Groundwater in the Great Lakes Basin

Commissioners’ Preface
The Great Lakes, which hold about 20 percent of the
world’s supply of fresh surface water, are one of the most
recognizable sights in the world, but an important part
of the region’s huge water resources is hidden from view.
Groundwater, the water stored underground in the cracks
and spaces in soil, sand and rock throughout the Great
Lakes basin, constitutes an immense unseen reservoir estimated
to be equal in volume to Lake Michigan, which has
some 4,920 cubic kilometres (1,180 cubic miles) of water.
Groundwater and surface water are inexorably linked in
terms of both quantity and quality. For example, Annex
16, which was added to the Canada–United States Great
Lakes Water Quality Agreement in 1987, acknowledges
that contaminated groundwater affects the boundary
waters of the Great Lakes System and specifies how the
two countries should coordinate their existing programs
to control this phenomenon.
Despite these connections, groundwater receives less
attention in the Agreement than it should. Newer government
programs for source water protection do include
groundwater, but Annex 16 is the shortest annex in
the Agreement. For this reason, in our 2006 advice to
governments regarding their review of the Agreement, the
Commissioners of the International Joint Commission
(Commission) noted that groundwater is a larger input to
the Great Lakes than previously recognized and recommended
a number of actions for inclusion in a new or
revised Agreement. 1
The Commission’s focus on groundwater is not new.
We first adopted groundwater as a Great Lakes
priority for the 1991-1993 biennial cycle. 2 A decade
ago, in fulfilling a Reference from governments asking
it to study and report on protecting the Great Lakes,
the Commission devoted a section to groundwater. 3
Groundwater has also been addressed in a number of
other reports to or by the Commission.
To a great extent, our 2006 recommendations to
governments were influenced by the advice we
received from our Great Lakes Science Advisory Board,
Council of Great Lakes Research Managers and Health
Professionals Task Force. Together these three advisory
groups have produced a comprehensive report on
groundwater in the Great Lakes basin. Their collaborative
enterprise brought together different but complementary
areas of expertise represented in our advisory
groups, and also featured four separate consultations
with other experts.
The result is this substantial document of 13 appendices
covering issues that range from progress on
understanding groundwater issues in the Great Lakes
basin to threats to groundwater quality from a variety
of sources. Actions needed on a priority basis include
expanding research into the factors affecting groundwater
quantity and quality; increasing monitoring and
data management efforts; regulating land use, on-site
wastewater treatment (septic) systems, concentrated
animal feeding operations and abandoned wells; and
providing financial support for remediating leaking
underground storage tanks and sewers.
As recommended, the Commission will continue to
monitor and report on the key issues identified in the
report. We are confident that the information, analyses
and recommendations in this report will be of immediate
assistance to governments, environmental groups,
industry and the public at large, and we expect that the
findings and advice will also benefit those charged with
negotiating changes to the Great Lakes Water Quality
Agreement.
1 See Advice to Governments on their Review of the Great Lakes Water
Quality Agreement: A Special Report to the Governments of Canada
and the United States, International Joint Commission, 2006 at
http://www.ijc.org/php/publications/pdf/ID1603.pdf.
2 See Groundwater Contamination in the Great Lakes, International
Joint Commission 1993 at http://www.ijc.org/rel/pdf/gwcontamination-1993.pdf_
3 See Protection of the Waters of the Great Lakes: Final Report to
the Governments of Canada and the United States, 2000 at http://
www.ijc.org/php/publications/pdf/ID1560.pdf
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