Beltway 8 Wetland Water Quality Project - Constructed wetlands for storm water polishing and wetland mitigation banking

The Harris County Flood Control District is implementing a wetland mitigation bank project that includes highway runoff as a significant water source. Part of this project is being implemented in cooperation with the Texas Department of Transportation through funding from the Intermodal Surface Transportation Efficiency Act for water quality improvement. This collaborative effort includes treatment and final polishing of storm water runoff from a portion of Beltway 8, northeast of Houston, Texas. The project includes approximately 89 ha (220 acres) of storm water-polishing wetlands and associated wildlife habitat. The overall train of natural treatment processes includes a tie-in to the existing belt-way storm sewer, a surge basin for initial collection and storage of storm water, a pump station and force mail allowing flexible water delivery to the rest of the system, a series of polishing ponds and polishing wetland marshes, and an interconnected array of habitat wetlands and swales including ponds, littoral marshes, and transitional wetland forest areas. Design of the polishing and treatment wetlands balances the multiple goals of water quality improvement, flood-flow retention, and creation of valuable wildlife habitat.