252 CONSERVATION OF GROUND WATER 



The hydrologic cycle provides a logical basis for distinction 

 of individual rights inherent in land ownership as against pub- 

 lic rights subject to appropriation. In the precipitation and 

 soil moisture phases the movement of water is chiefly verti- 

 cal, but in the ground-water and surface-water phase hori- 

 zontal movement dominates and the water crosses property 

 lines. 



In areas where the surface and ground waters have been de- 

 clared public water, available for use on a first-come, first- 

 served basis, the relationship between ground water and sur- 

 face water must be recognized, if the rights to each are to be 

 placed on a firm basis. Part of this recognition will involve 

 abandonment of the common fallacy that water is "lost" when 

 it seeps from a stream into a ground-water reservoir and that 

 it can be "saved" by preventing the seepage. The terminology 

 is an anachronism from the days when little was known about 

 ground water. Actually water "saved" by being held on the 

 surface is subject to loss by evaporation, while the water that 

 disappears into the ground is generally not subject to evapora- 

 tion losses and is usually recoverable. 



The return of water to the atmosphere by evapotranspira- 

 tion is receiving more and more attention, because by reduc- 

 tion of natural losses increased quantities of water are available 

 for man's use. The rate of evaporation has become a domi- 

 nant factor in selection of sites for reservoirs in arid regions, 

 and in several western states estimates of the undeveloped 

 ground-water potential are being made on the basis of evi- 

 dence as to the natural evapotranspiration in each locality. 

 Such natural losses can be salvaged by various means. It 

 should be possible to establish a right to such water by evidence 

 that there had been natural waste and that the developed 

 waters result entirely from reduction of that waste; such proof 

 might well be more conclusive than an attempt to establish the 

 adequacy of supply from some remote source area. 



water rights based on preferential use. Existing and po- 

 tential water users are entitled to know of any conditions, such 

 as discriminations on the basis of type of use, which might 



