296 Procejedings o^ the 



will depend upon a variety of conditions, and in nearly 

 every one of these conditions the forestation or lack of 

 such upon the headwaters of the stream plays an im- 

 portant part. First of all is the total amount of water 

 available which must, however, be considered in con- 

 nection with the nature of its discharge — whether 

 perennial or spasmodic. 



The ideal condition for a maximum development of 

 power would be that prevailing under a reservoir so 

 large as to be able to impound all the run-off resulting 

 from precipitation in the given drainage basis and its 

 complete regulation. To insure permanence in reser- 

 voir capacity, the water supply must be clear, free from 

 the presence of silt resulting from erosion, and removed 

 as completely as possible from evaporative influences. 

 The maximum development demands that the entire 

 quantity shall be under such perfect control that a 

 little more or less as desired may be utilized at any given 

 time; and that it be well sustained throughout the 

 year or other long periods, approaching as nearly as 

 possible a perfectly even flow, with but little, if any, 

 more in May and June than in September, January, 

 or any other month; since the power developed, to 

 be of commercial value, must permit of dependence 

 being placed upon it throughout long periods of time. 

 Otherwise it will not pay to install and operate the 

 necessary plants. 



Such conditions as have been described are not often 

 even approached in nature, but in many localities far- 

 seeing men are trying to approach them as nearly as 

 practicable through the construction of great storage 

 reservoirs and by forestation, and, where the head- 

 waters have been denuded of the timber, by reforestation. 



Here is, to a great extent, the keynote of the situa- 

 tion. Those regions that approach most closely to the 



