Ottawa River Water Quality ModelingThis Ottawa River Water Quality Model is a computer model of the Ottawa River that is used to predict how contaminants are transported downstream. The model defines (71) point sources of contamination from the Cities of Ottawa and Gatineau including: combined sewer overflows, storm outfalls, contributing tributaries, and wastewater treatment facilities. The Water Quality Model simulates river flow and current patterns for a 28-kilometre section of the Ottawa River extending from the Chaudiere Dam near Lemieux Island downstream to Masson and Cumberland. Certain types of bacteria such as Escherichia Coli (E. coli) are associated with human and animal faeces. When it rains, outfalls and other sources of contamination release plumes of bacteria that flow into the river. Concentrations of bacteria are highest where contaminants are first discharged to the river. Concentrations gradually decline as bacteria die off and plumes are diluted and distributed further downstream. The level of microorganisms in river water changes continuously. On average, the background concentration of E. Coli at the Chaudiere Bridge near Lemiuex Island is less than 100 counts/ml. Elevated levels of bacteria above the level recommended for recreational contact may result in beach closures. In general it takes 12 to 24 hours, after it rains, for contaminants from downtown Ottawa and Gatineau to flow downstream past the Cumberland Masson area and for the background level of bacteria to return to normal levels. The time of travel downriver is longer for plumes trapped alongshore. VideoThis video clip depicts how releases from Combined Sewer Overflows mix with river flow from the Ottawa River and become dispersed and diluted with time. Generally it takes approximately 12 to 24 hours for material that is released after a rainfall to work its way downstream. Watch the video: |
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