and support the NOS Nautical Charting Program. In addition to providing the surveyors with tidal bench marks from which boundaries can be delineated, it also provides information that enhances mapping of the coastal areas. The NOS and its predecessor agencies have been making tide observations since 1834. The early tide observation programs focused on the needs of nautical charting. In later years, the need for determination of marine bound- aries placed more emphasis on tidal programs for that specific purpose. To acquire the necessary tide data for establishing baselines for demarcating marine boundaries, the NOS operates three types of tide stations; primary, secondary, and tertiary. Briefly these can be described as follows: The primary tide stations comprise a portion of the National Tide Observation Network (NTON). They are permanent installations where continuous tide observations are collected for a minimum of 19 years. Their purpose is to provide 19-year accepted values for datum computation, control of datum determination from short-term observations, and to monitor long-term sea level variations which affect datum computations. The data from these stations is also used to review and update the National Tidal Datum Epoch. Secondary tide stations are required to obtain tidal data at intermediate locations within the NTON, and information about seasonal variations and general tidal characteristics within a particular bay or estuarine system. Tertiary tide stations are short-term stations at which continuous obser- vations are made for a minimum of 30 days. They provide a local datum and information concerning general tidal characteristics at intermediate points within the secondary network of stations. In response to requests from state governments, marine boundary or tidal datum survey programs were developed for individual coastal states. The first cooperative cost-shared program was with the State of Florida in 1969, followed by New Jersey, California, South Carolina, Mississippi, and Louisiana. II. BACKGROUND Prepared by A. K. Landsbergis and D. M. Martin In March 1974, NOS entered into a cooperative agreement with the San Francisco District, U.S. Army Corps of Engineers (COE) to establish 15 secon- dary tide stations in South San Francisco to determine tidal datums to assist in regulating development activities. Prior to the termination of the COE agreement in March 1976, California State officials became interested in the cost-sharing marine boundary program because of pending litigations throughout the state. Subsequently, NOS and the State Lands Division signed an agreement in January 1976 for a 4-year program to collect tide data from as many tide stations as could be reasonably funded under the terms of an agreement which was to be terminated December 1979. NOS provided the state with a detailed plan for tidal requirements for all the coastal and estuarine areas of California. At the beginning of the third year of the program, it was apparent that at the existing level of Federal/State funding, all the requirements could not be met by December 1979. NOS requested a list of priority areas from the state and in conjunction with NOS requirements to support hydrographic operations in California, a number of options were presented in June 1978. It was mutually agreed that the secondary network of stations would be completed in San Pablo Bay, Suisun Bay, and the Sacramento and San Joaquin Deltas. Secondary and tertiary station networks had already been completed for San Francisco Bay, Humboldt Bay, Tiajuana Estuary, and Moss Landing. By December 1979, all of the optional requirements of June 1978 were completed and approximately 50 percent of the original program plan were accomplished. The following is a summary of the proposed stations and those established during the program: Total Number Number of Stations Number of Stations Percentage of Proposed Established at to be Established Accomplished Tide Stations the End of Project Primary 4 2 2 50% Secondary 114 80 34 70% Tertiary 186 71 115 38% Total 304 153 151 50% III. FIELD ACQUISITION OF DATA Prepared by R. F. Edwing A. Introduction The tide party was the medium through which the CMBP Boundary was transformed from project instructions to an operational tidal observation network. The tide party, tasked with performing the field operations, was a mobile unit receiving technical direction and funding from Headquarters in Rockville, Maryland and logistical and operational support from the Pacific Marine Center (PMC) in Seattle, Washington. The tide party, by necessity, was responsible for much of its own administration, coordination, logistics, equipment maintenance, and transportation. Meshing those functions with the varied contingencies of running a field operation presented a challenge which required dedication, determination, and a team effort from all involved. The result was an efficient tidal observation network collecting valuable, high-quality tidal data. B. California Tide Party (CTP) At its inception in July 1975, the CTP was essentially a one-person field effort. At this time the program was a cooperative agreement between NOS and C0E with input from the State of