The Salinity Factor in the 
Reuse of Waste Waters 
H. E. HAYWARD 
United States Salinity Laboratory, 
Riverside, California 
In the arid zones of the seventeen western states and other 
arid regions throughout the world, it is generally recognized that 
the total area of irrigable land far exceeds the acreage that may 
be served with available supplies of irrigation water. For example, 
the 1950 Census of Agriculture reports over 24,000,000 acres of 
irrigated land in the seventeen western states, and the future 
program for irrigation agriculture calls for the use of as much as 
30,000,000 acres of land. An even higher estimate of 51,500,000 
acres of irrigable land in the seventeen western states was made 
by the National Resources Board in 1936. 
Paulsen has stated (2) that the “total average annual water 
supply in the 17 Western States is about 390 million acre-feet as 
compared to the present withdrawal use of about 100 million 
acre-feet. Except for irrigation, only a small part of the water 
withdrawn for use is consumed, estimated by some to be as little 
as 10 per cent.” This statement suggests a very favorable situa- 
tion, but the distribution of water supplies is such that some areas 
have surplus water at all times whereas other areas seldom have 
sufficient water. In the Southwest, the average annual runoff is 
less than one-fourth inch, and no streams flow out of the Great 
Basin. This indicates the importance of planning for irrigation 
agriculture so that there may be a more effective use of all avail- 
able water resources. Such a program involves, among other 
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