Carter-Stilley Mitigation Bank

Horry County, SC

Between 2019 and 2020, RDE was contracted by American Mitigation Company to conduct a series of hydraulic analyses at the Carter Stilley Wetland and Stream Mitigation Bank located in Horry County near Longs, SC. This project site is located along the banks of the Waccamaw River and is managed by the South Carolina Department of Natural Resources (SCNDR) as part of the Waccamaw River Heritage Preserve and Wildlife Management Area.

As part of the ongoing management of the mitigation bank, several existing roadway bridges have been proposed to be replaced with a series of culvert crossings. Prior to implementing these infrastructure upgrades, SCDNR requested that RDE verify that the proposed changes would not have an effect on the flood levels across the project site or the surrounding riparian and floodplain areas adjacent to the Waccamaw River. To address these concerns, RDE conducted a handful of analyses related to culvert hydraulics and flood mapping for proposed conditions. Based on the results of these analyses, RDE has coordinated with SCDNR and Horry County’s Flood Hazard Reduction Control Officer to support a “No Rise Certification” for FEMA flood mapping in the area.