IRRIGATION FARMING. 



cost. Many of them have been built by the efforts of a 

 few farmers acting originally in partnership, and have 

 been enlarged from year to year as more land was 

 brought under cultivation and population increased. 

 Farmers as a rule do not keep account of the amount 

 ot labor or money expended on such works, and in 

 cases where they own the irrigating ditches they do 

 not take into consideration the labor expended upon 

 the ditches at times when the farm work is not 

 pressing. When contractors figure on the cost of 

 building a canal exclusive of the rock work they usually 

 calculate the expense of excavating at from ten to fifteen 

 cents a cubic yard of earth removed. The actual 

 cost of this work has of later years been reduced, by 

 means of the big grading machines, to the minimum 

 of three or four cents a cubic yard. In arriving at the 

 cost of canal construction in various parts of the West, 

 the government officials have compiled the following 

 tabulated computation : 



AVERAGE COST PER MILE OF CONSTRUCTING IRRIGATING CANALS 

 AND DITCHES. 



Form and Capacity. To get the greatest possi- 

 ble velocity the ditch should be in the form of half a 

 pipe or a pipe split in half lengthwise. This would re- 

 quire the width of the ditch at the top to be exactly 

 twice its depth in the center. In other words, it would 



