Domestic water use can be made more efficient by 

 controlling leaks in transmission systems, installing 

 water meters and charging according to use, design- 

 ing plumbing fixtures and appliances that use less 

 water, initiating public information programs, re- 

 cycling municipal and industrial waste water, and by 

 water pollution control. 



Water use in manufacturing could be made more 

 efficient through additional recycling procedures. 

 Recent technological advances have allowed the steel 

 industry to reduce water requirements by 90 percent 

 in water-short areas. Perhaps the greatest saving can 

 be achieved by reusing cooling water, which accounts 

 for more than 65 percent of all industrial withdrawals. 



Among the opportunities for increasing usable 

 water supplies in a given area are: Interbasin trans- 

 fers, desalting, precipitation modification, and water- 

 shed management. 



The physical transfer of water from one watershed 

 to another has been a common means of augmenting 

 supply. For example, part of Denver's water supply 

 comes from the Colorado River Basin, which is 

 across the Continental Divide from Denver. Los 

 Angeles imports water from the Great Basin, the 

 Colorado Basin, and the Sacramento Basin. Each 

 project must be evaluated on its individual merits. To 

 properly evaluate interbasin transfers, it is necessary 

 to examine the legal framework, the ways of protect- 

 ing the exporting basin, the economics of the project, 

 the social and environmental implications, and the 

 institutional arrangements necessary to implement 

 the project. 



Because of increasing water demands and relatively 

 fixed natural supplies of water, it is likely that desaU- 

 ing will become significant in the future, especially 

 with smaller plants that have less than 10 million 

 gallons per day capacity, in areas where alternative 

 supplies are costly, where there are natural suppHes of 

 brackish water, where existing supplies need to be 

 upgraded, or where point sources of dissolved solids 

 can be treated. Desalting costs have been reduced 

 from approximately $7.00 per 1,000 gallons in 1952, 

 to approximately $ 1 .00 per 1 ,000 gallons for seawater 

 conversion, and $0.50 for brackish water plants at the 

 present time. The projects that are energy-intensive 

 will be less attractive as energy costs increase. '^ 



The prospects for successful modification of rain- 

 fall and snowfall patterns to increase yields look 

 promising. Cost estimates ranging from $1.00 to 

 $2.30 per acre foot of additional runoff have been 

 cited. However, these represent only the direct capital 

 and operation costs, and do not include indirect 



economic environmental, or ecologically related 

 costs. Uncertainties about both direct and indirect 

 effects, as well as many legal and institutional impli- 

 cations have caused much controversy about precipi- 

 tation modification. The National Water Commission 

 concluded that precipitation modification has poten- 

 tial in certain limited areas, but available information 

 is insufficient to develop a comprehensive national 

 policy. 



Forest and range lands are important sources of 

 the Nation's water supply. Commercial and noncom- 

 mercial forests occupy about one-third of the total 

 land area of the Nation. Forest lands receive a yearly 

 average of 42 inches compared to 24 inches annually 

 on all other lands. Forest lands yield 17 inches of 

 annual runoff compared to 4 inches from other 

 lands.2o 



Watershed management of forest and range land 

 can augment water suppHes by enhancing the natural 

 recharge of ground water, by slowing the rate of 

 overland flow, and by improving the infiltration rate 

 through proper vegetative and cultural practices. 



Watershed protection and management is needed 

 not only to ensure the optimum combination of water 

 quantity and quality at a given location, but also to 

 protect and enhance land resources such as soil and 

 vegetation. For some situations, increasing the water 

 supply through land management might be the best 

 way to succeed. In other cases, these techniques 

 create adverse side effects which should not be 

 overlooked. 



Small patchy openings created by timber harvests catch consider- 

 able quantities of snow, increasing water yields. 



" Water policies for the future, final report to the President and 

 to Congress, op. cit. 



'"Sopper, William E. Watershed management. Prepared for the 

 National Water Commission. Natl. Tech. Inf. Service, Springfield, 

 Va., No. PB206670. 2 p. 1971. 



310 



