The potential impact of climate change in ontario’s grand river basin: Water supply and demand issues

Abstract

The Grand River basin is expected to be one of the more sensitive areas in Ontario to the warmer and drier conditions that may result from anthropogenic climate change. The basin has a large and growing urban population, is dependent on the Grand River for wastewater assimilation and for some municipal water supplies, has experienced significant droughts in the past century, is heavily regulated, and is located well inland from alternative sources of water such as the Great Lakes. Accordingly, the Grand River basin was the chosen focus of a recent study examining the possible effects and implications of climate change and variability on water supply and demand issues. The Water Use Analysis Model (WUAM) was applied to the Grand River basin using 21 scenarios of future surface water supplies, streamflow regulation, population and water use. The ability of the system to maintain adequate streamflow (target flows) at particular sites was assessed for each scenario. Modifications to operating procedures and additional reservoir capacity were shown to be moderately successful adjustments to all but the most severe streamflow scenarios tested. Though it is difficult to justify specific adaptive measures (such as new reservoirs) based on the findings of this study alone, sufficient evidence exists to warrant further and more sophisticated assessments of climate variability and change in the Grand River basin. © 1999 Taylor & Francis Group, LLC.