Assessment of stormwater outfall impacts on the South Saskatchewan River in Saskatoon, Saskatchewan

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Stormwater is rainfall and snowmelt that runs off land into separate storm sewer (separated from sewage) orcombined sewer systems (potentially mixed with sewage). Urbanization has decreased quality and increasedquantity of stormwater runoff, negatively impacting receiving waters while often overwhelming existingmunicipal sewer infrastructure. Municipal stormwater management options include source control (controllingrelease into sewers), collection and conveyance (sewers); and end-of-pipe (treated/untreated). In terms ofquality, stormwater has high concentrations of pollutants such as nitrogen, phosphorus, organic matter,bacteria, viruses, metals, oil, grease, salts, etc. In terms of quantity, stormwater management is complicatedgiven the impacts of climate change with increased precipitation leading to sewer waters backing up ontoroadways and into homes/businesses, creating traffic problems and financial/insurance issues. As well,exposure to these potentially toxic waters poses a human and environmental health risk.Overall, research is needed to help improve the stormwater management and treatment infrastructure inSaskatchewan and the rest of Canada. Particularly, research is needed to create economically viable solutions toprovide at least primary treatment (settling of solids) for separate stormwater sewers prior to its release into thereceiving environment. The City of Sasktoon (City) is the largest municipality in Saskatchewan with separatedstormwater sewers with over 100 outfalls, many being directed without treatment to the South SaskatchewanRiver (SSR). The City acknowledges the need to better understand the impacts of these outfalls on the SSR andto identify the key outfalls to focus on for future infrastructure improvements. It is expected that regulationswill eventually be passed that will create the need for stormwater treatment, thus, this research project objectiveis to determine the impacts of stormwater outfalls on the SSR and to assess the potential for improved Citymunicipal stormwater management in anticipation of these regulations.