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Floodplain Development Permit Package,July 2019 <br /> .zr `v,. I <br /> r� <br /> ti b <br /> Figure 2. Floodplain Bench Example(CDM, 2016) <br /> Backwater Wetlands <br /> The second major wetland feature of the project design is the restoration of backwater channels and <br /> associated wetlands. Before major water development in the area, overland flood flows would create <br /> high flow channels across sandy upland areas on the project site. When flood flows recede, these <br /> channels will often retain their downstream connection to the river and will partially inundate even <br /> without the presence of major overland flow, due to water backing up from the downstream connection. <br /> The design approach for the backwater channels and wetlands is to create two linear backwater features <br /> and restore an abandoned oxbow area. These backwater areas will be comprised of a wide, vegetated <br /> floodplain which will support a variety of wetland grasses, sedges, and woody species. Within this <br /> floodplain will be a one-foot-deep, 10-foot-wide channel to provide a wetter ecosystem and support <br /> positive drainage of these features. These backwater features and their associated channels encompass <br /> a wetland area of 24.2 acres and an overall channel length of approximately 4,020 feet.The channels are <br /> slightly sloped upward from the main channel of the BTR and as water rises and falls within the BTR <br /> channel, water will move up and down the backwater channels. <br /> 2.2. DESIGN SUMMARY <br /> This project directly improves 2,700 feet of the BTR main channel and restores approximately 4,020 linear <br /> feet of additional habitat through the backwaters and oxbow area. Approximately 31.6 acres of wetlands <br /> are created or improved through this design.Total excavation is approximately 270,000 CY. <br /> Headwaters Corporation 3 of 7 <br />