C150163 Feasibility Study - Laserfiche WebLink

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I I I I I I I I I I I I I I I I I I I Cornish Plains Reservoir Based on the available topographic information and a visual inspection of the site, Cornish Plains Reservoir appears to be located in a depression and there does not appear to be a good location near the toe of the dam to discharge the outlet. Consequently, the Cornish Plains Reservoir outlet will be configured to discharge through the pipeline into Barnesville Equalizer or the North Side Extension ditch. Because of the length of the outlet pipe and the low head difference between Cornish Plains Reservoir and Barnesville Reservoir, a 36- inch diameter outlet pipe is necessary to meet the State Engineer's requirement of lowering the reservoir five feet in five days. A concrete-encased ductile iron pipe is recommended for the section of the outlet pipe that passes through the dam. Downstream of the toe of the dam, a gravel-bedded ductile iron pipe is recommended. Following more extensive topographic surveying during the design phase it may be possible to find an alternative outlet configuration that would allow the use of a 30-inch diameter" outlet pipe in lieu of the 36-inch diameter pipe. Barnesville Reservoir Barnesville Reservoir will be constructed in an existing depression. The storage capacity will be increased by excavating below the existing grade. The maximum storage elevation will be at or below the elevation of the natural boundary of the basin. The embankment merely provides freeboard. Because the reservoir is so deep in the ground, it is impossible to provide a gravity-flow outlet that will drain the reservoir. The only outlet from the reservoir will be a pumped outlet that can discharge through the pipeline into Drury Reservoir, Cornish Plains Reservoir, or the North Side Extension. The pumped outlet will have capacity sufficient to draw the reservoir down five feet in five days to comply with the State Engineer's requirements; however, the use of a pumped outlet will require the State Engineer's approval because their regulations require a gravity-flow outlet. Jack Wells Pumping Station and Pipeline Jack Wells PumpinQ Station . A pumping station will be required to pump water from Barnesville Equalizer to Cornish Plains and Drury Reservoirs or into the canal. Approximately 240 hp is required to obtain a flow rate of 20 cfs from Barnesville to Drury through a 24- inch diameter pipe. For pumps with 80% efficiency approximately 300 hp of pumping power will be required. Figures 13 and 14 show two pump configuration options considered. Both options would require similar intake structures, control systems, and power requirements. Both configurations could provide 20 cfs to Drury Reservoir or approximately 50 cfs to Cornish Plains Reservoir. At 20 cfs, Drury Reservoir would be completely filled from empty in approximately 15 days. At 50 cfs, Cornish Plains Reservoir would be completely filled from empty in New Cache Feasibility Study 25