320 THE IRRIGATION PROBLEM. 



August. The streams from the coast range have no snow reservoirs 

 of much extent, and are generally dry in summer. 



Let us assume that the streams on the east side of the valley are 

 well supplied with water for two hundred days in the year, and, to 

 make up for the overestimate on this point, let us neglect their flow 

 for the remainder of the year. 



How much land ought a cubic foot of water, supplied every second 

 for two hundred days, to irrigate? 



We will make a further supposition that the water is used for four 

 teen hours out of the twenty-four. Irrigation at night is practiced 

 in other countries, and we may be assured that in seasons of scarcity 

 it will be here, if it shall prove necessary to save the crops. One 

 day s supply will put twelve inches of water over an acre, or two 

 inches of water over six acres, and in two hundred days a supply of 

 a, cubic foot per second, will cover two hundred acres with twelve 

 inches of water. 



Wheat planted in October or November on summer-fallowed land, 

 well watered when the rivers are high, will probably make a good 

 crop without farther watering, except what it gets from the winter 

 rains, even when they prove scanty. 



Wheat planted in January or February will probably need one or 

 two irrigations, or three inches each to make a crop. Wheat or 

 barley planted later, and with irrigating facilities, (there seems to 

 bo no reason why, in these hot valleys, the sowing-time may not be 

 extended to April,) will probably ripen with twelve inches of water 

 judiciously applied. We know that good crops of wheat are raised 

 without irrigating, when there is a rain-fall of twelve inches, or even 

 less, which comes at the required times. 



On the tule or reclaimed lands, barley sowed after wheat harvest 

 has been gathered comes to maturity. 



The water required for cotton will probably not exceed that neces 

 sary for wheat. Bice cultivation is so unhealthful that its introduc 

 tion into California will hardly be looked upon with favor. 



Alfalfa, if cut five times for hay, will require twelve inches of 

 water or more, depending on the nature of the soil; this in addition 

 to the usual rain-fall. 



There is another point to be considered. The whole of the land 

 commanded by the canal will not be irrigated; some of it will be 

 waste or unsuitable for cultivation; some will be fallow, and if we 

 add the areas taken up by the roads, fences, buildings, farm-yards, 

 etc., we ought, according to experience elsewhere, to deduct one 

 fourth, at least, from the irrigable lands. This deduction, we as 

 sume, will make up for any kind of cultivation, such as gardens, 

 orchards, etc., requiring larger supplies of water. 



Our opinion is, therefore, that a reasonable allowance for the land 

 commanded by the canals is one- cubic foot a second for each two 

 hundred acres. 



In seasons when there is a great surplus of water, there can be no 

 objection to a more liberal use of it, but it seems to us indispensable 

 that the State should lay down a general rule. There ought to be 

 an established allotment, which may vary in different districts. The 

 cultivators who came first ought not to be allowed to appropriate 



