October ‘I960 OMIC EFFECTS OF iusting to hanging - r Supply TEXAS HIGH PLAINS RICULTURAL AND MECHANICAL COLLEGE OF TEXAS/ R~ D- I-EWIS. DIRECTOR TEXAS AGRICULTURAL EXPERIMENT STATION / COLLEGEISTATION, TEXAS - water supply. Summary Regional static water levels declined about 43 feet during the 22-year period, 1937-58. This is an average for the groundwater reservoir as a whole. It ranges from a few feet to around 100 feet in dif- ferent parts of the reservoir. The effects of this decline and the number, types and extent of adjust- ments vary considerably, depending on major soil types, initial (1938) thickness of the water-bearing stratum, the permeability of water-bearing ma- terials and the proportional amount of depletion experienced in specific hydrologic situations. The principal short-run physical effects of a decline in water levels are reflected by a reduction in well capacities. The long-run effect is a depleted The types of special practices or adjustments induced by or associated with the de- cline in water supplies include: (1) increasing the number of hours of pump operation, (2) lowering pumps, (3) installing additional wells, (4) installing closed water-distribution systems, (5) installing smaller pumps in old wells, (6) decreasing the acre- age of summer-irrigated crops and increasing the acreage of crops irrigated in fall and winter, (7) staggering grain sorghum planting dates, (8) con- centrating the available water supply on cotton, (9) irrigating alternate rows; and (10) reducing the number of acres of cropland irrigated per farm. Shifting from butane (L. P. gas) to natural gas for pump engine fuel is another significant eco- nomic adjustment. This is an economy measure not necessarily associated with changes in the water supply. As such, it is not included among the ad- justments made in response to a decline in water supplies. Physical patterns of ground water depletion are clearly defined. The number, types and extent of adjustments also are related closely to physical conditions and to the degree of depletion in spe- cific hydrologic situations. The economic patterns stemming from these adjustments are not so clearly defined. Several factors combine to obscure the full physical and economic effects of water level de- cline. Among these are: continuation, though at a slower rate, of irrigation development; elimination or reduction of transmission losses through the use of a closed distribution system; inflation; drouth and a modified irrigation program; and the shift from butane to natural gas for pumping fuel. Elimination or reduction of transmission losses particularly has had a masking effect. In some situations, the quantity of Water saved by piping water to the place of use may have been substan- tial. Thus, although the yield of a well may have deteriorated badly, the acreage served by the well may be near that served before the conduits were installed. Closed distribution systems, principally under- ground concrete tile, served approximately 40 per- cent of the land irrigated in 1958. Approximately 80 percent of the systems used in 1958 were in- stalled during 1954-58. The proportion 1 equipped with these systems ranges from in lightly depleted areas to 100 percent ' those more severely depleted. As the f ' past Water level declines havejhbeen offs extent by the elimination or reduction of‘ sion losses, future declines are likely 5 in a greater reduction in irrigated acre greater increase in costs than those that. during 1954-58. -. The effects of adjusting to declining y plies are reflected in increased per-acre '- in irrigation facilities, increased operatin acre and a reduction in the acreage of irrigated per farm. f As the physical and economic effects; ing to a declining water supply are -J fully by available measurement criteria, of water level decline cannot be expret cise mathematical terms. An examin series of adjustments, including their C? fectiveness and the possibility of further o», of a similar nature, together with u J level recession rates and the proportion n? in specific hydrologic situations, provide? for classifying the effect of water level the following categories. Areas not particularly affected by l) decline include about 194,000 acres, or 5.4 the acreage irrigated in 1958. In gen were poor water areas with relatively hi ment costs. Both costs and the water su tion have changed little since irrigatio veloped. Slightly affected areas include 291,2 8.2 percent of the land irrigated in 1958.5 ments in this category are among the f. in the reservoir. r Moderately affected areas include s; which the water-level decline and dec' adjustments have increased both inveg operating costs and impaired the Wate f some degree. This group includes 2,28 or approximately 64 percent of the land 5 1958. 1 Seriously affected areas include s which the decline in water level w" induced adjustments have seriously d; water supply, sharply increased the in irrigation facilities and substantially in) erating costs. Approximately 724,000 w; percent of the land irrigated in 1958, w in this category. f Severely affected areas include s 1 which the water supply has been severe and in which further increases in n1 would impair the economic feasibility o water use. Approximately 82,400 acres/l cent of the land irrigated in 1958, are '1 this category. f anging WATER LEVELS are a growing concern among finess and financial in- i, High Plains. The de- ibegan shortly after irri- developed on a signifi- accelerated by the Afelopment and increased use during tl1e drouth _l -56. It continued, al- f: reduced rate in most l the improved moisture * 1951-58. p reported was designed effects of the decline in the part of the area af- adjustments that have response to the change 'es. lt covers a 12-year ‘gins with a 1947-49 f- in TAES bulletins ; (2) and 763 (3) and mprehensive survey of crating conditions. A ’f changes in investment i, costs between 1950 ich was published in f4), provides a measure 4 about midway in the _ ,7, water-level declines lleconomicallv insicnifi- ‘jently, the data devel- ‘94-7-49 study p-rovide a I aising the effects of ‘ynges in water supply. _ate ‘adjustment to com- ‘ sible inflation in the gation facilities, for ‘type and unit cost of j~ and for seasonal ef- ength of the pumping P: developed in the “at studies provide a pange that can be at- ' decline in water sup- was restricted to the f. by the (State Board eers as fSubdivision i High Plains Under- agricultural economist, Research Division, Agri- " t Service, U. S. Depart- 'culture; and associate °rtlnent of Agricultural FSocioIogy, Texas Agricul- t Station. i ground Water Reservoir. It includes all or parts of 21 counties and covers a total area of 10,649 square miles. Although the study area was restrict- ed in area, for purposes of simplifi- cation, the study area is designated herein as the High Plains. The study is reported in three parts. The first consists of a descrip- tion and discussion of conditions for the area as a whole. The second examines development trends, adjust- ments and other pertinent changes during the 12 years in specific hy- drologic sub-areas. The third part assesses some of the economic effects of adjusting to the changing water supply situation. me Economic Effects of Adjusting to Water Supply, Texas High Plains William F. Hughes and A. C. Mageel‘ Present Situation WATER RESOURCES Water resources of the High Plains were studied by Johnson in the late 1890’s (5), by Gould in 1904-05 (6) (7), by Mienzer in 199 (8) and by Baker in 1914 (9). They have been examined in greater detail since irri- gation development got underway. Barnes, et al, published the most re- cent comprehensive study of the na- ture and occurrence of groundwater in the High Plains in 1949 (10). A map showing the location and thick- ness of the water-bearing strata with- in the district was compiled and published by the High Plains Under- Contents Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3 Present Situation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3 Water Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3 Irrigation Development Trends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5 Decline in Water Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Land Use and Type of Farming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6 Cropland Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6 Type of Farming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Size of Farm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6 Tenure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7 Crop Yields and Practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7 Water Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8 Commercial Fertilizer Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8 Irrigation of Every Other Row . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9 Other Developments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..lU Shift to Natural Gas for Pumping . . . . . . . . . . . . . . . . . . . . . . . . . . . ..10 Closed Conduit Water-distribution Systems . . . . . . . . . . . . . . . . . . ..lU Water-level Declines and Compensating Adjustments . . . . . . . . . . . . . . . . ..l1 Factors Contributing to Decline in Water Level . . . . . . . . . . . . . . . . . . .ll Specific Hydrologic Sub-areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..l1 Physical Effects of Water-level Decline . . . . . . . . . . . . . . . . . . . . . . . . . . ..l2 Compensating Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13 Other Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..l6 Effects of Adjusting to a Changing Water Supply . . . . . . . . . . . . . . . . . . . . . .18 Increased Investment in Irrigation Facilities . . . . . . . . . . . . . . . . . . . . ..l8 Increased Operating Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..20 Reduction in Proportion of Cropland Irrigated per Farm . . . . . . . . . . ..2l Summary of Water-level Decline Effects . . . . ..1 . . . . . . . . . . . . . . . . . ..22 Areas not Particularly Affected by Water-level Decline. . . . . . ..23 Areas Affected by Water-level Decline . . . . . . . . . . . . . . . . . . . . . . ..23 Slightly Affected Sub-areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..23 Moderately Affected Sub-areas . . . . . . . . . . . . . . . . . . . . . . . . . . ..23 Seriously Affected Sub-areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..25 Severely Affected Sub-areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..26 Literature Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..Z6 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27 Appendix Tables . . . . . . . . . . . . . . . . . . . . ., . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27 TABLE I. TI-HCKNESS OF WATER- BEARING STRATA, SUBDIVISION NO. 1 HIGH PLAINS GROUND -WATER RESERVOIR. 