California. It required only a limited amount of tide stations. With the entrance of the state of California into the program in January 1976, the scope expanded and the CTP assumed the structure it would keep throughout the program. This consisted of: Chief of Party (one) - NOAA Corps Officer Oceanographer (one) - NOS civilian employee Survey Technician (one) - NOS civilian employee Student Engineering Aide (four) - State of California employees The Chief of Party primarily managed the administrative duties and worked mostly at the field office. He was the main link in communications between the CTP, PMC, and Headquarters. His major responsibilities were: 1. supervision of employees, 2. maintenance of lines of communications, 3. approval and forwarding of project data, 4. periodic reports, 5. finances, 6. logistics coordination, and 7. securing installation permission from property owners. The Chief of Party position was a NOAA Corps Officer assignment through- out the program with the exception of the final 4 months when it was filled by an oceanographer. July 1975 through November 1975 - Lt. Gary Adair, NOAA November 1975 through April 1979 - Lt. Roger A. Morris, NOAA April 1979 through November 1979 - Lt. (jg) Fain McGough, NOAA December 1979 through March 1980 - Richard F. Edwing The Oceanographer primarily managed the field operations. He functioned as technical advisor and liaison between Headquarters and the field office. He also provided continuity to the program during changes in Party Chief. His major responsibilities were: 1. scheduling and field supervision of: a. tide station installations, b. tide station inspections, c. tide station removals, and d. emergency maintenance; 2. completion of all operational documentation; 3. Analog-to-Digital (ADR) and analog roll scan for data defects; 4. maintenance and repair of spare tide gages; 5. training of new employees; and 6. monitoring logistic and equipment maintenance requirements. The Oceanographer position was a permanent duty assignment for an NOS civilian employee detailed from Headquarters in Rockville, Maryland. January 1976 through May 1978 - Mark W. Allen May 1978 through March 1980 - Richard F. Edwing The Survey Technician functioned primarily as an aide to the Oceanographer by acting as a crew leader and assisting with most of the duties listed above. The Survey Technician required good knowledge and experience with tide gages, differential leveling, support equipment, and general construction. Often the Survey Technician functioned as a jack-of-all -trades, performing minor maintenance and troubleshooting on the boats, vehicles, support equipment, etc. The Survey Technician position was a temporary slot and, for the most part, was renewable. This enabled the same employee to be kept on continuously for a good part of the program. At times there were two Survey Technicians attached to the CTP to compensate for a heavy schedule or temporary difficulties in hiring Student Engineering Aides. The Student Engineering Aides provided assistance in establishing, main- taining, and removing tide stations. Local individuals with an engineering or science background were generally hired to facilitate their training. They were hired on 9-month temporary appointments. The more experience and skills Student Engineering Aides accrued, the more duties and responsibilities were entrusted to them. All of the positions required dedication, determination, and teamwork to accomplish the program's objectives. The travel was extensive, often requiring up to 3-week long road trips to establish, maintain, or remove distant tide stations. Overtime was mandatory due to the distances involved and quantity of work to be accomplished. Hardships such as adverse weather, equipment failure, strenuous physical labor, and disagreeable surroundings were not uncommon. However, the satisfaction gained from the successful completion of project goals and the enjoyment derived from working outdoors throughout coastal and estuarine California, more than made up for the rigors. C. Station Components/Instrumentation All secondary and tertiary tide stations established by the CTP consisted of the following components: 1. analog-to-digital (ADR) tide gage, float, and floatwire; 2. stilling well ; 3. support structure(s) ; 4. tide staff; and 5. tidal bench mark network. The ADR tide gages used in the program were procured from two manufac- turers, Fischer & Porter and Leupold & Stevens. Both types of gages, in general, employ identical principles of operation and were thus used inter- changeably throughout the program. Each has a maximum range of 50 feet and records water level heights to hundredths of a foot, mechanically converting angular positions of a rotating shaft with a float, wire, and float reel assembly into binary coded (8, 4, 2, 1) decimal output. This information is recorded on a 16 channel foil -backed data tape being punched every 6 minutes. The data sampling interval of 6 minutes is controlled by a solid-state timer. The gages are powered by a 7.5 volt battery and are protected from the elements by weatherproof security covers. The Fischer & Porter models 1550 and 1551 are identical except for their exterior