Best Management Practices in the form of detention basins were primarily established to control water quantity, but can they improve the quality of runoff? To address this question, four sub-watershed basins were sampled for water quality downstream from BMPs. New, active development characterizes the Casey Property which has a functional BMP. The Lowe's Property also has a functional BMP and has been developed for a few years. Paschal's Creek is an undeveloped watershed that is primarily forest, but in the last decade a BMP has been installed at the headwaters of the stream. The fourth site, Eastern State, has been developed for several years but the watershed lacks a BMP. Water sampling was completed for 24 hours after a single storm on 15/16 July, using automated ISCO samplers to collect water hourly. We measured the following water quality variables: dissolved inorganic phosphorus, dissolved organic phosphorus, total dissolved phosphorus, dissolved ammonium, dissolved nitrate+nitrite, total suspended sediment, total particulate phosphorus, and extractable iron. High concentrations of these variables may serve as indicators of pollution and provide measures for comparing water quality among sampling sites. Although dissolved nutrient concentrations easily passed standards for swimmable/fishable waters, suspended sediment and particulate phosphorus concentrations were quite high, especially for the Casey Property where new development is underway. Based on data collected during this single storm, we cannot conclude that BMPs are effective in filtering out pollutants. That is why it is imperative to understand if and how BMPs can help improve the quality of runoff from our increasingly urbanized landscape.
For additional documentation Ashley Heaton provided a PowerPoint Presentation entitled "Tracking Nutrient Pollution Downstream from BMPs" provided here in PDF form.