284 CONSERVATION OF GROUND WATER 



by waterlogging; (4) a controlled regimen of pumping from 

 the artificially stored water. 



It is unfortunate that the necessary geologic and hydrologic 

 information essential for these fundamental requirements is 

 not yet available. Even if it were available, there is no present 

 assurance that the fundamental requirements listed above 

 are possible of accomplishment in all parts of the area. 



Gila River Basin, Ariz. In the ground-water areas of this 

 basin, evapotranspiration losses, major relationships between 

 surface water and ground water, heavy pumping and deple- 

 tion of underground storage, and increasing salinity in certain 

 areas are the major characteristics. In this basin, too, the 

 amount of water pumped annually is great, approximately 

 3,000,000 acre-feet. In many areas the water levels have de- 

 clined more than 30 feet in the past decade. Here again, hy- 

 drologic data are so incomplete that average annual replenish- 

 ment or the amount of pumped water returned to the ground 

 cannot be firmly estimated. 



This is a particularly striking instance of a situation where 

 nonbeneficial vegetation accounts for major water losses. 

 These losses approach 500,000 acre-feet annually, to which, 

 of course, may be added the very large losses in such a climate 

 by evaporation from major surface reservoirs. Salt accumu- 

 lation has likewise been excessive through the use and reuse 

 of water for irrigation purposes. Dilution with fresh water in 

 this instance can and does afford considerable relief. 



Remedies appear to lie in the importation of water, the 

 salvaging of water now wasted, the reduction of salt inflow, 

 and even the reduction of some irrigation lands. All of these 

 measures are competitive or expensive, or both; they are un- 

 popular with some interests and certainly require an over-all 

 management wisdom administratively which usually does not 

 exist. 



Houston, Tex. Houston, with a population of nearly 

 600,000, is the largest city in the country dependent upon 

 ground water for all municipal and most industrial uses. The 

 pumpage in Houston and adjacent areas has increased from 