housing. A more detailed description of the Fischer & Porter ADR may be found in "Fischer & Porter - Instruction Bulletin (Number 35-1550C) for Type 1550 and 1551 Punched Tape Level Recorder (Spring Counterbalance Type) Design Level 'C ." A more detailed description of the Leupold & Stevens ADR may be found in Leupold & Stevens "Instructions: Stevens Digital Recorder Model 7031, 7032." The stilling well is a vertical tube with a relatively small opening (orifice) in the bottom. It is used in a tide gage installation to dampen high frequency waves while freely admitting the tide to actuate a float which, in turn, operates the tide gage. It extends to a water depth well below, if possible, that of the lowest tide. A schedule 40, 4-inch diameter PVC pipe was used by the CTP in most cases. Occasionally, however, stilling wells already established by other agencies, such as U.S. Geological Survey, Bureau of Land Management, COE, and California Department of Water Resources were available and were utilized by the CTP. These stilling wells varied in size and type. The tide staff is a nonrecording tide gage consisting of a vertical gra- duated staff from which the height of the tide can be read directly. It is graduated in feet ano tenths of a foot with the length varying, dependent upon type and manufacturer. Because of marine fouling, the tide staff is usually made of or coated with an easily cleaned surface such as fiberglass or vitrified enamel. It is used as a reference standard for comparative observa- tions and is related to local bench marks by differential levels. At each station, a network of at least five tidal bench marks was estab- lished through recovery of historical bench marks and/or the setting of new bench marks. The standard tidal bench mark of the NOS, to which the tide staff and tidal datums are referred, is a brass disk 3-5/8 inches in diameter. The gas purged pressure gage, commonly known as a "bubbler", is an analog type gage which was occasionally used as a backup gage or for reconnaissance. It is a portable pressure-recording instrument that produces a continuous strip chart record of water level changes. The underwater part of the gage consists of a small orifice chamber attached to a gas supply tube. The shore end of the tubing is connected to the gas system (pressure regulation mechanism and nitrogen gas storage tank) and to the transducer (temperature- compensated pressure bellows) and a strip chart recorder. The Metercraft Model 7601 was used by the CTP. Additional information on this tide gage is contained in Metercraft 's "Instruction: Dry Purged Pressure Recording Tide Gauge by Metercraft." D. Station Installation The CTP established tide stations at sites selected by Headquarters in Rockville, Maryland, and issued in annual Project Instructions. Prospective station sites were either historical, defined as having had previous tidal measurements and tidal bench marks established, or nonhistorical . The loca- tions selected by Headquarters were as geographically specific as possible, but were dependent upon features detailed on the best available NOS nautical charts, U.S. Geological Survey Quadrangles, and/or NOS aerial photography used to plan the station sites. In some cases where no support structures were apparent from the office information, a general area was provided for the CTP to locate a site. At certain locations a Metercraft Bubbler was required to be installed for a minimum of 3 days to determine whether tidal characteris- tics changed enough in that area to warrant an ADR tide station installation. The first step in establishing a tide station was a thorough reconnais- sance of the prospective site. A reconnaissance involved traveling to the site and: 1. Recovering all historical tidal bench marks (if any) and any other bench marks which were set in the area by other agencies. Any National Geodetic Vertical Control Network (NGVCN) bench marks within a 1-mile radius of the site also were recovered. If additional bench marks were needed, prospective sites were designated. 2. Locating a suitable support structure with sufficient water depth and accessibility. If no support structure was available then the selection of a suitable site for the construction of a support structure was necessary. In both cases a detailed list of materials and equipment needed to install the tide station was compiled. 3. Obtaining permission from the property owner for installation of the tide station. 