The research aims to advance this understanding through the help of a 1-dimensional (1D) numerical model of the lower Don River extending from Taylor Creek South to the mouth of the river at Keating Channel. Incorporating the simulation of instream processes can enable understanding of temporal and spatial distribution of sediments and metals in detail, which is required for advanced infrastructure planning and informed decision making to restore the river network where possible and mitigate the damage where it is not. Metals can bind to the sediments and can remain in the system for years creating ‘hot spots’ of deposition with possibly elevated local levels of other pollutants. Hydrologic models are commonly used, but they lack the capability to model instream processes that are important in case of metals. Challenges related to quantification of sediments and associated metals flushing through the system can be addressed through implementing appropriate modeling tools.
![pcswmm sediment transport pcswmm sediment transport](https://ars.els-cdn.com/content/image/1-s2.0-S1470160X18304461-fx1.jpg)
Moreover, Wet Weather Flow Management Guidelines (WWFMG) (City of Toronto, 2006) is a document currently used to design stormwater management solutions and restoration plans to control the surface water quantity and quality in the region. Regional Watershed Monitoring Program (RWMP) was launched by TRCA in 2002 to monitor the surface water quality in the region. Efforts have been made to restore the natural water cycle of the watershed by the local authorities such as the Toronto and Region Conservation Authority (TRCA). It recognized the limitations in quantifying such information on a watershed scale. A research study was conducted by (Louie, 2014) to quantify the trace metals distribution in the Don River system and study the spatial and temporal trends of copper, lead, and zinc concentrations. Metals sourced from roads, landfills, industrial effluents, and wastewater treatment plant are a particularly damaging component to the system and need to be quantified and addressed. Such a drastic hydrologic change has resulted in frequent flooding, channel widening and erosion, and poor water quality in the region.
![pcswmm sediment transport pcswmm sediment transport](https://ars.els-cdn.com/content/image/1-s2.0-S1364815221002176-gr4.jpg)
As a result, vast area of built-up land has shifted the watershed’s hydrologic cycle towards lower infiltration and higher runoff rates. The Don River watershed has been subjected to rapid urbanization over the last few decades.