1938 Thickness of Pep cfiulnu" water-bearing Area‘ “entage (“we strata of total per- area centage Sgfigge Percent Percent Under 50 feet 1424 13.4 13.4 50 to 100 feet 2296 21.6 35.0 100 to 150 feet 2029 19.0 54.0 150 to 200 feet 1633 15.3 69.3 200 to 250 feet 1535 14.4 83.7 250 feet 8. over 1490 14.0 97.7 Unclassified’ 242 2.3 100.0 Total 10.649 100.0 ‘Planimetered from Figure 6. “Mostly in the “under 50 foot" category. ground Water District No. 1 in 1956 (11). This map, supplemented by data supplied by the U. S. Geologi- cal survey and the Board o-f Water Engineers, is shown as Figure 6. These reports provide detailed in- formation regarding the geology and occurrence of groundwater in the High Plains. The more salient con- clusions concerning the geology and occurrence of groundwater in the study area are summarized by Barnes, “The water-bearing formations of the Southern High Plains in Texas are of Triassic, Cretace- ous, Tertiary, and Quaternary age. Qnly a few wells obtain water from the nonmarine Dock- um beds of Triassic age, and the potential value of the Triassic groundwater reservoirs appears to be small. Cretaceous forma- tions are found only in the southwestern part of the area where yields of 500 to 1,000 gallons per minute are obtained locally from porous limestones and from basal sands that aver- age about 12 feet thick. The Pliocene series of Tertiary age is represented. by the Ogallala formation of alluvial origin, which is the most important water-bearing formation in the region. The Ogallala has an av- erage thickness of about 300 feet, and approximately two- thirds of the saturated portion of the formation is composed of sand from which some wells yield as much as 2,000 gallons per minute.” (10) Regulations of the High Plains Underground W a t e r Conservation 4 District and special studies have pro- vided a large number ‘of well logs which permit more precise mapping of the thickness and extent of the water-b-earing strata than was possi- ble in 194-9. A comprehensive study based on these data is underway. Table 1 shows that the initial thickness (1938) of the water-bear- ing strata was 150 feet or less over about 54- percent of the reservoir area. Qnly 14- percent was underlain by a water-bearing stratum that was more than 250 feet thick in 1938. With reference to the annual rate of replenishment, Barnes, et al., states, “ . . . The average annual_re- charge to 9,000 square miles in the High Plains, which con- tained most of the irrigation wells in 1940, was estimated by White, et al.,‘to be on the order of 30,000 acre-feet a year” (10). An area of some 13,000 square miles is considered to be the con- tributing area to the groundwater reservoir, but the authorities cited caution that, because of physical dif- ferences, the additional 4,000 square miles may not contribute a similar proportional amount of recharge (10) . In their concluding statement, Barnes, et al., say, “Groundwater is considered to be a replenishable resource, but TABLE 2. ACREAGE 111111941 PLAINS. TEXAS. 1999-1 Acres ' Year Irri- Year gated” 1999 90.000 1944 f 1991 190.000 1945 ‘ 199a 200.000 1949 1999 290.000 1941 1940 250.000 194a 1941 9 1949 1942 3 1954 1949 400.000 1959 ‘Subdivision No. 1, High Pl“; ground Water Reservoir, on '1 zData for 1936-48 inclusive a, 3Acreage irrigated was of exceptionally high or well", precipitation. ‘Census of irrigation, 1950 respectively. . g- 5Acreage expanded from random sample survey-I ruary, 1959. 5- the rate of groundwater in the Southern High '1 Texas is so small com,‘ present pump-age that 4;)‘, tical purposes withdraw, be considered as comi storage . . . ” (10) “Present pumpage” in f citation was 1.25 millionil Withdrawals in 1953, W. about a third lower th 1. 1956 or 1957, approximate§ acre-feet (13). In summary, the water reservoir of the H’ ‘*4 a 40 0.0”’ i t / (“a 39 Z if’ § % g 0W7‘ B ‘a ? \ i‘ % k % \ % \ / § / \ w, 2o / \ / \ \9 / \ / x \. 6% ¢§ \ 29 fix 9 / \ / \ \1 \ \. 2 \ % \ \ IO / § / \ ' / \ / \ \. % \ % \ \@ /\ ¢\ 29 %\ /\ /\ / \ / \ \, | ¢\ %\1 ¢\ 0 / , I / § / .\ é p Before 1940 1940- 44 Figure 1. Proportion of farms, acres and irrigation wells by develop: 5 J5 01 | 45 £0 i?) U1 O (II -b 1'6 o1 o: i finite amount of water, practical purposes is to renewal. Thus with ‘unt of resources, the Q 'th other mining opera- of allocating their use DEVELOPMENT {development began near 1911 (14). By 1914, , ed principally I in the areas in the vicinity jMuleshoe and Hereford. lspread slowly until the hen technological im- ‘U pumping and power equipment made it pos- pp irrigation at a mod- [Development expanded Qfter, reaching a peak louth years of 1950-54, Ylof the present irrigated developed. During the "n season, approximate- {acres were irrigated on ,1 in irrigation develop- '_ in Table 2. The pro- on which irrigation the percentage of the ‘Rped and the proportion by development pe- in Figure 1. Irriga- ‘i oped on 38 percent of 'ng 1945-49. The larg- irrigated acres and in f s drilled occurred dur- ,2. years of 1950-54, Fig- (pment continued after a materially reduced i proportion of the wells 1,1950 and particularly Rghave been drilled on irrigation had been de- Irrigation was de- ,nly 9 percent of the 1955-58. tows that a dispropor- 4r of wells have been j the irrigated acreage 50. There are several ‘is, but mainly it re- if ing on the reservoir l‘ water-bearing strata if ell yields, are low, and dditional {wells to o-ff- Jof declining water sup- freasons are discussed of this report. l, study includes all land agement, irrespective of hip. DECLINE IN WATER LEVEL A systematic program of well- invento-ry and water-level Imeasure- ments was started in 1937 by the State Board of Water Engineers and the U. S. Geological Survey. The well-inventory program became im- practical to maintain as development was accelerated during the late for- ties. However, water-level measure- ments in a netwo-rk of representative wells have been continued without interruption since the program was started in January 1937. Data developed, from these meas- urements, show that average water levels for the study area declined about 43 feet between January 1937 and January 1959, Table 3. The de- cline has not been uniform nor has it proceeded at a uniform rate in all parts of the groundwater reservoir. Near the edges of the reservoir, where the water-bearing strata are thin and development is more recent, the 22- year decline amounts to less than 2O feet. In a few small areas near the east-central part of the reservoir, where water-bearing strata are thick and development is both concentrated and older, the 22-year decline ap- proximates 1OO feet. Between these extremes, th e water -level decline ranges chiefly from 2O to 6O feet. The location of the parts of the groundwater reservoir affected by de- clines in the water level are shown in Figure 2. The accumulated change in regional static water levels in re- lation to acreage irrigated is shown in Figure 3. I OLDHAM ' ¢ ‘ Q . I , \ ITH , v/ \\\4 -1}’-§5§i" >\ \ \ \ I \ M: l! I" I .79., ’ o ‘l: .4.‘ i‘. Y-i: " I '5": i'-".- ' .-' #2". "o. :- ' . . ..| '_ Y. I \ "'Io..-.'¢n i 'av_a{IaI_1a.'_._-_ o“ (I Pcfvdio SUBDIVISION No.I HIGH PLAINS GROUND WATER RESERVOIR U POTTER . _ z. , .._ ~\\\\ . ., WIS BZISCOE R0 . 16'” Ro éYi-f ".0 I! LYRR i ' i TERRY ' ' I Brownfield Adapted from mag grepared by (-/.I?U.PV.C.D. No.1. Amarillo‘ ' '““' UNDER 2o FEET . FROM 2o T0 4o FEET I FROM 4o T0 so FEET QVER 6Q FEET .,._laRmsrRo~e Vaffian? ;_;I :~ - ’ . ‘Q 30% \ /.. . . I‘ as‘ E 9 '- .‘ .‘ a“ ~ \ I o . u. ' '1: I~:~::-::‘:-. '. .. -. ‘ - "1 .‘.O’O *Q_O' . .0 ‘ . . ‘l. \\\\\\\“ :.-.l=rv#*r~, .-- ' \ . ',- - '. ' " ' _—' 9-7-11 J -- GARZA - - ' 3'. a Pas! [Tabaka . Figure 2. Approximate- decline of the water table, 1938-1958. LAND USE AND TYPE OF FARMING A high proportion of irrigated farms in the High Plains contain only cropland. The proportion of crop- land that is irrigated differs with the hydrologic conditions in different parts of the area. Cropland Use Although some new crops, notably soybeans and vegetables,’ have been introduced in recent years, cotton, grain sorghum and wheat are still the principal crops. In 1958, they occupied about 87 percent of the cropland. All other crops combined occupied less than 6 percent of the total cropland. Slightly more than 7 percent of the normally irrigated cropland was idle or fallow (acreage reserve) in 1958, Table 4. The acreages of the principal crops —cotton, grain sorghum and wheat— have fluctuated somewhat, but the proportion of irrigated cropland oc- cupied by these crops is similar to the proportions occupied in 1948 and 1954 when the proportion of irri- gated cropland classed as “idle or fallow” was much smaller than in 1958. Acreages of cotton and wheat have been reduced by acreage-allot- ment programs since the 1954 crop year, but most of the acreage taken out of cotton and wheat has been planted to grain sorghum and some barley. In 1948, when acreage allot- ments were not in effect, cotton, grain sorghum and wheat occupied 35, 38 and 19 percent, respectively, of the irrigated cropland in the area (15). Compared with 1948, the 1958 figures reflect a change of ~53 per- cent, +6.5 percent and —4.8 percent in the proportion of irrigated crop- land occupied by cotton, grain sor- ghum and wheat, respectively, Table 4. Type of Farming The proportion of cropland devot- ed to the principal crops is inde- pendent of hydrologic conditions. The proportion of cropland irrigated, however, is related to hydrologic con- ditions, as is brought out in greater detail in later sections of this report. Since the ability to absorb in- creased costs or decreased returns is closely associated with specific crops, the emphasis placed on particular crops (or the type of farming) pro- vides a basis for appraising the past and future effects of a decline in water supplies on farm income. lVIost of the comparisons hereafter are be- tween conditions within a particular type-of-farming area. The study area includes parts of two major type-of-farming areas, as described in TAES Bulletin 964, “Types of Farming in Texas,” by C. A. Bonnen. Since the study reported here involves considerably more de- tail than is possible in a statewide study, such as was reported in Bulle- tin 964, the study area is divided into four parts based on the proportion of irrigated cropland devoted to the principal crops + cotton, grain sor- ghum and wheat — and the major soil types. Thus, none of the four parts used in the study have exactly the same boundaries as the major type-of-farming areas. The four parts or areas used in the study are desig- nated as farming areas A, B, C and D, Figure 4. The proportions of irri- gated farms in the respective farm- ing areas are shown in Table 4. Farming areas A and B are simi- lar in that cotton and grain sorghum TABLE 3. ANNUAL FLUCTUATIONS AND ACCUMULATED DEPARTURE FROM 1937 STATIC WATER LEVEL, TEXAS HIGH PLAINS, 1937-58‘ ‘Annual Accumulated Annual Accumulated Year fluctuation, departure, Year fluctuation, departure, feet feet feet feet 1938 +0.05 +0.05 1948 +2.87 +10.65 1939 +0.92 +0.87 1949 —0.80 +11.45 1940 +2.24 —3.11 1950 +1.30 —12.75 1941 +3.61 +0.50 1951 +2.10 —14.85 1942 +0.37 +0.87 1952 +3.90 —18.75 1943 +1.74 +0.87 1953 +4.90 +23.65 1944 +0.83 +1.70 1954 +5.60 +29.25 1945 —1.86 +3.56 1955 +4.50 +33.75 1946 +1.62 +5.18 1956 +5.60 —39.35 1947 +2.60 +7.78 1957 +2.33 +41.68 1958 +1.09 —42.77 ‘Based on static water-level measurements by the USGS and State Board of Water Engineers, study area only. 6 +30 +20- +10- _2O_ WATER LEVEL IN FEET _30- ~50 was I940 194s I950 YEARS Figure 3. Accumulated gional static water level y acres irrigated, 1937-1958.._l§ are the principal crops, I and 8O percent, respec' cropland. Farming area‘; farms producing cotton? sorghum on sandy u whereas on farms in fa 1y cotton and grain sorgh duced on heavy soils. H Farms in farming ar, wheat among the pr'p These farms are similar, farming area B in all exf age in wheat. Farms in t‘ 1O percent or more of: in wheat, Table 4. Fa i is designated as a cott ghum-wheat farming at Farming area D is l’ ghum-wheat producing _ occupies less than 10.' cropland, Table 4 and ; Size of Fa In 1958, the average i contained 405 acres. A stituted 9O percent of.