Engineered wetlands model provides solutions in Chalk River for Canadian Nuclear Laboratories

DUC has built a reputation for collaboration in conservation circles.

For 85 years, DUC has worked with a diverse collection of partners to fulfill its mission and many of those partnerships have come from unexpected places. That was the case when DUC’s Conservation Pro division was asked to join forces with the Canadian Nuclear Laboratories (CNL) on a water quality improvement project northwest of Ottawa in Eastern Ontario.

Conservation Pro is DUC’s fee-for-service division, which designs, constructs and manages self-sustaining ecosystems with long-lasting benefits to communities. DUC’s expertise in habitat restoration supports collaborative conservation that meets the needs of businesses, individuals and organizations.

New partner in nature-based solutions for environmental protection

In 2019, DUC was approached by CNL to assist with a multifaceted project involving its Near Surface Disposal Facility (NSDF) in Chalk River, Ont. NSDF is a key facility required to enable CNL to conduct environmental remediation of contaminated soils and materials, which are already present at the site. The NSDF has been specifically designed as a permanent solution to reduce environmental risk and isolate low-level radioactive waste, in accordance with international guidance and regulatory requirements.

While it may seem an unusual pairing, DUC is proud to share its value as a nature-based solutions provider with the experts at CNL. DUC is helping to protect the nearby Ottawa River with an environmental project that includes a “polishing wetland” and three naturalized stormwater-management ponds that assist with water-quality improvement at the site.

The naturalized ponds will enhance downstream water quality by lowering total suspended solids and removing excess nutrients prior to release downstream. As a result, wildlife species which include the local Blanding’s turtle population—a Species at Risk in Ontario—will benefit from the restoration project.

The NSDF project design has been completed and is nearly through the approvals stage. Construction of the NSDF site could begin before 2024 and is expected to take three to four years, after which the “polishing wetland” and stormwater ponds will be completed.

Designed monoculture improves water quality but not attractive to wildlife

The big difference from DUC’s usual conservation projects is that the focus is not on wildlife habitat but on these three objectives: water quality improvement, Canada geese deterrence, and low ongoing maintenance costs. The “polishing wetland” and stormwater ponds will function as a cattail monoculture, an ecosystem that is highly efficient at improving water quality but not very attractive to wildlife.

“DUC has designed and constructed more than 100 naturalized stormwater treatment ponds and engineered wetland systems, so we were confident we could provide a cost-effective solution based on natural processes,” said Michael Williams, who leads DUC’s Conservation Pro division in Ontario. “We offer science-based and sustainable solutions. We haven’t worked around an industrial site that generates radioactive material in the past but the principles remain the same. Our expertise was sought and we rose to the challenge.”

Challenging environmental project will demonstrate industry best practice

Beyond expanding DUC’s portfolio of work, the project generates revenue that allows DUC to conserve and restore more wetlands across Ontario, which in turn benefits wildlife, water, and communities.

“CNL is very pleased with our collaborative work with DUC. After four option assessments, we ended up incorporating wetland components into both the NSDF exfiltration gallery and the surface water systems,” said Steve Innes, project director for the NSDF facility. “DUC has a great team of experts who clearly care and are passionate about what they do. They took on a challenging environmental project with us and we executed an end result that demonstrates an industry best practice.”

Note: The Government of Canada has committed to cleaning up historical radioactive waste in Canada. At no point in the process will DUC staff be working with or providing guidance related to nuclear materials and strict CNL safety protocols will be followed before, during and after the project is complete. Once constructed, the NSDF will operate for 50 years and following closure, the site will remain under CNL institutional controls and supervision for hundreds of years as part of regulatory compliance.