In 1904 the Imperial Canal was filled with silt for some distance, thus preventing the flow of the proper amount of water needed for irrigation. To remedy the defect a temporary canal was cut around the head-gate. This expedient had been tried and then the gap had been closed up before high water. At this particular time high water came earlier than usual, and a great flood tore out the channel of the temporary canal to such an extent that before it could be prevented the whole Colorado River was flowing through the breach, leaving its own bed perfectly dry to the Gulf of California, filling up the Salton Valley, burying up the Salton salt-works, and making an inland sea such as formerly existed there. After most strenuous efforts, and at the enormous expense of upward of a million dollars, the gap was at length repaired and the Colorado made to flow in its own bed. One should remember that in the development of these deserts the prospector owes a deep debt of gratitude to that patient, faithful little beast, the donkey, or "burro," as it is commonly known; without the service of this animal many a man would have suffered a lingering death. As a matter of fact, it is unsafe to venture far out into the desert unaccompanied by this oft-maligned creature--about the only animal fitted to carry supplies. [Illustration: _Built by the U. S. Reclamation Service_ The Roosevelt Dam, Arizona, showing south bridge and spillway] 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.