GATE STRUCTURES EOR IRRIGATION" CANALS. 
41 
figure 2, shows one of these gates before the canal bank has been 
completed. The roofing over the box will serve as a bridge. The 
wings of these gates extend at right angles to the flume a distance 
equal to the height of the flume. The upper wings and the cut-off 
wall under the upper end of the floor extend 2 feet below the floor, 
as a rule, but this dimension is adjusted to suit local conditions. The 
flume is 12 feet long, 4 feet or more high, and between 4 and 10 feet 
wide.. The radial gate face is made of a double thickness of 1-inch 
redwood, the wooden radial arms carrying the thrust of the water 
from near the center of pressure on the gate when the canal is full 
to the 4-inch galvanized iron pipe axle extending across the flume 
Drawn t>y 5 c obey. 
Section at A 
Fig. 10. 
-Reinforced concrete delivery gate from main canal, California Development Co. 
California. 
about 2 feet in front of the rear end of the flume. This gate is more 
easily lifted when the water is in the canal than when there is no 
water, as the hydraulic pressure thrusts the gate against the axle 
and tends to float the gate. An iron bar with a handle at the free end 
is attached to the gate so that the latter may be lifted easily and 
locked in position by locking the bar over a hasp loop. 
This type of construction might be readily adapted to lateral and 
even branch canal gates, as the forms are extremely simple, yet the 
structure is remarkably efficient. 
