GATE STRUCTURES FOR IRRIGATION CANALS. 
25 
to a " V " notch, and the opening finally is closed completely when 
the slides lap each other to the extent of 3 inches. As the weir 
is shortened the discharge increases over the formula discharge as 
soon as the depth exceeds about one- fourth the length. 
The stationary weir plate A is bolted into the concrete wall of 
the box and extends 3 inches inside the edge of the concrete at both 
,, „ V2 hole-" 
3 /8 Eve 80 It — 
Fig. 4. — Three-way division box of Consolidated Lower Boulder Reservoir & Ditch Co., 
Colorado. 
sides and at the bottom. Bolted to the wall and extending across 
the box are two guides — B-B — formed of pieces of wrought iron, 
the upper one 7 feet 1 inch long and the lower 6 feet 4 inches long. 
Each is 2 inches wide and one-quarter inch thick. The guideways 
are formed by riveting the above pieces to a filler piece of wrought 
iron of the same length as B-B, but 1 inch wide and one-half inch 
45613°— Bull. 115—14 4 
