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Show THE ALL-AMERICAN CANAL. 17 The following tabular data will give some idea of the amount of water which is carried by Colorado River past Yuma and the amount supplied by the river's principal tributaries: Table 1.-The discharge of Colorado River. [From records of the United States Geological Survey.] [Annual run-ofl in acre-feet.] Year ending Sept. 30- Green River at Green River, Utah. Grand River at Moab or Cisco, Utah. San Juan River near Bluff, Utah. Colorado River at Yuma, Ariz. 1894-95 4,440, 000 4,160,000 5, 980, 000 1895-96 1896-97. 1901-2............ 1 7,110,000 11,100, 000 9,870,000 18,900,000 19,200, 000 26,000, 000 13, 600, 000 26,100, 000 15,000, 000 16, 200, 000 19, 600,000 12,000, 000 19, 900, 000 15, 800,000 21, 300, 000 22,100, 000 13,000,000 1902-3..... 1903-4.. ... 1904-5 1905-6............ 6, 360,000 1906-7.. 8, 950, 000 4,290,000 8, 580,000 4, 710, 000 1907-8..................... 1908-9............ 1909-10_____ 1910-11 . 4,160,000 6,160,000 5, 370,000 7,080,000 1911-12..... 1912-13...... 1914-15............ 3, 620,000 5,740,000 8,070,000 5,350, 000 7,500,000 8, 780,000 2 2, 700,000 3,240,000 3, 340,000 1915-16....,................. 1916-17...................... 1917-18........____.......... 19 months only, January to September, inclusive. * 11 months (October, 1914, is missing). THE IMPERIAL VALLEY AND ITS DEVELOPMENT UNDER IRRIGATION. That in comparatively recent geologic times the Gulf of California extended far to the northwest beyond its present limits is a well-known fact. Its upper end was to the northward of Indio. The detrital matter washed down from the mountains gradually pushed the water back from their bases, and that which was brought from far inland by the Colorado River built a low flat delta ridge entirely across the ancient gulf, cutting off its upper portion from a connection with the ocean. It dried up, and the bed which it occupied is now generally referred to as the Sal ton Basin. The greater area around and including this basin, which lies between the Coast Range Mountains on the west and the Colorado River range on the east, is known in its northern part as the Coachella Valley and in its southern part as the Imperial Valley. Both the Salton Basin and the Imperial Valley overlap the international boundary, their southernmost portions being in Mexico. In its natural condition this entire region was an unproductive arid rigion. The annual rainfall here averaged only 2 or 3 inches. There 149799-20------2 |