Climate, Climatic Change, and Water Supply (1977) / Chapter Skim
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3. Methods for Estimating and Projecting Water Demands for Water-Resources Planning
3. Methods for Estimating and Projecting Water Demands for Water-Resources Planning
Pages 49-69
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From page 49... ...
Economists have indicated on several occasions concern about the continuing use of the terms "requirement," "use," and "need" when referring to the withdrawal or intake of water as a natural resource." These terms are called into question because they do not have an allocative connotation that is in keeping with the competitive market framework. Given the general problems associated with statistical demand estimation and, in the case of water, present conditions of"block pricing" and substitute goods such as self-supplied, reclaimed, or recirculated water, the prospect for determining demand functions relating to water (particularly for water as a production input)
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From page 50... ...
The terms "water requirements" or "water use" have been historically associated with water development planning and do not carry any precise or rigorous connotation of quantitative measurement of water withdrawals in relation to price. They are generally used in an engineering or technological context to relate the quantity of water employed in the production process per unit of output.
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From page 51... ...
. Other methods are possible for estimating irrigation water demand functions.
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From page 52... ...
CRAIG DAVIS P X n—2 r r2 percent By river basin Total water Value of production 16 0.58 0.34 2 Total water (except natural gas processing)
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From page 53... ...
WATER DEMANDS IN THE MINERAL INDUSTRIES Water needs of the mineral industries constitute only about 2 percent of water withdrawn by the industrial sector as a whole.~6~7 The largest water-using mineral industries are natural gas processing, phosphate rock, sand and gravel, and iron ore. Kaufman and Nadler carefully analyzed the results of a comprehensive canvass of mineral-industry water use in 1963.
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From page 54... ...
From the foregoing it can be inferred that statistical demand functions for water, as they are generally understood, essentially do not exist for the mineral industry. INDUSTRIAL WATER DEMANDS The factors affecting industrial water demands for a number of industries have been dealt with in some detail by Bower.20 2~ Bower formulates conceptually a joint function governing industrial water demand as follows: QIbQD6C t,QEt,WDt,WEt = where PP L OR poqr R S f(Q t,q t,T,PP,L,OR, poqr,R,S, E c,A ,, Q dt,q dt,~, C U,./C t Qt and At are the quantity and quality and their corresponding time patterns of water available at the intake; is the water- and waste-treatment processes within the production unit; is the technology of the production process; is the physical layout of the plant; is the operating rate; is the product output quality requirements; is the degree of recirculation; is the solid wastes from the production process; is the limitations on the final liquid effluent; is the limitations on the final gaseous effluent; Qua and qua are We quantity and quality and their corresponding time patterns of water available for dilution at the effluent point; is the availability of places for final disposal of wastes; and is the ratio of total water utilization costs to total production costs.
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From page 55... ...
As matters stand, there appears to be no clear-cut method of empirically deriving and projecting demand functions for industrial water use. In contrast to agriculture, reliance on water prices and pricing policies for both withdrawals and discharges seems to have been too tenuous an instrument for achieving the desired goal of dramatically reducing water demands and wastewater discharges.
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From page 56... ...
These were based on the B C, and D population TABLE 3.6 Sample Projections of Total Water Withdrawals and Consumption for Thermal Electricity Generation (billion gallons per day)
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From page 57... ...
In the overall, freshwater withdrawals by steamelectric generating stations might be influenced by setting water prices at levels that could only be considered unreasonable in the present economy. The consumptive use of water by thermal plants appears to be insensitive to price changes within what might be considered a reasonable price range.
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From page 58... ...
In light of the findings, it seems feasible that water-demand functions for irrigation water can be developed, using either statistical analysis or mathematical programming techniques, and applied in water-resources systems planning. For the mineral industries and certain industries that are heavy users of water, the prospects for developing and using statistical demand functions in systems planning appear to have been overshadowed by changes in the Water Pollution Control Act passed by Congress in 1972.
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From page 59... ...
United States Geological Survey, "Estimated Use of Water in the United States," quinquennially since 1950.28,43-46 2. United States Water Resources Council.
