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Dam Subdrains, No. 1 Dam seepage, Tenmile Tunnel seepage, natural runoff of <br /> precipitation, seepage flow from Chalk Mountain Dam, seepage from the Chalk Mountain <br /> Interceptor, and West Gravity Line flows. In addition to these sources, water has <br /> historically been diverted into the reservoir for various reasons through the Tenmile Tunnel, <br /> the West Tailing Delivery Line, the West Gravity Line, and the Chalk Mountain Interceptor. <br /> Limited historical data is available regarding the magnitude of any of the inflow sources <br /> listed above. <br /> The West Gravity Line currently carries water that is decanted off of Robinson <br /> Tailing Pond to Robinson Reservoir. It should be emphasized here that the assumption was <br /> made that the large volume of inflow that has historically discharged into the reservoir from <br /> the West Gravity Line would be eliminated in the future. The West Gravity Line inflow has <br /> historically included all precipitation runoff that is tributary to Robinson Tailing Pond. We <br /> have assumed that in the future this flow would be diverted from the tailing pond by <br /> means other than the West Gravity Line. <br /> For the purposes of this preliminary design, the Eagle River Basin hydrology was <br /> modeled using a computer model. This model utilizes historic runoff data for the years of <br /> 1981 through 1992 to simulate the effects of various system modifications and operating <br /> scenarios. The following is a list of assumptions and parameters that were used in the <br /> model to develop the total inflow to Robinson Reservoir: <br /> 1) No. 1 Dam Subdrain and Seepage Flow, and Tenmile Tunnel Seepage <br /> It was estimated that the total inflow to the reservoir from the <br /> subdrains and Tenmile Tunnel varies between 500 and 1000 gpm <br /> throughout the year. These flows were increased by 60 percent to <br /> account for unmeasured seepage flows from No. 1 Dam that enter <br /> the reservoir. This results in a total inflow from these three sources <br /> of 800 to 1600 gpm. It should be noted that this estimate was <br /> based on very limited actual measured data. <br /> 5 <br />