EECLAMATION OF ARID LANDS BEADLE. 483 



Other recent work includes smaller structures, . drains, and ex- 

 tension of the distribution system, which serves lands near the 

 town of Fallon. About 65,000 acres are now under ditch and 

 the area may be considerably increased. With additional storage 

 and canal systems 200,000 acres may ultimately be reclaimed. The 

 locality is extremely arid, with an annual rainfall of about 4 inches, 

 insufficient for any crop growth. Under irrigation the soil gives 

 good yields of alfalfa, grain, and vegetables. 



CARLSBAD PROJECT, NEW MEXICO. 



Near Carlsbad, New^ Mexico, two dams have been built across the 

 Pecos Elver, forming storage basins, and from the lower one of 

 these a canal system has been excavated to supply 25,000 acres of 

 land surrounding Carlsbad. The project was completed in 1912, 

 since which about 13,000 acres have been irrigated, producing good 

 yields of alfalfa, cotton, grain, truck, and fruit. 



RIO GRANDE PROJECT, NEW MEXICO AND TEXAS. 



This is an interstate and international project, using the w^aters 

 of the Kio Grande to irrigate land in New Mexico and Texas and 

 supplying Mexico at the international boundary a quantity of 

 water fixed by treaty. 



The largest irrigation reservoir in the world is formed by the 

 recently completed Elephant Butte Dam (pi. 11, fig. 1), spanning 

 the river canyon near Engle, N. Mex. This structure is of rubble 

 concrete, 300 feet from the bottom of the foundation to the crest, 

 which extends 1,250 feet between abutments. This gives a reservoir 

 capacity exceeding 2,500,000 acre-feet, or 800,000,000,000 gallons. 

 One of the problems connected with storage on the Rio Grande is 

 due to the great amount of silt carried by the stream, and this large 

 reservoir capacity is expected to care for years of silt accumulations, 

 which are further provided for by numerous openings through the 

 dam for sluicing (pi. 11, fig. 2). 



From the reservoir the water passes down the river channel to 

 the irrigable lands, which are located in a series of narrow valleys 

 along the stream in New Mexico and Texas. The development of 

 each valley involves a diversion dam, main canals on either side of 

 the river, and the necessary distributaries and structures. A number 

 of private canals watering small areas will be embraced in the general 

 development. 



In the Mesilla Valley the Leasburg Dam and main canal have thus 

 been built to connect with several community canals covering about 



