Successful Application of new Groundwater Resource Mapping Approaches in the Search for Municipal Groundwater Supply in Paleozoic Aquifers Near Acton Ontario
In 2008, Halton Region retained a consultant to locate additional groundwater supplies in an area of near flat lying Paleozoic-age dolostones forming the margin of the Niagara Escarpment cuesta near Acton, Ontario. Two previous groundwater exploration programs that utilized traditional groundwater prospecting techniques (i.e., water well records, published maps, and deep test well drilling) had failed to locate suitable groundwater supplies. Therefore a new approach was required. The regional hydrogeology indicated that groundwater flow in the bedrock aquifers occurred along bedding planes prone to preferential dissolution. The failure of an earlier drilling program demonstrated that transmissivity of the bedding plane features varied significantly across the study area. It was hypothesized that bedding plane features would be more prone to dissolution when intercepted by vertical fractures; however typical indications of fracturing were hidden from view by the overburden cover. Based on the hypothesis and the overburden cover, a prospecting program was developed using a combination of VLF and seismic geophysics to locate vertical fractures in the bedrock hidden from view by the overburden cover. The geophysical program identified a large number of potential sites. These sites were then prioritized using a number of criteria, including an understanding of the regional stratigraphy. Aquifer testing was then conducted at three of the sites, two of which proved to be capable of producing sufficient quantity and quality of waters for a municipal water supply. The presentation will integrate sequence stratigraphic and geomorphologic information to explain the regional variability of this important bedrock aquifer system in southern Ontario in relation to: why traditional groundwater prospecting techniques were of limited use in the escarpment margin region; how the geophysical techniques were used to predict the locations of the hypothesised fractured zones; an analysis of the aquifers at the successful and unsuccessful sites.
The Mapping and Evaluation of Groundwater Resources Ontario, Canada
To delineate and assess Ontario's overburden and bedrock aquifers the Ontario Geological Survey (OGS) has established a multifaceted groundwater mapping program to support sustainable resource development and effective watershed planning. The mapping program consists of five inter-related themes: GIS-based geoscience compilations; watershed-scale inventories; bedrock and surficial aquifer mapping; regional-scale data compilation; and thematic (research) investigations. Historic and/or previously existing geoscience mapping data has been digitized and integrated to form the foundation for additional work by the OGS and other public and private agencies. On-going components of the program involve the integrated use of geologic mapping, stratigraphic investigations, geochemical/geophysical surveys and numeric modelling. Primary thrusts of the program include: determining the regional extent and character of aquifers; identification of new potable groundwater sources; and understanding controls on water quality and quantity. The products and information generated by the program are fundamental to the implementation of provincial water management polices and strategies in that they directly contribute to the management of groundwater resources and an understanding of the physical environment. Outcomes of the groundwater program include: knowledge of aquifer-aquitard relationships allowing realistic vulnerability assessments and thus influencing land-use planning decisions; determination of groundwater withdrawals on the ability of aquifers to sustain production; and population growth centres targeting aquifers discovered by geologic investigations and modeling. Further, the geochemical survey components of the program are establishing regional ambient groundwater/stream sediment parameters to determine anthropogenic influences and delineate areas of potential health concerns and environmental impact. In order to maximize the value of the program and enable the information to be widely used, new products geared to non-geoscientists were developed. These products use limited technical language and several present spatial data on a Google Earth base.
Trends and Collaboration in Transboundary Aquifer Management in the Americas
In the framework of the UNESCO/OAS ISARM Americas project, a questionnaire on Sustainable
Socioeconomic and Environmental Aspects of Transboundary Aquifers was addressed to the participating
countries. The questionnaire inquired about interactions between countries sharing one or more aquifers,
during the past twenty years. Forty nine transboundary aquifers are considered, based on the answers
received. Very few interactions are reported; with a majority of positive ones.
When competition is reported, its main reason is the quantity of water, and in some cases its quality. However
the level of competition is sometimes assessed differently depending on the way it is interpreted.
