314 THE 1RRIGA TION A GE. 



suspect what was the matter. For this reason I would prefer a 

 reservoir wide and shallow, even at the risk of more trouble from 

 vegetation. You cannot have the water too warm for the best 

 results, with most products. t 



"Such reservoirs should also be used in hundreds of cases where 

 one now deems them necessary. All experienced irrigators know the 

 difference in efficiency between so many inches of water in large 

 heads and in small ones. Many a man is now irrigating from a well 

 who does not know this or does not know the extent of the difference. 

 Even with a well flowing several inches of water, either artesian or 

 by pumping, parties are losing efficiency seriously by not accumulat- 

 ing that head so as to make a large run. It is not possible to frame 

 a formula by which this may be calculated, but it is safe to say that a 

 man with a ten-acre tract, and a well furnishing one inch of water, 

 had better spend a thousand or fifteen hundred dollars for a reservoir, 

 or else unload on the first tendrfoot and buy under a ditch giving 

 large heads, as most of them do. The San Diego Flume Company 

 got into its present trouble largely by the stupidity of directors, who 

 ignored the plans of the projectors and limited consumers to a con- 

 tinuous flow of a single inch. 



'For valuable products, and for almost all products, one must 

 have an irrigating head of considerable size. It should be from three 

 to five inches for each acre to be irrigated, according to the texture 

 of the soil. Where the soil is too porous for good furrcw work the 

 resort must be to flooding, it should be at least ten inches of head for 

 each acre to be irrigated. All this means high efficiency of the water. 

 But it also means a large reservoir. 



"It does not, how T ever, imply that such a reservoir must be 

 cemented. Such a course w T ill generally be expensive, whether with 

 cement or asphalt, but almost all soil can be puddled with animals, 

 and many soils w r ill puddle themselves well enough in a little while. 

 As an inch will cover an acre half an inch deep in twenty four hours, 

 and half an inch w r ill wet about five inches in depth, the seepage on 

 any very tight soil would not amount to much compared with the 

 increased value of the greater irrigating head. When this reservoir 

 raises the temperature 15 or 20 degrees, the combined effect will 

 generally justify considerable size in the reservoir. One can 

 generally be built by home labor and nee^ not be deep enough to 

 require very much care with the outlet pipe. 



"Many think the evaporation from a large reservoir is too great 

 for economy. During very hot weather it would average about one 

 miner's inch a day from the surface of one acre. In cool summer 

 weather about half that. If it were very shallow this would be 

 increased and there would be still more loss if there were very much 

 vegetation in it. But even these losses, as well as the cost, will be 

 generally more than offset by the effect of the increased head and the 



