2 CONSERVATION OF GROUND WATER 



tions or as they are modified by our use of one or more of these 

 resources. Modern agriculture, and modern industry in part, 

 are sustained by intensive use of these related resources; this 

 use affects our water supply in many ways. (Some of these 

 effects are discussed in Chap. IV.) These relationships vary 

 from one area to another, but for analysis, areas may be 

 grouped by common characteristics. 



Of all our water resources, least is known about those which 

 are underground. This lack of knowledge has hampered their 

 effective development as well as use and conservation. In some 

 areas demands for ground water have increased even faster 

 than for surface waters. Because of this tremendous growth 

 in the use of ground water, many startling news reports have 

 appeared in the press and on the radio about the ground- 

 water situation in certain cities and other areas. In some parts 

 of the country the water-level trend in most wells has been 

 downward for several years. These areas are sufficiently nu- 

 merous and widely scattered over the Nation so that they have 

 given rise to statements that our ground-water resources are 

 being depleted quite generally and may be exhausted within 

 the lifetime of the present generation. 



These apparent shortages of ground water are not limited to 

 the desert areas where one might expect water resources to be 

 precarious but have been reported in every state in the Union. 

 In Louisiana, where rainfall is exceptionally plentiful, areas 

 where water levels in wells are declining are more numerous 

 than in Nevada, the most arid state. The more comprehensive 

 statements have pointed out that the "shortage" is not uni- 

 versal and that in many other localities ground-water supplies 

 are as abundant today as in the past. Some writers have called 

 attention to our failure to make more use of ground water in 

 these areas and have concluded that ground water is our most 

 neglected natural resource. 



There is a tremendous variety of natural conditions deter- 

 mining water resources of various localities, as well as a orreat 

 variety of ways in which these natural conditions have been 

 modified by man's activities. Much of the conflict in published 



