Section Synopsis
Pages: 117-124The provided text outlines the baseline hydrogeological and surface water conditions for a proposed Deep Geological Repository. It details the low hydraulic conductivity of the crystalline rock at depth, the presence of highly saline and ancient groundwater (estimated at over one million years old) below 600 meters, and the current state of surface water quality. While surface water is generally described as healthy, the report notes specific exceedances in E. coli, phosphorus, and certain metals like mercury and copper. The proponent concludes that the deep hydrogeochemical environment is stable and isolated from the surface.
Community Assessment Narrative
The proponent's description of the hydrogeological environment relies heavily on the concept of isolation, using low transmissivity and high salinity as primary indicators of stability. However, there is a notable tension between the 'confidence' expressed and the admitted scarcity of data. With only six deep boreholes and only five instances where deep groundwater flow was sufficient for sampling, the characterization of the entire project site's subsurface may be premature. The text tends to frame technical limitations—such as the inability to collect large water samples—as positive evidence of low permeability, which may overlook the potential for undetected preferential flow paths in fractured crystalline rock. Furthermore, the surface water analysis identifies several exceedances of water quality guidelines for mercury, E. coli, and phosphorus. The narrative characterizes the environment as 'normal' and 'healthy' despite these exceedances, which could be perceived as a bias that minimizes existing environmental stressors. There is also a complete absence of socio-economic or cultural context regarding how local and Indigenous communities utilize these water sources, which is a significant gap in a holistic impact assessment.
Corrective Measures & Recommendations
To improve the technical robustness of the assessment, the proponent should increase the density of the borehole network to better characterize the spatial variability of the rock mass and ensure that the current six boreholes are truly representative of the site's complex fracture network. A more comprehensive sampling program for deep porewater is required to validate the 'ancient' age of the groundwater across the entire repository footprint, rather than relying on limited horizons. This will help mitigate the risk of unexpected radionuclide transport through undetected hydraulically conductive features. Additionally, the proponent must conduct a detailed source-term investigation for the existing surface water exceedances, particularly mercury and E. coli. Understanding whether these levels are naturally occurring or the result of anthropogenic activity is crucial for establishing a defensible baseline. The proponent should also initiate a formal program to integrate Indigenous Knowledge regarding local hydrology and water use. This should involve collaborative monitoring with local communities to ensure that the assessment accounts for seasonal variations and cultural dependencies on specific waterbodies, thereby addressing the current lack of social and cultural considerations in the baseline data.
On 16 February, 2026 the Impact Assessment Agency of Canada (IAAC), with input from the Canadian Nuclear Safety Commission (CNSC), published a Summary of Issues (SOI) for the proposed Deep Geological Repository (DGR) for Canada’s Used Nuclear Fuel Project, put forward by the Nuclear Waste Management Organization (NWMO). The SOI identifies the key issues that IAAC considers relevant to the federal integrated impact assessment process for the project. NWMO’s response to the SOI will assist IAAC in determining whether an impact assessment is required under section 16 of the Impact Assessment Act. If an impact assessment is required, the issues outlined in the SOI—together with NWMO’s response—will help shape the scope of the assessment and inform the continued development and finalization of the Integrated Tailored Impact Statement Guidelines and associated plans.
Alignments to IAAC Summary (SOI)
The technical findings and public comments provided by Melgund Township show a high degree of alignment with the "Summary of Issues" (SOI) published by the Impact Assessment Agency of Canada (IAAC) on February 16, 2026. Specifically, the community’s concern regarding the limited number of deep boreholes (only six for site-wide characterization) directly supports the IAAC’s requirement under the Geology, geochemistry, and geological hazards theme, which emphasizes the need for a detailed understanding of rock permeability and the presence of faults and fractures to determine long-term containment suitability. The community’s observation that a small sample size increases the risk of missing major fracture zones validates the IAAC’s focus on "structural stability" and the "high uncertainty" noted in the Accidents and Malfunctions section of the SOI.
A significant alignment exists regarding water quality and cumulative impacts. Melgund Township’s identification of mercury exceedances in surface water—and the lack of investigation into their source—directly intersects with the IAAC’s concern under Human Health and Well-Being, specifically the "cumulative health effects in the region... including the intergenerational health implications of historic mercury releases from Dryden Mill." By flagging these exceedances, the community provides technical evidence that supports the IAAC’s broader concern that existing contamination could be exacerbated by the project or mask its future impacts. This also aligns with the IAAC’s Groundwater and Surface Water theme regarding "potential and cumulative project effects" on water quality.
