Former Menez Molve quarry (Berrien, 2022).
© BRGM - Flora Lucassou
The need
As part of the Finistère Drinking Water 2030 project, the Finistère Departmental Council asked BRGM to assess the water storage potential of 1,109 local quarries, with a view to using them for drinking water supplies. The study looked at quarries that had been shut down and repurposed as bodies of water, as well as sites that were still in operation, with a view to possibly using them in the longer term when they are no longer required as a source of materials.
The results
BRGM began by reviewing the current situation and assessing the regulatory feasibility of using bodies of water for drinking water supplies. Next, several criteria for quarry selection were defined with all the stakeholders (departmental council, government departments, quarry operators and contracting authorities producing drinking water):
- geometry suitable for water storage,
- close to existing drinking water infrastructure,
- local interest, etc.
Finally, five closed sites (including one slate quarry) were selected as being of immediate interest, along with two other sites still in operation, that could be of interest in the medium term. These quarries were then studied in more detail by BRGM, in order to confirm or invalidate their relevance in terms of water storage. A literature review was then carried out, along with field measurements to assess the volumes of water available and identify the strengths and weaknesses of each of the quarries, along with any additional knowledge required (hydrogeology and natural hazards).
Our Finistère Drinking Water 2030 action plan has three main goals: reduce consumption, secure production and consolidate management. BRGM has provided invaluable assistance for the second goal. The study identified five quarry sites that could be developed in the short/medium term, and 16 sites in the longer term. The methodology implemented can be shared at regional level to benefit the greatest possible number.
Using the results
Following local consultation, further studies must now be carried out by the local authorities on the sites selected before operational implementation can be envisaged.
Furthermore, sixteen quarries currently in operation with plans for renewal have been identified as being of long-term interest, for potential remediation projects. The Finistère Departmental Council is also looking into the possibility of directly reusing drainage water from the quarries.
The partners
- Finistère Departmental Council
- Brittany Regional Council
- Loire-Brittany Water Authority
