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Floodplain Development Permit Package,July 2019 <br /> 1 y�iY•ti����+� ter. <br /> • � mti�•my- '} '� may � � <br /> a� ♦ * 4 <br /> �� �4• •� Property Boundary <br /> "gymm"" " V <br /> Backwater Wetland <br /> _7 Floodplain Bench <br /> Backwater Channel <br /> +� + • ' 4e <br /> T' Big Thompson Confluence <br /> Vicinity and Location <br /> 0 200 400 800 <br /> Feet <br /> AMf In <br /> Figure 1: Project Overview <br /> Floodplain benches at the project site will create a bench with widths of 80-210 feet(most areas near 100 <br /> feet) along approximately 2,700 linear feet of the BTR channel. The BTR is heavily incised in this reach, <br /> and approximately four to six feet of excavation from the existing bank elevations will be required to <br /> achieve the desired wetland characteristics. These benches will slope slightly upward such that the outer <br /> boundary of the benches, where they meet the existing upland, will be 0.5-feet higher than the river's <br /> edge of the bench. This will ensure that any inundation from flows high enough to submerge the <br /> floodplain benches will drain back to the river as it recedes. As designed, the floodplain benches will <br /> create a much larger channel cross section to carry peak flows, reducing the overall velocity of these high <br /> flows and allowing sediment and nutrient deposition along the bench. These lower velocities will also <br /> contribute to the increased stability of this design approach. <br /> Headwaters Corporation 2 of 7 <br />