HRWP Ecologically Significant Groundwater Recharge Areas

An Ecologically Significant Groundwater Recharge Area (ESGRA) can be defined as an area of land that is responsible for replenishing groundwater systems that directly support sensitive areas like coldwater streams and wetlands (Greenbelt Plan, 2017). The protection of groundwater-dependent ecologically sensitive areas depends, in part, on understanding where on the landscape the groundwater comes from and taking steps to ensure the recharge function of these areas is protected (Figure 3). ESGRAs are identified using regional-scale modelling to predict where groundwater recharge at a given location will emerge or “discharge” within ecologically sensitive areas.

The ESGRA layer was developed in 2019 for entire jurisdiction by the Ecosystem and Climate Science team at TRCA in collaboration with the Oak Ridges Moraine Groundwater Program (ORMGP). Ecologically sensitive systems that ESGRAs support include fens (type of rare wetland that depends on groundwater inputs), groundwater dependent cold water fish species, and groundwater dependent plant species. Relevant to this data layer, ESGRAs are defined under the Growth Plan for the Greater Golden Horseshoe (2020) and the Greenbelt Plan (2017). The term also has policy associations in TRCA’s Stormwater Management Criteria (2012). Mapping of ESGRAs can be used to inform decisions around municipal growth through the land use and infrastructure planning processes.