CGRG Bibliography of Canadian Geomorphology
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Author : Broster, B.E.; and Daigle, A.E.
Date : 2004.
Title : Glacial valley-fills and implications to water management and land-use in New Brunswick: the Fredericton example.
Publication : 49th Annual Meeting of the Geological Association and the Mineralogical Association of Canada. May 12-14, 2004. Brock University, St. Catharines, Ontario.
Issue :
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Abstract
In many communities across New Brunswick, glacial valley-fill sediments provide the best source of potable water; supplies that are often considered to be an unlimited renewable resource. Until recently, few municipalities have been concerned with the potential for saltwater intrusion, aquifer contamination or calculation of sustainable yields. However, some supply-aquifers in coastal areas are now experiencing saltwater intrusion, while in other areas aquifers are threatened by surface-borne contamination, unrestricted extraction, and conflicting land uses. As climate changes, saltwater intrusion will worsen with landward migration of the freshwater/saline interface. In other areas, increased rural and urban demands require accurate delineation of supply aquifers and exploration for new resources. To ensure that communities will have access to freshwater in the future, QUEST is pursuing a research program including: (1) locating buried valleys, (2) subsurface mapping of valley-fill sediments, and (3) quantification of the sustainability of aquifers. Three-dimensional modeling of the sedimentary architecture of valley-fills is a major component of the program. These models will enable characterization of potential aquifers and aquitards, and delineation of their extent and interrelationship to surrounding beds. Such models can facilitate the identification of potential recharge or contamination pathways into buried aquifers, and calculation of unit volumes for estimates of potential storage capacity. A preliminary study, at Fredericton, New Brunswick is nearing completion. An ideal test site, the city is situated in an estuarine valley at tide-head, with its aquifer buried directly under the urban centre. Underlying sediments are typical of glacial valley-fills and over 1000 boreholes have been drilled into the subsurface. This data set has been collected and culled to approximately 475 records containing significant data and verified positioning. Work is still ongoing as more drilling data is recovered and the data set and model will provide a useful tool for engineers and land-use planners. Three-dimensional modeling represents the best mechanism to calculate exploitable resources and to address and prepare for adaptation to the potential impacts of climate change. Where borehole records exist, this mapping tool is a cost-effective approach to delineating aquifer architecture without incurring expensive and unnecessary drilling that can compromise containment by drilling through protective aquitards.
Bibliography of Canadian Geomorphology