‘ farm, or 363 acres, wi, irrigated, Table 4. The] of farm ranged from ‘ farming area B to 663 :5‘ ing area D. Cropl ranged from 82 perce area D to 96 percent in, A. The proportion of v; gated in farming area i percent, compared wi y‘ 83 percent, respectively areas B, C and D. F = j contains a high prof low-yielding wells that = veloped on the fringes i; g Y jand the water supply fficient. This is in- 117 acres of dry- f farm and the 8.2 » d planted to cotton, report since 1940 has - in the size of irri- in the number of farm. According of Agriculture, ated farm in the 21- ):»: reservoir area ores with 238 acres Although the figures comparable, the av- ‘farm included in the 405 acres in 1958, 'ch to determine the ' subdivision that has area as a whole or four farming areas o. Data developed in 511959 surveys provide if the change that oc- 'ze in two of the four f? between 1954 and m sizes have moved "ections in Farming Table 5. In area A, 10f farms of less than eased between 1954 i,’ proportion of farms f; 350 acres increased :13. There was a sharp proportion of 351 to in area A and an al- ine in farms of simi- f": B, Table 5. A and B include the i- reservoir area that T g the greatest total g al declines in water fTenure _'lon of owner-operated ased since 1954. For ole, 64 percent of the ‘rators had an equity is, they owned all or they operated, com- ; 50 percent in 1954. _on of F full owner- _. ; differs-I considerably ‘t areas, ranging from §rcent in area A to 63 _= C, Table 6. ted farms contain less 1T, farm than tenant or nal” operated farms. The land owner who rents ‘additional cropland operated the largest aver- age number of cropland acres per farm, Table 6. The operators of irrigated farms show a high degree of residential stability. The average length of resi- dence on the farm is closely associ- ated with land tenure. Owner-oper- ators averaged 17 years of occupancy on their farms and tenant operators 8.6 years, Table 6. The crop share lease predominates on tenant-operated farms of the High Plains. Slightly less than 3 percent of the leasing agreements were cash leases, which were equally distributed among the four farming areas. A few partnership an d manager-operated farms were enumerated in the sur- vey. Father-and-son-operated farms, which are included among the owner or owner-additional operator groups, were considerably more numerous than farms operated under cash leases. CROP YIELDS AND PRACTICES Moisture conditions during 1957- 58 were better than those of the 1950- 56 period. The more favorable mois- ture situation, in conjunction with increased use of fertilizer and hybrid grain sorghum, was reflected in gen- erally higher yields, particularly for dryland crops and irrigated grain sorghum. Dryland and irrigated crop yields are reported in Table 7 by farming area and soil type, and for the reservoir area. The average yield of dryland crops in 1954-58, which included 3 dry years and 2 years with favorable moisture supplies, approached the longtime average for dryland crops in this part of the High Plains, Table 7. Because of unfavorable fall weather in 1957, the 5-year (1954-58) aver- age yield of irrigated cotton was somewhat lower than the average yield obtained in 1954. Although the difference is neither so pronounced nor so wide as in 1954, irrigated cot- ton on heavy soils outyielded irri- gated cotton grown on sandy (mixed) soils, Table 7. Use of hybrid grain sorghum, which has come into general use in recent years, and expanding use of fertilizer have increased grain sor- ghum yields, particularly in the heavy soil area. The 1954-58 average yield of irrigated grain sorghum in farm area A, is somewhat below the yields obtained in 1954. This is an TABLE 4. SIZE OF FARM. LAND USE. CROPLAND USE AND ESTIMATED VALUE PER ACRE, BY FARMING AREA, IRRIGATED FARMS ONLY, 1958 _ Farm area‘ Area Item Unit A B C D t o, a1 Proportion oi farms Percent 37 30 19 14 100 Size of farm Acre 320 293 543 663 405 Cropland per iarm do. 309 269 472 542 363 Noncropland per farm do. 11 24 71 121 42 Irrigated cropland per farm do. 192 239 423 450 289 Nonirrigated cropland per farm do. 117 30 49 92 74 Cropland use: Cotton Percent 38.8 31.3 19.3 3.2 23.7 Grain Sorghum do. 51.7 48.4 46.8 45.8 48.5 Small grainz do. 1.2 5.2 21.1 38.0 14.7 Other crops do. 5.0 7.5 4.4 6.4 5.7 Fallow3 do. 3.3 7.6 8.4 6.6 7.4 Irrigated cropland use: Cotton do. 57.2 34.7 21.2 3.8 29.7 Grain sorghum do. 31.7 49.2 48.9 47.6 44.5 Small grain’ do. 1.8 2.2 19.3 35.9 14.2 Other crops do. 6.6 7.7 4.2 7.3 6.4 Fallows do. 2.7 6.2 6.4 5.4 5.2 Nonirrigated cropland use: ' Cotton do. 8.2 3.7 3.2 0.0 5.6 Grain Sorghum do. 84.8 41.8 28.4 36.8 64.1 Small graini do. 0.0 28.7 37.8 49.4 15.3 Other do. 2.1 5.9 6.0 1.8 3.0 Fallow3 do. 4.9 19.9 24.6 12.0 13.0 Estimated value per acre‘ Dollar 327 324 267 232 289 ‘See text. pages 6 and 7, for description and Figure 4 for location of farming areas. 2Wheat. barley. and oats. “Includes formerly irrigated land that was idle or in acreage reserve in 1958. ‘Estimated market price of land and buildings for the farm as a unit, Ianuary 1959. 7 area with generally 'short water sup- plies, and the available water is usual- ly applied to cotton, see Table 4. Al- so, grain sorghum is not fertilized as heavily 0r as commonly in this area as in the heavy soils areas. Yields of irrigated grain sorghum in areas with heavy soils are up over those received before adoption of hy- brids and use of fertilizer. The 1954- 58 average yield is 380 pounds great- er than in 1954, Table 7. -The 1958 average yield of 4,100 p-ounds per acre is probably more representative of the yields that might be expected with the use of hybrids and fertilizer. The 1954-58 average yield does not reflect 5 years of general fertilizer and hybrid sorghum use. The 5-year period includes the transition from standard to hybrid varieties and a substantial expansion in use of com- mercial fertilizers. Water Use Data are not available to permit a determination of water use for the area as a whole. Few farmers know the exact amount of water applied per irrigation or the total amount ap- plied to a particular crop during the year. But there are sources of data that can be drawn on to provide some estimate of water use. The first of these is a series of water measure- ments made by the High Plains Un- derground Water Conservation Dis- trict No. 1. Second, are the some- what less precise yet nevertheless useful reports by farm operators of OLDHAM -___-7.- t-inti l 0 l; . BAILEY . , __ 4 /~A 7 COCHRAN . Lon/land YOAKUM TERRY SUBDIVISION No.l HIGH PLAINS GROUND WATER RESERVOIR POTTER ' ' t . ,a°'l,lr‘ .§" ARMSTRONG a v°",,\ov g. Qfiolog a‘ ' t0. o“ é l - "ppxflfl _ amscoe ‘If-jEI-II 55-155; . h , =.'~.}i7_-’§:; -1j-_:v:/,~»:».§a higher soil moisture i applying at least one "_ tion, when commer- e used on grain sor- i of locally favorable Ions in 1958, it was maintain high mois- lfewer than the usual gations. In addition litlifference, there are it» farm operators in " times a crop is irri- J onal and individual i» number of irriga- l accuracy of results iparing the yields ob- ‘= without commercial i: of fertilizer applica- iry widely between A ammonia was the ' izer used on grain éeat. A few applica- ids per acre were re- l more common rate .3 ranged between 8O _ per acre. Some an- -» was applied on ~- fertilizer at a rate ', per acre predomi- Hand yield differences associated with the Yields were associ- practices commonly 8' soil conditions. in of farm operators ",0, the proportion of ized, rates of ferti- f er pertinent details f use of commercial g: are shown in Table YTable 8 are average with the indicated I the weather condi- Weather conditions i ; or greater experi- fertilizer might lead "I 1S. ‘in Table 8 reflect the y 1 year, no definite _i~ respect to the use i‘ fertilizer can be are indicative, how- 'ght be expected in ture conditions simi- A 1958. Under these texcept for the results 1' cotton on sandy Ethe 1958 results sug- _1~ the number of TABLE 5. SIZE OF IRRIGATED FARMS BY FARMING AREAS, 1954 AND 1958 Farming Area Range in farm size A B C D stuigtalfrea 1954 1958 1954 1958 1958 1958 1958 — — — — — — — ——Percent—————————- 150 acres and less 12 8 12 13 3 0 7 151-250 acres 45 40 39 42 16 9 31 251-350 acres 28 21 23 26 36 27 26 351-450 acres 5 15 12 3 6 7 9 451-550 acres 5 7 2 6 3 12 7 551 acres and more 5 9 12 10 36 45 20 irrigations provides a low rate of return from the water used, particu- larly on grain sorghum and wheat. With moisture conditions similar to those of 1958, the use of fertilizer without an additional irrigation was profitable for grain sorghum grown on both heavy and sandy soils and for wheat grown on heavy soils. Al- though use of fertilizer on cotton following grain sorghum has in- creased yields as much as 500 pounds per acre under ideal conditions, fer- tilizer did not increase the yield of cotton grown on heavy soils in 1958, Table 8. Except for the results obtained with cotton in sandy (mixed) soils, an additional irrigation on fertilized cotton, grain sorghum and wheat was not profitable in 1958. Some in- crease in yield was obtained in all three instances, but at 1958 prices, the yield increases were not large enough to defray the added water costs, except in the lowest cost water areas. Under 1958 conditions, the in- creased production from fertilizer and from added irrigation on cotton grown on sandy (mixed) soils was highly profitable. The yield increases obtained with fertilizer on cotton 'with less than three irrigations were not as great as those obtained from the use of additional irrigation with- out fertilization. Despite the lower increase in yield resulting from ap- plication of fertilizer, with low well yields and relatively high water costs, it may be more profitable to increase yields by applying fertilizer rather than by applying additional water. When water supplies are ample, the two practices may be combined ad- vantageously. Irrigation of Every Other Row Another practice that has come into general use in recent years, par- ticularly in farming areas A and B, is that of irrigating every other row. In 1958, the practice of irrigating every other row was followed by about half of the farm operators in farming areas A and B. Slightly less than a third of the acres irrigated in these farming areas were irrigated by the every other row method. The practice is seldom applied in farming areas C and D, The practice of irrigating every other row has some advantages. When water supplies are scarce, the practice permits a timely, though re- duced, application of water over TABLE 6. TENURE STATUS OF IRRIGATED-FARM OPERATORS, BY FARMING AREA, HIGH PLAINS. TEXAS, 1958 Type of operator A11 Tenant Owner-additionalz Owner ($22 Farming ‘“°°‘1 (1:35- Lived (12:2- Lived a fro?!