A consultant’s report into Chedoke Creek, in the wake of Sewergate reads like a primer on how to completely destroy a watershed. A partial list of what ails the creek—and Cootes Paradise and Hamilton Harbour downstream, in addition to the open gate at the combined sewer overflow tank that triggered the environmental disaster– includes:
- Clean surface water running into the old landfill site behind Cathedral of Christ the King, picking up contaminates and then leaching back into the creek.
- Loss of the wetland that originally existed at the mouth of the creek, which would have acted as a filter to trap sediments and pollutants
- 1960’s placing sections of the creek in a concrete channel resulting in rapid water flows and loss of natural vegetation,
- Sanitary sewer overflow allowed into the creek
- Contamination by salt-containing melted snow
- Fertilizers and pesticide contamination from upstream agricultural lands and the golf course.
The report suggests complete remediation could cost as much as $110 Million over several years. It suggests some neat term measures that could be taken.
The city is already under orders from the Ministry of the Environment to undertake targeted dredging to remove contaminated sludge from the creek. The report recommends the city also consider small scale aeration, shoreline planting, vegetative mats and beneficial reuse of sediment, and others. The report suggests these measures should be extended beyond Chedoke Creek into Cootes Paradise where the bulk of the pollution occurred.
The vegetative mats referred to in the report are an interest concept. Floating vegetative mats, also known as floating treatment wetlands (FTWs), have been used to manage and remove excess nutrients and metals from surface waters under a variety of conditions. The plants used for FTWs accumulate and store nutrients within their tissues, which can be mechanically removed from the area thereby improving surface water quality.
The report suggests there needs to be more extensive testing of water and fish and plant habitat in Cootes Paradise before a more detailed cleanup plan can be developed.
The report also suggests certain enzymes can be added to the water to help in the clean up process; “certain species of bacteria are capable of decomposing organic sediments and are commonly used in wastewater treatment to provide a number of beneficial functions including reduction of residual biosolids. Enzymes can be added to the process to expedite the decomposition reactions and further reduce the generation of solids. “