4. Locating a potential tide observer. The next step was the actual establishment of the tide station. A typical installation consisted of the stilling well being attached by various types of brackets and/or stainless steel bands to a pile. Piles were utilized from piers (figure 1), fenders, channel markers, bridges, railroad trestles, or were sometimes freestanding. If a pile or a previously established stilling well (from another agency) or some other suitable structure was not available then a support structure had to be constructed. The support structures constructed were either freestanding piles (figure 2) jetted into the bottom with bracing batters or a three- to four-corner platform (figures 3 and 4). The tide staff was fastened to a support backing, usually a 2- by 6-foot treated plank, and was preferably attached to a different pile than the stilling well in order to isolate any settlement problems. The tide staff was placed so that it covered the full range of tide, was easily visible to the tide observer, and accessible for cleaning and surveying. Most of the tide stations were installed at lower low waters to allow the stilling wells and staffs to be secured to the support structures as far down as possible. In some cases, this was not feasible and scuba diving was required to properly make the installation. At some of the San Diego County Lagoon tide stations a Metercraft Bubbler was installed in addition to the ADR tide gage as a backup gage. In addition the analog records were used to examine short-term water level fluctuations, wave groups, freshwater runoff variations, and possible wind and rainfall events that are unique to these small systems. The Metercrafts were installed and operated in accordance with the "User's Guide for the Gas-Purged Pressure Recording (Bubbler) Tide Gage." Bench marks at each tide station were established in accordance with the "User's Guide for the Establishment of Tidal Bench Marks and Leveling Require- ments for Tide Stations (User's Guide)." A network of at least five tidal TIDE STAFF (SCAUE ..SECURED TO 2x^ TREATED BOARD) ^3^?% ADR TIDE GAGE 4 PVC OR GALVANIZED PIPE SECURED TO PIER WITH GALVANIZED STEEL BRACKETS SECTION NOAA/NOS DATE- 1/81 PIER INSTALLATION CONCEPTUAL SKETCH FIG. 1 DRAWN BY RJM ADR TIDE GAGE APPROX. HIGHEST WOOD BATTER PILE (2"x4") / / > i i NOAA/NOS DATE-- 1/81 FREESTANDING PILE INSTALLATION CONCEPTUAL SKETCH FIG. 2 DRAWN BY; RJM TOP VIEW 1 1 ' jK* i ; w "T3 4-0 4" PVC PIPE SIDE VIEW PLATFORM LENGTH CAN BE EXTENDED TO REACH SUFFICIENT WATER DEPTH LAND BASED APPRQX HIGHEST WATER LINE SIDE INTAKES OR ORIFICE AS NECESSARY NOAA/NOS DATE 5/81 PLATFORM GAGE INSTALLATION CONCEPTUAL SKETCH FIG. 3 DRAWN BY.RJM 10 TOP VIEW m ^-o"- m II I ||>tas II I 4-0' SIDE VIEW 4 DIA PVC PIPE APPROX HIGHEST WATER LINE SIDE INTAKE OR RIFICE AS NECESSARY FREESTANDING NOAA/NOS DATE: 5/81 PLATFORM GAGE INSTALLATION CONCEPTUAL SKETCH FIG. 4 DRAWN BY: RJM 11 bench marks were established at each tide station by recovery and/or the setting of new bench marks. The types of bench marks set, at least 200 feet apart, were bedrock, deep rod, and monument (large man-made structures). They were standard NOS brass survey disks stamped with the last four digits of the respective tide station number, a designating letter, and the year. All differential leveling between the tide staff, tidal bench marks, and the NGVCN bench marks was performed to the data quality standards (frequency, accuracy, collimation tests, observing routine, closing error) in accordance with: "User's Guide for the Establishment of Tidal Bench Marks and Leveling Requirements for Tide Stations," by Lt. Cdr. A. Nicholas Bodnar, Jr., NOAA Tidal Requirements and Acquisition Branch, NOS, December 8, 1977. "Classification Standards of Accuracy, and General Specification of Geodetic Control Surveys," prepared by Federal Geodetic Control Committee, NOS, February 1974, reprint May 1978. "Specifications to Support Classification, Standards of Accuracy, and General Specifications of Geodetic Control Surveys," by Federal Geodetic Control Committee, John 0. Phillips, Chairman, NOS, July 1975, reprint May 1978. Differential levels to all five bench marks were run at each tide station upon installation. The instrumentation available were two Zeiss Ni*2 automatic levels. At secondary stations, Second order, Class I differential levels were run using the 3-meter Zeiss precise rod L12 with an invar scale and half- centimeter graduations. At tertiary stations, third order differential levels were run using the Metagrad Phi 1 adephia rods graduated in centimeters. Two Zeiss parallel-plate micrometers and sighting targets were available for water crossings. The hiring and training of the tide observer was one of the most important aspects of the tide station installation. A competent, well-trained tide observer makes a significant difference in the quality of the tidal data produced by a tide station. To document tide station installation and record data, a number of NOAA forms were used. They were: 1. Tide Station Report (NOAA Form 77-12), 2. Precise Level ing-Three Wire (NOAA Form 77-29), 3. Abstract of Precise Leveling (NOAA Form 76-183), 4. Leveling Record, Tide Station (NOAA Form 76-77), 5. Description of Bench Mark (NOAA Form 76-75), 6. Recovery Note, Bench Mark (NOAA Form 76-89), 7. Weekly Tide Station Report (NOAA Form 77-24), and 8. FAILog (NOAA Form 44-6). In addition to these forms, photographs, a large-scale map section indicating the station location, a sketch of the bench marks, tide gage, and staff locations, and a description of how to reach the tide station from a 12 major landmark, were forwarded to Rockville, Maryland, as a tide station package. E. Tide Station Operation and Maintenance Once a tide station was installed it was incorporated into a regular cycle of monitoring and maintenance. Monitoring was accomplished in two steps. First was a monthly roll scan by the CTP