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IRRIGATION In 1913 water was available from the Government irrigation systems for 1,290,107 acres, and 942,272 acres were under contract to receive water. Conservative engineers estimate that there are 30,000,000 acres of our desert which may be reclaimed.

The Salt River project in Arizona is one of the best known of the Government irrigation projects. Its principal structure is the Roosevelt dam, 280 feet high and 1,125 feet long on top. The storage capacity of the reservoir created by this dam is 1,284,000 acre-feet, or sufficient to cover 1,284,000 acres one foot deep. It supplies water to about 190,000 acres of land in the vicinity of Phoenix, and power created at the dam site is transmitted electrically about 100 miles down the valley to pump water to additional areas.

Gunnison Tunnel, a six-mile bore through the Vernal Mesa in Colorado; Shoshone dam, 328 feet high, in northern Wyoming; and Laguna dam, a weir nearly a mile long across the Colorado River 12 miles above Yuma, Arizona, are other notable engineering works of the Service. A unique pumping project has been built in western North Dakota, where the pumps are placed on floating barges which accommodate themselves to changes in the river banks and in the water level. The pumps force water through pipes with flexible joints to settling basins on the shore. Power is generated with lignite mined from a Government coal mine in the vicinity.

Two of the largest structures erected by the Reclamation Service are under construction at the present time, the Elephant Butte dam near Engle, New Mexico, and the Arrowrock Dam in southern Idaho. The Elephant Butte Dam will be 290 feet high and 1,200 feet long on top. The reservoir created by this dam will have a superficial area of 40,080 acres, and a capacity of 2,627,700 acre-feet. It will serve a double purpose in protecting the lower valley from destructive floods and insuring an ample water supply for 180,000 acres of land in New Mexico, Texas and Mexico. The Arrowrock dam in Boise River canyon will be 350 feet high, and its cubical contents will be about 500,000 cubic yards. Its purpose is to store the flood and excess waters for the irrigation of about 200,000 acres of land in the vicinity of Boise.

A brief summary of the work of the Service shows that it has built 7,961 miles of canals and ditches, 401,000 feet of flumes, 120,000 feet of culverts, and 831,000 feet of pipe lines; its excavations amount to more than 99,000,000 cubic yards; it has built 697 miles of wagon roads and 51 miles of railroad, and has in operation 2,331 miles of telephone lines; it has developed 32,466 horsepower, and built 351 miles of electric transmission lines. Its tunnels have a length of over 22 miles, its canal structures number 50,233, and it has built 3,339 bridges, and 82 miles of dikes. The capacity of its reservoirs amount to 5,051,210 acre-feet.

As a result of this work it is estimated that

100,000 people are already established in homes on the Government projects. Flowing out of the engineering activities are countless beneficial factors which are tending to eliminate isolation, to promote betterment of social and educational conditions, and to dignify agriculture as a profession. Centralized graded schools, trolley lines in the farming sections, country clubs and assembly halls, churches and organizations for producing and marketing products, co-operative creameries, canneries, laundries, etc., are among the numerous agencies being developed to make rural life attractive and complete.

The government aid is not intended to discourage or interfere with a continuance of private enterprise, and the government is supposed to enter only fields where private capital is not strong enough to develop the opportunities properly or where, if left to individuals, the possibilities would be only partly utilized.

Engineering skill has performed wonders in irrigation construction; great dams and reservoirs have been built, mountains tunneled, canyons spanned depressions bridged, rivers diverted, and waters conducted in devious ways for long distances and by these means and by canals been made available to the land. Naturally irrigation has been most associated with arid regions; but when pursued in many of the more humid sections, results have been obtained that proclaim its widespread beneficence.

Storage Reservoirs. The storage reservoir has come to be an essential part of irrigation schemes, and water for this purpose is mostly obtained from streams having their sources in the forests and melting snows of the mountains. In the springtime and early summer these streams are converted into swollen torrents, and in the earlier years their waters hurried to the oceans, unused, but they are being more and more diverted and stored to reclaim the dry lands. The early systems depended mostly upon the natural flow of the streams for water-supply, diverted by dams and canals, but in the growing season the streams were lowest, and, when water was most needed, it often was not available. This condition resulted in the extensive building of dams and storage reservoirs, in which are collected the flood-waters, thus not only insuring a supply when most needed but making possible the reclamation of vast additional areas hitherto accounted worthless. From these artificial lakes and reservoirs the waters are conducted into main canals and thence through lateral channels to the farms. A feature of the great enterprises undertaken by the government is the erection of works to collect and store these immeasurable flood-waters, making them available for distribution as needed. At the time of the passage of the reclamation act, however, irrigation systems had already been built along nearly