Hamilton’s $1-billion plan to stop sewer overflows and flooding

Hamilton is eyeing a $1-billion plan to dig up and separate the lower city's combined sewer system that is so often to blame for flooded basements and sewage spills.

That separation of sewage and stormwater pipes won't happen fast - think decades, not years - but it needs to happen, say a new study, especially given the growing risk of climate change-fuelled storms.

Councillors saw the results of a flooding and drainage study Wednesday that recommended a range of short- and long-term actions to protect both homeowners and the environment from Hamilton's chronic sewer overflow woes.

We do see a future free from the constraints of the old combined sewer system," said Mark Bainbridge, director of wastewater planning - but realizing that vision will require significant financial resources."

The study recommends about $367 million in spending on priority" projects to prevent flooding and cut sewer overflows in the next 10 years - with priority areas evaluated based on historic flood risk, pipe age and topography.

More than $1 billion will likely be needed to gradually separate most combined sewers - and thus virtually eliminate" sewage-laced storm overflows. The time horizon for all of that work extends far beyond 20 years.

Projects you might see sooner rather than later include a west-end sewer separation project based on the outcome of a pending environmental assessment, as well as a project to reroute an Ainslie Wood creek - which historically was directed straight into the sewer.

The daunting price tag only highlights the need" for Hamilton to look seriously at a dedicated stormwater management fee, suggested Mountain councillor John-Paul Danko.

It's pretty clear to me we will need assistance from upper levels of government to come anywhere near that level of investment," he added.

Stormwater fees - which opponents derisively label a rain tax" - are increasingly used in other communities to offset the huge costs of climate-proofing aging and inadequate sewer systems.

Hamilton council has debated such a fee repeatedly in the past without taking action. The next report outlining the options is expected in 2023.

Combined sewer pipes are only located in the lower city and were built nearly a century ago to flow both sewage and storm water together. When storms dump too much water into those combined sewers, the excess can back up into basements or spill into the harbour, Chedoke or Red Hill creeks via overflow pipes that act as relief valves.

The city has separated some sewers in the past, upgraded its wastewater treatment plant and spent tens of millions of dollars building emergency underground tanks that catch watery sewage otherwise destined to end up into creeks.

But storm-swamped sewers still spit 2.3 billion litres of watery waste into the environment in 2020 - and a malfunctioning sewage tank gate infamously allowed 24 billion litres of sewage to escape into Chedoke Creek between 2014 and 2018.

Separating combined sewers will help keep flushed sewage out of the environment, said Bainbridge - but stormwater by itself can be full of pollutants, too. Think pesticides, spilled fuel and other roadway contaminants.

That means if the city builds new dedicated stormwater outlets in future, it will also have to look for new ways to clean that water before it ends up in local creeks, the harbour or Lake Ontario, he said.

Matthew Van Dongen is a transportation and environment reporter at The Spectator. mvandongen@thespec.com