Billion gallons 
600 
500 
400 
300 
200 
1960 1970 1980 
Withdrawals 
Ze 
1990 2000 2010 
Figure 17—Total freshwater consumption and withdrawals, 1960-85. with projections to 2040. 
Because the North is more heavily 
industrialized than other parts of the 
country, it showed the largest 
percentage increases in consumption of 
water between 1960 and 1985 (132 
percent). Increases were much smaller 
for the South (68 percent), the Pacific 
coast (49 percent), and the Rocky 
Mountains (37 percent). The U.S. and 
regional totals for withdrawals and 
consumption also mask significant 
differences among the major categories 
of water use: thermoelectric steam 
cooling, irrigation, municipal central 
supplies, industrial self-supplies, 
domestic self-supplies, and livestock 
watering. Projections of water demands 
were made for these six categories by 
Assessment region (see frontispiece) 
and form the basis for the following 
presentation of projected demands. 
The projections of water withdrawals 
to 2040 are estimates of future demand 
levels if recent trends in demand for 
water continue. 
Thermoelectric Steam Cooling 
With thermoelectric power, the 
principal method of generating 
electricity 1s to convert water into 
steam and then use steam pressure to 
propel a generator’s turbine. Most of 
the new electrical generating capacity 
in the United States in the past 15 years 
has been based on coal and nuclear 
fuel. The Northeast relies primarily 
upon nuclear and oil-fired units, and 
the Pacific coast, on natural gas and 
hydropower. All other regions depend 
mainly on coal as a source of energy. 
Consumption of water is only a 
fraction of withdrawals for 
thermoelectric steam cooling. The 
primary concern over water quality 1s 
the heating of water prior to discharge 
back to the source—a concern that has 
largely been alleviated through cooling 
towers and other means. 
The oil-price shocks of the 1970’s 
caused many structural shifts in energy 
Consumption 
2020 2030 2040 
consumption that have lowered the 
relationship between electricity 
demand and gross national product. 
More efficient motors, better electricity 
generation and transmission 
technologies, and other conservation 
measures have contributed to an 
expected slowing in the rate of increase 
of future demands for electricity. There 
is also potential for increased imports 
of hydro-based electricity from 
Canada. This outlook does not mean 
reduced needs for water for 
thermoelectric power generation—t 
means a slowing in the growth in 
demand in the short term. After the 
turn of the century, it is expected that 
relatively large increases in generating 
capacity will be necessary (fig. 18). By 
2040, withdrawals for thermoelectric 
cooling are projected to be 228.3 
billion gallons per day, with 
consumption amounting to only 6 
percent of withdrawals. Most of the 
added capacity is assumed to be in the 
North and South. 
