IRRIGATION IN FIELD AND GARDEN. 



BY PROFESSOR E. J. WICKSON. 



(Reprinted from Farmers' Bullettin No. 138, issued by U. S. Dept. of Agriculture.) 

 MEASUREMENTS OF SMALL STREAMS. 



Before discussing sources of supply it is important to cite a meth- 

 od by which the quantity of water available in a small brook, outflow 

 from a large spring, or discharge from a drainage system may be 

 easily ascertained. Without an estimate of the supply, reservoir 

 building or the determination of the area which can be irrigated is 

 merely guesswork. Recourse to the miner's method of measurement 

 is best for such sources as^vill frequently be drawn upon for the farm 

 supply. It consists in causing the water to flow through an opening, 

 the capacity of which is known, and which is readily capable of ad- 

 justment to the flow in any case. 



A simple form of this device and its use is shown in fig. 2. The 

 illustration represents a board 1 inch thick, 12 inches wide, and about 

 8 feet long. The opening is 1 inch wide and 50 inches long, and the 

 distance from the top of the board to the top of the opening is exactly 

 4 inches on the upstream side. On the downstream side the opening 

 is beveled so that the hole presents sharp edges to the stream. A 

 sliding board is hung upon the top of the first board with a strip 

 screwed along its upper edge, this sliding board being wide enough to 

 cover the opening on the upstream side. In the slot there is a closely 

 fitting block made to slide on the beveled edges, and fastened by a 

 screw to the sliding board. It is obvious then, that when the sliding 

 board is moved backward or forward, by means of its end, which is 

 extended for a handle, the block moves in the slot and determines the 

 length of the opening. 



In operation the board is placed in the stream as shown in the 

 figure, so as to dam the flow completely, and the sliding board is 

 moved backward or forward until the water is all passing through the 

 slot, the water being kept up to the top of the board, or 4 inches 

 above the top of the opening. The length of the opening measures 

 the number of miner's inches of water flowing through. If the flow 

 is too great to pass through the opening 1 inch wide the opening may 

 be made wider, the water still to be kept 4 inches above the top of the 

 opening. The laws of several States provide that in devices for 

 measuring water for sale by the miner's inch the opening shall be 6 

 inches high, and shall be provided with a slide as shown in fig. 2. 

 The number of miner's inches then discharged is equal to the number 



