194 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1910. 



is taken from this by means of a tunnel (pi. 9, fig. 2) through a low 

 range of hills and carried out by gravity to the fertile areas sur- 

 rounding the lakes lying at lower altitude. The canals may be ex- 

 tended into areas in the northern end of California. 



The lower lakes or marshes are supplied in part by waters origi- 

 nating in California, which flow northerly into Oregon. By storing 

 the floods near the headwaters these lower lakes may be reduced 

 in area and the available lands thus uncovered may be irrigated 

 by the waters from Upper Klamath Lake. The project has many 

 ramifications, waters derived from Oregon being used to irrigate 

 lands in California, and vice versa. The first unit of approxinuxtely 

 30,000 acres has been placed under irrigation at a cost of $30 per 

 acre. 



The general elevation of the irrigable area is 4,100 feet above sea 

 level. The temperature ranges from 5° below zero to 100° above. 

 The soil is exceedingly fertile, being decomposed basalt mingled with 

 lake-bottom deposits. The duty of water is 1.8 acre-feet per acre per 

 annum. The principal crops grown are alfalfa, wheat, oats, barley, 

 rye, vegetables, and some deciduous fruits ; potatoes are an important 

 crop. The climate is especially adapted to dairying and stock rais- 

 ing, and forage crops grow to perfection. 



The entire watershed area is 3,700 square miles, and the estimated 

 run-off 2,124,000 acre-feet. The annual average rainfall on the 

 watershed area is 20 inches, but the rainfall on the irrigable area is 

 only 15 inches. 



South Dakota., Belle FourcJie project. — The engineering work on 

 this project has resulted in the construction of one of the largest 

 earth embankments in the country, built in a depression occupied by 

 Owl Creek. It is 115 feet high, 20 feet wide on top, and more than a 

 mile long (pi. 10, fig. 2). The reservoir thus created will be filled 

 with water by an inlet canal (pi. 10, fig. 1) from the Belle Fourche 

 River and will be the largest lake in the State. The watershed area 

 is 4,270 square miles, the average annual rainfall on watershed 20 to 

 30 inches, and the estimated annual run-off 363,000 acre-feet. 



When completed this project will reclaim about 100,000 acres of 

 land lying north and northeast of the Black Hills. Water is now 

 available for about 47,000 acres. The farm unit on public lands is 

 80 acres, except within 2 miles of townsites, where it is 40 acres. 

 Settlers are required to pay a building charge of $30 per acre and an 

 annual charge of 40 cents per acre for operation and maintenance. 



The average elevation is 2,800 feet above sea level. The climate is 

 delightful, with little snow in winter, the temperature ranging from 

 20° below to 95° above zero. As in other parts of the arid region, 

 the sensible temperature does not vary as widely owing to the dryness 

 of the atmosphere. Fruits, such as apples, cherries, plums, and small 



