The institutions that have guided development of Canada’s water resources have been varied and have evolved in response to different and changing human and biophysical circumstances. Canadians have sought ways to promote development through providing additional storage of water, reducing variability of river flows, and redirecting and utilizing groundwater flows. Only recently have there been concerted efforts to reduce the demand for water. Harnessing water resources has often led to unintended impacts and problems, some of which are described in earlier chapters. Since water is connected through the hydrologic cycle, it is sometimes difficult to manage one water use without significantly affecting another. Many water resource problems can be termed “wicked” or “meta-problems” because they extend beyond the scope of a single government agency and level of government, and are associated with high levels of change, complexity, uncertainty and conflict (Mitchell, 2002). Differences of opinion over the goals to be achieved, and uncertainty and disagreement about the means to solve meta-problems are common. Problems can be chronic or acute, and may be bound or framed in technical, economic, legal, political and social ways. Proposed solutions will be multifaceted; hence information concerning human use and biophysical aspects of water and related resources will be required if decision making is to be adequately informed.
Urban development interferes with water resources by altering the hydrological cycle and increasing demands on provision of water services in the affected areas. Changes in the hydrological cycle include altered fluxes of water, sediment, chemicals and microorganisms, and increased releases of waste heat. In general, such changes lead to flow and sediment regime changes, geomorphological changes, impaired water quality, reduced biodiversity and overall degradation of water resources. At the same time, growing urban populations impose increasing demands on provision of water services, including water supply, drainage, wastewater collection and management, and beneficial uses of receiving waters. Integrated urban water management is used to mitigate the conflicts between urban development demands on water services and the resulting impacts on local water resources. Specific aspects of urban development impacts on receiving waters and threats to water availability for municipal water supply are addressed in this chapter. Even though the emphasis was placed on water quantity and availability issues, certain aspects of water quality are also included where appropriate.