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Hours July 12 & 13: Rock Garden will be CLOSED to the public for the SOLD OUT Enchanted Garden event. RBG Centre / Hendrie Park remains OPEN 10 a.m. to 5 p.m.

Lower Chedoke Remediation: Community Participation

July 9, 2025

By Tys Theijsmeijer, Senior Director of Ecosystem Stewardship Programs and Policy

Water quality challenges in the southeast corner of Cootes Paradise Marsh—where Chedoke Creek enters—remain a significant concern, especially during the hot summer months. Along the Desjardins Trail at Princess Point, visitors will encounter a stark contrast: while most of the marsh is now filled with clear water and dense aquatic vegetation, this waterfront area often appears murky and coated with green algae.

During a recent late June visit, I observed conditions very different from past years—essentially a floating raft of green algae. Although visually unappealing, this bloom is a mixed signal: on one hand, it shows that plant life (specifically algae) is finally able to grow, suggesting some degree of ecological response; on the other, it highlights the continued excess of nutrients entering from Chedoke Creek.

This section of the marsh consistently shows the highest nutrient concentrations, with phosphorus levels—a key indicator of nutrient pollution—averaging over 0.3 mg/L. That’s nearly ten times higher than what’s considered acceptable in natural environments. Technically, this level of enrichment classifies the water as hypertrophic meaning it supports excessive algal growth that will smother other aquatic life.

Side-by-side images showing Chedoke Creek near Princess Point in Hamilton, Ontario. The left photo features a paved trail beside the creek with green algae and aquatic plants on the water’s surface, bordered by trees and a partly cloudy sky. The right image is a satellite map showing the location of Princess Point, the Desjardins Recreation Trail, Chedoke Creek, Highway 403, and the Hamilton Cemetery.
RBG Photo Desjardins Trail – mouth of Chedoke Creek in Cootes Paradise Marsh – June 29th 2025.

While the presence of these conditions is not new, what is new is the progress being made. The City of Hamilton is now actively consulting on next steps to address the issue—an important and long-awaited development for the restoration of Cootes Paradise Marsh.

Remediation of the damaged habitat and workplan projects continues to move forward. For the lower Chedoke Creek sewage and habitat damage area it is now open to public consultation. This is at stage 1 of review, following the standardized Environmental Assessment process, and includes public consultation, with Open House #1 scheduled for July 22nd.

While water quality in Chedoke Creek has improved in recent years, it still has a long way to go before becoming a healthy and positive contributor to the wetland. Currently, Chedoke Creek stands out as the most polluted tributary in western Lake Ontario, and as such, remains the central focus of ongoing and future remediation efforts.

View of habitat recovery from the York Blvd Bridge looking West over Cootes Paradise July 29th 2025. Chedoke flows into the lower right corner creating the open water/lack of plants with water than passing under the bridges to Hamilton Harbour
View of habitat recovery from the York Blvd Bridge looking West over Cootes Paradise July 29th 2025. Chedoke flows into the lower right corner creating the open water/lack of plants with water than passing under the bridges to Hamilton Harbour

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