Evaluation of stormwater remediation options on McVicar Creek, Thunder Bay, Ontario / by Kestrel Wraggett

Abstract

Stormwater discharge has been shown to impair aquatic ecosystems through the transportation of nitrogen, nitrate, ammonium, phosphorus, orthophosphate, organic carbon, fecal coli form bacteria, biochemical oxygen, metals and grease and oil from urban environments (Mallin et al., 2009). Stormwater is generally considered a non-point source of pollution which can cause difficulty in managing habitat and ecosystem degradation. Current municipal stormwater management is often focused on the deployment of end of pipe solutions in the form of detention or retention basins (Roy et al, 2008). There is however a growing recognition that the public needs to be involved and aware of urban drainage planning ifwe are to move away from strictly engineered solutions and shift to integrated stormwater management (Rauch et al., 2005). In 2002, the Lakehead Region Conservation Authority (LRCA) recognized that McVicar Creek, one of Thunder Bay’s major tributaries to Lake Superior, was potentially contributing significant sources of stormwater related pollutants to the Thunder Bay Area of Concern. The lower reaches of the creek are highly developed putting the water system at high risk of excessive urban runoff causing ecosystem impairments. This thesis is aimed at providing stormwater remediation recommendations along McVicar Creek through quantitative and qualitative research techniques. McVicar Creek was the selected location due to the urbanized environment surrounding the creek and the initial recognition from the LRCA. Three representative sites were selected that best characterized stormwater impacts along the creek. The sites were chosen based on previous research completed on the creek by Lakehead University and the Northshore Remedial Action Plans (RAP). Ofthe three sites selected, one site was further studied as a case study site in order to complete a multi-decision making workshop with stakeholders. All three sites had in-depth subwatershed catchment assessments and water quality data. In addition, soil texture and composition, soil nutrients, soil organic matter, infiltration rates and upstream and downstream water quality were examined. These parameters were evaluated to determine the efficacy of Low Impact Development (LID) best management practices on the site. In relation to the literature, the quantitative data show the case study site is a suitable option for LID remediation. The areas within the case study site that have less than ideal LID soil conditions could be altered through engineering practices and designs to achieve successful implementation. The water quality results show excess amounts of ammonia, nitrate, nitrite phosphate and chloride exceeding specified guidelines outlined by the provincial and federal governments. The stakeholder group concludes that a watershed-wide education and outreach campaign is a more valued stormwater remediation option in Thunder Bay.