| OCR Text |
Show routed through the reservoir with the pumps or intake into the tunnel discharging at 15,000 gpm as the reservoir water level exceeds elevation 6,280 feet. The results of the flood routing calculations for the different water collection alternatives are given in Table 4.3-3. An additional surcharge of 3 feet (about 45 acre-feet) was added to the maximum water levels to allow for the maximum daily runoff from rainfall and snowmelt on the drainage areas for the month of May 1984, derived from the results of the hydrological study. A minimum freeboard of 3 feet is added to determine the top of dam elevation. I I f Four pumps with 4,000 gpm capacity each will be used for the pump alternative of discharging Dry Fork reservoir water into the area of Barney's Wash. The horsepower of the pump engine is estimated at 1,000 hp for an effective pumping head of 800 feet and an efficiency of 85%. The discharge pipe will be a 24-inch dia. steel pipe with a length of 6,800 feet to the point of discharge in Barney's Wash. 3. Freeman Gulch and Markham Gulch Area - The runoff from Freeman Gulch and Markham Gulch will be intercepted by collection channels and intercepting dikes located above the waste dumps and will be drained into the Dry Fork reservoir. A concrete-lined triangular channel will be used, excavated with side slopes of l(H):l(V) on the hillside and . 3(H):l(V) on the side of the access road. A minimum width of 10 feet for the access and maintenance road will be provided. Draining Freeman Gulch into the Dry Fork. reservoir will involve placing an intercepting dike across the gulch, constructing a channel with a length of about 15,100 feet, and providing a 125-foot drop structure at the drainage divide of Freeman Gulch and Dry Fork. Draining Markham Gulch will involve a channel with a length of about 10,900 feet starting from the drainage divide of Cottonwood Gulch, passing through an intercepting dike at the main channel of Markham Gulch, and discharging into a tributary of Freeman Gulch above the Freeman dike. 4 - 19 |
