OCR Text |
Show 8 PROBLEMS OF IMPERIAL VALLEY AND VICINITY. by a large levee, north of Volcano Lake, extending eastward and connecting with high land near Andrade. This levee is in Mexico and its maintenance is complicated thereby. In 1905 the river scoured out the channel of the Imperial Canal and turned its entire volume into the Salton Basin, eroding a deep gorge and raising the level of Salton Sea. It submerged the salt works and forced the removal of the main line of the Southern Pacific Railroad. At great difficulty and expense, after several unsuccessful attempts, the river was returned to its old channel in February, 1907. The control of the river would be greatly facilitated if the floods were reduced in volume by storage. Investigations have been made concerning the feasibility of storing the floods and reducing their volume to an amount easily controlled. The floods divide themselves naturally into two general classes-those from the Colorado River, which drains large areas in Wyoming, Colorado, New Mexico, Utah, and Arizona, and those from the Gila basin, which lies mostly in Arizona and partly in New Mexico and Mexico. While the area drained is much larger for the Colorado than for the Gila and the water supply vastly greater, the habits of flow are such that the Gila River, owing to its flashy character, sometimes furnishes flood waves at its mouth near Yuma almost as large as the maximum discharge of the Colorado at the same point. These floods from the Gila, however, are infrequent and of relatively short duration. While their sudden character and erratic occurrences make them peculiarly menacing to the levees or other property on the banks of the river, they do not present so great a menace to the Imperial Valley on account of their short duration and relatively small volume. The Colorado River rises gradually, carries a large volume of water for several weeks, and declines gradually. Should it break into the Imperial Valley at time of flood, the long duration of high water would cause great erosion and render its control exceedingly difficult. This is the experience actually obtained when this occurred. The Gila, on the other hand, might break into the Imperial Valley but the relatively short duration would not furnish nearly so much water to the Salton Sea, and consequently not incur the danger of submerging the entire valley. The quick decline would make its control comparatively easy. The great floods of the Gila occur in the winter, while those of the Colorado occur in summer. So far as known, they never have coincided; but if this ever should occur, it would greatly increase the menace. A reservoir site of 2,200,000 acre-foot capacity has been investigated near Sentinel, on the lower Gila, which, if built and maintained, would practically eliminate the menace from the floods of the Gila, but the investigations show such poor conditions for foundation and abutments that the feasibility of this reservoir is subject to doubt. The control of the Colorado River proper is, for the reasons above stated, the main element involved, and this has been investigated extensively. Possible reservoir sites have been found on the Grand and the Green rivers, which, if constructed and operated for the purpose of flood protection, would greatly reduce the volume of the floods, for though the areas intercepted by each are small compared with the total area of the Colorado River Basin, they drain mountains with high precipitation that furnish a relatively large volume of water. A |
Source |
Original book: [State of Arizona, complainant v. State of California, Palo Verde Irrigation District, Coachella Valley County Water District, Metropolitan Water District of Southern California, City of Los Angeles, California, City of San Diego, California, and County of San Diego, California, defendants, United States of America, State of Nevada, State of New Mexico, State of Utah, interveners] : |