484 ANNUAL EEPOET SMITHSONIAN INSTITUTION, 1915. 



35,000 acres. An additional diversion is now under construction in 

 this valley controlling 60,000 acres. 



In El Paso Valley the old Franklin Canal has been purchased and 

 enlarged. This passes through the city of El Paso, where it has 

 been concrete lined to give increased capacity. About 29,000 acres 

 will eventually be watered. 



Other tracts to be reached lie in Rincon and Palomas Valleys. In 

 all, the project contemplates the irrigation of about 155,000 acres in 

 the United States. The soils are very fertile and the market facili- 

 ties unusually good. Alfalfa yields 3 to 6 tons per acre and 

 the price averages above $10 per ton, reaching at times as high as 

 $15 or $20. Vegetables, truck, and fruit are very successful, and the 

 27,000 acres harvested in 1914 under the Government works yielded 

 crops worth well over a million dollars. 



UMATILLA PROJECT, OREGON. 



Former reports have described the portion of the Umatilla project 

 lying -east of the Umatilla River, supplying 25,000 acres by means 

 of a canal system heading in Cold Springs Reservoir, which is filled 

 by a feed canal from the Umatilla. Recently an extension to the 

 project has been under construction west of the river, adding about 

 11,000 acres to the irrigable area. The work includes the Three Mile 

 Falls Diversion Dam, a main canal heading at the dam, and a system 

 of laterals carrying water to each farm. 



On the older part of the project about 5,000 acres are now in 

 crop. The conditions are favorable for the growth of fruit, which 

 is gradually becoming the principal product. Good yields are also 

 obtained from alfalfa, grain, vegetables, and truck crops. 



One of the difficulties encountered in the operation of the Umatilla 

 project is due to the fact that portions of the irrigable land are very 

 sandy, causing the irrigation water to escape rapidly to a depth 

 where it is not available to the plant roots. To sustain crop growth 

 on such land it is necessary to irrigate it frequently and the " duty " 

 or quantity of water required per acre is excessive. In some cases 

 the duty may be as low as 15 or even 20 acre-feet per acre, i. e., 

 during the irrigation season the total application to the field is 

 equivalent to a depth of 15 or 20 feet. The average duty on the Uma- 

 tilla project is now about 7 kcre-feet, and for all the reclamation 

 projects the average is between 2 and 3 acre-feet per acre. 



The great importance of this subject is realized when it is remem- 

 bered that usually the available water supply and not the available 

 land limits the extent of a project and largely determines the cost 

 per acre. Also the cost of operating the works and guarding against 



