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Utilizing cross sectional surveys develop a hydraulic model (HEC RAS) for restoration sites. <br />Contractor shall perform a hydraulic and geomorphic assessment as outlined below. The goal of this <br />analysis is to identify meandering, braided and transitional reaches of the river, assess trends in the <br />study reach and estimate impacts of the proposed river restoration improvements on the river’s <br />geomorphology. <br /> <br /> <br />?Survey approximately 100 river cross sections and develop the HECRAS model. <br /> <br /> <br />?Using hydrologic conditions prepared in Task 3.4.1 develop a HECRAS for the existing conditions <br />for the representative 1.5-year, 2-year, 10-year and 100-year return interval peak flows. <br /> <br /> <br />?Evaluate at each project site the hydraulic conditions and calculate hydraulic parameters for the <br />discharges noted above. <br /> <br /> <br />?Collect and analyze stream bed material gradations. For the purpose of this analysis six sites will <br />be selected with one sample taken from each site for a total of six samples. <br /> <br /> <br />?Review hydraulic characteristics, bed material and other characteristics to compare with typical <br />procedures to determine stream parameters. Review river reaches for trends in meandering, <br />transitional or braided sections. <br /> <br /> <br />?Determine incipient motion sediment sizes for each reach for the range of flows extending up to the <br />100-year peak based on average-reach parameters. The sizes moving should be compared with the <br />bed material distributions to evaluate the percent of the bed mobilized at various flow levels and to <br />identify any potential deposition zones that would be more prone to braiding. <br /> <br /> <br />?Review available thalweg and/or water surface profiles to identify if there is a change in gradient <br />that might tend to result in sediment deposition or degradation. Review available surveyed cross <br />section information for developing a comparative assessment of the river sections relative to each <br />other and relative to changes over time. <br /> <br />3.4.3 Master Plan Drawings <br /> <br />Develop and prepare design to 35% level of detail for the selected restoration. Specific tasks to be <br />performed for each project area are described below. <br /> <br /> <br />?Prepare base maps using the aerial photos from Phases 1 and 2 and superimposing the cross <br />sectional surveys and information from PHABSIM surveys. <br /> <br /> 4 <br />