Modeling investigation to support an integrated approach to the management of municipal water resources Southern Ontario

Jurisdictions for the management of water resources in urban areas traditionally have been determined by municipal boundaries, resulting in little collaboration between municipalities within a common catchment on water-related issues. An integrated approach to water management demonstrates the potential to increase the reliance of municipal systems in the future. Through surveys, when considering this integrated approach, waterworks practitioners from across Canada identified aging infrastructure, climate change and urbanization as the greatest contributors to increased risk in municipal water systems that must be considered when developing water management strategies. These three areas became the focus of the ensuing modelling investigation.

To better understand some the risks associated with integrated water management, a model was developed to simulate the hydrological impacts of upstream development on downstream communities for a small catchment in southern Ontario. Runoff hydrographs were determined through EPA SWMM simulations for (i) pre-development, (ii) post-development (status-quo), and (iii) green infrastructure development. The runoff from these three scenarios are described using climate-adjusted design storms of duration 1, 6 and 24 hours at return frequencies of 2, 5, 25 and 100 years. The effects of these events on flood risk to downstream communities was evaluated using a HEC-RAS simulation of a 2 kilometre river reach.

The presentation discusses the model development and preliminary results, as well as the methods used in adjusting IDF curves to account for climate change. A goal of this project is to demonstrate the benefits of integrated water management while using tools readily available for use by municipalities and their consultants.