186 ANNUAL EEPORT SMITHSONIAN INSTITUTION, 1910. 



of water is 4 acre-feet per annum at the farm. About 60,000 acres 

 are suitable for raising apples and peaches. Orchard lands produce 

 as high as $500 per acre in the valley. The bottom lands, comprising 

 from 80,000 to 90,000 acres, are adapted to the growing of alfalfa 

 and sugar beets. 



Idaho, Boise project. — When fully developed the Boise project 

 will reclaim approximately 243.000 acres and will supplement the 

 supply for about 79,000 acres of land in the fertile valleys of the 

 Boise and Snake Rivers in southwestern Idaho. The general ele- 

 vation is 2,500 feet above sea level, and the temperature ranges from 

 28° below to 107° above zero. The thermometer rarely reaches zero, 

 however, and freedom from wind marks the winter months. The 

 summers are long, sunshiny, and warm, and with irrigation promote 

 the most rapid vegetable growth. The soil is largely of volcanic 

 origin, free from rocks, easily worked, and rich in the necessary 

 mineral constituents. With rotation of crops and the addition of 

 vegetable mold it becomes very productive. 



Farms in a good state of cultivation produce 3 to 8 tons of alfalfa 

 per acre in three cuttings, 2 to 5 tons of clover, 50 bushels of wheat, 

 and 75 bushels of oats. After the last cutting the fields furnish 

 pasturage. Both clover and alfalfa seed yield good crops. Apples, 

 prunes, and small fruits produce well and are shipped in quantities 

 to eastern markets. Sugar-beet culture is also profitable. 



Storage reservoirs on the headwaters of the Boise River are 

 necessary and are being built. A diversion dam (pi. 5, fig. 1) has 

 been completed on Boise River, 8 miles above Boise, diverting water 

 into a canal irrigating lands under it and supplying Deer Flat reser- 

 voir in the vicinity of Xampa, which has a capacity of 186,000 acre- 

 feet. The watershed area of the Boise River is 2,610 square miles; 

 the average annual rainfall on watershed is 25 inches, and the 

 estimated annual run-off of watershed is 2,190,000 acre-feet. The 

 average rainfall on the irrigable area is 12.7 inches. 



Idaho, Minidoka project. — The irrigable area under the Mini- 

 doka project consists of about 76,700 acres under a gravity system 

 and 48,000 acres under a pumping sj^stem. The lands lie on both 

 sides of Snake River, in the southern part of Idaho, in Lincoln and 

 Cassia Counties. 



The works include a diversion, power, and storage dam on Snake 

 River at a point about 6 miles south of Minidoka, Idaho, and two 

 canal systems (pi. 5, fig. 2), one on each side of the river, heading at 

 the diversion dam and covering lands in the vicinity of Acequia, 

 Rupert, Heyburn, and Burley. Power is developed at the diversion 

 dam for generating electrical energy for pumping water to lands on 

 the south side of the river too high to be reached by a gravity system. 



