CGRG Bibliography of Canadian Geomorphology
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Author : Cummings, D.I.; and Russell, H.A.J.
Date : 2007.
Title : The Vars–Winchester esker aquifer, South Nation River watershed, Ontario: CANQUA Fieldtrip, June 6, 2007.
Publication : Geological Survey of Canada, Open File
Issue : 5624.
Page(s) : 76 p.
Abstract
Groundwater is the source of potable water for >65% of the 250,000 residents in the South Nation River and Raison River watersheds. Of particular importance are two subparallel eskers, the Vars–Winchester and Crysler–Finch eskers, which provide >80% of the groundwater used by municipal water systems. The esker aquifers are prolific, with municipal wells yielding > 500 US gallons per minute (>31 L/s) compared to fractured-bedrock wells that typically yield < 10 US gallons per minute (<0.6 L/s) (Charron, 1978). The development of hydrogeological models to estimate groundwater flow in the esker aquifers has been hampered by a lack of knowledge of the size, shape and internal heterogeneity of the eskers. This presents significant constraints to advancing source water protection plans under the Ontario Clean Water Act (2006). Water-supply management in Ontario has been significantly refocused through the Clean Water Act (2006). A notable part of this act is the “source-water protection” element that mandates municipalities to develop science based approaches to protect surface water and groundwater from which municipal drinking water is extracted. In the South Nation River watershed, the Vars–Winchester esker aquifer has been targeted as the first in a series of groundwater-focused source-water protection studies; the Crysler–Finch esker aquifer will be studied subsequently in 2007–2008. To facilitate this work, a collaborative partnership between the South Nation Conservation Authority, the Geological Survey of Canada (GSC), and the University of Ottawa has been developed. The GSC is delineating and characterizing the eskers using a basin-analysis approach that employs shallow reflection seismic geophysics, boreholes with continuous core collection and outcrop sedimentology. The University of Ottawa is concentrating on shallow hydrogeological measurements and numeric flow modeling of the esker aquifers. Exploitation of eskers for groundwater is relatively common in Ontario, and in glaciated terrain in general (e.g. Caswell, 1988a; Artimo et al. 2003; Bolduc et al. 2006; Riverin, 2006). Despite this, most studies have concentrated on understanding eskers from a sedimentological perspective related to ice sheet processes (e.g. Brennand, 2000), aggregate resources (Gorrell, 1991; Spooner and Dalrymple, 1994) and mineral exploration (Levasseur and Prichonnet, 1995), with comparatively little effort invested in understanding eskers as aquifers. Partially buried or buried eskers in glacial basins can form prolific aquifers (Caswell, 1989) that present numerous challenges to groundwater studies due to the local variability of coarse sediment, elusive high hydraulic-conductivity pathways, narrow width, and long longitudinal extent. The basin analysis approach employed by the GSC to study the Vars– Winchester esker (Appendix A-1) is ideally suited to address these challenges, and will provide a scientific basis for improved source water protection planning.
Bibliography of Canadian Geomorphology