Drought Sensitivity of Municipal Water Supply Systems in Ontario

The sensitivity of municipal water systems to drought was explored in 1999, with particular attention to major urban centres in Ontario’s Toronto-Niagara Region. A framework of sensitivity was developed, recognizing both water system characteristics, such as type of water source and storage capacity, and situational factors, such as population growth rates. The framework was developed from the literature, scoping interviews with officials in six southern Ontario municipalities, and in-depth interviews and document analysis in three case study municipalities: City of Toronto, Regional Municipality of York, and Regional Municipality of Niagara. The framework suggests that system characteristics that increase sensitivity to drought include groundwater and river water sources, older and/or poorly maintained water system components, and limited storage capacity relative to demand. Situational factors increasing drought sensitivity include rapid population growth and lack of demand management measures. Conversely, system characteristics that reduce sensitivity include interconnection of distribution systems and an abundant water source. Suggestions are offered for utilizing the framework as a checklist for assessing drought sensitivity of municipal water systems