_Built by the U. S. Reclamation Service_
The Roosevelt Dam, Arizona, showing south bridge and spillway
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But the use of dams and canals to conserve and supply water for irrigation prevailed even in most ancient times. Extensive irrigation works were built in Egypt three thousand years ago, and in India, China, Persia, and the countries bordering on the Euphrates and Tigris Rivers irrigation dates back centuries before the Christian era.

The Romans introduced irrigation into southern Europe. When Pizarro conquered the empire of the Incas he found the people possessed of wonderful systems for irrigation. Likewise, Cortez found the Aztecs making extensive canals. Remains of great irrigation works are found to-day in Arizona and New Mexico, where our modern engineers wisely adopt the canal routes which were established by a race now extinct.

At the present time India is irrigating twenty-five million acres of land, the United States thirteen million, Egypt seven million, and Italy three million. It is estimated that the United States has left one hundred and eighty million acres of arid and semi-arid land available for reclamation and four times as much that is incapable of being reclaimed.

No other question of to-day is of such vital and far-reaching importance as that of the reclamation of the millions of acres of sleeping arid lands in the western part of our country. Mines may be exhausted, forests slain, and cities annihilated, but wastes made fruitful through the potency of water will remain everlasting sources of wealth to the nation.

During the last few years our government has been very active in promoting irrigation by building impounding dams and constructing canals and tunnels for the delivery of water. In connection with the various irrigation works the government has already established five hydro-electric plants which furnish water, motive power, and light as may be required. From the big Roosevelt Dam and the drops of the level in the canal connected therewith, twenty-six thousand horse-power will be developed incidental to the reclamation of two hundred thousand acres of land.

The miracle-working agent, water, has already reclaimed thirteen million acres of our domain, and these areas now produce two hundred and sixty million dollars annually; moreover, they furnish homes to more than three hundred thousand people. Prosperous rural communities with thousands of happy, rosy-cheeked children, blooming orchards, broad, fertile fields prolific beyond comparison, and flourishing cities replace wastes of sand and sage-brush.

The United States Government alone has spent already sixty millions of dollars under the Reclamation Act which went into effect in 1902, and the end is not yet, for as the vista of human achievements in this line broadens still greater works will be inaugurated and successfully consummated. In Arizona, California, Colorado, South Dakota, Montana, New Mexico, Oregon, Utah, Washington, and Wyoming the United States Government already is working on or has completed twenty-six important irrigation projects.

The most wonderful work combining the highest engineering skill and daring is found in the western part of Colorado, where from Black Canyon, an almost inaccessible gorge three thousand feet deep, the whole Gunnison River has been diverted to the Uncompahgre Valley. To take the water out of the river it was necessary to bore a tunnel six miles long through a mountain from the canyon to the valley.

To determine the feasibility of diverting the course of the river, it was first necessary to make an exploration of the canyon. No one before had ever had the hardihood to even make the attempt, on account of the extreme danger of a journey between the narrow black walls of this gloomy abyss.