154 CONSERVATION OF GROUND WATER 



Platte River Valley, Nebr'" The watercourse of the Platte 

 River is a major source of water for Nebraska and is one of 

 the best examples in the country of multiple use of water. 

 The waters of the South Platte in Colorado and of the North 

 Platte in Wyoming and Nebraska have already been used 

 extensively for irrigation before they join in the west-central 

 part of the state to form the Platte River. For more than 

 a hundred miles downstream from this junction, water is 

 repeatedly diverted from the stream, used for irrigation, and 

 returned to the stream (except for the quantities lost by 

 evapotranspiration). Increasing concentration of mineral 

 salts results from this multiple use, but fortunately the river 

 as it flows east traverses areas of progressively increasing 

 rainfall, and waters contributed to the watercourse in the 

 eastern part of the state serve to dilute the water moving 

 down the valley from the west. Maintenance of a satisfactory 

 salt balance is recognized as an important consideration in 

 the planning for maximum utilization of the water in Platte 

 River Valley. 



In long stretches of the valley movement of ground water 

 is toward the river, the channel of the Platte being low 

 enough to act as a drain for the ground-water reservoir of 

 the watercourse. In other stretches of the valley the move- 

 ment of ground water is either parallel to the river or away 

 from it. Ground water moves away from the river especially 

 during periods when the river is at high stage, and this is 

 borne out by recorded stream -flow losses and by detailed 

 contours of the water table in several areas. Recharge to the 

 ground-water reservoir is chiefly from precipitation on the 

 valley floor and adjacent areas, supplemented by influent 

 seepage of the river and principal tributary streams and by 

 the seepage and return flows from irrigation canals and ir- 

 rigated lands. 



There are about 5,500 irrigation wells in the 2,500 square 



7T Reference: Waite, H. A., et al., Progress Report on the Geology and 

 Ground-water Hydrology of the Lower Platte River Valley, 

 Nebraska, U.S Geol. Survey Circ. 20, 211 pp., 1949. 



