Annex 8: Groundwater quality

The purpose of this Annex is to gain a better understanding of how groundwater influences Great Lakes water quality and ecosystem health, and to identify priority areas for future action.

Groundwater may represent as much as 50% of the water entering the Great Lakes, either directly (via groundwater discharge along the coasts) or indirectly (via discharge into rivers and streams that then discharge into the lakes). Groundwater-based contaminants and excessive nutrients can impair the quality of the waters of the Great Lakes, particularly the nearshore region, with potential effects on aquatic species and recreational waters.

Because groundwater is a potential source of contaminants and excessive nutrients and a pathway for transfer to the Great Lakes, groundwater quality is linked to the successful delivery of key commitments in other Annexes, including Areas of Concern, Lakewide Management, Harmful Pollutants, Nutrients, and Habitat and Species.

Some areas near the Great Lakes are known to have contaminated groundwater. In some cases, initiatives are underway to direct management and/or implement remediation actions in these locations. They include provincial contaminated site remediation efforts such as the Deloro Mine Site, and some of the work done through the Federal Contaminated Sites Action Plan, and the federal remediation of the Port Hope Area. These actions will protect or improve the water quality of the Great Lakes.

This Annex includes commitments to develop a binational state of Groundwater Science Report, create an interagency groundwater issues team, identify priorities for future research, and identify priority areas and sites for monitoring, management or remediation actions to address groundwater impacts and stressors.

Canada will lead, with Ontario’s support:

  1. (a) Development, in cooperation with the United States, of a binational state of Groundwater Science Report in 2015 synthesizing relevant and available groundwater science.

Canada and Ontario will:

  1. (a) Assemble technical and scientific expertise to:
    1. Assess the state of groundwater science as it pertains to implications for Great Lakes water quality and ecosystem health; and
    2. Identify groundwater science priorities and information gaps.

Canada and Ontario will:

  1. (a) Facilitate the coordination, sharing and exchange of information to identify priority sites or areas using, but not limited to, existing and available inventories, where point sources may impact water quality and ecosystem health of the Great Lakes; and
  2. (b) Identify priority sites or areas where point sources may impact the water quality and ecosystem health of the Great Lakes, including nearshore areas.
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