Journal of Student Research 2018

73 Urban Photsphorus Runoff and Loading to Half Moon Lake, Wisconsin However, more information is needed on the long-term impacts of BMPs on urban P loading reductions (Liu et al. 2017). BMPs efficiency at reducing P loading needs to be quantified over a range of precipitation patterns and variable storm water hydrology in order to improve design. The objective of this study was to monitor P loading from a small urban watershed draining into Half Moon Lake, Eau Claire, Wisconsin, over a period of years to evaluate the effectiveness of BMP implementation. Flow and composite total P and soluble P samples were collected from a storm drain culvert in the summer before BMP implementation in 1999 (i.e., increased street sweeping and construction of infiltration areas in parking lots) and then post BMP implementation period of 2010-17 over a range of precipitation events to evaluate BMPs effectiveness. Study Site Half Moon Lake, a shallow (area = 153.3 acre, mean depth = 1.6 m) eutrophic oxbow lake located in downtown Eau Claire, Wisconsin, offers many recreational activities for users as well as habitat for aquatic wildlife and plants (Fig. 1)

However, excess P loading for decades has resulted in eutrophic conditions and high algal biomass dominated by cyanobacteria (James 2017). Figure 1. Map of Half Moon Lake, Eau Claire, Wisconsin, showing the location of storm sewer 2. Source: Wisconsin Department of Natural Resources 608-266-2621 Half Moon Lake – Eau Claire County, Wisconsin DNR Lake Map Date – Aug 1965 - Historical Lake Map