STORIES FROM THE GREENBELT: The Oak Ridges Moraine Groundwater Program – 24 years of groundwater management

Written by Steve Holysh, Program Coordinator & Senior Hydrologist Oak Ridges Moraine Groundwater Program

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.

Now a partnership of 5 municipalities (York, Peel, Durham, Toronto and Halton) and 10 associated conservation authorities, the ORMGP enters its 25^th 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:

• A laser focus on data and proper data management;
• A partnership that works, including many agencies and consulting companies that both provide and make use of the collective data, and work together to continually improve interpretations;
• A QA/QC system that involves using the data (not just collecting), which allows for errors to be caught and fixed on an ongoing basis, leading to an ever-improving database;
• A focus on the long term (>100 years) and how to pass hidden groundwater stories on to future technical staff – let’s not make the same costly mistakes every few decades and continue to learn from ongoing and past work;
• A holistic approach to water management with climate, groundwater and streamflow data all collected and interpreted together;
• A one-of-a-kind numerical model custodianship program that has collected and verified nearly 100 sophisticated numerical models. With an estimated value in the millions of dollars, these models are considered to be ‘living;’ models that are made available for ongoing and future projects They can be updated as new data is collected.

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