.METHODS OF APPLYING WATER. 129 



must follow as soon us the ground is in good working 

 order. A bird's-eye view of a well-planned irrigated 

 farm is given in Figure 44. It will be observed that the 

 land lies on a gentle slope over which water may be 

 spread with easy gradient and in equal ratio to all por- 

 tions. The various plats may or may not be fenced, ac- 

 cording to the owner's judgment-, and in most cases 

 fences are obsolete except for pasturage. 



In the use of water it may be estimated that 1000 

 gallons of water a minute will irrigate an acre an hour 

 of row crops, such as potatoes, corn, etc., and it requires 

 two men to handle this amount of water properly, as it 

 is equal to ninety miner's inches. An inch of water 

 nominally will cover an acre of land. The cost of irri- 

 gating an acre will vary all the way from 75 cents to 

 -$1.50 for a season of 100 days. Water rates in Colorado, 

 where water is rented, are usually $1.50 an acre per annum, 

 and this rate is fixed by the county commissioners. It 

 is a good rule, in the arid region at least, to have the 

 water running constantly on some portion of the farm, 

 although this is not an inflexible rule on account of the 

 wastefulness which it entails. Old irrigators never shut 

 off the water when a shower comes up. In all irrigating 

 work it is well to imitate nature as nearly as we can. It 

 will be well to remember in this connection that the soil 

 must be adapted to the way, which on the other hand is 

 itself not adapted to all soils. 



Subsidiary Canals. Where the supply canal is 

 large and the banks thick, it is well to divert the water 

 from it in only one place. A shallow subsidiary canal may 

 be made parallel with it, into which sufficient water is 

 allowed to flow to supply the laterals. It is very easy 

 for a stream to get beyond the control of the irrigator, 

 and he must watch the aperture in the canal bank 

 closely and take measures to prevent this. In the most 

 primitive forms of irrigation the shovel is relied upon 

 9 



