GATE STRUCTURES FOR IRRIGATION CANALS. 
35 
drop in the structure 2 feet. The side walls through the bank are 5 
feet apart and 18 inches thick, carrying a bridge slab 6 inches thick 
for a roadway 6 feet wide. This slab is reinforced the short way 
with half-inch rods placed 6 inches on centers. Below the bridge 
the lower wings, which are 6 inches thick, slope down from the bank- 
crest height to 6 feet above the floor. 
The vertical sides of the water cushion are 10 feet high, 18 inches 
thick, and flare at an angle of 30° with the axis of the ditch. Below 
the cushion the lateral is lined for a distance of 10 feet with 6 inches 
of concrete, the sides sloping up at J to 1 from a bottom width of 8 
feet. The earth section below the lining shows signs of erosion for a 
short distance, so it probably would have been better to construct the 
water cushion about 5 feet longer or line the lateral 8 or 10 feet more. 
There is a 4-foot cut-off at the canal end of the structure and a 
3-foot cut-off at the lower end. Each of these is 1 foot thick. The 
gate proper is of sheet steel with a rack-and-pinion lift. 
This structure contains 111.7 cubic yards of concrete mixed in a 
1 : 2-J : 5 proportion for plain and 1:2:4 proportion for reinforced 
concrete. The material in the concrete cost $9 per yard, and the 
labor of concreting, excluding the excavation, was $2.29 per yard. 
Form lumber, on a basis of using it four times, cost 57 cents per 
yard. The excavation was in wet material, about one-half being 
cemented gravel. Water and cement were hauled one mile. The 
itemized cost is as follows : 
Itemized cost data for low line lateral Jieadgate. 
Item. 
Time or quantity. 
Rate. 
Amount. 
Excavation: 
Foreman 
$17. 50 
Laborers 
69.00 
Team 
7.50 
Carpenters 
2.00 
Material: 
Cement 
133 barrels 
$2.10 per barrel 
279. 30 
Lumber 
5,000 feet b. m.. 
27.50 
Sand 
$4.80 per yard 
220. 80 
Gravel 
$6.70 per yard 
402. 00 
42 cubic yards /. . 
42.00 
Gravel J 
$1 per yard 
6.00 
Steel 
3.20 
Hauling 
25.00 
Concreting: 
Foreman 
32.00 
Laborers 
135. 00 
Carpenters 
64.00 
Helper 
24.75 
Concrete structure 
1,357.55 
100. 00 
Steel gate 
Total cost of structure 
1,457.55 
Screening some old gravel at site. 
