Downstream Monitoring…

Downstream Monitoring Location in the ACS Is Inappropriate and Under‑Represents Actual Impacts

The Assimilative Capacity Study (ACS) relies on water samples collected at the Highway 17 bridge as the “downstream” point for assessing impacts to the Goulais River. This choice is problematic for several reasons:

- The ACS data collected at the Highway 17 bridge already shows Total Phosphorus (TP) at or above the Provincial Water Quality Objective (PWQO).

- MECP has acknowledged this in correspondence, noting that “as per MECP receiver policies, this concentration should not be allowed to increase.”

- Despite this, the ACS treats the Highway 17 bridge as the end of the receiving water system, even though the river continues well beyond this point and flows into Goulais Bay.

- Goulais Bay has a documented history of boil water advisories, including one in May 2025, attributed to natural discharge from the Goulais River during snowmelt and rainfall. Public reporting at the time noted that turbidity was caused by runoff from the river. Elevated turbidity is strongly associated with elevated phosphorus levels, which is precisely why Ontario has a PWQO for TP.

By selecting the Highway 17 bridge as the downstream monitoring point, the ACS does not account for:

-Water quality conditions further downstream
-Cumulative impacts as the river approaches Goulais Bay
- The known vulnerability of the bay to turbidity and bacterial contamination
- The fact that the river is already at the PWQO before any discharge is introduced

This raises serious questions about whether the ACS meets the requirements of Policy 2, which prohibits further degradation when a waterbody is already at or above the PWQO.

Call to Action:
Given these concerns, I respectfully request that MECP:

- Require the ACS to be redone using an appropriate downstream location—at or near the actual end of the river system—not the Highway 17 bridge.

- Require a full 2–3 years of monitoring data, consistent with MECP practice for capturing seasonal and year‑to‑year variability.

- Re‑evaluate whether the current ACS should have been accepted during the ECA pre‑submission stage, given that it relies on a monitoring point already at the PWQO and does not represent the full receiving environment.

- Pause or reject the current ECA application until a complete and defensible ACS is provided, as the ACS forms the backbone of the effluent limits and environmental protection framework.

The current ACS uses a condensed 16‑month dataset, an inappropriate downstream location, and documents TP levels already at the PWQO. These issues must be corrected before any approval is considered.