Benchmark Engineering designed the Oak Grove drainage improvements project, funded through Rankin County’s ARPA program, to restore 4,663 LF of a tributary draining a 280-acre watershed. The channel lies within a 40-foot drainage easement along the rear property boundaries of over 60 residential lots. The project aimed to alleviate flooding, reduce erosion and sediment, and safeguard adjacent properties from further damage.
To meet permitting requirements, the design incorporates Priority 4 restoration and Streambank Soil Bioengineering stabilization. Creative solutions were required to address restrictive easement widths and limited channel access. Stabilization of the channel slopes was achieved using Nature-Based Solutions, including live staking combined with Turf Reinforcement Mat (TRM) to support vegetation reestablishment. Revegetating the riparian zone was integral to the design, improving water quality by acting as a natural filter for pollutants like sediment and chemicals.
The design emphasizes aesthetic and environmental sensitivity by preserving the channel’s natural meander and incorporating dual-channel features with bankfull benching where feasible. This approach includes a smaller, low-flow channel to efficiently convey normal flows and wider floodplain benches to accommodate high flows, thereby increasing hydraulic capacity and minimizing erosion during peak conditions. By mimicking natural stream processes, the design promotes stability, supports riparian vegetation, and boosts biodiversity.
