Post-Disturbance Ecological Monitoring of the South Tailings Pond (STP) Wetlands Complex and Diversion Channel

In 2005, Suncor Energy received approval to build the South Tailings Pond for the Millennium Mine, which led to alterations to fish habitat in McLean Creek and its wetlands. To offset the impacts, Suncor created a diversion channel and a dispersed-flow wetland system known as the STP Wetlands Complex. Fisheries and Oceans Canada authorized the project under conditions requiring long-term ecological monitoring of the creek and wetlands. Monitoring conducted in 2017 evaluated hydrology, water and sediment quality, vegetation, benthic invertebrates, and plankton communities to ensure the constructed habitats function as intended.

Monitoring of the STP Wetlands Complex in 2017 showed encouraging ecological progress, with benthic invertebrates, vegetation, and plankton communities developing quickly and resembling those in natural reference sites. Hydrologic patterns reflected natural variability, with water levels and discharge influenced by rainfall and seasonal events, and water quality mostly within expected ranges despite a few exceedances in aluminum, sulphide, and iron. Vegetation assessments revealed good health, increasing species richness, and signs of maturing wetland systems, though some stations still fell short of success criteria. Plankton and benthos communities were robust and increasingly similar to reference conditions, indicating overall ecosystem functionality, even as ongoing monitoring is needed for complete stabilization and compliance across all indicators.