12 THE IRRIGATION AGE. 



acres irrigated, without regard to the volume used on these acres, are 

 a temptation to extravagance on the part of the irrigator. On the 

 other hand, contracts providing payment proportioned to the quantity 

 delivered and for delivery in amounts which can be most efficiently 

 distributed, cannot fail to lead to economy in the use of water, and 

 consequently to a high duty. Under such a system the irrigator is 

 benefitted by his saving and pays for his waste. Such contracts can 

 only be employed in connection with a system of rotation in delivery 

 to irrigators. This rotation benefits the canal company as well as the 

 irrigator, because it lessens the loss from evaporation and seepage. 

 If a canal is large enough to supply 100 farms it will still supply them 

 whether they are all irrigated every day or one-half given twice the 

 usual supply every other day. On large canals the economy of such 

 rotation is very great. It would permit of dividing canals in sections 

 and supplying the lands under them, one section at a time. A canal 

 60 miles long could be divided into three sections of 20 miles each, and 

 all the loss from seepage and evaporation on the lower forty miles 

 saved while the irrigators of the upper section were being supplied. 

 In the same way, by keeping the full supply in the canal, water could 

 be rushed through to users under the lower section with less loss than 

 where the flow is depleted by laterals along the route. The greatest 

 saving in rotation, however, would be made in the laterals. Where 

 water is permitted to slowly dribble through continuously the waste 

 is enormous. By devising a system for grouping the laterals and 

 inducing the irrigators therefrom to take water by turns, the engineer 

 can do as much toward raising the duty obtained as the actual culti- 

 vator. 



The co-operation of the western states with the Department of 

 Agriculture in making this broad investigation of the duty of water 

 will be of immense value just now when the time is ripe for a western 

 awakening which will induce the government to enter into actual 

 appropriations for the construction of irrigation works which will 

 place under cultivation vast additional areas. It is important that all 

 the light possible should be thrown upon the subject. 



