INCREASING REQUIREMENTS 227 



the river, but this may be no handicap to users of the rivers 

 that discharge surplus water continuously into the ocean. In 

 many places ground water is superior to the stream water for 

 certain uses, because of uniform temperature or chemical 

 quality; particularly where the stream is polluted by sewage, 

 the antibiotic action of aquifers will be an advantage. The 

 ground-water reservoir along a watercourse may also be 

 capable of a higher sustained yield than the surface water if 

 the stream fluctuates markedly in discharge, because water 

 can be pumped from storage underground during periods of 

 low stream flow, to be replaced when the stream is at higher 

 stage. Manipulation of storage along watercourses can also 

 be used to advantage in reducing flood peaks. 



