The City of Toronto's Water Pollution Solution (technically known as the Wet Weather Flow Management Master Plan) is a long-term plan to protect the environment and sustain healthy rivers, streams and other water bodies. And it's about reducing the adverse effects of wet weather flow through the extensive storm sewer system - 4,500 km in all - to some 2,600 outfalls or outlet pipes. In some cases, stormwater mixes with wastewater in the combined sewers or infiltrates into sanitary sewers. This causes the wastewater system and the City's sewage treatment plants to be overloaded and untreated water enters our rivers, streams and Lake Ontario.
The result: degraded water quality conditions from an environmental and physical perspective including stream bank erosion, loss of fish habitat, basement flooding, and frequently unsafe water quality at many popular beaches along the lakeshore.
To address these problems, Toronto has developed a 25-Year Plan outlining programs and projects that, together, provide a solution for stormwater pollution. Some of the key benefits of this plan are:
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Clean waterfront beaches that are healthy for swimming
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Eliminating discharges from combined sewer overflows
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Basement flooding protection
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Protecting City infrastructure from stream erosion
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Restoring degraded local streams
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Improving stream water quality
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Reducing algae growth along the waterfronts and in streams
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Restoring aquatic habitat
In order to evaluate and demonstrate the beneficial impacts of this plan on the lakeshore water quality, the City of Toronto prepared a three-dimensional water quality model using DHI's MIKE 3 software. Seasonal or annual exceedances of water quality objectives are generally the decision variable of concern. A demonstration of the model's simulation of the present day effects of pollution in Toronto's waterfront during a typical summer storm vs. what the waterfront will look like when the benefits of Toronto's Water Pollution Solution kick in has been prepared.
Click on the picture to download/view the AVI file demonstrating the before and after scenarios:
For more information about the DHI Software technology applied, please feel free to contact: Erland Rasmussen ebr@dhi.dk or Pat Delaney pad@dhi.us US office - DHI Inc.