‘ L‘ a in“; Percent per on farmpercenl per on farmpercenl S; onllfzrm s; farm farm farm farm Acres Years Acres Years Acres Years Acres A 48 319 10.1 17 348 15.3 35 280 19.1 309 B 34 289 7.8 10 256 13.5 56 258 15.1 269 C 22 477 6.4 15 563 17.1 63 452 19.7 472 D 30 438 6.9 25 956 12.9 45 380 13.9 542 Average 36 344 8.6 16 515 14.7 48 329 17.0 363 ‘Irrigated farms only, see Figure 4 for farm area delineation. iPart of the farm owned and part rented. more acres in a similar period of time than otherwise possible by irri- gating all rows. Also, its use pro- vides for the building up of larger heads of water, which contributes to a more uniform distribution on sandy soils. The results obtained in 1958 with this practice are shown in Table 9. OTHER DEVELCPMENTS The shift from butane P. gas) to natural gas for pumping and the installation of underground concrete- tile distribution systems, which have occurred mainly during the past 5 years, are very important to the irri- gation economy. Shift to Natural Gas for Pumping Excluding the area in which the water-bearing stratum was less than 5O feet thick in 1938, natural gas was used on 61 percent of the farms and 68 percent of the wells in 1958. The proportion of wells fueled by natural gas is higher in the heavy soils area, farming areas B, C and D. Pumps powered by butane and electricity predominate in farming area A. Most of the area with an initial water- bearing stratum of 5O feet or less is located in farming area A. In this area of thin, water-bearing stratum, approximately 31 and 62 percent of the wells were powered by butane and electricity, respectively. It is not unusual for both types of power to be used on the same farm. In the rest of farming area A, Fig- ure 5, where water-bearing strata are thicker, butane and natural gas are used on 38 and 47 percent of the wells, resp-ectively. A few favorably located wells have been fueled by natural gas since the early 1940’s, but the major shift to natural gas began in 1952. Only 3 percent of the wells fueled by natural gas in 1958 began using natural gas before 1952. Approximately 28 per- cent of the 1958 gas-fueled plants were connected in 1953 and 1954, and 69 percent were shifted to na- tural gas in the 4--year period, 1955- 58. Because of low energy require- ments of pumps and high installation DRYLAND AND IRRIGATED CROP YIELDS, BY FARMING AREAS AND BY SOIL TYPE‘ costs of gas lines, natural» a particularly competitive ] power in areas with water-bearing strata. In o *3 ties, most of the change i, gas has been to replace bu plants powered by electr“ been converted to natural the expense fjinvolved has i, delay the change. Gaslineg virtually the only investm volved in changing from. natural gas. The change‘ tricity to natural gas req p‘ ferent type of power unit p, head, as well as the cost o» Closed Conduit Water Systems ' In 1958, underground c or aluminum surface pip tion systems were used it, mately 97 percent of the on 9O percent of the acr in areas with water-bear 5O feet or less. For Water Reservoir area as ‘ percent of the irrigated *- equipped with closed distr' terns in 1958. The propo i TABLE 7. Average yield by Average yield by soil if Item Unit farming area’ type A A B C D Sandy (mixed) Heavy . Cotton f. Dryland‘ 1954 yield per acre Pounds 122 3 3 3 122 3 1957 yield per acre Pounds 246 275 166 3 246 239 - 1958 yield per acre Pounds 304 387 250 3 304 340 i» 1954-58 average per acre Pounds 196 200 166 3 196 183 ‘ Irrigated‘ 1954 yield per acre Pounds 548 600 3 3 548 600 " 1957 yield per acre Pounds 497 490 517 550 497 508 1958 yield per acre Pounds 570 626 639 622 570 629 T‘ 1954-58 average per acre Pounds 532 558 561 532 532 555 . Grain Sorghum Dryland‘ 1954 yield per acre Pounds 1060 3 3 3 1060 3 ~ 1957 yield per acre Pounds 1140 1270 1930 1160 1140 1330 1 1958 yield per acre Pounds 1300 1380 1270 1700 1300 1490 ; 1954-58 average per acre Pounds 980 950 800 1130 980 1000 t,’ Irrigated 1954‘ yield per acre Pounds 2750 3220 3 3 2750 3220 ‘ 1957 yield per acre Pounds 2800 3590 3880 3770 2800 3720 , 1958 yield per acre Pounds 2900 4140 4030 4160 2900 4110 t} 1954-58 average per acre Pounds 2650 3460 3690 3730 2650 3600 Wheat ,. :1 Dryland 31957 yield per acre Bushel 3 15 26 11 3 15 1958 yield per acre Bushel 3 27 30 25 3 27 3 1954-58 average per acre Bushel 3 14 15 11 3 l3 f Irrigated 1957 yield per acre Bushel 30 25 34 33 30 33 1958 yield per acre Bushel 30 25 35 34 30 34 " 1954-58 average per acre Bushel 27 26 29 29 27 29 ,~ Barley ‘; Irrigated 1957 yield per acre Bushel 3 58 48 55 3 54 1958 yield per acre Bushel 3 48 49 44 3 47 * 1954-58 average per acre Bushel 3 48 59 52 3 52 ‘Cotton yields rounded to nearest pound, grain sorghum to nearest 10 pounds, wheat and barley yields rounds. bushel. 3See Figure 4 for area included in farming areas. 3None reported or not applicable. ‘1954.- survey. 10 led on farms equipped 'tribution systems dif- ely between farms, but y a whole, these systems t of the irrigated land i Illppad. _' y 15 percent of the ~ rated were equipped W- surface pipe distribu- 1A few were equipped ‘ sprinkler systems and concrete-lined ditch- U concrete-tile distribu- V- rted, was installed in , only 17 percent of r enumerated were in- ‘1954; 80 percent were i_ en 1954 and 1958; g ation dates of 3 per- OWII. v-of closed distribution y underground con- Qmore common in the I) soil areas (farming in areas with heavy Level 'nes and ensating stments linuaunuo TO DE- “ n LEVEL decline in the water [u amount of water h is closely associated ’_- of time irrigation f d or age of develop- eability of the water- “on or (3) a combi- gand (2). F time irrigation has ‘_~ is also associated i‘ (1938) thickness of Hg strata, but in the ‘est decline, this as- cidental. Originally e near the surface in 8- kney and Hereford ‘p t irrigation was de- “shallowater” areas. "tion With respect to _ and to time of de- iled in the Muleshoe ge from the adjacent permitted long-con- without the heavy , d in other areas of I I. The relation between the age of irrigation development an d the amount of water-level decline is shown in Table 10. A similar associ- ation between the age of develop- ment and the thickness of the water- bearing stratum is shown in Table 11. The first well was drilled on 37, 50, 85 and 88 percent of the farms in decline intervals 1, 2, 3 and 4, respectively, by 1949. The regional static water level in 1949 had an accumulated decline of 11.45 feet, Table 3. By 1949 only 21, 40, 49 and 55 percent of the wells used in 1958 had been drilled in decline in- tervals 1, 2, 3 and 4, respectively, Table 10. Some indication of the effects of the decline in water supply is revealed by comparing the pro- portion of farms on which irrigation was developed and the proportion of wells drilled since 1949. For in- stance in decline interval 4, irriga- tion was developed on only 12 per- cent of the farms between 1950 and 1958 whereas, 45 percent of the wells used in this decline interval in 1958 were drilled during the same 9-year period, Table 10. Comparisons for the other decline intervals show a similar relationship. The comp-arison is not entirely ac- curate, as the entries under “propor- tion of farms developing irrigation” reflect the date on which the first well was drilled. As few farms are developed completely in a single year, part of the wells drilled after 1949 were drilled to expand the irrigated acreage on farms where irrigation had been developed previously. SPECIFIC HYDROLOGIC SUB-AREAS The greatest decline in water level has occurred in areas in which the initial water-bearing stratum was thickest, Figures 6 and 2. This sug- gests that the deleterious effects of TABLE 8. FERTILIZER USE AND CROP YIELDS RELATED TO SOIL TYPE AND NUMBER OF IRRIGATIONS. 1958 Farming area A Sandy (mixed) soils Farming areas B. C and D heavy soils Item Grain Grain Unit Cotton Sorghum Cotton Sorghum Wheat Number of farms reporting fertilizer use‘ No. 24 90 164 165 Proportion of farm operators using fertilizer Percent 31.5 16.6 37.0 67.5 67.7 Proportion of acreage fertilized Percent 15.5 17.9 26.0 66.2 43.5 Rate of fertilizer application’ Nitrogen, per acre fertilized Pounds 56.0 82.6 45.8 76.0 74.1 Phosphorus. per acre fertilized Pounds 42.7 2.7 18.5 1.0 2.2 Potassium. per acre fertilized Pounds 11.4 0.0 6.7 ' 0.0 0.0 Fertilizer cost per acre Dollars 11.21 6.79 6.29 6.55 6.63 Crop Yields per acre No fertilizer Fewer than three irrigations“ “ 515 2.617 636 3.083 26 Three or more irrigations‘ 5 623 3.125 707 3.596 29 F ertilized Fewer than three irrigationss 5 600 3.880 632 4.270 36 Three or more irrigations‘ 5 734 4.150 662 4.471 38 Estimated yield differences from Increased irrigation“ 5 108 508 71 513 3 Fertilizer alone’ 5 85 1.263 -—-4 1,187 10 Fertilizer and increased irrigations 5 219 1.533 . 26 1.388 12 ‘Data are average for the number of farms indicated. “Pounds of elemental nitrogen. phosphorus and potassium per acre. “Average of 2.6 irrigations per acre. ‘Average of 3.6 irrigations per acre. sPounds of lint. pounds of sorghum grain and bushels of wheat per acre. “Difference in yield between “less than three irrigations" and “three or more irri- gations" with no fertilizer. ‘Difference between “nonfertilized" and fertilized yields with “less than three irri- gations." ‘Difference between “fertilized" yields with “three or more irrigations" and “un- ferti1ized" yields with “less than three irrigations." ll water-level decline- would depend more upon the p-roportion of total water extracted than upon the total amount of decline experienced. A moderate amount of decline in an area underlain by a thin water-bear- ing stratum, may constitute a high proportional decrease in water sup- plies and may have more immediate implications, than a heavy decline in an area with a thicker water-bearing stratum. The reservoir area is delineated in specific areas wherein the effects of depletio-n can be ascertained. The decline in water levels between 1938 and 1958, Figure 2, in combination with the original (1938) thickness of the water-bearing strata, Figure 6, provides the basis for such delinea- tions. F0-r purposes o-f this study, each combination of a “decline inter- val” with an original “water-bearing thickness interval” constitutes a spe- cific hydrologic sub-area, Table 12. The approximate location of these specific hydrologic sub-areas is shown in Figure 7. Water level profiles of the hydrologic sub-areas selected for study are shown in Figure 5. Since “more than 6O feet” of water-level decline could not be ex- perienced in an area where the in- itial thickness of the water-bearing stratum was “under 5O feet” thick, the procedure followed provided 23 possible combinations of water-level decline and thickness of water-bear- ing strata, specific hydrologic sub- areas. An examination of the adjust- ments and their effects in these sp-e- cific hydrologic situations p-ermitted some combination of areas for this study. When the initial thickness of the water-b-earing stratum exceeded 150 feet, the type and extent of ad- justments were closely associated with the amount of decline, whereas, when the initial thickness of water-bearing stratum was less than 150 feet, the LESS THAN 5O FEET FROM 5O TO I00 FEET FEET SUBAREA Nos. SUBAREA N01. l-l l-Z 2-! 