oceanographer. This was performed during the first part of each month when all the tide rolls had been forwarded to the CTP by the tide observers via mail. All tide rolls were mailed in special cannisters by the observer and were sent certified or registered mail to help prevent their being lost. Upon receipt by the CTP the rolls were scanned for data defects such as mechanical, time, and/or observer problems. The problems were noted for corrective action by the CTP and as a processing aid for the Tidal Analysis Branch in Rockville, Maryland. All but the most subtle problems were identified and remedied in a timely fashion by this first step. The second step was performed by the Tidal Analysis Branch in Rockville. If additional problems were identified by the Tidal Analysis Branch in the course of processing a roll, the CTP was notified by telephone and a follow-up preliminary evaluation form. Emergency repairs were performed on a tide station if either of the pre- vious steps turned up a problem. In addition, the CTP was notified of problems by telephone and/or Weekly Report by the tide observer responsible for the tide station. At tide stations of sufficient duration, semiannual inspections were performed. This would involve leveling to three bench marks, a visual inspec- tion of the tide gage and the past week of punched data, contact with the tide observer, and if the ADR gage was a Leupold & Stevens, a torque test to measure the bearing friction. Torque tests were performed more frequently at tide stations susceptible to bearing deterioration, such as tide stations in areas of low tidal range and/or high salinity. Annual inspections were performed at tide stations of sufficient dura- tion. The annual inspection was identical to the semiannual inspection except that all five bench marks were leveled and their descriptions verified. The removal of a tide station involved leveling to all five bench marks, removal of all equipment except the bench mark, and restoration of the site to its original condition, unless otherwise requested by the property owner. A tide station was removed only upon instructions from Headquarters in Rockville, Maryland. F. Logistical Support The CTP operated out of several locations in the San Francisco Bay region throughout the course of the program. At each location the CTP set up logis- tics along the same basic line. 13 At each location, an office area was set up to provide working space for administrative purposes and to serve as the communications center. A telephone recorder was used to record emergency calls and other messages. A shop area was set up to provide space for the storage of equipment and materials, equip- ment repairs, and fabrication of station components. Vehicles assigned to the CTP consisted of a carryall and two utility trucks. The carryall was primarily used for leveling inspections and the trucks for station installation and removal. Boats provided vital support to the CTP. Two 10-foot fiberglass Livingston Whalers with 10 hp outboard motors were easily transported on top of either truck. A 21-foot Glasspar runabout and a 24-foot flat-hulled Monark work boat were transported by trailer. All boats were employed in reconnais- sance, maintenance, construction, and in the support of scuba diving opera- tions. The Monark was equipped with special gear to enable the tide party to set 4- by 6-inch treated redwood piles for freestanding support platforms (figure 2). An aluminum "A" frame fit into chocks on the Monark and was used in conjunction with a block and tackle, and a power winch. This equipment was used to hoist the pile and securely set it into position. Prior to placement, a 4-inch PVC floatwell with orifice and a tide staff was secured to the pile. These were correctly positioned from depth measurements taken during recon- naissance. A 1-inch PVC pipe was also attached to the pile by banding. This pipe ran the length of the pile and was connected to a gasoline-powered jet pump to a jet in the pile. After the main pile was set, 2- by 4-inch or 2- by 6-inch redwood batter piles were set by sledge hammer and/or jetting to provide support. Then a small platform and the tide gage were added. Specialized equipment was also needed to install bench marks (figure 5a). For bedrock and monument marks (figure 5b), a gasoline-powered rock drill/ hammer was used to drill the holes needed to mortar-in the bench marks (figure 5c). To install deep rod bench marks the following equipment and procedures were employed. After a site was selected, and permission obtained, the local utility companies were contacted (if deemed necessary) to determine if any cables or pipes were located in the area. This was accomplished during reconnaissance. Installation was begun by digging a hole approximately 1-1/2 feet deep by 1 foot in diameter. A section of 5/8-inch diameter, 8-foot long galvanized steel rod (NOS is now using 9/16-inch diameter type 304 stainless steel rods in 4-foot sections) was held vertically in the center of the hole and pushed in as far as possible by hand. A gasoline-powered rock drill with a pipe tamper attachment elevated by a portable aluminum "A" frame (or by standing up on the side of a