As the proposed Samonix land-based salmon farming project undergoes Québec's BAPE environmental review process, one of the most closely watched aspects of the proposal is water.
The Ottawa River is one of the Pontiac region's most important natural resources, serving as a source of drinking water, recreation, tourism, fishing, wildlife habitat, and cultural significance. Because the proposed facility would draw water from the river and discharge treated wastewater back into it, many residents have questions about how the system would operate and what impacts it could have on the river.
According to project documentation, the proposed aquaculture complex would produce up to 12,000 metric tonnes of Atlantic salmon annually using a recirculating aquaculture system (RAS), a technology designed to continuously treat and reuse water within the facility.
Unlike traditional fish farms that constantly exchange large volumes of water with the surrounding environment, the Samonix facility is designed to recirculate approximately 99 percent of the water used in the production process. Even so, a continuous supply of fresh water from the Ottawa River would still be required.
The project's water intake would be located approximately 150 to 160 metres offshore at a depth of roughly 7 to 10 metres. Water would be drawn through a screened intake designed to prevent fish, mussels, and other aquatic organisms from being pulled into the system. The intake velocity is proposed at approximately 0.035 metres per second, which is below commonly accepted thresholds intended to reduce the risk of entrainment of aquatic life.
According to project documents, daily water withdrawals would range between approximately 2,300 and 4,000 cubic metres per day. To put that into perspective, one cubic metre equals 1,000 litres, meaning the facility could withdraw between 2.3 million and 4 million litres of river water each day.
While that may sound substantial, the Ottawa River is an extremely large water body. The project's environmental assessment estimates the river's minimum average flow at approximately 402 cubic metres per second, equivalent to more than 34.7 million cubic metres of water moving downstream each day. Based on those figures, the project's water withdrawals would represent only a tiny fraction of the river's overall flow.
Before entering the fish production systems, river water would undergo extensive treatment. The proposed treatment process includes coagulation, flocculation, sedimentation, filtration, ozonation, and ultraviolet disinfection. These processes are commonly used in municipal water treatment facilities and are designed to remove suspended particles, organic matter, microorganisms, and other impurities. A portion of the treated water would be used for domestic purposes within the facility, while the remainder would be directed into the fish-rearing systems.
The facility would raise salmon through different stages of development. Young fish would be reared in freshwater, while older fish would be transferred to brackish water systems that more closely resemble the conditions salmon experience as they migrate toward the ocean. Salt would be added to create these brackish water environments.
As fish grow, they produce waste. Uneaten feed, fish feces, dissolved nutrients, and biological by-products accumulate in the water and must be removed to maintain fish health. This is where the recirculating aquaculture system becomes critical.
Within the facility, wastewater would undergo multiple stages of treatment. Solids would be removed through filtration and dissolved air flotation systems. Biological treatment systems would convert ammonia produced by fish waste into less harmful forms through nitrification and denitrification processes. Additional filtration, ultraviolet disinfection, and ozone treatment would further improve water quality before discharge or recirculation.
The project proposes separate treatment systems for freshwater and brackish water streams before they are combined and subjected to final treatment.
Even after treatment, some substances would remain in the discharged water. The environmental assessment focuses particularly on chlorides, nitrogen, phosphorus, and suspended solids.
Chlorides are salts dissolved in water. In the Samonix project, chloride concentrations originate primarily from the addition of salt used to create brackish water environments for salmon during later growth stages. Elevated chloride concentrations can affect freshwater organisms if present at sufficiently high levels for extended periods.
Nitrogen is a naturally occurring nutrient found in fish waste and organic material. In excessive concentrations, nitrogen can contribute to water quality problems and excessive plant or algae growth in some aquatic environments.
Phosphorus is another nutrient associated with fish waste and uneaten feed. Like nitrogen, elevated phosphorus concentrations can contribute to eutrophication, a process where excessive nutrient levels stimulate plant and algae growth, potentially affecting aquatic ecosystems.
Suspended solids are tiny particles of organic matter, sediment, or biological material that remain suspended in the water. High levels can reduce water clarity and affect aquatic habitats.
According to the project documents, wastewater treatment systems have been designed specifically to reduce these substances before discharge into the Ottawa River.
Once treated, effluent would be discharged through an outfall pipe located approximately 140 to 160 metres from shore at a depth of roughly 6 to 7 metres below low-water levels. The discharge system would use diffusers designed to promote rapid mixing and dilution within the river.
Project modelling indicates that chloride concentrations would decrease rapidly after leaving the diffuser. According to the environmental assessment, chloride levels are expected to fall below the Canadian Council of Ministers of the Environment's chronic toxicity threshold within a short distance of the discharge point and approach natural river concentrations further downstream. However, these predictions are based on modelling assumptions and would need to be confirmed through ongoing monitoring once the facility is operating.
A key part of the regulatory process involves Environmental Discharge Objectives, commonly referred to as OERs in Québec.
Environmental Discharge Objectives are site-specific performance targets established by Québec's Ministry of the Environment, the Fight Against Climate Change, Wildlife and Parks (MELCCFP). They are designed to ensure that wastewater discharges do not create unacceptable impacts on receiving water bodies. OERs establish concentration limits and performance targets for various substances based on the characteristics of both the discharge and the receiving environment.
The Samonix project would be required to meet these objectives before wastewater could be discharged into the Ottawa River. The company has stated that it will comply with current OER requirements as well as any future updates issued by the ministry.
To verify compliance, the project proposes an extensive environmental monitoring program.
According to project documentation, wastewater would be monitored weekly for parameters including chlorides, pH, dissolved oxygen, nitrogen, phosphorus, and total suspended solids. Monthly acute toxicity testing and quarterly chronic toxicity monitoring would also be conducted. Additional inspections would evaluate treatment systems, stormwater infrastructure, and restoration of disturbed areas.
The company also proposes maintaining detailed records of chemicals, medications, and disinfectants used on-site. An Environmental Compliance Officer would oversee monitoring activities, ensure sampling protocols are followed, and validate reports submitted to regulators.
For many residents, the central question is not simply whether the facility can meet regulatory standards on paper, but whether those standards will continue to be met consistently over years and decades of operation. Supporters of the project point to the multiple treatment systems, extensive monitoring requirements, and the Ottawa River's substantial flow volume as evidence that impacts can be effectively managed. Critics, meanwhile, often argue that long-term environmental performance can only be fully assessed through continued oversight and real-world operating experience.
As the BAPE review continues, questions surrounding water withdrawal, wastewater treatment, river health, and environmental monitoring are likely to remain among the most closely examined aspects of the proposed project. Water is at the centre of how a land-based salmon farm operates, and understanding how that water moves through the facility may help residents better evaluate both the potential benefits and the potential risks associated with the proposal.