City study says no Cootes cleanup needed after huge sewage spill

But the city is proposing water-quality monitoring in future at sites where sewage is sometimes dumped into local creeks during major storms

Hamilton says studies ordered by the province show no cleanup or special monitoring is needed in Cootes Paradise marsh as a result of an infamous 24billion-litre sewage spill.

But the city is proposing a future program to keep tabs on water quality in various “urban watercourses” affected by storm-fuelled sewer overflows.

It is unclear if the proposal will satisfy the Ministry of Environment, Conservation and Parks — or the Royal Botanical Gardens, which owns the marsh and has expressed concern that the spill set back Cootes Paradise restoration efforts.

Spokesperson Nick Kondrat said RBG officials are still reviewing the latest

study from SLR Consulting and will have more to say later. “However, our initial assessment is that we strongly believe that additional analysis is required to evaluate the severity of damage” from the four-year spill.

The ministry is also still investigating whether the spill broke the law, and had ordered the city to submit a “surface water monitoring plan” for the marsh by May 1.

A city report argues the ordered monitoring plan related to the spill is “unwarranted.” But the report also notes that council has committed to a wider program of water testing at “discharge” sites in urban watercourses.

City staff declined to answer Spectator questions about that program until after a Wednesday council meeting.

But Ward 1 Coun. Maureen Wilson said she is hopeful the city and its partners — including the RBG and Bay Area Restoration Council — will move forward on a new “watershed governance model” that tackles all manner of pollution dumped into Cootes Paradise.

The SLR report concludes there was no lasting damage to the marsh from the sewage spill, but also notes it is hard to know where pollution is coming from because there are so many sources.

Wilson called that “a damning indictment” of how the city has historically treated the marsh, which sucks up not only sewage but old landfill leachate and toxic run-off from parking lots and highways. “We really need a watershed-wide approach,” she said.

The Spectator exclusively revealed in November that the city was keeping secret the scope of a four-year spill that leaked 24 billion litres of sewage into Chedoke Creek, spurring a public apology from council.

Late last year, RBG head of natural areas Tys Theijsmeijer said he was concerned that the spill contributed to a loss of aquatic plant, insect and bird species in the marsh.

For example, he noted many regenerating marsh plants near the mouth of Chedoke Creek into Cootes Paradise appeared to be “completely wiped out” in 2018, the worst year of the spill. The latest SLR report said the impacts of the spill were shortlived.

An earlier study by SLR also suggested it is “unnecessary” — and probably pointless — to clean up contaminated sediment on the bottom of Chedoke Creek, arguing sewage overflows will continue to pollute the area in large storms.

By contrast, a competing study by Wood Environmental last year recommended dredging the creek pollution to prevent it from moving downstream into the marsh.

The RBG has also discussed novel environmental cleanup options for Chedoke Creek with the city, which include adding floating wetlands and mechanical aeration pipes to the creek.