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3. Dam Layouts I I I I Three dam and reservoir layouts were completed for the si te on West Divide Creek (See Figure IV-4). The largest, an estimate of the maximum reasonable size, was laid out first. The other two layouts were then completed so as to provide 2/3 and 1/3 of the storage available for the largest. The resulting three storage volu- mes ranged from 4,500 to 14,000 acre-feet. Quantities and costs were then calculated based on these three layouts for both earth embankment and roller compacted concrete (RCC) type dams. 4. Flood Hydrology and Spillway Layouts I I I I Spillway design floods were developed, and reservoir routing was completed according to the methods described in Section IV, A 4, Hydrologic and Hydraulic Criteria. The peak inflow of the design flood is 22,270 ds. Routing this flood through each of the three reservoir sizes results in a maximum spill-way width of 190 feet for the smallest reservoir and spillwayirldths of 160 and 120 feet for the intermediate and large reservoirs respectively. Spillway sizes are the same for both RCC and earth embankment dams. 5. Outlet Works Design I I I The criteria used for the outlet works design are presented in Section IV, A, 4. The two smaller dams utilize a 36 inch concrete outlet pipe. The largest dam requires a 48 inch concrete outlet pipe. Flow control for all three layouts is provided by hydraulically operated sluice gates at the upstream inlet of the outlet pipe. Controls for the gates will be located on the dam crest in all cases. A standard USBR impact type stilling basin is included in the quantity and cost estimates for each dam. IV-17 I I II I I I I I 6. Quantities and Cost Est:lmates Estimates of the quantities and costs of materials needed for the major features of each of the six Haystack dams are presented in appendix 01-13 through 01-15 and 02-10 through 02-12. The results are summarized below.