Northland College
IN-15: Stormwater Modeling

The College has quantified stormwater drainage watersheds, the types and areas of impervious surfaces within these watersheds, and used a stormwater modeling program called "WinSLAMM" to look at current stormwater runoff from campus. For a baseline, the College estimates pre-settlement runoff levels (our "zero stormwater discharge" goal) by using runoff levels from nearby and/or similar sites. The College is also using WinSLAMM to model the effectiveness of our existing LID practices on a campus-wide level, particularly for assessing rain gardens. The College uses the resulting information to re-design its rain gardens. Such a re-design was done last year for the rain garden associated with the Center for Science and the Environment (our second largest building). The College has also used RECARGA to assess the effectiveness of existing LID practices for the Ponzio Campus Center parking lot. Furthermore, stormwater monitoring and modeling is a method by which the College employs the campus as a living laboratory. In the Natural Sciences Program, students have been studying the effectiveness of the stormwater retention basin at Fenega Residence Hall by measuring water quality parameters like E. coli and turbidity from the inlet and outlet for the past 5 years. Hence, actual data, not just modeling, is being used to evaluate the basin's true effectiveness (the results have shown that, in general, the Fenega retention pond is effective at reducing E. coli levels).