2-2 O IOO * I50 “ 7‘ f 7 ' % 7 200 6» ;7///// /y/T \ K xfsop 259" — urqwnznso PART or snunum 30o 0am from HPuWC 0 Na /, U $6‘ S. ,8 811E. mldsu/Omtnls and pubhcaI/ons THICKNESS OF WATER BEARING STRATA IN I938 FROM IOO T0150 FEET MORE 7mm n50 If suemzn t a-s 456-1 456-2 4 ' 5 D o, é i‘ 5 i; $49 19.5.9 937 l", ‘s. ‘ 4F.‘ Figure 5. Hydrologic sub-area profiles. extent and effects of adjustments were related chiefly to the proportion of water resources that have been extracted and the initial thickness of water-bearing strata. For purposes of analysis, the 12 specific hydrologic sub-areas that in- clude those situations in which the initial thickness of the water-bearing stratum exceeds 150 feet are com- bined in four sub-areas. The acre- age included in some of the sub- areas is so small that sufficient data are not available for appraisal. For these reasons, the 23possible specific hydrologic sub-areas are reduced to 11 for further study. Since there are wide differences among parts of some of the selected sub-areas, further sub- divisions are made as indicated in later tables. The square miles and the propor- tion of the total area in different in- tervals of water-level decline are shown in Table 12. The area and proportion of the six water-bearing strata thickness intervals affected by different amounts of water-level de- cline are shown in Table 12. Each specific hydrologic sub-area is identified by a code number or TABLE 9. COMPARISONS OF YIELDS. OBTAINED BY IRRIGATING EVERY OTHER ROW WITH YIELDS OBTAINED BY IRRIGATING ALL ROWS. FARMING AREAS A AND B, 1958 e l Irrigating every other row Irrigating all rows Item Nufiflfl; °f Yields Nflgfnj; °f Yields Cotton. pounds per acre‘ No fertilizer 543 17 579 Fertilized 585 ' l2 628 Grain Sorghum pounds per acre‘ No fertilizer Z481 15 29-67 Fertilized 3550 9 3757 ‘Average yields from the number of farms shown. 12 symbol which indicates y bearing strata “thickness; and the water-level “d val” combined in the s” areas. The numbering s bines the “thickness” an interval numbers used in The first digit in the s cates the thickness interv second the decline interv a in the specific sub-area. p; bol 1-1 denotes an area in? j initial (1938) water-beard was “under 5O feet” ~31 ' water-level decline is “O t‘ the symbol 1-2 denotes u,‘- a similar initial thickness bearing stratum that has a water-level decline of i, feet.” Similarly, the sy f dicates an area with an i, bearing stratum ranging to 150 feet” thick and a; decline ranging from “4-0 Where sub-areas grouped for discussion, 1 digits is used to- denote a of the water-bearing str vals combined. Some i? individual or grouped s . further sub-divided depen, meability of the water-be tion, well yields, p-umpin combination of the areas are designated by i, of a small letter followi if area symbol. I The areas of irrigated the various hydrologic s shown in Table 13. 9' PHYSICAL EFFECTS or LEVEI. DECLINE The principal physical‘; the decline in water le flected in a reduction in s PROPORTION OF FARMS DEVELOPING IRRIGATION AND PROPOR- WELLS DRILLED, BY PERIODS, RELATED TO WATER LEVEL DECLINE 1938-58 Water level decline intervals‘ i‘ m and Tl" peIlOd 2 3 4 - eet) (20-40 feet) (40-60 feet) (60—|— feet) of farms developed xfon’ — — — — — — — Percent — — — — — — — i1 1940 5 10 20 47 n 2 10 27 6 30 30 38 35 40 30 9 6 23 20 6 6 i of wells drilled“ 1940 1 4 7 17 3 5 13 17 17 31 29 21 43 38 35 24 36 22 16 21 i~ delineated in Figure 2. '_ 'on in well yield began i‘ late 1940’s and further have been experienced as in water level progressed. ’_- decreases in well yields ,_ ations was obtained dur- rse of the well-measuring _ cted by the Texas Agri- riment Station in 1947- and (3). There are of declining well per- f‘ However, the only author- fence 0f changes in well “reported by Leggat, in l, According to Leggat, ative performance of 51 ‘ Smith, Floyd, Hale and unties between 1938 and ed an average decrease in d'ng from 11 percent in p. to 20 percent in Hale j Smith counties. A larger l) as reported for the old swell field at Lubbock, in average well yield de- W 625 to 250 gallons per ,7). n‘ iinformation covering well - since 1951 is not avail- j indicators, however, can (approximate the changes ‘rformance. Chief among ]~= change in number of a_ted per well which, al- ject to modification by H practices, generally re- ftional wells ‘installed to [the irrigated acreage on j Decreases in number of ted per well, particularly II-iearly 1950’s, along with if longer pumping seasons, pumps, installation of well was drilled on the farm. '- in 1958 only; this excludes farms and wells where the original water p165 feet or more below land surface. closed distribution systems and instal- lation of smaller pumps in old wells, indicate a decrease in water supplies. Changes in numbers of acres irri- gated per well between 1947 and 1958 are shown in Table 14~. COMPENSATING ADJUSTMENTS Several factors may combine to influence the type and extent of spe- cial practices adopted by a farm op- erator. The tendency of these special practices to be more widely adopted in some situations than in others, suggests that these special practices are required to cope with conditions in the area of their adoption. Such is the case with respect to certain TABLE 11. types of special practices or adjust- ments made in response to declining water levels in the High Plains. The types of adjustments or special prac- tices induced by, or associated with water-level declines, are outlined be- low. The extent to which the more important practices are applied in specific hydrologic situations is shown in Table 15. Increasing the hours of pump 0p- eration was among the first and most frequently r e p o r t e d adjustments made in response to a decline in water supplies. Changed irrigation practices, mainly adoption of pre- planting irrigation, since 1947-49, and differences in annual irrigation requirements that stem from seasonal variations in precipitation, preclude a precise measurement of the extent to which pumping seasons have been lengthened t0 meet a decline in water supplies. Lowering of Pumps was an early adjustment. Its application was gen- erally restricted to those parts of the area in which Water-bearing strata were thick enough to make the prac- tice feasible. Some of the pumps in earlier wells drilled in the sub-areas with less than 100 feet of Water-bear- ing materials were lowered as the water level declined, but pumps in many wells drilled after 1950 were usually set at or near the bottom of these thinner water-bearing strata. The extent to which this practice has been followed in the various hy- drologic sub-areas is shown in Table PROPORTION OF FARMS DEVELOPING IRRIGA'I'ION AND PROPOR- TION OF WELLS DRILLED, BY PERIODS. RELATED TO ORIGINAL (1938) THICK- NESS OF WATER-BEARING STRATUM Thickness of water-bearing stratum, 1938‘ Item and 1 2 3 4 5 5 devebpment Permd (0-50 ( 50-100 (100-150 ( 150-200 (200-250 (250 feet) feet) feet) feet) feet) feet +) Proportion of farms developed for irrigation“ — — — — — — — —- Percent — — — — — — — —- Before 1940 7 6 11 27 19 27 1940-44 0 4 19 1 1 20 20 1945-49 19 54 44 33 48 31 1950-54 30 30 16 , 24 10 22 1955-58 44 6 l0 5 3 0 Proportion of wells drilleda Before 1940 0 2 3 13 5 9 1940-44 0 3 9 8 9 14 1945-49 11 31 28 21 36 22 1950-54 37 45 37 42 31 33 1955-58 52 19 23 16 19 22 ‘As delineated in Figure 6. ’Year first well was drilled on the farm. - “Wells used in 1958 only: this excludes farms and wells where original water level was 165 feet or more below land surface. 13 SUBDIVISION N0. I HIGH PLAINS GROUND WATER RESERVOIR OLDHAM I POTTER Von; - . 2 l T \L‘ Amarillo BAILEY sou/ms: MRMWQD. m1, uses, a BME. ARMSTRONG 5o T0 n00 FEET I I — 20o TO 25o FEET I LEGEND LESS THAN 5O FEET IOO TO I50 FEET ISO TO 2OO FEET ' MORE THAN 250 FEET v uucuxssmso Figure 6. Thickness of the water-bearing strata. 14 1938. SOURCE- um ' SUBAREAS ___ 3—l 3-2 3-3 456- I 456 -2 456 —3 56- 4 Unclassified Low permea- bility SUBDIVISION No.I HIGH PLAINS GROUND WATER RESERVOIR I ouomm POTTER vna I ‘ _ "\ Amarillo -—— —- LEGEND A I - ~01 PARTICULARLY 1*‘ MK‘ ARMSTRONG AFFECTED Tanyon ‘ RANDALL _ ‘\ A '4 5H6“ MODERATE SERIOUS SEVERE LYNN ' Q Brmm/il/l ' rnwfia Figure 8. Areas affected by water level decline. 