Reported cooperative interactions differ not only in intensity and level of success, but also in the field and range
of subjects and objectives on which it has been developed; it ranges from information exchange to a complex
strategic management on several subjects. In some cases, while no interactions are reported at the level of
the governments, scientific cooperation is reported as a positive interaction between countries sharing an
aquifer, such as in the case of most aquifers shared by Mexico and Guatemala. Countries indeed find many
reasons to cooperate. The most often mentioned activities to foster cooperation are the conduction of bi or
The information collected lead to the conclusion that the balance of interactions over the use of shared aquifers
leans towards cooperation.
Transboundary Groundwater Along the Canadian-American Border
Canada does not have obvious problems as a consequence of the intensive use of surface water or
groundwater. Canada mostly struggles to keep the quality of its waters, in the highest standards, and to
overcome the knowledge gaps of its groundwater resources. In assessing water resources, it has become
obvious that both surface and groundwater resources are equally important. Because of this shift, Canada is
interested in transboundary groundwater issues, both between provinces and internationally.
There is no competition in Canada for groundwater resources between provinces or internationally. When an
aquifer extends beneath the border of two jurisdictions, conflict may arise when one jurisdiction depletes
groundwater resources that affect the quantity and quality of water available to the other jurisdiction. The most
important cases of transboundary aquifers within Canada are located in the Prairie Provinces, but no
competition has been reported. The equitable and "reasonable" use of shared waters is the most essential
principle considered when negotiating a groundwater apportionment method. Other factors considered are: the
priority use, the sustainable yield of the aquifer, and the joint apportionment of surface water and groundwater
Over 20 million Canadians live in watersheds that cross the Canada-US border (over 17 million of them in the
Great Lakes-St Lawrence watershed), and are therefore affected by American policies, or else affect American
water quality. The International Joint Commission is one well-developed and valuable mechanism for
coordinating policies between Canada and the United States. Other mechanisms include provisions under the
North American Free Trade Agreement, supported by its environmental commission, which attempt to ensure
that the Agreement's policies are consistent with environmental protection and conservation as well as
strengthening the development and enforcement of environmental laws and regulations. Policies affecting
freshwater in the two countries are not harmonized, and a recent opinion poll suggests there is overwhelming
public support in both Canada and the United States for increased harmonization of environmental regulation,
with safe freshwater seen as the top priority in Canada.
During the last five years, Canada has been involved in the ISARM (Internationally Shared Aquifer Resources
Management) initiative. ISARM is an UNESCO led multi-agency effort aimed at improving the understanding of
the management of transboundary aquifers. As a result, seven trans-boundary aquifers were identified
between Canada and USA. There are no international committees yet defined for the joint assessments of
those aquifers; however, the Geological Survey of Canada, the U.S. Geological Survey, the Plattsburg State
University of New York, and the Quebec Ministry of the Environment have closely cooperated in the assessment
of the Châteauguay aquifer.
The ISARM initiative included an inventory of transboundary aquifers from Argentina to Canada, as well as the
analysis of those aquifers, covering four areas of research: a) scientific aspects; b) legal instruments: current
situation and trends; c) institutional aspects; and d) Socio-economical and environmental aspects.
The Canadian government is currently seeking to harmonize water-related policies between jurisdictions
within Canada, and between Canada and the United States. While there are no direct interactions between the
two governments sharing the seven transboundary aquifers, there has been substantial scientific cooperation
in two of them. Canada is currently seeking to increase the Canada-US cooperation in transboundary aquifers.
