Urbanization, in general, increases impervious cover in a watershed. When impervious cover is increased, precipitation does not infiltrate as it would naturally. Instead, rainfall is quickly piped and channelled directly to the watercourse. An increase in surface runoff from the urbanized areas can result in erosive damage to our streams and structures such as public and private property. Erosion control is part of the overall stormwater management criteria to protect natural channels from adverse effects of increased erosion due to urbanization. If a site drains to a sensitive creek, or if a subwatershed study, MESP, or similarly comprehensive study is required, then the proponent must complete a geomorphologic assessment study to determine the appropriate erosion threshold. After that, continuous hydrologic modeling will be undertaken for the development of the site to determine the volume requirement that mitigates the erosion impacts. TRCA provides the guidance the required processes from desktop analysis to final report.
This tutorial demonstrates how the requirements will be addressed in the modeling work. It covers model creation for pre- and post-development conditions and scenario comparison of various erosion indies.
Please download the attachment for practicing and viewing results.
tutorial – erosion analysis