truck's utility body) was used to drive the rod down (figure 5d). Rods were connected to each other by couplers sealed with pipe joint compound. When the rod had been driven to refusal or 50 feet, the excess was cut off and the bench mark disk crimped on below grade, using a hydraulic hand pump. A short section of 4-inch PVC pipe was placed around the bench mark and a cement kickblock was poured around the pipe. A witness post was also installed if circumstances warranted it. 14 a. BENCH MARK DISK TOP VIEW SCALE 1/2=1 NOTE: 1234 A 1977 WOULD BE STAMPED IN THE FIELD b. BEDROCK/ MONUMENT BENCH MARK 3% mmn " CD I ! I I (9ZIQ) 3"iniASNI1100 (t?909) H0OI1NV QdVA AAVN (1115) VI0IN39 (£t>IQ) 13M0Od0 (t?919) QNVHSI 3UVIN l\ \\ \ \\ \ \ (8££S) H1N3 X33UD VWONOS (9S09) 310Nld INIOd (I88fr) 1N3IUO INIOd NI1N3H0 (£Z8fr) NVS INIOd d3NNI (6t?8fr) QNOWHOIU a w (908t>) oinvsnvs Q ro Q c\J o 133d V \ \ CO CO LU LlI E E LlI LU CO CO < % tn \ o T \ \ \ \ \ V Q CM I O IO O 0> o cr> lj LU if) lu on CD O o CO o LU £ < a CD CD CO LU QC to Or 1 32 Figure 7 shows plots of monthly mean sea level data during 1978 for several stations within the San Francisco Bay area. The curves show the relatively uniform response of sea level within the Bay and the general trend of a high sea level during the winter months and a low sea level during the summer months. H. NGVD The NGVD is a fixed reference adopted as a standard geodetic datum for elevation. The NGVCN is a system of bench marks connected by first- or second-order leveling establishing NGVD throughout the continental United States. When the NGVCN was within 1 mile of a tide station it was connected to the tidal bench marks by second-order levels. This allowed datums established at one station to be compared to datums established at another station through the NGVD relationship. Many of the stations have a NGVCN connection. Several changes were made in the format of the new published bench mark sheet as follows: 1. California is listed with the designated NOS number 941 and California Part I, Part II, and Part III will be deleted. 2. Each station location listed is accompanied by a four-digit number rather than the former index map numbering system. 3. It is stated on the bench mark sheet that MLLW is reduced to mean values referenced to the 1960 through 1978 tidal epoch. 4. The NOS leveling and adjustment date for NGVD is stated. Most regions in California, particularly in the Suisun Bay, San Joaquin, and Sacramento River regions, have NGVD based on different adjustments. It is common to find the 1956 and/or 1967 through 1968 adjustment used to compute NGVD in the various regions of the San Francisco Bay Estuarine System. This leads to inequalities in the system particularly in regions with different rates of subsidence. The National Geodetic Survey (NGS) of NOS is working on a system to eliminate these inequalities. Figure 8 shows the relationships between MLLW, MSL, and MHW referenced to NGVD along the California coast for tide stations in the NTON. Between San Diego and Point Reyes NGVD-MLLW vary between 2.5 and 2.9 feet. In inland bodies of water along the coast, such differences could be higher or lower depending upon the tidal conditions within the body of water. The differences between NGVD and MLLW are greater along the Northern California coastal region compared to Central and Southern regions. If the sea level relative to land were the same over the entire coastal region, the MSL-NGVD relationships would be virtually the same, but this con- dition does not exist. The difference between MSL and NGVD varies from approximately -0.1 to +0.3 foot over the coast of California. M 33 M J J A I I I I I N I 9.5- 9.0- SAN FRANCISCO (4290) 2 _) CD < 85- 75- 7.0- 6.5- r— < Q 19.5- LU > ^ a m < 19.0- *■— * h- UJ UJ Ll 18.5- 11.0- 0.5- ALAMEDA (4750) SAN MATEO BRIDGE (4458) POINT ORIENT (4881) 10.0- 32.0— 31.5- BENICIA (5111) 31.0- FIG.7 MONTHLY MEAN SEA LEVEL IN SAN FRANCISCO BAY FOR 1978 DRAWN RJM 34 x (09Z6) A1I0 1N3DS3WD (OEOS) S3A3d INlOd (OQZfr) V03WV1V (8Sfrt?) 031VW NVS (O62t0 QDSlDNVdd NVS (OSf?£) A3d31N0k\l (0112) sinn nvs idOd (01?£l) vuvauve vinvs (OZZI) 0NV1SI NODNIU (01780) VOINOKI VINVS (0990) oaa3d NVS (0S90) H9V38 onmavD (08S0) H0V38 lidOdM3N (0£20) viior vi (OZIO) 093IC1 NVS o o yj o (/) cc o _l — LU tr c/) < Q < 00 o Li_ 1 O O cvJ O I O CO I O O I "ngj 35 The difference between MHW and NGVD varies from 1.8 to 2.2 feet between San Diego and Point Reyes. Such differences are higher in Northern California. Again with MHW-NGVD as with NGVD-MLLW such differences can be greater or less along the coastal region than inland bodies of water, depending upon the range of tide, other tidal conditions, and topography. The NOS presently has published NGVD-MLLW information for California with station locations originally occupied in the 1930's. Most of these sites were reoccupied during the CMBP. Since there is evidence of subsidence in parts of California, for example, the Suisun Bay, San Joaquin and Sacramento Rivers regions, NGVD-MLLW will not be published for all reoccupied sites where NGVD-MLLW were formerly published. However, NGVD-MLLW can be provided on a continual basis for those sites where subsidence is occurring