GATE STRUCTURES FOR IRRIGATION CANALS. 



17 



it was necessary to build high curtain walls above the openings in 

 order to bulkhead out the surplus waters. The canal below the struc- 

 ture is 20 feet wide on the bottom, carries water 6 feet deep, and has 

 side slopes 1 to 1. The structure as shown contains 197 cubic yards of 

 concrete, hand-mixed in a ratio of one part cement to seven parts 

 river gravel taken bank run. The unit cost of the concrete was about 

 $9.50 per cubic yard. The cement cost $1.50 per barrel f. o. b. Pueblo, 

 while the cost of the gravel was practically nothing but the digging 

 and the hauling. Earth and shale excavation cost 40 cents per cubic 

 yard for 110 yards. 



Scale in feet 



Orsrted by Frpd C 5ccbey 



•Rods-3C-C 



Fig. 1. — Headgate, Doyle Arroyo feeder, Napesta Ditch & Reservoir Co., Colorado. 



The total cost of the structure, including the steel gates, which were 

 made in Pueblo, was about $2,500. The lifting device is the double 

 stem, bolted together with spool spreaders, a type which is much used 

 in southeastern Colorado. 



HEADWORKS, NORTH LARAMIE LAND CO. CANAL, WYOMING. 



A good example of modern construction for a headgate serving a 

 small canal is that of the North Laramie Land Co. (PL V, fig. 1.) 

 A simple and efficient form of temporary diversion dam raises the 

 water sufficiently to secure the desired discharge into the canal. This 

 canal is 14 feet wide at the water line, 8 feet wide on the bottom, and 

 45613°— Bull. 115—14 3 



