OCR Text |
Show 44 THE ALL-AMERICAN CANAL. to the canal, so that when the basin behind them is full they will discharge over the barriers into the canal. In this way a number of pockets will be provided for the interception of sand, gravel, and cobbles and these can hereafter be increased in extent by adding to the height of the overfall barriers. THE CANAL FROM SIPHON DROP TO PILOT KNOB. At the Siphon Drop the water from the Yuma project will be dropped, as explained, to a lower level, while the water for Imperial Valley will be held at grade. The all-American canal, strictly speaking, will begin at this point. It has been planned at a capacity of 9,000 second-feet. It will follow rather difficult ground, generally near and finally well in among the outlying hills and knolls which are features of the higher ground between a number of sand washes. An agreement will be necessary with the Southern Pacific Co., in order to secure permission to encroach on its right of way. In addition, a bridge will have to be provided for the main line on the Southern Pacific Railroad, and one for the Inter-California Railroad. In this section, too, the canal is to have a freeboard of at least 6 feet. At the lower end of this section there will be a rock cut, or tunnel, through a spur of Pilot Knob. Adjacent to and either above or below this spur the Pilot Knob power station will be located. At a convenient point below the power-house offtake there will be a controlling gate in the canal. By means of this the flow in the canal to the westward will be regulated. Any surplus water will be discharged either through the waste gates at Araz or through the powerhouse offtake canal and a by-pass which is here to be provided. The canal throughout this section is to have a bed width of 150 feet, a depth of 15 feet, and side slopes .varying from \h to 1 to the flatter slope of 2 to 1, the slope being adjusted to the varying character of the material to be excavated. The canal gradient will range from 0.0000786 to 0.0000862. In this section, too, when the canal is flowing at capacity the mean velocity will be about 3.5 feet per second. CANAL LOCATION AT PILOT KNOB AND THENCE WESTERLY. The range of hills which parallels Colorado River on its right rr west bank in California terminates at Pilot Knob, which lies in the extreme southeasterly corner of California. While not very high nor of large surface extent, Pilot Knob is nevertheless a conspicuous topographic feature. This is due in a measure to its isolation. It is separated from the chain of hills and mountains to the north by a somewhat broken section of the mesa which forms the flat eastern slope of Imperial Valley extending from the base of this mountain range to the lower-lying Imperial Valley lands. |
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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. |