Sewergate: Hamilton eyes sewage-sucking cattails to clean Cootes Paradise this summer

The fight against Cootes Paradise pollution should ramp up this summer when the city sends a flotilla of sewage-sucking cattails to battle pollution-loving algae blooms.

The Spectator revealed the magnitude of a four-year, 24-billion-litre sewage spill into Chedoke Creek and its receiving marsh in 2019, spurring public outrage, provincial charges and a city promise to help clean up the urban waterway.

Much of the work, however, is still a year or more away. The provincially ordered dredging of sewage-laced hot spots" in the creek, for example, will likely not start before summer 2022.

Councillors also considered a broader study of challenges facing the creek Monday, including sewage overflows, contaminated stormwater and a leaky landfill that combined could take decades and $150 million-plus to fix.

But take heart, marsh paddlers: visible progress" is coming as early as this August, said city water director Andrew Grice.

Grice said the provincial environmental regulator has asked the city to come up with quick win" cleanup projects since dredging cannot start until next year. Right now, the likeliest, fastest options include:

• floating vegetative mats" - think miniature floating wetlands - that feed on excess nutrients found in sewage;

• small mechanical bubbling" machines that add oxygen into dead zones;

• manual cleanup of rotting, floating algae that occasionally builds up near the Princess Point dock.

A mess of dead green algae in April spurred odour complaints and chased kayakers away from the marsh, which is normally a paddling magnet. Sewage overflows provide extra food for those stinky algae blooms.

Grice said the city will consult with marsh owner Royal Botanical Gardens (RBG) before updating councillors on the plan later this summer.

So what would a floating wetland look like?

Expect to see a raft of floating reeds" lurking near the mouth of Chedoke Creek or in the marshy bay near Princess Point, said Tys Theijsmeijer, head of natural lands for the RBG. The size of such vegetative mats can vary, but some are large enough to cover a backyard swimming pool.

Cattails are the best plant for the job of sucking sewage detritus out of the water, Theijsmeijer said, and they can be harvested" to allow a new batch of reeds to grow next spring. The rafts could also become nesting habitat for birds like the black tern, a species of special concern the RBG would love to lure back to Cootes on a permanent basis.

Mechanical aeration is another option to make deoxygenated dead zones habitable again for wildlife. But Theijsmeijer said the challenge this year is unusually low water conditions in Lake Ontario and, by extension, Hamilton Harbour and Cootes.

The bay nearest Princess Point is barely eight inches deep - so not enough water to cover a bubbling" machine.

The province has not set a deadline for the quick win" projects, but the Ministry of Environment, Conservation and Parks told The Spectator by email it wants short-term mitigation measures implemented as soon as possible.

Grice said it will likely be August at the earliest before a pollution-fighting flotilla is launched.

Matthew Van Dongen is a Hamilton-based reporter covering transportation for The Spectator. Reach him via email: mvandongen@thespec.com