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March 31, 2025 / Steve Holysh, Program Coordinator & Senior Hydrologist Oak Ridges Moraine Groundwater Program
Part of the Stories from the Greenbelt series

The Oak Ridges Moraine Groundwater Program – 24 years of groundwater management

Groundwater is the hidden lifeline of the Greenbelt, flowing silently beneath the surface through layers of soil, rock, and glacial sediment. It provides clean, reliable drinking water for many communities and sustains rivers, streams, and wetlands—especially during dry periods when surface water runs low. About 20% of the rainfall and snow that falls on the Greenbelt soaks into the ground, replenishing aquifers and supporting ecosystems from below. This underground reservoir plays a vital role in the health of the Greenbelt’s environment, helping to regulate streamflow, filter pollutants, and maintain biodiversity across the landscape.

In the late 1990s, with urbanization marching northwards from the Toronto area, the Regional Municipalities of York, Peel and Durham recognized the need for action. A series of public meetings highlighted the public’s concern for the integrity of the Oak Ridges Moraine, and of the need for improved management of, and access to, environmental data (and groundwater data in particular). The seeds for the Oak Ridges Moraine Groundwater Program were sown.

The ongoing mandate of the ORMGP is to provide a multi-agency, collaborative approach to collecting, analyzing and disseminating water resource data as a basis for effective stewardship of water resources.”

Now a partnership of 5 municipalities (York, Peel, Durham, Toronto and Halton) and 10 associated conservation authorities, the ORMGP enters its 25th year with some $1 billion in geological and hydrogeological data and knowledge accrued over the years. The ongoing mandate of the ORMGP is to provide a multi-agency, collaborative approach to collecting, analyzing and disseminating water resource data as a basis for effective stewardship of water resources. This involves providing partner agencies with a regional geological and hydrogeological context for ongoing groundwater studies and management initiatives. Improved water-related decision making is the end goal.

Within Ontario, groundwater is expected to play an ever-increasing role into the future as global food production in other countries diminishes, largely owing to over-pumping of groundwater.  This is a global trend, recently highlighted in a series of 2023 New York Times articles. Relatively speaking, as a ‘water rich’ area, the Great Lakes basin, including the Greenbelt, is expected to see increased requests for water taking permits as large food producers look for new areas to exploit. In terms of overall preparedness, the ORMGP is blazing a path by collecting, managing, interpreting and disseminating a wealth of geological hydrogeological, and hydrological data and information.

Several aspects of the ORMGP are unique:

Head on over to Oakridgeswater.ca and explore a fascinating suite of maps and see how your water is being managed.