with the understanding that there is a reduced accuracy in the NGVD-MLLW values and caution should be taken in the use of data from such locations. VI. PROGRAM ACCOMPLISHMENTS A. Introduction The program accomplishments listed here represent targeted goals directly attained by the NOS/CMBP within a specific time period. What cannot be fully listed are the many benefits and long-range uses that the tidal network estab- lished by the program can provide. Federal, state, and private sectors will utilize the network and tidal data for decades to come, for delineating boundaries, mapping coastal areas, construction, scientific research, and man- aging coastal resources. The 304 tide stations originally proposed were the optimum number planned to fulfill all possible NOS/State of California requirements. Approximately 50 percent (153 stations) of the proposed network was established, with budgetary and operational restraints preventing full completion. These stations were established in high priority areas as jointly determined by NOS and the State of California. B. Tide Stations The program originally required four new primary tide stations in addition to the existing NTON stations. Primaries were established at Port Chicago, Suisun Bay, and San Mateo, South San Francisco Bay. Two future primary stations will be selected from three, currently operating, long-term secondary stations. North Spit, Humboldt Bay, is one and the other is to be determined by data evaluation and other requirements from stations operating at Sacramento and Stockton. Eighty (70 percent) of the planned 114 secondary stations, and 71 (38 percent) of the planned 186 tertiary stations were established during the program. The tertiaries were operated in conjunction with their controlling secondaries as required. 36 The following table provides a summary established in various geographic locations: of the number of stations Geographic Location Tiajuana Estuary San Diego County Lagoons Moss Landing South San Francisco Bay North San Francisco Bay Tomales Bay San Pablo Bay Suisun Bay Delta Region Humboldt Bay Total Primary Secondary Tertiary Total 3 9 4 11 7 9 6 27 _4 80 2 4 20 12 3 5 8 9 _8 71 5 9 8 32 19 3 14 15 36 12 153 In addition to the planned activities a special project was undertaken which required a 6-month extension of the program from December 1979 to June 1980. This project involved a study of the Sacramento River and some coastal marshes and lagoons in Southern California. C. Tidal Bench Marks An essential part of the establishment of a tide station is the installa- tion and leveling of a system of tidal bench marks to which tidal datums are ultimately referenced. These bench marks provide a permanent record and method of recovering tidal datums long after the actual tide station has been removed. The datums computed for each bench mark are periodically updated using data from the 20 control tide stations currently in operation. As a result of the program, approximately 950 permanent tidal bench marks were established or updated. As a rule, if a tide station is within 1 mile of the NGVCN, a level connection is made to establish the relationship between the local tidal datums and NGVD. This allows datums established at one tide station to be compared to datums established at other tide stations through the NGVD relationship. Most stations established during the program were connected to NGVD. Those stations not connected were generally too far from the NGVCN. D. Tidal Datums The tidal datums established at each tide station are the principal product published and provided by N0S to the user. Datums can be transferred through surveying and utilized in engineering, charting, scientific, and legal applications. Of the 2,375 stations months of data collected, 2,156 stations months, or 90 percent, were processed and found acceptable for computing tidal datums. Presently, datums have been published for 105 of 153 station locations estab- lished (69 percent completed). The remaining station locations will be published by the end of Fiscal Year 1983, except for several of the San Diego County Lagoon and a few Sacramento River stations. These stations do not 37 exhibit periodic tidal fluctuations (due to freshwater influx, excessive pumping activities, etc.), therefore, conventional tidal datums cannot be computed. E. Bench Mark Publications The tide stations at Imperial Beach (941-0120), Cabrillo Beach (941-0650), and Santa Barbara (941-1340) have been removed, but plans are to update the bench mark publications to the revised format and elevations of bench marks referred to the 1960-78 tidal epoch, historical stations at. Holly Sugar Refinery (941-4759), Naglee Bridge (941-4778), Clifton Court (941-4794), and Grant Line Bridge (941-4785) were reoccupied, but no bench mark sheets will be published because of the daily extraction of water by irrigation pumps. Other historical tide stations, Selby (941-5142), Frank's Tract (941-5095), Union Island Highway Bridge (941-4827), Jacobs Road (941-4882), Webb Ferry (941-5147), Junction Old and San Joaquin River (941-4781), Carquinez Strait Lighthouse and Vicinity (941-5166), Tubbs Island Wharf (941-5356), South Pacific Railroad, Dumbarton