BETTER GROUND-WATER MANAGEMENT 281 



wise conservation practices in this field of public necessity, 

 some general observations may be made on the ground-water 

 situation for the country as a whole. 



At the present time about one-fifth of the total water used 

 in the United States comes from underground sources. This 

 ground-water use is concentrated over particular reservoirs; 

 in many areas, due chiefly to excessive pumping, the local 

 supply is being exhausted at a greater rate than it is naturally 

 recharged. The detailed reasons for this exhaustion are many; 

 they are described in the body of this survey. If some kind of 

 broad generalization must be made, the limited evidence 

 available supports the view that ground water on a nation- 

 wide basis is not running out. With ground-water use prob- 

 ably exceeding 25 billion gallons a day, some 15 billions are 

 used in irrigation, 5 billions by industry, 3 billions for munici- 

 pal systems, and the remainder for rural use exclusive of ir- 

 rigation. Ground-water use is estimated to have more than 

 doubled from 1935 to 1950. While the use is increasing and 

 there are areas of obvious deficient water supply for present 

 and future needs, the over-all situation does not disclose any 

 basis for fear that an adequate supply is not available for the 

 Nation's needs. 



What is urgently required is to learn quickly and reliably 

 how much water we are using and what our future needs are 

 likely to be. In a nation in which accounting practice has 

 reached a high level of performance in all industrial opera- 

 tions, it is still true unfortunately that for ground- as well as 

 surface-water resources bookkeeping is still inadequate both 

 for current and for long-range purposes. Reporting and ac- 

 counting are deficient, and yet are required for any intelli- 

 gent coordinated conservation program. 



One forgotten axiom of ground-water development and 

 use is that there is no more water than there is. In other words, 

 one cannot remove from the ground more water than origi- 

 nally fell. This is sometimes attempted or sometimes hoped 

 for in areas where rainfall is unfortunately meager; these high 

 hopes are unrealistic. For example, in the Southern High 



