While several places in Québec are concerned about their future drinking water supply, the Îles-de-la-Madeleine archipelago has significant groundwater reserves, but these are of a unique character given the risks of groundwater infiltration by salt water.
According to a study carried out by researchers from the University of Laval on behalf of the Ministry of Environment and Combating Climate Change (MELCC) and presented to citizens last Wednesday evening, the municipality of the islands has a good deal in the long term with management of its wells, although vigilance is required is.
PHOTO COURTESY / Laval University
The numerical hydrogeological modeling carried out as part of this study makes it possible to estimate the total freshwater reserves of the archipelago at 2.715 million cubic meters (Mm3), while the annual recharge of the water table is 49 Mm3. The annual drinking water consumption of 2.24 million m3 corresponds to only 4.6% of the refill quantity.
The islands’ municipality has a network of 45 wells – only 38 of which are currently operational – which allow pumping pressure to be distributed to the water table to slow the rise of salt water to the surface.
Michel Lemieux, full professor in the Department of Geology and Geology at the University of Laval, who coordinated the study, points out that there is also space for new drilling if needed. “But the current networks are adequate and could be enough to meet the additional demand from population growth or even to account for the effects of climate change, which would reduce groundwater resources,” he says. So it is a question of groundwater management and exploitation. Flow management needs to be done in a fairly subtle way.
However, the islands’ drinking water well network is vulnerable to even the slightest surface contamination related to human activities. Mr. Lemieux also recommends that the community expand the protected areas to include all sectors likely to be drilled in the future. “Just protecting the catchment areas, as we are currently doing, is not enough,” emphasizes the professor. We must plan for the future by protecting the resource. This is important as it can be accessed in the future if the need increases or if the current wells have to be closed for some reason.
The parish of Îles-de-la-Madeleine has the largest number of city fountains in Quebec. In comparison, Trois-Rivières ranks second, with about thirty wells, with a population almost five times that of the Madelinot archipelago.