In the the same as in the first estimate and are, therefore, not repeated above. second alternative estimate, future enlargements of the earth sections are anticipated but not covered in this estimate. LAGUNA DAM TO SIPHON DROP, 7,600 SECOND-FOOT CANAL Earth, 2,300,000 cubic yards at 20 cents- at 30 cents.. Raising and ballasting 1 mile of track_ Concrete lining 4,400 feet of canal along railroad track Total 15 per cent contingency.. Structures: 3 highway bridges.. $460,000 9, 000 161, 500 636, 500 95, 475 $731, 975 102, 000 85,000 Wasteway- 20,000 Check 235,000 5 miles telephone line.. Total.. Paved overflow for receiving storm water into canal. 22, 000 20, 000 1, 125 15 per cent contingency Grand total.. ARAZ TO UPPER POWER SITE, PILOT KNOB, OPPOSITE ROCKWOOD GATES, 6,000 SECOND-FOOT CANAL Excavation: Earth, 504,000 cubic yards at 20 cents. $100, 800 Rock, 109,000 cubic yards at 75 cents___ 81, 750 Concrete lining 400 feet canal 4 inches thick, 74,400 square feet at 17 cents.__ 12, 648 UPPER POWER SITE, PILOT KNOB, OPPOSITE ROCKWOOD GATES, TO PILOT KNOB, 6,000 SECOND-FOOT CANAL PILOT KNOB TO WEST SIDE MAIN CANAL, 6,000 TO 1,500 SECOND-FOOT CANAL • Structures to be located at place selected for power site or permanent wasteway (see "Power development," p. 97). ? Estimate of amount of sand that will blow in during construction. Estimate for construction of all-American canal of capacity to serve the Imperial irrigation district with 1,600 second-feet additional capacity for Yuma project down to siphon drop (7,600 to 1,500 second-feet) • Constructed for full development as far as possible. Will cost about the same as though built full height. DIVISION OF COSTS 1. Between the Yuma project for power development Laguna Dam to siphon drop, excavation_ Amount to be apportioned between the Yuma For the Imperial irrigation district, two-thirds Laguna Dam to siphon drop, structures.. Amount to be apportioned between the Yuma For the Yuma project, two-ninths (contract For the Imperial irrigation district, seven- 2. Between the Imperial irrigation district and the Connecting with Laguna Dam (contract Oct. 23, Laguna Dam to Araz (seven-ninths above). 60 per cent apportioned to the Imperial irrigation district. 40 per cent apportioned to the new lands 24-foot siphon spillway for operation with power plant No. 1. 93% per cent apportioned to the Imperial irrigation district_ 62% per cent apportioned to the new lands. 3. Summation of costs to different interests: The Yuma project— One-third apportioned on excavation above.. The new lands 1,086, 005 40 per cent apportioned on structures above. 1, 441, 138 5, 916 as given above.... Less amount apportioned to new land, as 1, 086, 005 1, 447, 054 2, 533, 059 Net cost to Imperial irrigation district. 24, 504, 057 POWER DEVELOPMENT (a) Plans are made for a temporary or construction power plant at or near Pilot Knob, where a drop of about 30 feet can be obtained by discharging the water into the Imperial Canal. This power plant should be constructed and made available for the generation of power at as early date as possible in order to furnish cheap power for construction purposes. The plans are for the development of two units of 4,500 turbine horsepower each, with provision for adding a third unit of the same size. In the preliminary report the temporary power plant was located at the lower or south end of the rock cut at Pilot Knob. Since that report was made another site nearly opposite the Rockwood gate has also been investigated. Test pits at both sites have been put down as deep as possible without resorting to pumping of the water. The tailrace of the upper one of these sites would discharge into the Imperial Canal between the Rockwood and Hanlon gates. The tailrace from the lower site will discharge into the Imperial Canal below Hanlon gate. It is as yet a question which of these sites should be developed. If developed at the upper site and a siphon spillway used to regulate the flow in conjunction with the power house and later a sluice gate located at the lower power site were constructed, considerable heavy construction work would be avoided until after the upper portion of the system could be placed in operation and electric power generated. This would give an estimated expenditure of $4,880,258 for canal construction from Laguna Dam after deducting the following items from the first three items under "Recapituation" (p. 89): (b) West of the sand hills there are two drops where it is planned to develop power. These we have called power plant No. 1 and power plant No. 2. (c) At power plant No. 1, which is located 4 miles west of the east-side mesa canal, there is a fall of 24 feet. Three miles east of this power site there is a drop of 6 feet, which may in the future be carried downstream to power plant No. 1 by raising the canal banks and the structure at the power plant, giving a total fall of 30 feet. The plans at this site are for the development of 4 units of 4,500 turbine horsepower each. (d) Power plant No. 2 is situated 5 miles west of power plant No. 1. At this site a head of 47 feet can be obtained. The plans are for the development of 4 units of 6,500 turbine horsepower each. At (e) The above developments are for the maximum capacity of the canals. power plants Nos. 1 and 2 the discharge during the minimum flow of the river may fall to 20 or 25 per cent of the maximum capacity. This will limit the amount of power available for commercial purposes after deducting the amount required by the Yuma project and Imperial Irrigation District for operating purposes and pumping at the period of minimum discharge. (f) It is planned that the power equipment installed in the construction power plant at Pilot Knob will be used in power plants Nos. 1 and 2. The first plant will be built entirely for construction purposes. Credit has been given in the estimate for the machinery that will be transferred to the other plants. Therefore the cost of the plant given below should be depreciated within the period covered by construction and charged to the cost of furnishing power for construction purposes. (g) The estimated cost of developing the power plants without transmission lines is as follows: |