Water quantity problems exist in the Rio Grande, upper and lower Colorado, Great 

 Basin, and California water resource regions. 



The water supply situation in some areas — such as the High Plains, which extends 

 from central Texas and eastern New Mexico north into eastern Colorado, Kansas, 

 and southern Nebraska — is being affected by ground water mining. As a result of 

 ground water mining and rising energy costs, the use of ground water for irrigation 

 over substantial areas may become uneconomic during the next two decades or so. 

 Demand-supply situations in arid parts of the Southwestern United States are stimu- 

 lating studies of ways to develop water markets. Such markets are mostly lacking 

 under current institutional arrangements. 



Most of the Nation's water shortages are caused by annual and seasonal variations in 

 precipitation and water flows. Variations caused by unusual storms bring about 

 another major problem— flooding. Flooding occurs in all parts of the United States. 

 Flood damages are greatest in coastal and southern California, in a broad range 

 extending up the Mississippi River drainage, and in another broad area extending up 

 the Atlantic coast from South Carolina to Maine. 



Water quality will continue to be a concern under the projected demand-supply 

 situation. For example, nonpoint sources of pollution are especially important for fish 

 habitat and the composition of the fish community. These concerns will continue to be 

 reflected in public policies aimed at management of water quality. 



Opportunities for Management— There are opportunities in local areas on forest 

 and rangelands to increase and extend water supplies, ameliorate the effects of 

 flooding, and improve water quality. Depending on the local situation, these opportu- 

 nities can be taken advantage of by: 



— Improving vegetation management to enhance the natural recharge of 

 surface and ground water, to reduce evaporation and transpiration losses, and 

 to change the timing of waterflows. 



— Improving protection of watersheds from wildfire. 



— Maintaining wetlands. 



In addition, water supplies can be increased by; 



— Expanding and improving reservoirs to increase storage, regulate flows, and 

 reduce evaporation; and 



— Improving snow management. 



Water supplies can be extended by: 



— Improving conservation, including more reuse; and 



— Improving opportunities for water marketing. 



Expected increases in flood damage can be limited by: 



— Controlling floatable debris, such as logging residues; 



— Increasing use of structures to control waterflows, providing that further 

 flood plain development can be restricted; 



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