196 ANNUAL, REPORT SMITHSONIAN INSTITUTION, 1910. 



$65 per acre of irrigable land, and the operation and maintenance 

 charge at present amounts to $1.50 per acre per annum. 



Washington, Yakima project. — On the eastern side of the Cascade 

 Mountains in the State of Washington is a succession of valleys in 

 the upper part of the drainage basin of the Yakima River. It is 

 estimated that with storage the water supply is sufficient for about 

 460,000 acres of land. Dams are being built at the outlets of several 

 mountain lakes, the capacity of which when ultimately deyeloped, 

 Avill total 1)30,000 acre-feet. The development of a comprehensive 

 system of irrigation in Yakima Valley will be accomplished by the 

 successive construction of several units of a general project, the work 

 being gradually extended to embrace the entire irrigable area. 



Tieton unit : The lands under this unit are in Yakima County, near 

 the city of North Yakima. The engineering features are difficult and 

 expensive. For 12 miles the main canal (pi. 11, fig. 2) is constructed 

 along the steep sides of the Tieton Canyon, and in five places the can- 

 yon walls are tunneled, the total length of the tunnels being more than 

 .'. miles. The lands to be irrigated are rolling and the distribution 

 system is also expensive. In order to replace in the Xaches River 

 the water needed to supply prior appropriations, it was necessary for 

 the Government to construct storage works at Bumping Lake, Wash., 

 on the headwaters of that stream. The lands in the vicinity, not 

 more favorably situated for fruit raising, range in value from $300 

 to $1,000 per acre. The elevation is from 1,300 to 2,100 feet above 

 sea level and the temperature ranges from —21° to 102°. Although 

 a great variety of crops could be grown the lands are so valuable 

 that it is probable the principal crops will be fruit and hops. 



Sunnysicle unit: The first unit of this system is now available 

 for 11,590 acres of land in addition to the 40,000 acres under the 

 old canal. The cost of water right is $52 per acre, payable in not 

 more than 10 annual installments, and the operation and mainte- 

 nance charge at present is 95 cents per acre of irrigable land. Work 

 on the system consists of the enlargement and extension of the exist- 

 ing Sunnyside Canal, which was purchased by the Government for 

 incorporation in a more complete system. The extension of this 

 will cover more than 50,000 acres of new land. The average eleva- 

 tion is 700 feet above sea level, and the temperature ranges from 

 —21° to 110°. The soil requires 3 acre-feet of water per acre per 

 annum. The farm unit is 40 and 80 acres of irrigable land. For- 

 age, hops, vegetables, and fruits are grown. The orchards of 

 Yakima Valley are famous for their yields of fine fruits. 



Wapato unit: The irrigable lands under this unit are in the 

 Yakima Indian Reservation. There are about 116,000 acres suscep- 

 tible of irrigation, 15,000 acres of which are now receiving water 

 during high-water periods through canal systems constructed for 



