UNITS OF WATER MEASUREMENT 



227 



fall to be from two to three inches, a deficiency of one 

 inch amounts to from one-half to one-third of the total, 

 which must be a serious hindrance to crop growth, 

 without the most careful soil management. 



On light, sandy soils, and with careless tillage in 

 general, the above figures indicate that there may fre- 

 quently be occasion for irrigation. The annual rainfall 



Fig. 73. Flume for measuring miner's inches. 



is ample for full crop production, if it could all be 

 utilized. 



Many units are used in the measurement of water 

 for irrigation. The two most common methods of stating 

 the quantity of water used are: (1) In depth of water 

 over the area, as acre-inches or acre-feet. (2) A given- 

 sized stream flowing through the growing season. The 

 two most common units under the latter system are the 

 second-foot and the miner's inch. It is frequently esti- 

 mated that a flow of a second-foot of water one cubic 