Furthermore, the community’s finding that Indigenous Knowledge (IK) is absent from the watercourse baseline identifies a critical gap that the IAAC has flagged under the Indigenous Peoples section. The SOI explicitly calls for the "Consideration of Indigenous Knowledge" and expresses concern over "missing baseline data" regarding land and resource use. Melgund Township’s assessment confirms that the proponent’s current submission fails to meet these federal expectations, particularly regarding the identification of culturally significant water sources. Finally, the community’s critique of the proponent’s "absence of evidence" regarding glacial meltwater penetration aligns with the IAAC’s overarching concern regarding "high uncertainty" and "limited, inaccurate, or missing baseline data" needed to predict long-term effects.
Recommendations
The working group recommendations focus on enhancing the technical and cultural integrity of the impact assessment to ensure it meets the rigorous standards outlined in the IAAC Summary of Issues. To address the "high uncertainty" and "suitability of host rock" concerns identified by the Agency, it is recommended that the proponent significantly increase the density of the borehole network. This expansion is necessary to move beyond the current limited characterization and provide a statistically valid representation of the site’s complex fracture network. Furthermore, a more robust deep porewater sampling program must be implemented to verify the "ancient" age of groundwater, thereby providing the "detailed understanding" the IAAC requires to ensure long-term waste containment and prevent unexpected radionuclide transport.
To address the IAAC’s concerns regarding "cumulative health effects" and "potential effects on water quality," the working group recommends a formal source-term investigation into existing mercury and E. coli exceedances. Establishing whether these levels are baseline natural conditions or legacy anthropogenic issues is essential for a defensible assessment of the project’s future impacts. Finally, in alignment with the IAAC’s mandate for "meaningful consideration" of Indigenous concerns, the proponent must establish a collaborative program to integrate Indigenous Knowledge into the hydrological baseline. This approach will ensure that seasonal variations and cultural dependencies on waterbodies are not overlooked, directly addressing the gaps in social and cultural data identified by both the community and the Agency.
Key Claims
Underlying Assumptions
Critical Observations & Gaps
Analysis Table| Issue Identified | Implication | Information Required |
|---|---|---|
| Only six deep boreholes were used for site-wide characterization, with very few deep groundwater samples successfully collected. | Small sample sizes increase the risk of missing significant geological features like major fracture zones. | Additional boreholes and more diverse sampling locations to ensure statistical and geological representativeness. |
| Surface water exceedances for mercury, copper, and E. coli are noted but not investigated for their source. | Existing contamination could be exacerbated by project activities or could mask project-related impacts in the future. | A detailed investigation into the origins of these exceedances and their potential cumulative effects with the project. |
| There is no mention of Indigenous Knowledge or traditional land use related to the watercourses mentioned. | The assessment may fail to protect waterbodies of high cultural or spiritual importance to local Indigenous groups. | Consultation with local Indigenous communities to identify culturally significant water sources and incorporate their observations into the baseline. |
| The claim that no glacial meltwater has penetrated the deep zone is based on 'limited' measurements. | The 'absence of evidence' regarding glacial meltwater is used as 'evidence of absence' of potential pathways. | More extensive isotopic testing across a wider area to confirm the lack of recent water recharge at depth. |
Working Group Recommendations
Request a baseline Human Health Risk screening regarding the reported E. coli and Mercury exceedances in local watercourses (Mennin and Wabigoon rivers) to assess safety for recreational and subsistence use.
Request a detailed 'Source Identification Study' for the reported exceedances of E. coli, mercury, and copper in the Mennin and Wabigoon rivers.
Challenge the sufficiency of the hydrogeological baseline, specifically the reliance on only five deep groundwater samples to characterize the entire repository block.
Understanding the Impacts of Nuclear Waste on our Community
This digital archive houses the public comments submitted to the Impact Assessment Agency of Canada regarding Project 88774: The Nuclear Waste Management Organization Deep Geological Repository (DGR) for Canada's Used Nuclear Fuel Project. The impact assessment is led jointly by the Impact Assessment Agency of Canada and the Canadian Nuclear Safety Commission. This archive preserves community perspectives, concerns, and observations shared during the assessment process, particularly in relation to Melgund Township, Northwestern Ontario and the communities of Dyment and Borups Corners who are the closest and most impacted of all in the process.