32 DOMESTIC WATER SUPPLIES FOR THE FARM 



temporarily during the flood period of rivers fed from mountain 

 snows, etc., or in lakes supplied by such streams. Similar con- 

 ditions exist where the torrents resulting from cloud-bursts tem- 

 porarily flood certain parts of our great deserts. 



M ' 



FIG. 15. Section illustrating conditions governing movement of water away from 

 streams or lakes. N, Normal position of water table; F, position of water table 

 during floods. 



Underground Waters and Mountains. - - There is also a widely 

 prevalent belief held by the inhabitants of lowlands that the 

 ground waters, especially the deeper supplies, come from distant 

 hills or mountains. Where true artesian conditions exist, such as 

 described in Chapter VIII, there is a possibility that the waters 

 may have originated in the manner indicated, being absorbed by 

 the outcropping edges of the formations in the distant highlands. 

 Such is the case of the deep waters of the Atlantic Coastal Plain, 

 of those of the High Plains which stretch outward from the base 

 of the Rockies to the east and of the waters of the innumerable 

 basins among the western mountains and in the gravel and wash 

 plains at their base. 



In the great majority of localities, however, no such relation 

 of the ground water to mountains exists, even in the case of the 

 deeper waters, since neither the geological formations nor the 

 water bearing passages, such as joints, solution channels, bedding 

 plains, etc., are continuous for any great distances. In fact, not 

 only the shallow waters but the deep waters as well, are com- 

 monly of relative local origin, being in most instances absorbed by 

 the soil or rocks within a few miles of the well, or within 50 or 

 100 miles at the outside. 



Underground Rivers. " Underground rivers " often figure 

 conspicuously in the popular mind, the conception being, in many 

 cases, of vast streams flowing majestically through the earth far 

 below the surface, much like the streams of the surface. Under- 