15 15. The practice hasbeen extensively adopted in the older developed areas where the water-bearing strata are more than 15O feet thick——(hydro- logic sub-areas 4156-2, 4156-3 and 56-4). In these sub-areas, pumps have been lowered, some of them as many as six times, in almost all wells drilled before 1940 and in more than three-fourths of all wells drilled be- fore 1950. Farm operator reports of well per- formance before and after lowering, along with the smaller decrease in acreage irrigated per well, Table 14, indicate that the practice has been among the most effective means used to offset the effects of a decline in water levels. Also, it costs consider- ably less to lower a pump than to install a new well. Installation of additional wells is applied to some extent in all parts of the reservoir. It is more common, however, in those sub-areas in which the initial water-bearing strata were less than 150 feet thick, hydrologic sub-areas 1-1, 1-2, 2-1, 2-2, 2-3, 3-1, 3-2 and 3-3. The sub-areas in which this practice is used most extensive- ly are suggested by the changes in acreage irrigated per well, Table 14. Drilling additional wells is among the more expensive adjustments to a decline in water supplies both in added investment and added operat- ing costs. The practice permits the offsetting of a certain amount of the decrease in well yields that have ac- companied the decline in water levels. It also tends to perpetuate the over- draft and shortens both the physical and economic life of water supplies, TABLE 12. SIZE OF HYDROLOGIC SUB-AREAS‘ particularly in those areas in which the initial water-bearing strata were less than 1OO feet thick. Closed distribution systems, princi- pally underground concrete tile are another adjustment to a change in water supplies in certain situa- tions. Elimination or reduction of transmission losses between the well or wells and the point of water dis- tribution is the major benefit derived from the use of this facility. This water-conserving effect largely ex- plains the frequent installation of this type of facility in areas experiencing the greatest proportional depletion of water resources. Water conservation is not the only benefit derived from the use of closed delivery systems. Other benefits, such as ease of han- dling water, elimination of ditch breaking by wind action on water, elimination or reduction of ditch construction and maintenance, and reduction in land area needed for ditches also are realized. The use of this type of facility may or may not reduce irrigation labor requirements, depending on individual circum- stances. The chief disadvantage lies in the cost of the system, which may exceed the entire cost of all other irrigation facilities on the farm. The proportion of farms equipped and the number of acres served by closed distribution systems in the various hydrologic sub-areas are shown in Table 15. The high inci- dence of use of these facilities in sub- areas 1-1, 2-1 and parts of 3-1 does not necessarily constitute an adjust- ment to a change in water supplies. A high proportion of the if parts of these sub-areas initi low-capacity wells and clos w: were part of the equipment; at time of development. i predominant soils in these =l open textured, which incr need to reduce transmissio In sub-areas 1-2, 2-2, 2-3,‘ 4-56-3a and 56-4-a, where a centage of farms are equi these facilities, few, if an distribution systems were j original development equi farms in these sub-areas. i 7O percent of the closed systems in these sub-areas .5’ installed since 1954-, sev; after irrigation was more ly developed. if OTHER ADJUSTMENTS Other adjustments that f made in response to a , water supplies include the ' irrigating every other r0W,'-: lation of smaller pumps, ‘A off-season irrigated crops f duction in the proportion‘ land irrigated per farm. t 1 The practice of irrig, other row is extensively ~_ ' portions of farming area All initial water-bearing stra -»; than 5O feet thick, or wh proportion of the total has been extracted. It isl- to some extent in farmi and on a few farms in ar_ D. In 1958, the practice w’ 6O percent of the farms a - mately 4O percent of the 1938 Water level decline intervals in feet? Thifiknfiis °ftvgtc:er' Number 1 Number 2 Number 3 Number 4 e“ ‘ g s ' 0-20 feet 20-40 feet 40-60 feet so feet + j Interval . Square Square Square Square Squat "<- Number Feet , mile percents mile Pelican? mile Percenta mile percents mile 1 Under 5O 1317 92.5 101 7.1 6 .4 0 0 1424 2 50-100 1240 54.0 994 43.3 62 2.7 0 ' 0 2296 ‘ 3 100-150 533 26.3 1166 57.5 325 16.0 5 .2 2029 4 150-200 442 27.1 814 49.8 353 21.6 24 1.5 1633 f 5 200-250 218 14.2 845 55.1 395 25.7 77 5.0 1535 6 250 and over 94 6.3 701 47.0 435 29.2 260 17.5 1490 ‘; — Unclassified5 242 100 0 0 0 0 0 0 242 Total 4086 38.4‘ 4621 43.4‘ 1576 14.8‘ 366 3.4 * 10649 ‘Each combination of intervals (“Thickness of water-bearing strata" and “Water level decline") constitutes a so "i logic sub-area. (See Figure 7). 5 fBased on water level declines from Ianuary 1938 to Ianuary 1958. “Percentage of area with different thicknesses of water-bearing strata included in the decline interval. ‘Proportion of reservoir area. Z “Most of the unclassified area has a water-bearing stratum in the 0 to 50 feet range and is included hereafter with, 16 area A, Figure 4. "on of the acreage irri- method differs consid- jg the hydrologic sub- in farming area A. Tub-areas in which the Lbearing strata were less l; thick—sub-areas 1-1 _ proportion of the acre- ~ by this method de- ‘thickness of the water- ? t increases. For exam- irtion was 36 percent in 7-"17 percent in the sub- . 6 percent in sub-area jei proportion of land ir- is method increases as 1' water level increases. I the practice is applied j- 89 percent of the land ‘sub-areas 2-1, 2-2 and ‘ely. ' ‘ of irrigating every ;followed on 82 and 86 _ farms in sub-areas 1-1 ‘ctively. The time that §was adopted in these gests that it has been I the effects of water- but it does not neces- te an adjustment to a Y, r supplies, particularly -1. In general, wells in fiwere low-capacity wells, j a was initiated when, Y, er, irrigation was de- ‘a sub-areas involved F a A, where irrigation fis generally older, the been adopted chiefly lion of smaller pumps ells is another indica- jeased water supply and _' yields. The practice .0nfined to hydrologic 1; 2-1, 2.2, 2-3 and 3-2 i 17, 17 and 17 percent, of the original pumps cplaced by pumps of . 0st of the wells, where __ n replaced by smaller . {1- s j- some extent by the shift mp fuel. sical and economic ef- fting to declining water it y partly reflected by the p} criteria used in this . effects necessarily can- jessed in their entirety. "on of the series of com- idjustments, with their 7»: tial effects in specific gsub-areas provides the I roximating these effects i, tion, extent, time and ;-- adjustments that may 77in the future. A broad viification follows, 1' Particularly Affected titer-level Decline tely 194,000 acres 0r of the land irrigated in cluded in this category. ‘velopments in this cate- 'efly recent and are char- fually by high-lift, low- ‘? . The acreage included i d in sub-areas 2-1 (78,- iand 3-1 (94,700 acres) in I ANNUAL OPERATING farming areas C and D and in sub- areas 3-1a (14,700 acres) and 456-1a (6,400 acres) in farming area B, see Figures 4, 7 and 8. Generally, these were initially high-cost, relatively poor water areas, and the cost situa- tion has not particularly worsened or improved since irrigation was devel- oped. Areas Affected by Water-level Decline The second and major category includes parts of the area in which irrigated farm operations have been affected in varying degrees by a di- minishing water supply. The cate- gory is further divided according to the degree of these effects. Slightly Affected Sub-areas This group includes sub-area 456-1 with 291,200 acres of irrigated land located in farming areas B, C and D. Irrigation developments in this sub- area are among the most recent in the area. A slight reduction in number of acres irrigated per well, which may Operating cost per acre‘ Farming areas A and B’ or may not be related to water-level declines, is the principal change oc- curring on farms in sub-area 456-1 during 1955-58. Although irrigation development is characterized by the highest investment per well in the area and pumping lifts are consider- ably greater than in most other parts, the per acre investment in irrigation facilities and the operating cost per acre, are among the lowest. The average annual water-level de- cline rate is somewhat lower than that in adjacent sub-area 456-2. As most conditions except pumping lift and age of development are similar between the two sub-areas, it seems reasonable to expect that future ad- justments in sub-area 456-1 will par- allel those that have been applied under the more aggravated conditions in sub-areas 456-2 and 456-3. Moderately Affected Sub-areas Included in this group are sub- areas in which the water-level decline and decline-induced adjustments have increased both the investment and operating costs and impaired the COSTS ASSOCIATED WITH IRRIGATION WATER, PER ACRE. BY TYPE OF FARMING p, AREAS AND BY HYDROLOGIC SUB-AREAS, 1947-58 Farming areas C and D’ Reported‘ stgfiglafgiitestp acisjigtsrztgjgfi Reported“ Adjusted“ 1947 1954 1958 1947 1954 1958 1954 1958 1958 1958 (2) (3) (4) (5) (5) (7) (8) (9) (10) (11) - — — — — — — — — — — — — — — ——-—Dollars——-——--_-__-__-__-4_-_. 9.43 8.12 8 8 8 7.97 13.48 6.67 7.76 12.69 4.16 8 8 8 10.48 9.35 10.68 7.76 6.07 5.96 5.81 9.07 6.01 7.23 3.16 11.08 6.63 1.81 7.35 4.34 6.09 9.77 2.69 5.26 7.46 7.46 12.65 6.42 6.42 8.59 6.60 9.25 7.91 7.91 12.80 3.49 9.28 5.26 1.84 5.06 3.77 4.21 5.32 4.23 5.84 6.96 6.96 10.03 3.49 9.85 3.78 1.84 5.86 3.20 3.63 8.03 2.49 4.65 4.69 4.69 6.83 4.56 4.99 2.95 2.95 6.90 3.26 8.32 4.65 2.12 2.54 4.10 4.38 6.50 3.85 5.04 5.52 5.52 7.48 3.23 7.17 4.83 2.12 5.52 4.17 4.71 5.61 4.10 6.07 3.32 5.41 2.09 5.41 8.75 3.20 6.90 4.31 2.04 3.84 4.87 3.87 6.27 8.96 8.96 12.55 -el cost. ' nditures for fuel or energy. oil. repairs and maintenance: per- j as as shown in Figure 4; hydrologic sub-area. Figure 7. its adjusted “to a standard fuel and rate, 100 percent natural gas used at 1958 gas rates. 1: with standardized fuel costs adjusted to a standard pump operation season, 4-year average (1954. 1956. 1957 ours of pump operation at 1958 costs per hour of operation. ’not included in seasonal adjustment because of the adoption of preplanting irrigation after 1947. Ythe high proportion of wells on natural gas, 1958 reported costs in farmin Jdjusted to 1956, 1957, 1958 average hours of pump o g gg-justjed to natural gas equivalent costs. formations with low permeability. acre average for respective situations and years. g areas C and D are not adjusted to a peration at 1958 cost per hour of operation. 23 water supply to some degree. This group includes 2,283,100 acres, ap- proximately 64 percent of the acres irrigated in 1958, see Figure 8. The following sub-areas and parts of sub-areas are included in this cate- gory: SUB-AREA 3-1, FARMING AREAS A AND B, 81,600 ACRES: Water levels declined at an average rate of 3.75 feet per year during 1955-58 and some 10 to 15 percent of the initial water-bearing formation has been un- watered. On the the farms included in this study, the acreage irrigated per well declined 43 acres, 0r 33 per- cent, in 1955-58, Most development in this sub-area is relatively recent and little data are available on de- velopment or operating costs prior to 1958. The 1958 per acre investment in irrigation facilities and the per acre operating cost were above aver- age for the area, Tables 16, 17, 18 and 19. SUB-AREA 3-2, FARMING AREAS A, B, C AND D, 443,600 ACRES: Water levels declined at an average rate of 3.5 feet per year from 1949 to 1958 inclusive, and about 23 to 35 percent of the initial water-bearing strata were unwatered by January 1959. The number of acres irrigated per well decreased from 118 to 78, or 34 percent, between 1947 and 1958 in farming areas A and B, and from 138 to 123, 11 percent, in farming areas C and D. Adjusting to this change in Water supplies has raised the investment in irrigation facilities from $26 per acre in 1947 to $72 per acre in farming areas A and B. Op- erating costs per acre, adjusted basis, increased about 25 percent between 1954 and 1958. SUB-AREA 466-2, FARMING AREAS B, C AND D, 1,098,000 ACRES: Some 13 to 26 percent of the initial water- bearing formation has been un- watered in this sub-area since 1945. The acreage irrigated per well de- clined from 155 to 118, or 24 per- cent, between 1947 and 1958. Ad- justing