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Show 18 BOULDER CANYON PROJECT DANGEROUS SHIFTING CHANNELS In 1905 the river turned northward from its channel on the crest of the delta and flowed into the Imperial Valley for nearly two years before the break could be closed, thus forming a lake of some 300 square miles known as the Salton Sea. Through heroic efforts on the part of the Southern Pacific Railroad Co., at the request of President Roosevelt, the break was closed in 1907 and the river returned to its channel. The United States then expended approximately $1,000,000 in the building of what is known as the Ockerson Levee to prevent another such disaster as that of 1905. This levee was barely completed, however, when in 1909 the river washed much of it away and turned westward into what is known as Bee River to Volcano Lake, still in Mexican territory, but in a lower depression on the delta. The river flowed on this course for 10 years, and was kept there by means of an extensive levee system built by the people of Imperial Valley. By 1919, through its immense silt deposit, the river had filled the bed of Volcano Lake and Bee River to such an extent that it was again flowing on a ridge and the levees could no longer be made to hold it. The Imperial irrigation district then at an expense of approximately $700,000 constructed an artificial channel from Bee River to what is known as Pescadaro River and turned the river southerly into a triangular depression between Volcano Lake on the west and the old channel on the east. This is the area referred to by Mr. Weymouth in his report from which quotation is made. This is the last remaining depression on the delta. SILT AGGRAVATES FLOOD DANGER The river has an annual discharge at Yuma of more than 100,000 acre-feet of silt. This silt greatly aggravates the flood menace. No temporary works can be built to hold it. It was the silt deposit that built the deltaic ridge on which the river now flows. It was the silt deposit that filled the Bee River and Volcano Lake, so that the river could no longer be held at that point, and the same silt deposit will quickly fill the depression where the river now flows. The gradient to the north into Imperial Valley is much greater than that to the south into the Gulf, and when the depression is filled there is no means known which, at any cost within, reason, can prevent the river from again flowing into the Imperial Valley. The dam proposed in this bill will catch and hold the silt. Most of the silt finding its way onto the delta is from and above the canyon section. If no other dams were provided on the river, the one proposed in this bill would retain all of the silt finding its way into the reservoir for a period of 300 years, and for more than 100 years before its storage capacity and usefulness would be seriously interfered with. As other dams are constructed on the river they will catch and retain the silt, thereby further extending the usefulness of the Boulder Canyon Reservoir. PAST FLOODS ABOVE IMPERIAL VALLEY The Colorado River is subject to periods of great floods and great droughts. It has been known to reach a maximum discharge of more |
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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] : California exhibits. |