Diverting Water from Streams 



295 



In laying out such a system of irrigation as the one under 

 consideration, it thus becomes a matter of the greatest moment 

 that proper attention be paid to drainage, and that ample pro- 

 vision be made for it. If this is not done, a relatively few 



Fig. 56. Waste gate and regulator at head of Kern Island canal, looking across 

 the canal. (Grunsky, U. S. Geol. Survey.) 



years are almost certain to convert a great benefit into one of 

 the most serious of scourges. Drinking waters are likely to 

 become polluted, malarial fevers prevalent, and the land unpro- 

 ductive, both on account of water-logging and the excessive 

 accumulation of alkalies. 



