OCR Text |
Show THE ALL-AMERICAN CAXAL. 81 number of test pits were put down at frequent intervals, mostly in the bottom of the washes, the material in the ridges being as a rule exposed on the steep slopes and also in the cuts of the Southern Pacific and Inter-California Railroads. Some drifting into the steep side of the ridges was done in order to expose the material in place. West of the point south of the westerly point of Pilot Knob the locations of the test pits were selected in open places on the mesa floor between the sand dunes. On this portion the distance between the pits was about 1 mile near Pilot Knob, up to more than 2 miles toward the west side of the sand hills. In 1913 the Imperial Irrigation District put down three test pits through the sand hills along the international boundary, and in 1918 the Imperial Laguna Water Co. put down several more along the same line. These test pits all showed the same general character of material as those described below through the sand hills. (&) The material from Araz to the high rocky ridge at Pilot Knob is composed of sand, gravel, compacted sand, and cemented gravel. The high rocky ridge at Pilot Knob, 600 feet across, is a spur of the main mountain extending to the east, on the eastern end of which is located the Imperial Irrigation District's quarry. (c) From the above ridge southwest to the international boundary and thence along the boundary to a point south of the western edge of Pilot Knob the material is sand, gravel, compacted sand, and cemented gravel. From this latter point to a point a mile west of the western edge of the sand hills the material is sand and gravel, the major part of which is very loose. Only in a small portion of the total depth of holes put down in the blow sand area would the material stand even a few inches in height without cribbing. A portion of the compacted sand and cemented gravel from Araz to and around Pilot Knob will require the use of powder to loosen up for steam shovels or drag-line excavation. (d) The material below the mesa floor through the sand hills contains sufficient gravel and coarse sand so that there is no danger of it drifting from the spoil banks. The test pits are shown on the profile (see Exhibit B). CANAL SECTIONS AND CAPACITIES. (a) With a duty of 1 second-foot to 100 acres, the above area of 900,000 acres will require a diversion of 9,000 second-feet in addition to the amount required for the Yuma project of 1,600 second-feet, or a total of 10,600 second-feet from Laguna Dam to siphon drop. (&) All the larger sections of the canal were designed to give a velocity of 3.5 feet per second when running at capacity and 2.5 feet per second or better when running at half capacity. 149799-20-----6 |
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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. |