Point (941-4510), and Alameda Electric Light Plant (941-4756), were not reoccupied and have been dropped from the published list. The historical stations not reoccupied but retained are Point Isabel (941-4843) and Angel Island, West Garrison (941-4817). The tide station at South Bay Wreck (941-4609) has tidal datums but no bench marks established. Tidal datums cannot be computed for Knights Landing, Sacramento River, because of the high river staging masking the tide; therefore, no published sheet will be available for this location. Many of the bench mark sheets for locations listed in California Part I and Part II were dropped from the published list. This was because of either insufficient length of series, lack of adequate 19 year control, or evidence of bench mark instability. If a tide station has less than three recoverable bench marks and the differential elevations change significantly, the tidal bench mark sheet also would be dropped from publication. However, the information would be kept on file and provided to the public upon request. F. Index Maps Users of the products provided by the program, will be informed of the data available by two sets of index maps, now available. One set of charts shows the locations for all tide stations in the state for which bench mark sheets are published. The second set of charts shows all station locations where tidal observations were made. To supplement the index maps, a station list will be provided giving the station number, name, geographic position, installation and removal dates, bench mark publication date, and length of series used for computing the published datum. The index maps will be maintained and updated at N0S Headquarters in Rockville, Maryland. Distribution of the index maps to the user will be handled jointly by the N0S and the State Lands Division. Details for requesting maps will be published in appropriate professional journals. 38 VII. RECOMMENDATIONS A. Introduction This section is based upon experiences and information derived not only from the CMBP, but also from NOS involvement in other state cooperative programs Recommendations &re made on preserving past program's accomplishments, on updating them, and on conducting future tidal surveys. EL Bench Mark Maintenance Each tide station established during the program had a minimum of five bench marks installed and/or recovered. Periodic maintenance of the bench marks is essential to the preservation of the tidal datums established. The bench marks are the only means of recovering the datums at the station once the instrumentation has been removed, other than through the complete reinstallation of the station. If the number of bench marks at a station drops to two or less, then the datums are potentially lost, unless the difference in elevation between the two bench marks has remained constant. Even with two marks, the credibility of the datums is questionable, since local movement could affect the elevation of both marks equally. A bench mark maintenance program would consist of periodic inspections of each station location involving recovery of the bench marks, stability levels, updating descriptions, and possibly the collection of additional tide data. If any bench marks have been destroyed or show excess movement, they should be replaced. A program of this nature is currently being implemented in Florida and New Jersey. C. Future Tidal Surveys Some areas of the state were surveyed much more intensively than others due to pending litigation and other Federal/State requirements. Budgetary and operational restraints prevented planned lower priority stations in other areas from being established. Thus, only limited data is available from certain coastal regions, particularly between Port San Luis and San Francisco (except Monterey Bay), and between Arena Cove and Humboldt Bay. These areas should be included in any future tidal survey. Future tidal programs also should resurvey the region between the Carquinez Strait and the San Joaquin-Sacramento River systems. The tidal characteristics in this region, coupled with subsidence, have changed drastically. This transition is an ongoing process and needs to be monitored closely. D. NGVCN At stations where the CMBP did not determine rates of subsidence, only conditional NGVD-MLLW values are provided. These values will not be published, but can be provided to the State of California, State Lands Commission upon request. Releveling of the NGVD network in some areas will be required to detect and measure such movements. It is recommended that a joint program between NOS and the State be established to relevel the NGVD network in these areas . 39 E. Integrated Logistics Support (ILS) NOS has developed and adopted a systematic standardized approach for the tidal support of its water levels measurement system, called ILS. In addition to documenting operational and maintenance procedures, it involves modification of ADR tide gages to reduce gage down time ana thus data loss. It is recommended that any future tidal survey be performed in accordance with ILS standards to increase the efficiency of the operation and produce high quality data. PENN STATE UNIVERSITY LIBRARIES ADODDVCHMHS