Irrigation and Hydro-electric Developments 

 feet, a maximum height of 280 feet and a volume 

 of 342,000 cubic yards of masonry. At the Granite 

 Reef on the Salt River is a rubble concrete divert- 

 ing weir which has a maximum height of 38 feet, 

 is 1000 feet long, and required 40,000 cubic yards 

 of masonry in its construction. 



The canals of the system aggregate 32 miles 

 with capacities greater than 800 cubic feet per sec- 

 ond; 64 miles with capacities 300 to 800 cubic feet 

 per second; 71 miles with capacities 50 to 300 cubic 

 feet per second, and 409 miles with capacities less 

 than 50 cubic feet per second. 



Tunnels: There are twenty-three tunnels con- 

 nected with the project works, aggregating two 

 miles in length. 



Power development: The project will ulti- 

 mately yield about 19,000 horse power; the present 

 power development exceeds 6000. 



The area under rental contracts for water or 

 other arrangements, including 10,000 acres of In- 

 dian lands, aggregates about 170,000 acres. 



The net cost of this Salt River Project was 

 reported in 1912 as $9,508,831. 



Yuma Project. — ^Another notable irrigation work 

 carried out by the United States Reclamation Ser- 

 vice, in which both Arizona and California are 

 interested, is the Yuma Project. Some ten miles 

 up-stream from Yuma a low masonry diverting dam 

 has been constructed across the broad bed of the 

 Colorado River and out over the adjacent sub- 

 mersible flats to the base of granite hills. The 

 length is over four-fifths of a mile. It sends enough 

 of the river to meet the irrigation requirements into 

 a large canal, which is crossed by the railroad just 

 west of the river at Yuma, where a glimpse may 

 be had of the entrance to the concrete inverted 

 siphon, probably the largest of its kind in the 

 world, which carries the canal water under the 

 Colorado River from the California to the Arizona 

 side. 



Truckee-Carson Project. — In Nevada the traveler 

 coming west on the Central Pacific may note on 

 the Truckee River, about twenty-five miles after 

 passing Hazen, a concrete structure which turns 

 water from this stream south into the region of 

 Fallon, near Carson Sink, where this supply, to- 

 gether with the water of the Carson River, is "being 

 used to conquer the desert. A feature of this 

 Truckee-Carson irrigation project is the great La- 

 hontan Dam on the Carson River, about eighteen 

 miles above Fallon. This is an earth and loose 

 rock structure with elaborate and well-constructed 



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