^ / /i H A 



LANDS THAT MAY BE IRRIGATED. 21 * t 



TEE ^CALlFO/Osj 



c H A p n 



THE AMOUNT OF WATER NEEDED FOR IRRIGATION. 



There are but few fields or gardens so situated that 

 water may not be applied to them in one or more of the 

 methods which have been at one time or another, or may 

 be, adopted to irrigate the soil. The only prerequisites 

 are, the supply of water and the power to bring it into 

 such a position that it can be spread over the land. 

 Where, however, the cost of procuring and applying 

 water will be greater than the profit to be derived from 

 its use, it may be concluded that there irrigation is im 

 possible. There are some lands situated so far above the 

 supply, that the cost of raising the water and of providing 

 reservoirs to receive and hold it until it could be distrib 

 uted, would be greater than the value of any benefits 

 likely to accrue from its use. There are others so low 

 that to irrigate them, without at the same time provid 

 ing for a perfect system of sub-soil drainage, would be to 

 turn them into marshes and ruin them for agricultural 

 purposes. In these cases, if the cost of drainage should 

 exceed the value of the benefits received from the land, 

 it would manifestly be impossible to irrigate them. 



On the other hand, where these hindrances do not 

 exist, there are very few physical features of the land 

 that could stand in the way of irrigating it. Level lands, 

 or lands level in one direction with a slope in another; 

 lands sloping in every direction ; hill sides either of mod 

 erate slope or such abrupt slope that terraces must be 

 made to retain the soil ; all these may be prepared by 

 simple methods of engineering to receive any supply of 

 water that can be economically brought to them. Equally 

 those lands which happen to lie beneath the level of a 

 stream or tidal river ; a marsh, submerged wholly or par- 



