Monitoring and Modelling of Soil Loss from Southern Ontario Basins during Pre-Development and Development Activities

Bill Trenouth, Bahram Gharabaghi, Ahmad Asna and Ed McBean


Although it is a natural process, rates of soil erosion can climb to levels that are 250 times above background levels during land disturbance and construction activities, with rates that are 40,000 times above background levels having been reported in the literature. In the context of Southern Ontario’s rapidly-developing peri-urban areas, the importance of such findings cannot be understated. With a focus on construction sites in the Lake Simcoe Basin, background monitoring was carried out at two sites and data from a third, active construction site was also included for analysis. Water quality monitoring data was used to estimate event-based sediment yields from each location, and continuously-collected rainfall, water level and turbidity data was used to calibrate an event-based hydrologic model (SEDCAD). Based on the results of this research and the outputs of the calibrated model, an event-based sediment yield equation calibrated for Southern Ontario conditions was developed in conjunction with an IDF design tool. The IDF design tool can be used to effectively size and site construction-phase erosion and sediment controls before shovels break ground. The regulatory framework by which such controls are assessed is also discussed, and improvements to existing stormwater management guidelines are proposed.

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