to this decline has raised the investment in irrigation facilities from $23 per acre in 1947 to $58 per acre in 1958 in farming areas A and B. The amount of increase in farm- ing areas C and D is not known. The present per acre investment in farm- ing areas C and D is only $4 less than that in areas A and B and much the same kinds of adjustments have been applied as in areas A and B. Operating costs, adjusted basis, have TABLE 20. RATES OF DECLINE IN WATER LEVEL, DEPLETION RATE AND ESTI- MATED RESIDUAL LIFE OF WATER RESOURCES BY HYDROLOGIC SUB-AREAS Decline in _ 2 Eslifnated Hydrologic Acreage irrigated waleblevel Dizlstlgn reslligeual sub-area in 19-58 A“ rate Years g ranges Acres Percent Feséafier Nigel? Percent Years 1-1 139,300 3.9 1.50 10 4 0 to 23 1-2 31,000 .9 3.50 10 4 0 to 4 2-1 202,300 5.6 2.15 6 13-26 17 to 40 2-2 289,300 8.2 2.75 10 35-70 5 to 24 2-3 43,300 1.2 5 5 5 5 3-1 176,300 4.9 3.75 4 10.15 23 to 36 3-la° 14,700 .4 3.50 5 5 5 3-2 6 443,600 12.4 3.50 If! 23-35 14 to 28 3-2a 22,000 .6 5 5 3-3 62,300 1.7 3.90 14 37-55 12 to 24 456- r 291,200 8.1 2.50 4 3- 7 56 to 116 456-1a“ 6,400 .2 5 5 5 5 456-2 1,098,000 30.8 2.80 14 13-26 40 to 93 456-2a° 20,000 .5 5 5 5 5 456-3 495,800 13.9 3.50 15 17-35 28 to 71 456-3a“ 87,300 2.4 3.24 15 19-32 31 to 78 56-4 144,100 4.0 3.86 22 28-42 30 to 55 56-4a° 8,100 .3 5.00 12 20-30 28 to 48 ‘Average annual rate of water-level decline for the indicated period of years pre- ceding and including 1958. ’Proportion of water-bearing formation unwatered, Ianuary 1959. “Range in years required to deplete remaining water-bearing formation with de- cline at the indicated average annual rate. ‘Total thickness of initial water-bearing strata unknown. “Largely in small isolated tracts or data too few for valid comparison. “Indicates areas wherein the permeability of water-bearing formation is below nor- mal for the sub-area. 24 increased about 31 perc” 1954. Other adjustments v, increasing nature during period have been minor. ' Conditions in sub-area "y_ similar in all respects to thj adjacent sub-area 456-3 e4 age of develo ment and I, of water-leve, decline. :- suggest that future adjus‘ their effects in sub-area likely to be similar to tho area 456-3. i SUB-AREA 456-2a, FARMIN 20,000 ACRES: Irrigation; ment in this sub-area is m, than that of sub-area ‘ l local exceptions, it is chi by low-capacity, high-lift W prior to the 1958 survey ‘f and because of the relati acreage, only a few sam” were enumerated in the 19 On the farms enumerated, . age irrigated per well decr 132 to 101 acres, 0r 23 i’ tween 1955 and 1958. T "_ vestment in irrigation faci aged $97 per acre, among _ investment costs in the though data prior to 195, available for this sub-area; eluded here because of its-I. velopment cost and the sh in the number of acres ir ' well during the 4-year peri SUB-AREA 456-3, FARMING C AND D, 495,800 AC t‘ levels have declined at j rate of 3.5 feet since 1944 t‘ 35 percent of the initial p ing strata has been unwa 1937. Generally, irrigatio ment in this sub-area is a k older than that in the adj; area 456-2. Conditions in; area represent a slightly 4M condition from those re“ sub-area 456-2. Adjustme same type have been a’ have been used more frequ‘ acreage irrigated per -lf from 140 to 96, 31 percen ing areas A and B and fr 129 or 13 percent in far C and D between 1947 Adjusting to this change , supplies raised the investm gation facilities from $23 A $67 per acre in 1958 if areas A and B. Like sub- data prior to 1955 are n0_ for the portion of sub-ar farming areas C and D. 5 similar in type and numb a p; if eas A and B have been 3' g areas C and D, and nable to expect that have been experienced. j-- I. FARMING AREA B, The greatest decline in the Reservoir has A, ed in this sub-area. , however, only about in initial water-bearing “unwatered during the ,i~ From 1937 to 1958 levels declined at an of 3.86 feet per year. parent severity of con- of adjusting to the ter supplies has been y"; in the Reservoir. jwere initially near the the thick water-bearing de it possible to ad- decline by lowering _ is one of the lower cost the change in water ,'ed the investment in ' ities from $27 per acre '9'per acre in 1958. Al- “ng costs per acre, ad- 'creased 62 percent be- f“ d 1958, they are still l_';' for the entire area. A crease during 1947-58 investment in irriga- sterrls from the cost of 1' ps and the installation , wells. Additional well are reflected in the freage irrigated per well, ' ‘ed from 147 to 120 percent, between 1947 lAffected Su b-areas ‘there are sub-areas in ‘line in water levels and f- adjustments have se- ted the water supplies, ‘ed the investment in ilities, and/ or substan- the operating costs. done of these effects is » in the individual sub- iximately 724,000 acres, of the acreage irrigated included in this cate- fng sub-areas are includ- iously affected group: 31-1, PRINCIPALLY FARM- ,AND D, 139,300 ACRES: _velopment in this sub- urred principally since l characterized by low- capacity wells and, except for the de- velopments in farming area D, by relatively low pumping lifts. Water levels declined at an average rate of 1.5 feet per year during January 1949-58. As the thickness of the in- itial water-bearing stratum ranges from 0 to 50 feet, the proportional amount of depletion cannot be ascer- tained. The effects of adjusting to this decline include an increase in the amount invested in irrigation facili- ties from $93 in 1954 to $116 per acre in 1958 and an increase of 69 percent in operating costs during this period. The number of acres irrigated per well declined about 10 percent from 1954 to 1958, in farming area A and 61 percent in farming area D during 1955-58. The practice of irrigating every other row, which permits irri- gation of almost twice the acreage possible with each row irrigated, is followed on 82 percent of the land irrigated in Farming Area A. Dur- ing this period, 1954-58, there was a decline of 7 percent in the proportion of cropland irrigated per farm. The per acre investment in irriga- tion facilities is among the highest and operating costs, adjusted basis, are the highest in the sub-area. Pres- ent cash outlays for water (operating costs) approach the upper limits of economic feasibility under present price levels, see Appendix Table 2. Further adjustments of a cost-increas- ing nature, or a decline in commod- ity prices, could easily remove the profit margin from irrigation in this sub-area. SUB-AREA 2-1, FARMING AREAS A AND B, 124,300 ACRES: Conditions in this sub-area are similar in many re- spects to those in adjacent sub-area 1-1. Irrigation was generally devel- oped a little later, pumps are gen- erally larger, and serve about twice the acreage served per Well in sub- area 1-1. Water levels have declined at an average rate of 2.15 feet per year since 1952, the last year in which they stood at 1937 levels. From 13 to 26 percent of the initial water- bearing formation was unwatered during 1953-58. Adjusting to this de- cline in water supplies has decreased the number of acres irrigated per well by 20 percent, increased the in- vestment in irrigation facilities from $72 to $89 per acre, and increased per acre operating costs, adjusted basis, 56 percent between 1954 and 1958. Some 36 percent of the acre- age irrigated in 1958 was irrigated by the every-other-row method and 95 percent of the acreage received water through some form of closed delivery system. These two practices have masked at least part of the ef- fects of water-level decline. Although this is one of the most recently de- veloped areas, approximately 17 per- cent of the original pumps have been replaced by pumps of smaller size. SUBAREA 2-2, FARMING AREAS A ‘ AND D, 289,300 ACRES: Irrigation ex- panded rapidly in this sub-area dur- ing 1940-50. The number of acres irrigated per well in 1947 indicates that wells in this sub-area initially were average to above-average capac- ity. This condition has been altered materially as the water supply has diminished. Water levels declined at an average rate of 2.75 feet per year and 35 to 70 percent of the water- bearing strata was unwatered, chiefly »- during the 1949-58 period, Extensive use of several types of adjustment have been applied in an attempt to cope with the problem of declining water supplies, particularly in the 235,000 acres located in farm- ing area A. A principal adjustment has been the drilling of additional wells, which is reflected by a 49 per- cent decrease in acreage irrigated per well from 1947 to 1958. This decrease in acreage irrigated per well does not fully reflect the effects of a diminished Water supply, since 70 percent of the acreage irrigated in 1958 was irrigated by the every- other-row method. Also, water was delivered to 70 percent of the acreage irrigated in 1958 by some form of closed delivery system. Approximate- ly 25 percent of the pumps used in 1.958 have been lowered one or more times since they were installed and 17 percent have been replaced by smaller pumps. The measurable effects of adjust- ing to the decline in water levels in farming area A include: (1) an in- crease from $28 to $100 per acre from 1947 to 1958 in the per acre investment in irrigation facilities, (2) a 60 percent increase in operat- ing costs per acre, adjusted cost basis, during 1954-58 and (3) a 10 percent decrease in the proportion of _ cropland irrigated per farm from g 1954-58. Previous surveys have not covered sub-area 2-2 in farming areas C and 25 D. The 1958 survey ‘shows that many of the same type of adjustments, though less extensively used, have been made as in farming areas A and B. SUB-AREA 3-3, FARMING AREAs A, C AND D, PRINCIPALLY 62,300 ACRES: Sub-area 3-3 occurs in all four farm- ing areas, but only the larger bodies located in farming areas A and C were covered in earlier surveys. Water levels declined at an average rate of 3.90 feet per year and 37 to 55 percent of the initial water-bear- ing strata was unwatered during the 14-year period of 1945-58. Adjustments in this sub-area are much the same as those made in sub-area 2-2. Approximately 29 per- cent of the pumps used in 1958 have been lowered once or twice since they were initially installed and 59 per- cent of the acreage irrigated in 1958 received water through closed deliv- ery systems. Additional wells were installed as the water level declined. This is reflected partly by the reduc- tion in number of acres irrigated per well, which ranges from 25 percent in the mixed lands of farming area A since 1947 to 3 percent from 1955 to 1958 on the hardlands of farming area C. During 1954-58, the propor- tions of cropland irrigated per farm in farming areas A and C were re- duced by 10 percent. Adjusting to the change in Water supplies has increased the per acre investment in irrigation facilities from $26 and $23 per acre in 1947 "- to $66 and $73 in 1958 in farming areas A and C, respectively. The per acre operating cost, adjusted cost basis, increased 121 and 87 percent during 1954-58, respectively, in farm- ing