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From page 60... ...
For the agricultural and industrial sectors of the economy, the forecasting of future water demands may be greatly improved by implementing a series of detailed process analysis studies to determine the required minimum amounts of water that will be necessary for these sectors to function efficiently under adverse conditions. Placing too great a reliance on the concept of market supply and demand functions as opposed to gaining a comprehensive understanding of the technological possibilities for reducing resource inputs may be an error.
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From page 61... ...
There is a real threat that crop failures would lead to widespread starvation. Evidence is accumulating which shows that the climates of the Earth are changing, and it has been suggested Mat they might be changing in a direction which could have a net adverse effect on world food production, and global economic and political stability (I.F.I.A.S.
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From page 62... ...
1 WATER-USE FORECASTS FOR 2000 AND 2020 Projections of water withdrawals and consumptive use to the years 2000 and 2020 were made by the United States Water Resources Council in 196847 and by Wollman and TABLE 3.10 Irrigation of Agricultural Land Summary: 192~1969 EData are for 17 Western States (Alaska and Hawaii excluded) and Louisiana, except as notedia Item 1920 1930 1940 1950 1959 1969 19690 Approximate land area milt acres 1190 119~)
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From page 63... ...
1985 2000 2020 Cropland Harvested 311,285.2 286,708.1 292,242.6 285,585.4 271,920.4 255,656.1 Feed crops Grainsb 125,395.0 93,658.2 102,936.3 99,795.9 91,147.2 63,016.8 RoughageC 76,432.0 78,829.4 68,787.2 67,446.5 64,396.1 61,862.7 Food crops Grains 52,376.0 51,413.6 43,976.3 42,786.1 40,306.1 37,297.2 Vegetables, fruits, and sugar 8,992.9 9,638.1 9,024.3 9,006.4 9,154.7 9,078.6 Others 3,176.0 2,923.1 3,105.9 3,087.8 2,982.9 2,908.1 Over crops Oil' 26,261.0 33,841.6 53,044.2 52,773.5 52,801.1 51,277.7 Cotton, tobacco, and miscellaneous 22,765.5 21,230.1 14,843.0 14,841.1 14,335.5 13,222.0 - Total crops harvested 315,598.4 291,533.7 295,717.4 289,737.4 275,123.6 258,663.2 Cropland not Harvestedh 136,278.5 147,130.0 165,843.4 172,601.4 186,401.5 202,420.4 Total Cropland 447,563.7 433,838.1 458,086.0 458,186.8 458,321.9 458,076.5 Forest and woodland 163,684.3 145,711.5 105,231.8 102,759.6 95,339.7 86,404.5 Pasture, range, and other lanai 508,909.8 526,323.5 481,566.3 478,927.2 472,341.4 463,098.2 Total land in farms 1,120,157.8 1,105,873.1 1,044,884.1 1,839,873.6 1,025,003.0 1,007,579.2 Irrigated Cropland Harvestedj 27,436.8 29,902.8 36,919.1 36,446.6 36,218.8 36,003.5 Feed crops Grains. 5,255.4 6,585.0 10,196.5 9,975.5 9,581.0 9,495.6 RoughageC 7,483.6 9,144.9 10,581.6 10,557.3 10,983.3 10,932.2 Food crops Grains 2,961.9 3,785.5 4,208.9 4,086.9 3,869.2 3,772.2 Vegetables, fruits, and sugar 3,601.8 4,826.6 5,049.9 5,191.8 5,514.5 5,837.0 Others 1,158.0 1,007.1 1,263.9 1,276.4 1,319.4 1,358.7 Other crops Oil' 395.0 479.8 1,264.1 1,292.4 1,380.3 1,443.5 Cotton, tobacco, and miscellaneous 3,465.0 4,281.2 4,743.6 4,454.6 3,961.8 3,565.8 Total irrigated crops harvestedk 24,320.7 30,110.1 37,308.4 36,835.0 36,609.6 36,405.0 Acreages are exclusive of Alaska and Hawaii.
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From page 64... ...
