La Baie: Protecting future potable water sources

The protection of drinking water sources has become paramount. Pressure on water resources continues to increase, and a growing number of communities are looking to strengthen their resilience in the face of emerging environmental challenges. 

Driven by this commitment, the City of Saguenay took proactive steps to ensure a sustainable supply of drinking water for part of La Baie. After discovering the presence of perfluoroalkyl and polyfluoroalkyl substances (PFAS) in its potable water, the City tasked Englobe and its experienced Water Sciences team to develop forward-looking solutions tailored to the region’s specific characteristics

PFAS: Engaging expertise to combat a growing threat 

Often referred to as “forever chemicals,” PFAS comprise a broad family of synthetic substances that have been used for decades in many industrial and consumer products. Their chemical stability is both their greatest strength and most harmful quality; these substances essentially do not degrade in the environment and can persist in water, soil and various ecosystems for extended time periods

In Canada, PFAS are receiving increasing attention due to their potential presence in some drinking water sources. Used primarily in firefighting foams, waterproofing coatings, cleaning products, and various other industrial applications, they can migrate over long distances and contaminate groundwater and surface water.

In light of this reality, Englobe’s water sciences team leveraged its expertise to assist the City of Saguenay in identifying and developing new drinking water supply solutions.

Supporting a proactive approach through solid data 

The first phase of the project involved obtaining an accurate, reliable assessment of available water resources. Initially, experienced Englobe specialists ran a comprehensive meta-analysis of existing data to strengthen its structure, value, and impact for decision-making. By combining its regional presence, its in-depth knowledge of the Saguenay region and the quality of its collaboration with local stakeholders, the team provided significant added value from the outset of the project. 

Drawing on its experience and significant results from other PFAS-related projects across Canada, the team quickly clarified its technical findings and proposed concrete courses of action. This crucial phase helped lay a solid foundation for the next phase of the work, clarify priorities for action and accelerate the implementation of the required measures.

Finding new water sources for a resilient future

Once the preliminary study was completed, Englobe experts identified two areas with high hydrogeological potential for development of new potable water sources. 

Thanks to the long-standing relationship between Englobe and the City of Saguenay, the project quickly moved into a field validation phase. More than a dozen exploratory wells were drilled, in full compliance with best environmental practices and a constant focus on protecting wildlife, flora, and natural habitats.

Ultimately, two temporary drinking water wells were installed. This made it possible to document, test, and validate the area’s aquifer capacity, ultimately strengthening La Baie’s water resilience.

Reimagining the land for a sustainable future

In addition to offering concrete solutions to ensure access to this essential resource, the project also paved the way for a more comprehensive approach, focused primarily on strategic, optimal, and sustainable land management. 

Water scientists from Englobe and the City of Saguenay jointly developed their vision by connecting La Baie’s varied, mixed land-use components - agricultural areas, wetlands, natural areas, residential areas and industrial zones - to identify ways to foster greater water resilience for the future. 

Finding new sources of drinking water capable of meeting the needs of approximately 19,000 residents is a rare occurrence, both in Québec and across Canada.

Overcoming increased complexity and major technical challenges

 A detailed territorial analysis 

Identifying a suitable aquifer - a geological formation that naturally contains and conveys groundwater - required a thorough understanding of regional geology as well as detailed knowledge of groundwater behaviour and soil characteristics. 

Carried out at a depth of nearly 50 metres, the drilling posed a significant technical challenge. In addition to assessing water quality, this step also had to ensure that the new sources could provide a steady, sufficient flow capable of meeting residents’ needs. Complex materials – primarily sand and granular deposits – were also present in the drilled soils, adding to the complexity of the process.

Innovating for efficient drilling 

In light of these challenges, large-diameter equipment was initially deployed to improve operational efficiency. In addition, the teams used a dual rotary drilling technique, a particularly effective method for drilling through complex soils while maintaining structural stability. 

Similarly, appropriate injection procedures helped control drilling conditions and further enhanced the stability of the surrounding soil. 

Ensuring excellent water quality 

As potable water is a valuable and strategic resource, our water sciences team implemented a rigorous sampling approach to ensure water quality that meets federal standards, among the most stringent in the world. 

Detailed 3D maps of underground water flow were also created to better understand the region’s hydrogeological interactions. This in-depth knowledge helped optimize the selection of future supply sites.

Building water resilience for the future 

Thanks to its cutting-edge expertise in water sciences and close collaboration with the City of Saguenay, the Englobe team helped strengthen La Baie’s water resilience. 

By significantly improving understanding of the region’s hydrogeological conditions, the team helped protect an essential resource while offering residents greater peace of mind in the face of future environmental challenges.