areas A and C. SUB-AREA 3-2a, FARMING AREA B, 22,000 ACRES: Development and ad- justment data prior to the 1958 sur- vey are not available for this sub- area. Irrigation developments are characterized by generally high lift,' low-capacity wells and relatively high investment and operating costs per acre. Although the data with respect to adjustments are few, with a conse- quent possibility of sampling error, this subgroup is placed in the serious- ly affected category because of the high investment and operating costs and the 18 percent decline in acres irrigated per Well during 1954-58. SUB-AREA 456-3a, FARMING AREA B, 87,300 ACRES: Irrigation develop- 26 ments in these sub-areas are charac- terized by generally lower capacity wells and somewhat greater pumping . lifts than those in sub-area 456-3. The average annual water-level de- cline of 3.24 feet per year since 1945 is slightly lower than the annual re- cession rate experienced in sub-area 456-3 for the same period. The types of adjustment in the two parts of this sub-area are similar. However, they have been applied with greater fre- quency in sub-area 456-3a. Approxi- mately 71 percent of the farms enumerated were equipped with closed distribution systems in 1958. As in most of the other sub-areas, these systems were installed princi- pally after 1954. The acreage irri- gated per well declined from 99 to 78 acres, a decrease of 21 percent during 1955-58. Here too, much of the effect of water-level declines is obscured by the water-conserving ef- fects of closed distribution systems. Development costs in 1947 and 1954 are not available. In 1958, they averaged $85 per acre, $18 per acre greater than in sub-area 456-3. Op- erating costs per acre, adjusted cost basis, are about $3, or 56 percent, greater than those in sub-area 456-3. Severely Affected Sub-areas Included here are areas in which the water supply has been severely depleted and/ or where further in- creases in operating costs would im- pair the economic feasibility of con- tinued water use. Approximately 82,- 400 acres, 2.3 percent, of the acreage irrigated in 1958 are included in this category. The following sub-areas are includ- ed: SUB-AREA 1-2, FARMING AREAS A AND B, 31,000 AcREs: Water levels declined at an average rate of 3.5 feet per year during the 10-year pe- riod, 1949-58. As the initial water- bearing stratum in sub-area 1-2 was less than 50 feet thick, the 10-year decline of 35 feet has unwatered much of it. Irrigation developments in this sub-area were highly similar to those in adjacent sub-area 2-2. The adjustment to a decrease in water supplies also is similar in many re- spects. SUB-AREA 2-3, FARMING AREAS A AND C, 43,300 ACRES: Conditions in sub-area 2-3 reflect a more aggra- vated situation than those in sub-area 2-2 with which it is associated. SUB-AREA 56-4a, FARMING? 8,100 ACRES: Conditions in fer a sharp contrast to tho which had a similar initial , of water-bearing stratum j has experienced a similar =f water-level decline. Irrigati opments in sub-area 56-4a j recent and, _,afe characteriz capacity wellstwith pump se eraging 290 feet, compar average pump-setting dep w feet in sub-area 56- . i‘ Water levels declined at = f“ rate of 5.0 feet per year, -‘ the Reservoir, during 1947' of the effects of this decl", flected by a drop from 83 t, irrigated per well, a 33 1' crease, during 1955-58. A; of 10 percent in the pro“ cropland irrigated per farm} during this 4-year period. Adjustments to meet this water supplies consisted r of lowering pumps, 71 pe_ installation of closed delive] (66 percent of farms eq 1958). The cost of adjus ', change in water suppli known, as data for this I were not obtained in 1947 n, ' The present investment in facilities, $126 per acre, is} est, and operating costs pe justed cost basis, are amon est in the area. Literature 1. Magee, A. C., et. al.,f-" Water for Irrigation 0 Plains,” TAES B J February 1952. I 2. Bonnen, C. A., et. i Irrigation Water on I Plains,” TAES Bullet cember 1952. f 3. Magee, A. C., et. al.,l'_ tion Practices for l, Crops on the p-i TAES Bulletin 763, f 4. Hughes, Wm. F ., and‘ C., “Changes in Inv Irrigation Water i»; High Plains, 1950- Bulletin 828, March '. 5. Johnson, W. 1)., ‘j Plains and Their U U. S. Geological .. Annual Report, Part ‘» raphy, pp. 609-741, l; Annual Report, Part -‘ raphy, pp. 637-669, a gC. N., “The Geological ater Resources of the ‘ Portion of the Panhan- -Texas,” U. S. Geological Water Supply Paper 154-, ' C. N., “The Geological Aater Resources of the i» Portion of the Pan- 0f Texas,” U. S. Geologi- ' ey Water Supply Paper F! Q O. E., “Ground Water _"-‘ of Portales Valley, exico,” (Manuscript re- A files of U. S. Geological '1 ‘Washington, D. C.). . L., “Geology and Un- '0 Waters of the North- fo Estacado,” University i: Bulletin 57, 1915. i]. R., et. al., “Geology iund Water in the Irri- .7 gion of the Southern p»: ins in Texas,” Progress No. 7, Texas Board of ggineers, U. S. Geologi- 0y, 194-9. i‘ rdon W., map entitled jv-v of the Water Bear- i = 1938,” The Cross Sec- tember 1956, Lubbock, . N, et. al., “Ground ,_ the High Plains of ' U. S. Geological Sur- i; prepared by W. L. 1 st, Chief Hydrologist, _j- No. 1. "j t, W. L., “Ground f. the High Plains in “Progress Report No. 6, lard of Water Engineers . S. Geological Survey, T1947. _Wm. F., and Motheral, irrigated Agriculture in TAES Miscellaneous '0 59, September 1950. j- rtment of Commerce, pus of Agriculture, Vol. ' and State Economic A» t‘ 26, Texas. Ward R1,; “Summary d Water Development uthern High Plains, f . S. Geological Survey _ Board of Water Engi- perating, Texas Board ‘Engineers, Bulletin ruary 1954. Supply Paper 889-F, _ I 86 18. Hughes, Wm. F ., and Magee, A. C., “Economics of Water Man- agement for Cotton and Grain S o r g h u m Production, High Plains,” TAES Bulletin 931, May This study draws on the work of a number of agencies and individuals concerned with various phases of the hydrologic and agricultural problems of the High Plains. The principal 1959. sources and individuals are listed un- der “Literature Cited.” Particular credit is due Jerry Cronin, Ground Acknowledgments Water Branch, U. S. Geological Sur- vey, USDI; and Warren R. Grant, formerly with the Texas Agricultural Experiment Station, for their assist- ance. This study was partly financed by funds advanced under contract with the Bureau of Reclamation, U. S. De- partment of Interior. APPENDIX TABLE 1. INVESTMENT IN IRRIGATION FACILITIES AND OVERHEAD COSTS PER ACRE IRRIGATED, BY FARMING AREAS AND HYDROLOGIC SUB- AREAS Farming areas A and B‘ Farming areas C and D‘ Hydrologic Investment per ownership cost Investment per ogrsite 1:21p sub-area acre irrigated Pei’ acre acre irrigated acre irrigated irrigated — — — — — — — ——Dollars————————*—- 1-1 116.00 11.60 81.00 9.62 1-2 97.00 9.16 2-1 89.00 10.38 62.00 7.43 2-2 100.00 11.90 59.00 6.71 2-3“ 67.00 7.90 3-1 86.00 9.87 61.00 7.30 S-laa" 120.00 14.22 3-2 72.00 8.72 53.00 6.30 3-2a3" 81.00 9.56 3-3 66.00 7.98 73.00 8.75 456- 55.00 6.57 57.00 6.73 456-1a3" 108.00 12.74 456-2 58.00 6.84 54.00 6.37 456-2a3" 97.00 11.25 456-3 67.00 7.96 52.00 6.06 456-3a‘ 85.00 10.00 56-4 59.00 7.00 56-4as" 126.00 15.24 ‘F arming Areas shown in Figure 4. sub-areas shown in Figure 7. ’Amount required to deiray interest. depreciation. taxes. risk or insurance costs on investment in irrigation facilities. Variations in overhead costs per acre reflect the amount and type of facilities involved in the various sub-areas. see Table 18. “Small sample. ‘Indicates areas where the permeability of water-bearing formation is low. APPENDIX TABLE 2. APPROXIMATE BREAKOVER POINT FOR OPERATING WATER EXPENDITURES PER ACRE AT SPECIFIED LINT AND GRAIN SORGHUM PRICES. 320-ACRE IRRIGATED FARM‘ 25:33:21 Seasonal average price per hundredweight of grain sorghum Prise Per - - - - - - - - -- - Dollars - - - _ _ _ - - - figftgtfjn 0.25 0.00 2.75 2.50 2.25 2.00 1.75 1.50 1.25 1.00 0.75 Cents 04 02.00 00.40 20.14 25.00 20.47 21.12 10.70 10.44 14.10 11.70 0.42 00 02.14 20.00 27.40 25.12 22.70 20.44 10.10 15.70 10.42 11.00 0.74 02 01.40 20.12 20.70 24.44 22.10 10.70 17.42 15.00 12.74 10.40 0.00 01 00.70 20.44 20.10 20.70 21.42 10.00 10.74 14.40 12.00 0.72 7.00 00 00.10 27.70 25.42 20.00 20.74 10.40 10.00 10.72 11.00 0.04 0.70 20 20.42 27.00 24.74 22.40 20.00 17.72 15.00 10.04 10.70 0.00 0.02 20 20.74 20.40 24.00 21.72 10.00 17.04 14.70 12.00 10.02 7.00 5.04 27 20.05 25.71 20.07 21.00 10.00 10.05 14.01 11.07 0.00 0.00 4.05 20 27.07 25.00 22.00 20.05 10.01 15.07 10.00 10.00 0.05 0.01 0.07 25 20.00 24.05 22.01 10.07 17.00 14.00 12.05 10.01 7.07 5.00 0.20 24 20.01 20.07 21.00 10.00 10.05 14.01 11.07 0.00 7.20 4.05 2.01 ‘Adapted from Table 9. “Economics of Water Management for Cotton and Grain Sorghum Production. High Plains." Texas Agricultural Experiment Station Bulletin 931. May. 1959. 27 i’ MAIN narrow Q nrs SUBSTATIONS i nus new LABORATORIES A coorrmrmc STATIONS Location of field research units oi the Texas Agricultural Experiment Station and cooperating agencies ORGANIZATION OPERATION Research results are carried to Texas farmers, ranchmen and homemakers by county agents and specialists of the Texas Agricultural Ex- tension Service jOLICI/y l4 Wéiléa/TA ~95 jOIWLOfPOI/U P0972 State-wide Resear ‘k it ‘n? u. The Texas Agricultural Experiment St is the public agricultural research ag I of the State oi Texas, and is one o! A parts of the A6=M College of Texas. I IN THE MAIN STATION, with headquarters at College Station, are 1 matter departments, 2 service departments, 3 regulatory servi t,’ administrative staff. Located out in the major agricultural areas of 21 substations and 9 field laboratories. In addition, there are l4 I stations owned by other agencies. Cooperating agencies include A Forest Service, Game and Fish Commission of Texas, Texas Pri U. S. Department of Agriculture, University of Texas, Texas J College, Texas College of Arts and Industries and the King Ran experiments are conducted on farms and ranches and in rural ho’ THE TEXAS STATION is conducting about 400 active research projec in 25 programs, which include all phases of agriculture in Tex _' these are: ' Conservation and improvement of soil Beef cattle Conservation and use of water Dairy cattle Grasses and legumes Sheep and goats Grain crops Swine Cotton and other fiber crops Chickens and turkeys a. Vegetable crops Animal diseases and - i Citrus and other subtropical fruits Fish and game I Fruits and nuts Farm and ranch i; Oil seed crops Farm and ranch busin_ Ornamental plants Marketing agricultural I Brush and weeds Rural home economics? Insects Rural agricultural ecof Plant diseases ‘ Two additional programs are maintenance and upkeep, and cen AGRICULTURAL RESEARCH seeks the WHATS. WHYS. the WHENS, the WHERES and the HO ‘ hundreds oi problems which confront operate farms and ranches. and the many industries deli mg on or serving agriculture. Workers of the p Station and the field units oi the Texas Agric Experiment Station seek diligently to find soluti ' these problems.