Controlling Highway Runoff Pollution in Drinking Water Supply Reservoir Watersheds

About the report:

This study evaluated the effectiveness of an innovative stormwater best management practice in treating highway runoff and protecting the integrity of the drinking water reservoir in Warrenton, Virginia. The research focused on the use of a biodetention pond, which combines the concepts of detention ponds and bioretention in an attempt to provide higher overall pollutant removal. Storm event and background concentrations were all within or below the expected range for highway runoff pollutants and below Virginia's ambient maximum contamination levels for drinking water. The majority of the pollutant removal efficiencies were below values reported in the literature for well-designed wet/dry detention ponds and bioretention areas. Concentration comparisons for one storm event indicated serious problems with sediment re-suspension or short-circuiting in the biodetention facility. Design recommendations are made to potentially improve pollutant removal in the biodetention facility, and design guidelines are offered for future biodetention pond construction. In spite of pond short-circuiting and re-suspension, the study concludes that the biodetention pond adequately protects the integrity of the Warrenton Reservoir and is an innovative alternative for treating stormwater runoff.

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