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Scope of Work <br /> Sub-task 4A. Property Mapping <br /> Assemble and review Moffat and Routt county records and plat maps, records <br /> of oil and gas leases and tracts. mineral ownership, road and utility easements. and aerial <br /> photographs of the reservoir area. <br /> Assemble existing data on recent property transactions in the area to assist in estimating <br /> property acquisition costs. <br /> Prepare a land use and property ownership map of the dam and reservoir area showing <br /> recorded ownership. easements, disputed areas. areas of potential adverse possession, and <br /> utility and road locations. Scale of map shall be determined by available information but shall <br /> not be larger than 1:24000. <br /> Sub-task 4B. Spillway and Flood Hydrology <br /> Review the two previously approved PMF calculations and meet with dam regulatory <br /> officials of the Office of the State Engineer to reach an understanding of which PMF report to <br /> use. Compute the 100-year flood hydrology as the inflow design flood for the service spillway <br /> utilizing the SCS unit hydrograph technique with a regional hydrologic check. Compute the <br /> downstream flow duration relationship of reservoir releases for use in the channel stability and <br /> hydroelectric computations. Conduct inflow design flood and PMF reservoir routings as part <br /> of developing the configuration of project components. Develop a concise, composite <br /> hydrology report. <br /> Sub-task 4C. Sediment Evaluation <br /> Examine existing sediment data and studies for Elkhead Creek and nearby drainages. <br /> Perform additional sediment sampling, coordinated with other water quality data requirements, <br /> obtaining not less than 4 estimates of suspended load above and below the reservoir under <br /> varying hydrologic conditions. Revise sedimentation estimates for Elkhead Reservoir. <br /> Sub-task 4D. Preliminary Sizing <br /> Based on the mapping of Sub-task 3A prepare revised estimates of reservoir capacity and <br /> elevation/area/capacity relationships. Estimate potential impacts to existing properties, <br /> structures and improvements. Based on the mapping of Sub-task 3A and geotechnical data <br /> from Sub-task 4E, review and revise (if necessary) the proposed dam position and alignment. <br /> Sub-task 4E. Geotechnical Investigations <br /> Review and summarize existing geological and geotechnical information and mapping. <br /> In coordination with USBR geologists, prepare field investigation plan for drilling, sampling, <br /> test pits. and laboratory analysis. Observe field work and laboratory analysis. Prepare a <br /> report evaluating integrity of existing structure, summarizing investigations and making design <br /> recommendations addressing seepage control. embankment camber/settlement, foundation and <br /> abutment preparation and related geotechnical issues. <br /> 3 <br />