Table 7.9 — Fresh water consumption in ttie United States in 1975, by major use, with projections 



of demand to 2030 







(Million gallons a day) 









Major use 



1975 



1985 



1990 



2000 



2010 



2020 



2030 



Irrigation 



86,391 



92,820 



91,011 



92,506 



95,395 



100,290 



99,972 



Steam electric 



1,419 



4,062 



6,583 



10,541 



14,376 



17,674 



21,373 



Manufacturing 



6,059 



8,903 



11,992 



14,699 



18,059 



21,632 



25,117 



Domestic and 

















commercial: 

















Central 



4,976 



5,665 



5,988 



6,638 



7,308 



7,971 



8,550 



Noncentral 



1,292 



1,408 



1,394 



1,436 



1,526 



1,595 



1,658 



Commercial 



1,109 



1,216 



1,263 



1,369 



1,469 



1,567 



1,667 



Minerals 



2,196 



2,777 



3,021 



3,609 



4,087 



4,669 



5,203 



Livestock 



1,912 



2,233 



2,275 



2,551 



2,825 



3,095 



3,316 



Public lands and other 



1,236 



1,461 



1,538 



1,731 



1,929 



2,127 



2,326 



Total 



106,591 



120,545 



125,065 



135,080 



146,974 



160,620 



169,182 



Source: See source note table 7.1 



future years. The rates of growth are expected to be 

 largest in manufacturing (142 percent from 1975 to 

 2000) and steam electric cooling (643 percent). 

 Greater use of recycling techniques, while reducing 

 overall withdrawals, will increase consumptive use. 

 For example, the use of cooling towers at steam 

 electric plants will cause greater loss to evaporation 

 than does once-through cooling. 



Consumption by Region and Use 



Major differences appear among water resource 

 regions in the amount of water used consumptively. 

 As expected, regions that irrigate heavily are also 

 large water consumers. The largest consumptive use 

 — 27 billion gallons a day — was in the California 

 region, which accounts for about 25 percent of the 

 total national consumptive use (table 7.3). The Miss- 

 ouri Basin was the second largest water consumer 

 with 15.5 billion gallons a day, or 15 percent,- and 

 the Pacific-Northwest and Texas Gulf regions each 

 accounted for more than 1 1 billion gallons a day, 

 or about 1 1 percent. Total consumptive use is pro- 

 jected to increase to 135 billion gallons a day (26 

 percent) by the year 2000, but the interregional 

 proportions are not likely to change very much. 



The concentration of heavy consumptive use in 

 the California, Missouri, Pacific-Northwest, Texas 

 Gulf, and the Arkansas-White-Red regions reflects 

 the large demands for irrigation water. For example, 

 91 percent of the consumptive use of 27 billion 

 gallons a day in the California region is for irri- 

 gation — the proportion is 92 percent for the Missouri 

 region. 



Overall, consumptive use for irrigation is projected 

 to increase by about 7 percent from 1975 to 2000 

 (table 7.3). The most significant change is expected 

 in the Texas Gulf region, where consumptive use 

 will decline by 34 percent from 9.3 to 6.1 billion 

 gallons a day because ground water mining is 

 depleting the water table and reducing the amount 

 of ground water available. This suggests a potential 

 decline in agricultural use in the High Plains area 

 unless water supplies are increased or some other 

 form of technology is adopted to bring consumptive 

 uses in line with longrun annual supplies. The Rio 

 Grande, Lower Colorado, and Great Basin will all 

 show modest decreases in ground water consumed. 



Water consumed in manufacturing processes is 

 highest in the Great Lakes region, which accounts 

 for nearly a quarter of manufacturing use. The 

 Ohio, Middle Atlantic, South Atlantic Gulf, and 

 Texas Gulf regions are also major consumers of 

 manufacturing water. Consumptive use in manufac- 

 turing is projected to more than double by 2000 

 (table 7.5). This growth will likely be shared by 

 nearly all regions, but those mentioned above will 

 continue to be most important. 



The most dramatic increase in water consumption 

 will be in steam electric cooling, which is projected 

 to increase from 1.4 billion gallons a day to 10.5 

 billion gallons a day by 2000. Consumptive use will 

 increase in almost every region, but most significantly 

 in the South Atlantic Gulf and the Lake States 

 (table 7.4). This is almost entirely due to the shift 

 from once-through cooling to cooling towers to 

 minimize thermal pollution. Other types of consump- 

 tive use are projected to increase, but at a slower 

 rate. 



284 



