FUTURE NEEDS FOR DEVELOPMENT 271 



shown that the reservoirs yielding the great bulk of the Na- 

 tion's well water are replenished in areas which in the aggre- 

 gate would be only a minor fraction of the total area of the 

 country. 



A few fundamental facts, outlined in the following para- 

 graphs, can aid materially in giving the public an apprecia- 

 tion of the possibilities and complexities of effective manage- 

 ment of ground-water resources. 



SIGNIFICANCE OF " WATER-TABLE " FLUCTUATIONS 



The decline of "water tables" (including piezometric sur- 

 faces of confined aquifers) has been heralded widely, and many 

 writers have made dire predictions for the future on the basis 

 of data collected in various localities where these declines have 

 occurred. There is need in all analyses of the national ground- 

 water situation to realize the great variety of reasons for the 

 measured declines in water levels. 



Declining water levels are inevitable if water is taken from 

 a well, and if the draft is increased the water levels will decline 

 further, whether the increase is obtained by drawing more 

 water from one well or by drawing from more wells. If the 

 creation of this depression results in diversion of water from 

 seeps or other points of natural discharge, the draft may be 

 sustained perennially. The declines might then be viewed 

 with pride, as evidence that the community has not left its 

 talents buried in the ground but has put them to some use. 

 The decline in "water table" may be as much an indication 

 of progress as the carloadings of agricultural or industrial 

 products shipped from the community. 



A declining "water table" is also characteristic of the region 

 that has used its water resources not wisely but too well and 

 is taking far more from its ground-water reservoir than is re- 

 placed naturally. In such a region the reservoir will eventually 

 be emptied unless pumping is reduced or unless some means 

 can be found to put more water into that reservoir than is done 

 by nature. Superficially the records in such an area are the 

 same as those in developed areas where the pumping does not 



