258 FARM DEVELOPMENT 



by law in most of the western states, the conditions dif- 

 fering in different states. 



In Figure 153 is shown the construction of a box for 

 measuring the flow of water in miners' inches. Formulae 

 are also used for the calculation of the amount of water 

 flowing from weirs of a given construction with the water 

 above standing at a given height. The United States 

 Department of Agriculture, the State experiment sta- 

 tions of Colorado, Wyoming and other states, have pub- 

 lished bulletins treating of the measurement of irriga- 

 tion water, which can be 

 secured by those needing 

 detailed information. 



As a unit of measur- 

 ing water for irrigation 

 purposes, the miner's 



Figure 154. Plank scraper for opening irrigation inch is not SO gfenerallv 

 ditches. <=> * 



used as the cubic foot 



per second, or the acre foot. In recording measure- 

 ments of large quantities of water, the miner's inch, 

 although fairly accurate, is too small a unit. 



" The miner's inch is a unit of rate of the discharge of 

 water expressed in terms of a standard orifice or outlet 

 opening, usually i inch square, and a standard head."* In 

 different states this head varies from 3 to 9 inches, but 

 the head most commonly used is 6 inches. " Under a 

 head of 6 inches and coefficient of 0.62, the discharge 

 through a i-inch orifice would be 0.0244 cubic feet per 

 second or 0.183 United States gallons (of 231 cubic 

 inches). Usually the orifice is of fixed depth and ad- 

 justable length." (See Figure 153.) The standard head 

 of 6 inches (in sketch the head is marked by block B, 6 

 inches long and tacked on side of box), or whatever head 

 it may be, is maintained by the gate C. This gate is 

 placed securely in the ditch bank and raised or lowered 



* Trautwine's Engineer's Pocket Book. 



