Bioretention for highway stormwater quality improvement in Texas : final report.

PDFTech ReportFHWA/TX-13/0-5949-4Project 0-5949Best practicesBioremediationDetention basinsDrainageRunoffResearch projectsFiltrationInfiltrationWater quality managementRoadside floraTexasTexas. Dept. of Transportation. Research and Technology Implementation OfficeLi, Ming-HanSung, Chan YongSwapp, MarkKim, Myung HeeChu, Kung-HuiMcFalls, JettTexas A&M Transportation InstituteUnited States. Federal Highway AdministrationNTL-ENERGY AND ENVIRONMENT-ENERGY AND ENVIRONMENTNTL-HIGHWAY/ROAD TRANSPORTATION-HIGHWAY/ROAD TRANSPORTATIONUS Transportation CollectionThis final report summarizes five years\ue2\u20ac\u2122 worth of work in evaluating the applicability and performance ofbioretention best management practices (BMPs) for highway environments in Texas. Within the five-year time frame,the research team did a literature review, conducted pilot experiments, and constructed a field demonstration site. Thefield site was tested with two different designs: (1) dry (or non-internal water storage [IWS]) and (2) internal waterstorage types. The field site is near the intersection of SH 21 and SH 6 in Bryan, Texas. The site includes a waterhydrant for irrigation and synthetic runoff tests. The report includes introduction, research methods, test results,discussion, drawing examples, designs and maintenance guidelines, a special specification, a planting plan guide, asummary of the site selection process, and test data.In summary, bioretention BMPs can reduce peak flow and increase detention time. Non-IWS designmoderately removed suspended solids, less effectively removed copper and zinc, less effectively removed totalnitrogen, and moderately removed total phosphorus. The IWS layer significantly improved all performances, includinghydraulic and water quality.The significance of this research project is that bioretention BMPs are a promising method for highwayapplication in hot, semi-arid areas. Furthermore, the IWS layer is a viable application to improve bioretentionperformances