Groundwater Quality and Availability

Source protection concerns about drinking water supplies tend to focus on groundwater and the lack of information on the quality of this resource in many parts of Ontario, as well as the future threats to groundwater quality. It turns out that there is a considerable amount of groundwater information in the Central Ontario Zone. At the regional scale, assessment of groundwater resources (i.e., available supply) has been mapped and documented.17 At the watershed level, studies of groundwater availability have been completed for a number of watersheds, such as the Grand, Credit, and Humber rivers, and Duffins, Bowmanville, Soper, and Wilmot creeks. The groundwater resources of the Oak Ridges Moraine have also been documented.

Groundwater susceptibility mapping (i.e., showing current clean sources of groundwater that are susceptible to contamination) has been completed at a regional scale for all of Central Ontario. In addition, more detailed maps have been prepared on a watershed basis for the Oak Ridges Moraine. However, additional mapping will be essential to help plan for the anticipated population and business growth in the Central Ontario Zone.

17. See Singer, S.N. and C.K. Cheng. 2001. A Guide to the Assessment of Groundwater Resources in a Watershed. Ontario Ministry of the Environment. Toronto, Ontario.