OCR Text |
Show 38 THE AT.T.-AMERICAN CANAL. and Volcano Lake levees which need raising and strengthening. A small proportion of the steam-shovel excavation on the south slope and a large proportion of that on the east slope of Pilot Knob will be rock, suitable for river bank and levee facing. When once loaded upon cars this material should be placed, so far as it is economically feasible, where it will be useful in affording protection against the flood menace. In the boardrs estimates of cost no addition has been made for long haul when material is thus disposed of, it being assumed that some provision will be made to meet this small additional cost out of special funds that will have to be raised from time to time for protective work. Excavation of the sand-hill stretch of canal by electrically operated shovels is contemplated. Power for the shovels will be furnished from the power station at Pilot Knob. Some grading and construction of track and the establishment of permanent camps would be done before this power is available, while the power house is being constructed and the connection with the Laguna Dam is being made. Active excavation with a full plant would begin about IS months after the work on the upper sections of the all-American canal begins. Each steam shovel would be operated so as to give a net output of two shifts or an average output of at least 4,000 cubic yards per day, or 120,000 cubic yards per month. Twelve shovels in operation would excavate about 1,440,000 cubic yards per month. As their full task would be 50,000,000 cubic yards, they should complete the canal prism from the easterly edge of the mesa at Pilot Knob to the mesa canal heading in about three years. The excavated material under such method of work would be sent to spoil dumps so located as to be of maximum benefit in checking the drifting sand. With a fair allowance for profit this work can be done at about 30 cents per cubic yard, and this price has, therefore, been adopted as the basis of the cost estimate for this part of the work. Westward to the mesa power station No. 2 the canal will no longer be deep in the ground and excavation can readily be handled with drag-line excavators. Westward from the deep cut below power station No. 2 grading outfits are contemplated, and some means must be provided to compact embankments which sustain a high water pressure. Based on such considerations as above, the unit prices which were used to form the basis of the cost estimate will be found noted in Mr. Preston's report. Work should first be concentrated on the stretch from Laguna Dam to Pilot Knob; this will take about 18 months from the tune that definite instructions for its construction are issued. During |
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] : California exhibits. |