Figure 7.6 



Major Areas of Potential Groundwater Development 



Alluvial Basin 



Regional data not available for Alaska, Hawaii, and Puerto Rico. 



In most regions, water supplies vary from high flows 

 during spring and early summer to low flows during 

 late summer to early winter. Many times the high 

 water-use season corresponds to the low water-yield 

 season. For this reason, analysis of average water 

 supplies and demands does not reveal some water 

 shortage problems. Although the Nation's total 

 streamflow varies greatly from year to year, the 

 longterm trend shows that the flow has been remark- 

 ably constant and that no general or persistent down- 

 ward trend is evident, though the 10-year moving 

 average indicates rather prominent swings of a near- 

 periodic nature (fig. 7.7).'' 



■• Langbine, Walter B. Water resources review for December 

 1977. U.S. Department of the Interior, Geological Survey. 18 p. 

 1978. 



Problem Areas 



A comparison of water supply and demand data 

 shows that the Nation's water supplies are generally 

 sufficient to meet water needs for all purposes. How- 

 ever, major problems are evident in most of the 

 21 water resource regions; more particularly, there 

 are serious local problems in nearly all of the 106 

 subregions. These include shortages resulting from 

 poor distribution of supplies, instream-offstream 

 conflicts, competition among various offstream users, 

 ground water overdrafts, quality degradation of both 

 surface and ground water supplies, and institutional 

 conflicts that prevent a unified approach to water 

 management. 



To better relate potential water supply problems to 

 the Resources Planning Act Regions used in this 

 report, the subregions have been reaggregated to 

 represent the Resources Planning Act Regions as 

 closely as possible. 



290 



