Figure 16—Now that many point sources of pollution are under control, nonpoint sources have 
become relatively more important as contributors to residual pollution of inland surface waters. 
(Photo courtesy of USDA Soil Conservation Service.) 
believe that further significant 
improvements in water quality from 
this type of control will be expensive 
and difficult to achieve. 
With achievement of control of many 
point sources of pollution, nonpoint 
sources have become relatively more 
important as contributors to residual 
pollution of inland surface waters (fig. 
16). Nonpoint sources of pollution 
include land disturbance and 
management activities on the land. 
Relatively minor changes in the 
environment caused by nonpoint 
sources of pollution can have major 
impacts on the composition of fish and 
wildlife populations in local situations. 
The Demand Situation for 
Water 
Three types of water use must be 
considered in any assessment of the 
water situation: withdrawal use (water 
removed from a stream or aquifer), 
consumptive use (that part of water 
withdrawals that is not returned to a 
stream or aquifer for reuse), and 
instream use (for navigation, 
hydroelectric power generation, 
recreation, and fish and wildlife 
habitat). 
The growth of the United States as an 
industrialized nation has been closely 
tied to the use of water. Water was the 
source of transportation, food, and 
power for use in industry. The 
development of the steam engine in the 
early 1800’s freed industries from 
dependence on water power, and the 
Industrial Revolution was well on its 
way. From colonial days to the 
beginning of the 20th century, demand 
for drinking water and water for waste 
disposal increased the most rapidly. By 
then, civilization had tainted most 
coastal waters and many inland 
streams. Water-related diseases were 
common. Destructive floods often 
occurred as flood control structures 
were not yet built. 
During the next 75 years, the Nation 
came a long way in the management of 
its water resource. By the early 1970's, 
it became clear that while previous 
policies and actions solved many 
volume-related water problems, much 
remained to be done about problems of 
water quality. Legislation was passed 
with the intent of significant 
improvement in the quality of the 
Nation’s waters. Coincidentally, the 
water-quality-related legislation 
resulted in a major shift in the 
relationships among population, gross 
national product, and water 
withdrawals. Water conservation and 
recycling became more attractive under 
the new legislation, and it had the 
effect of retarding the growth in 
demand for withdrawals and 
consumption. 
Trends in Water Use and 
Projected Demands 
In 1985, total freshwater withdrawals 
in the United States totaled some 344 
billion gallons per day—84 billion 
from ground water, 259 billion from 
surface water, and 0.6 billion from 
waste water. Consumption in 1985 
totaled 94 billion gallons per day, or 27 
percent of withdrawals and less than 7 
percent of daily precipitation (app. 
table 6-8). 
Data from the U.S. Geological Survey 
indicate that total water withdrawals in 
the United States increased 59 percent 
between 1960 and 1985 and 
consumption, 53 percent (fig. 17). 
These totals mask significant 
differences in withdrawal and 
consumption among geographic 
regions and uses (app. tables 6-8). 
Between 1960 and 1985, withdrawals 
in the South and Rocky Mountains rose 
89 and 76 percent, respectively, as 
compared with increases of 40 percent 
in the North and 32 percent on the 
Pacific coast. 
17 
