Suspected blue-green algae observed at Belwood Lake and Shade’s Mills: GRCA
Posted Sep 1, 2026 03:25:53 PM.
The season may be winding down but summer heat is continuing and the Grand River Conservation Authority (GRCA) says it’s creating the perfect conditions for blue-green algae, with suspected blooms observed at Belwood Lake and Shade’s Mills.
A small bloom was first detected near the boat launch at the Belwood Lake Conservation Area reservoir and a few days later, a small bloom was spotted near the dam and islands in the Shade’s Mills Conservation Area reservoir.
The Ministry of the Environment, Conservation and Parks, and both Wellington-Dufferin-Guelph Public Health and Region of Waterloo Public Health, have been notified.
The formation of blooms is not uncommon for this time of year and permanent signage is posted in the Belwood area and other GRCA lake reservoirs due to the potential for seasonal blue-green algae.
Visitors to Belwood Lake and Shade’s Mills are being urged to avoid contact with the algae, don’t eat fish from the lake, and don’t drink the water.
Boating is still permitted but don’t touch the algae or swim in areas where scum is visible.
“When an algal bloom starts to grow, a noticeable green or brown scum will form on the surface of water bodies and the water look like green or bluish-green pea soup,” said a notice from the GRCA. “Once blue-green algae are in full bloom, it may look like spilled ‘paint’ along the shoreline. A new blue-green algal bloom often smells like fresh cut grass, while an older bloom can smell like rotting garbage.”
Anyone who came into contact with suspected blue-green algae and is experiencing symptoms is directed to contact their physician.
More information about blue-green algae in the watershed can be found by clicking here.