Geological and Hydrogeological Mapping on the Oak Ridges Moraine
Ontario's Source Water Protection Program requires the production of Assessment Reports that are to be
utilized for land use decision making. The reports are to provide maps of wellhead capture zones, significant
recharge areas and areas of aquifer vulnerability. Many of the ongoing projects are hampered by the scale of
investigation and the lack of aquifer mapping within Ontario. It is not surprising to find that aquifer mapping is
absent given the complex glacial stratigraphy found in many areas of the province. There has never been a
systematic approach within Ontario to investigate aquifer mapping at various scales of investigation. Ongoing
work in the Oak Ridges Moraine area has provided some advanced geological and hydrogeological mapping
that has provided significant advancements to support flow system understanding, however work is still
needed to investigate scale and data quality issues. This paper explores some of the trials and tribulations in
mapping the necessary for source water protection Ontario's Source Water Protection Program requires the
production of Assessment Reports that are to be utilized for land use decision making. The reports are to
provide maps of wellhead capture zones, significant recharge areas and areas of aquifer vulnerability. Many of
the ongoing projects are hampered by the scale of investigation and the lack of aquifer mapping within Ontario.
It is not surprising to find that aquifer mapping is absent given the complex glacial stratigraphy found in many
areas of the province. There has never been a systematic approach within Ontario to investigate aquifer
mapping at various scales of investigation. Ongoing work in the Oak Ridges Moraine area has provided some
advanced geological and hydrogeological mapping within the area. Significant advancements have been
made in terms of supporting flow system understanding, however work is still needed to investigate scale and
data quality issues. This paper explores some of the trials and tribulations in mapping the necessary source
water protection products.
Groundwater Information Network: enabling online access and analysis of Canadian groundwater information
A cornerstone of effective groundwater resource management is access to available groundwater information and tools for analysis, modeling, and eventually decision-making. In Canada, information access is inhibited by the heterogeneous nature of groundwater information, which is collected and maintained by many agencies using different digital structures and contents, and by varying online availability. To overcome these issues, a collaboration of federal and provincial agencies has developed the Groundwater Information Network (GIN, http://gw-info.net). In its first phase, GIN provides a single online data pipeline to the water-well databases hosted by six provincial agencies (British Columbia, Alberta, Manitoba, Ontario, Quebec and Nova Scotia) and to some key aquifer information hosted by Natural Resources Canada. GIN also provides two online portals that can be used to view, download and analyse the information. At the core of GIN is an online mediator that distributes requests for information to the host databases, and translates the replies into a common format (Groundwater MarkUp Language). This allows the portals to treat the distributed information as a single virtual online repository, one with consistent links back to the original databases. Discussed will be the GIN system, including its architecture, functionality, and portals, as well as its overall role as a point of access to some Canadian groundwater information as well as to related web-mapping and analysis tools.
Quantifying Cumulative Effects of Multiple Rock Quarries on Aquifers
The determination of the cumulative effect of more than one quarry on groundwater resources is a task that is being requested by regulatory agencies with increasing frequency, generally as part of a license or permit application advanced by a single quarry operator. One key complicating factor is that data from potentially- competing adjacent quarry operators must be collected to assist the applicant in assessing the cumulative effect of multiple quarries in the same general area. A second complicating factor is that the cumulative effect is strongly dependent on the timing of the development of the quarries under consideration, which is difficult to predict and/or determine from all parties. Notwithstanding these difficulties, the cumulative effect (principally groundwater level drawdown and its effect on wells and surface water features) of a cluster of three existing quarries and one proposed quarry were assessed in support of a quarry license application for the proposed quarry. The method involved the development of regional-scale groundwater flow models of existing and future conditions. The model of existing conditions was based on a structural geological model validated by on-site core logging and geophysical logging and off-site geological mapping. The hydrostratigraphy was aligned with the structural model, and with thicknesses and hydraulic conductivities inferred from the results of packer testing, single well response testing, pump testing, and from calibration of the simulated hydraulic heads to those measured in numerous on-site multi-level monitoring wells and those inferred from static water levels recorded in off-site water wells. The models of future conditions were based on the adjustment of the model of existing conditions to reflect an assumed "worst case" configuration of quarries, with and without the proposed quarry. The modelling results were used to quantify the cumulative effects assuming the successful licensure of the proposed quarry, and the proportion of these effects that would be attributable to the proposed quarry.