Section Synopsis
Pages: 101-107This document outlines the baseline meteorological and geological data collected by the NWMO for a proposed Deep Geological Repository (DGR). The meteorological section details on-site monitoring since 2021, acknowledging data gaps due to power failures and significant underestimation of winter precipitation compared to regional stations. The geological section emphasizes the site's location within the stable Canadian Shield, citing extensive borehole testing, seismic monitoring, and historical data to support the claim of long-term tectonic stability and low seismic risk.
Community Assessment Narrative
The provided text exhibits a notable tension between its assertions of 'extensive understanding' and the technical limitations revealed in its data collection processes. While the proponent is transparent about equipment failures and data gaps, the reliance on regional data from Dryden to validate on-site conditions is undermined by their own findings. Specifically, the July 2022 rainfall discrepancy—where the regional station recorded nearly triple the on-site precipitation—suggests that localized microclimates may be more significant than the proponent acknowledges. Attributing such a large variance simply to 'localized' weather without further investigation weakens the argument that regional stations are truly representative of the site.
Furthermore, the geological assessment adopts a highly confident tone regarding long-term stability, projecting safety for 'several million years.' While this is based on the historical stability of the Canadian Shield, the transition from a few years of microseismic monitoring to multi-million-year forecasting lacks a transparent discussion of uncertainty or the limitations of short-term observation. The document focuses heavily on technical metrics but lacks any mention of how these findings have been communicated to or validated by local and Indigenous communities, which is a critical component of an Impact Assessment. The admission of underestimating snow water equivalent is a significant technical gap that could impact future hydrological and safety modeling if not corrected with more robust instrumentation.
Corrective Measures & Recommendations
The proponent should immediately upgrade on-site meteorological instrumentation to include high-precision weighing precipitation gauges equipped with wind shields and heating elements. This is necessary to correct the admitted underestimation of snow water equivalent and total winter precipitation. Accurate hydrological baselines are essential for designing site drainage and assessing potential contaminant transport; relying on flawed data or distant regional stations could lead to significant under-design of safety infrastructure.
Additionally, the proponent must provide a detailed methodology for how the short-term microseismic data (collected since 2021) will be integrated with paleoseismological evidence to support the claim of multi-million-year stability. A three-year data window is insufficient to characterize long-term seismic risks in a cratonic setting where 'rare' events are the primary concern. This analysis should be presented in a way that explicitly addresses the uncertainties inherent in geological forecasting to ensure transparency for regulators and the public.
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 from Melgund Township’s review of the proponent’s baseline data show a strong alignment with several key themes identified in the IAAC Summary of Issues (SOI) published on February 16, 2026. Specifically, the community’s observation regarding the underestimation of snow water equivalent and the "zero precipitation" recorded in December 2023 directly supports the IAAC’s concerns under the Groundwater and Surface Water theme. The IAAC identifies a need to understand "potential and cumulative project effects" on "hydrological regimes." Melgund’s analysis demonstrates that the current baseline data is technically flawed, which would inherently lead to the inaccurate hydrological modeling the IAAC is concerned about.
Furthermore, the community’s identification of significant temporal data gaps due to power failures at monitoring stations validates the IAAC’s broader concern regarding Uncertainty related to project effects. Under the "Indigenous Peoples" and "Accidents and Malfunctions" sections of the SOI, the Agency highlights risks associated with "limited, inaccurate, or missing baseline data." Melgund’s specific evidence of power loss in 2021-2022 and 2023 provides a concrete example of these data gaps, suggesting that the proponent’s current monitoring infrastructure is insufficient to meet the IAAC’s requirement for a "detailed understanding of the site."
There is also a critical alignment regarding long-term stability. The IAAC SOI, under Effects of the Environment on the Project, specifically flags "Seismicity" and the "Long-term containment of waste... for millions of years." Melgund Township’s finding that the microseismic network has only been operational since 2021 highlights a significant temporal gap in the proponent's safety case. The community’s concern that a three-year window is insufficient to characterize risks in a stable cratonic setting directly reinforces the IAAC’s call for a better understanding of "structural stability" and "geological hazards" over a multi-million-year timeframe.
Recommendations
The working group recommends that the proponent immediately prioritize the modernization of on-site meteorological stations. To address the issues identified in the IAAC’s Groundwater and Surface Water section, the proponent must move beyond standard sensors and implement high-precision weighing precipitation gauges with wind shields and heating elements. These upgrades are essential to correct the documented underestimation of winter precipitation. Without this high-fidelity data, the "hydrological regimes" and "water quality and quantity" concerns flagged by the IAAC cannot be accurately assessed, potentially leading to the under-design of critical water management infrastructure.
Additionally, to address the IAAC’s concerns regarding Seismicity and Long-term containment, the working group recommends that the proponent develop a formal framework for integrating short-term microseismic data with paleoseismological evidence. This recommendation is intended to bridge the gap between the limited three-year monitoring window and the million-year safety case required by the Agency. By explicitly addressing the uncertainties in geological forecasting and ensuring redundant power for all monitoring equipment, the proponent can provide the "transparency in reporting" and "high-quality baseline data" that both the IAAC and Melgund Township require for a rigorous impact assessment.
Key Claims
Underlying Assumptions
Critical Observations & Gaps
Analysis Table| Issue Identified | Implication | Information Required |
|---|---|---|
| Underestimation of snow water equivalent and zero precipitation recorded in December 2023 despite 67cm of snow. | Inaccurate winter precipitation data leads to flawed hydrological modeling and risk assessment for water management. | Implementation of more sophisticated all-weather precipitation sensors and a re-evaluation of the 2022-2023 water balance. |
| Temporal data gaps in 2021-2022 and February 2023 due to power loss at the monitoring station. | Gaps in baseline data can lead to a failure to capture extreme weather events, which are critical for infrastructure design. | Installation of redundant power supplies (e.g., solar/battery backup) for all critical on-site monitoring equipment. |
| Significant discrepancy in July 2022 rainfall (79.6 mm on-site vs 215.3 mm at Dryden). | If the site has a distinct microclimate, regional data cannot be used to validate the safety case for on-site conditions. | A spatial correlation study to determine the limits of using regional meteorological stations for site-specific modeling. |
| The microseismic network has only been operational since 2021, providing a very limited temporal window. | Short-term data may miss low-frequency, high-impact seismic events necessary for a million-year safety case. | Commitment to long-term monitoring and integration of findings with regional tectonic stress models. |
Working Group Recommendations
Challenge the reliance on Dryden Regional station data to fill on-site gaps, specifically citing the significant discrepancy in July 2022 rainfall (215.3 mm at Dryden vs 79.6 mm on-site).
Request a detailed integration plan of the short-term microseismic data (collected since 2021) with long-term paleoseismological evidence to validate the claim of stability.
Request a corrective action plan for the admitted underestimation of winter precipitation (snow water equivalent) and a retrospective correction of the 2022-2023 water balance data.
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.