MODELING THE EFFECTS OF RESTORATION ON SEDIMENT AND NUTRIENT LOADING TO LAKE ERIE FROM THE WOLF CREEK WATERSHED

Maumee Bay State Park (MBSP) issues advisories for beaches during the recreational season (May to September) due to high levels of Escherichia coli and algal toxins associated with water in Lake Erie. The Wolf Creek watershed (39.9 km²) was identified as a proximal source of bacterial contamination to the beaches. GLRI funding was used to restore a riparian habitat and a wetland to reduce loadings of E. coli, sediment, and nutrients. The riparian restoration consisted of a broadening and deepening of the creek channel to slow water flow and remove both suspended and rolling bed sediment. The restored wetland was placed downstream and designed for subsurface flow to promote adsorption and filtration of nutrients and bacteria. Land-use, drainage patterns, and soil type were incorporated into a SWAT model that was calibrated using water quality data (total phosphorus, mg/L; E. coli, CFUs/100 mL; total suspended sediment, mg/L; and discharge, cfs) collected from 2007 to the present. The calibrated model was used to evaluate the impact of the restoration projects on the loading values and MBSP beach advisories. The significance of relevant drivers (remediation, precipitation, wind, seasonal weather patterns, etc.) on loadings was determined using the model. The calibrated model’s success in replicating the interaction between remediation and water quality can improve future remediation designs and will be used to scale up applications in other regional watersheds, such as the Maumee River basin, which provides sediment and nutrient inputs into Lake Erie.