Modeling and analysis of phosphorus reduction by rain gardens and other BMPs in stormwater runoff from small urban developments

Abstract

As part of The Discovery Museums (TDM) Low Impact Development (LID) Design and Monitoring report (Master of Engineering Group Project) for the town of Acton, , the effectiveness of low impact development technologies at improving the quality of stormwater runoff from TDMs parking lot was evaluated. Several Best Management Practices (BMPs) and LID technologies were assessed to determine which devices would be most suitable for the site. The P8 Urban Catchment Model was chosen to model phosphorus concentrations in stormwater runoff before and after the implementation of LID. The results were then assessed to determine whether or not these technologies significantly improve the runoff water quality. In this thesis, the analysis is extended to assess the improvement in phosphorus concentrations if rain gardens are implemented on a fraction of residential areas in the Nashoba Brook watershed. The effectiveness of a rain garden at improving the phosphorus concentrations in runoff was evaluated by modeling the device in P8. Both the TDM site analysis and the Nashoba Brook hypothetical analysis yielded results with significant reduction in total phosphorus loading. These results should encourage further research on the widespread use of LID.