Bonem in 1971.3~ Preliminary projections that are subject to revision have been made to 1985 and 2000 under the Water Resources Council's 1975 National Assessment Program (Table 3.141. To test the usefulness of a simplistic national "projection model," based on an extrapolation of past production growth trends and fixed water requirements per unit of output, the Series E OBERS growth rates were used with 1970 agricultural and steam-electric withdrawals data and the 1973 Census of mineral industry and manufacturing water-use data.
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From page 65... ...
covered are nevertheless stated to represent some 98 percent of total water withdrawals. If the climatic changes that portend are in fact realized, then the irrigation demands may be substantially greater than the preliminary Water Resources Council second national assessment estimates as they are currently shown.
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From page 66... ...
(mad) Categories 1975 1985 2000 1975 1985 2000 Domestic Central 21,520.4 24,698.0 29,086.0 5,003.4 5,744.8 6,756.0 Domestic Noncentral 2,072.7 2,296.0 2,371.7 1,288.5 1,392.1 1,417.5 Manufacturing Total 58,176.8 33,086.5 45,701.6 6,275.0 9,199.9 15,758.3 Food end kindred 2,500.6 1,440.3 1,137.6 310.3 465.7 770.5 Paper, pulp, and board 8,595.6 5,821.5 5,193.2 1,039.7 2,065.0 4,112.6 All other manufacturing 4,910.7 2,496.5 2,606.7 598.6 865.0 1,400.6 Textile mills 559.6 265.7 211.6 65.1 93,1 144.5 Chemicals 14,005.4 5,867.6 5,445.4 1,305.5 2,128.3 4,260.1 Primary metals 17,324.0 5,591.0 3,398.0 2,007.0 2,282.0 2,685.0 Transport, machinery 1,331.4 579.4 479.4 143.8 226.7 364.4 Petroleum refining 2,313.8 1,578.4 1,201.6 533.5 687.5 955.4 Minerals, Total 7,506.1 8,810.4 10,912.4 2,333.2 2,628.4 3,145.8 Metals 1,081.2 1,288.2 1,605.3 233.5 272.5 300.1 Nonmetals 3,518.7 4,385.7 5,745.6 470.8 599.1 785.0 Fuels 2,907.4 3,137.0 3,622.4 1,627.9 1,758.9 2,022.4 Crop Irrigation 179,053.4 184,984.5 163,652.9 92,024.5 98,153.5 93,742.2 Livestock 1,851.9 2,153.1 2,444.1 1,851.9 2,153.1 2,444.1 Steam Electric 92,602.0 86,801~0 70,047.0 2,103.0 3,647.0 9,147.0 National Parks 13.8 18.0 21.7 10.3 13.5 15.9 Fish Hatcheries 628.0 697.2 726.3 0.0 0.0 0.0 BLM Lands 1,050.7 1,129.9 1,232.8 1,050.7 1,129.9 1,232.8 National Forests 393.0 591.5 793.4 393.0 591.5 793.4 Total Requirements 364,868.8 345,266.6 326,990.0 112,333.5 124,653.5 134,453.1 Man-made Evaporation 13,114.0 13,556.2 13,779.8 13,114.0 13,556.2 13,779.8 Total Requirements plus Evaporation 377,982.7 358.822.8 340,769.8 125,447.5 138,209.7 148,232.9 Net Exports 450.7 651.7 862.2 450.7 651.7 862.2 Net Depletions 378,433.4 359,474.5 341,631.9 125,898.2 138,861.4 149,095.1 Groundwater Withdrawals 68,665.5 66,410.5 63,481.5 Net Imports 0.0 0.0 0.0
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From page 67... ...
Water Resources Council data are for domestic use only. Key: See Figure 3.4.
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From page 68... ...
Key: See Figure 3.4. those developed by the United States Water Resources Council for 1968 and 1975, may substantially understate agricultural water demands if any unfavorable climatic change is experienced during the coming 50-year plan.
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From page 69... ...
69 47. The First National Assessment of the Water Resources Council, The Nation's Water Resources, Washington, D.C.
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