20 

 Weir box and takeout from pipe line under pressure. 



Where the water is carried in a pipe line under pressure the water must 

 be delivered through a valve connected to the pipe. A good type of 

 measuring weir box will consist of a rectangular box placed around the 

 valve, with the measuring board placed at the top of one side of the box. 

 Fig. 11 shows a form of measuring box very similar to those installed on 

 the cement pipe lines of the irrigation system of the Fruitlands Irrigation 

 and Power Company near Kamloops. It consists of a concrete measuring 

 box placed around a takeout valve cemented to the pipe line. The valve 

 is obtained from the Kellar and Thompson Manufacturing Company of Los 

 Angeles. It is cemented over a hole cut in the cement pipe and regulates 

 the flow in the box. The box is rectangular, made of four concrete walls 

 4 inches thick, reinforced with strands of barb wire 6 inches apart. A 

 notch is formed in one of the side walls and a rectangular weir plate made 

 of galvanized iron strips is cemented in. To measure the depth of water 

 above the crest a metal bracket is cemented in the wall opposite the weir 

 opening and at the same level as the weir crest. The water which passes 

 over the crest discharges into the irrigator's flume or ditch. In case of an 

 earthen ditch it is necessary to prevent erosion or washing away of the soil 

 by the falling water by providing a receiving box or basin or by protecting 

 the soil with paving. 



Similar boxes' are used in southern California for delivering water from 

 cement pipes and iron pipes, and could well be used in British Columbia 

 for delivery from wooden pipes into the private flumes or ditches. 



Figs. 12, 13, 14 show the type of box used by the Gage Canal Company 

 of Riverside, California. The box is not built in place but is cast in wooden 

 forms. It consists of a floor slab and a tapering rectangular box. Fig. 14 

 shows the box in position connected to a private concrete flume. The in- 

 side of the box is 45 inches deep, 16 inches square at the top and 22 inches 

 square at the bottom. The walls and floor slab are 2 inches thick. The 

 opening for the weir is 12 inches high and 14 inches wide and the metal 

 weir plate which is cemented in this opening gives a rectangular notch 10 

 inches wide and 8 inches deep. 



Some irrigation companies in southern California simplify the construc- 

 tion of the weir boxes by using in place of the rectangular box, two or more 

 sections of large size cement pipe placed vertically around the valve. The 

 weir is formed by cementing a weir plate in a notch cut in the upper part 

 of the pipe. 



3. Miners' Inch Board or Box. 



The miners' inch as a unit of measurement has the disadvantages pre- 

 viously stated but the method of measurement associated with the miners' 

 inch unit has many advantages. 



1st. The irrigator can tell at a glance how much water is being de- 

 livered. It requires no computation or reference to tables. 



2nd. It is well adapted to measuring small volumes of water and is 

 fairly accurate if properly carried out. 



3rd. The flow through a miners' inch board is affected much less by a 

 change in water level than the flow over weir. A 10 per cent, rise of water 

 level will increase the flow over a weir by 15 per cent, while with a miners' 

 inch board the flow is increased only 5 per cent. 



