The Eightmile Branch Tributary watershed, located in Columbia, SC’s Windsor Hill neighborhood, has a variety of documented stormwater problems, including 43 homes currently located in the FEMA floodplain, six homes in the floodway, extensive channel erosion in certain locations, and a variety of stormwater maintenance related issues.
Thomas & Hutton worked with the City and provided a comprehensive stormwater infrastructure inventory, closed system stormwater modeling, floodplain modeling, and an alternatives analysis to recommend proposed improvements to solve flooding and erosion problems and update aging storm drainage infrastructure in the approximate 500-acre watershed. A wide variety of project alternatives were evaluated for effectiveness, feasibility, environmental impacts, and costs. Our team worked to inspect and evaluate the entire reach of the tributary and provided conceptual stream restoration designs for further evaluation.
From the study, the recommended projects included storm drainage system upgrades, culvert upgrades at road crossings, urban stream restoration, Bioretention areas, and channel improvements. Thomas & Hutton presented the final recommendations to the City and is currently assisting with its final design, utility relocation coordination, environmental permitting, and construction of the recommended projects.