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Irrigation and Drainage 



surface, and tend to develop swamps in the lowest -lying and 

 flattest sections of the area traversed. 



It is further clear, too, that under the conditions set up by 

 such a network of canals, there must be a much more rapid 



Fig. 55. Head of Kern Island canal, looking down stream. 

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



action of water upon the subsoil to form alkalies ; and since, 

 with the nearer approach of the ground water to the surface, the 

 capillary action and evaporation must be much augmented, it 

 is plain that the deterioration of land through the increase of 

 alkalies is the thing to be feared rather than wondered at. 



