City says 24 billion litres of sewage and runoff leaked into Chedoke Creek

The City of Hamilton says one of its sewage overflow tanks leaked an estimated 24 billion litres of storm runoff and sewage into Chedoke Creek over more than four years.

The spill works out to about four per cent of the annual volume of flow to the city's wastewater treatment plants, according to a media release.

"It's kind of horrifying and it's also really profoundly disappointing and kind of sad that this has happened and that nobody noticed for that amount of time," said Lynda Lukasik, executive director of Environment Hamilton.

"This will end up going through the courts and the city could face fines under provincial legislation," she added. "Depending on what the ministry's investigation uncovers we taxpayers may be on the hook for a substantial fine."

Residents only learned of the leak which was allowing untreated wastewater to flow into the creek in July 2018, when the city says staff discovered it. But an investigation revealed a bypass gate, which was supposed to be fully closed, had been left about five per cent open on Jan. 28, 2014.

"Despite extensive investigations, the City has not been able to determine why the bypass gate was opened," states the release.

Once the spill was discovered, the city says it stopped the discharge and began cleaning up the area.

Staff reported the spill to the Ministry of Environment, Conservation and Parks (MECP), which issued orders under the Environmental Protection Act and is continuing to investigate.

Ministry issued 2nd order to city on Nov. 14

Gary Wheeler, a spokesperson for the MECP, said the ministry's role is to ensure the city is doing everything it needs to in order to clean up the spill and ensure the sewage tank is fixed so no further leaks can happen

The ministry ordered the city to undertake several steps including evaluating the amount that was spilled and timelines for remediation and report back by August 15, 2018, he said. Hamilton was also required to identify all sewer overflow locations and evaluate the need for improved monitoring and reliability.

Wheeler added that a second order was also issued to the city on Nov. 14, calling for clarification and confirmation around things like impacts, remediation recommendations and monitoring.

He declined to provide any other information about the investigation.

"Hamilton City Council takes this matter very seriously and today is sharing additional information that has become available based on the City's investigations," stated the city in its release, which came out shortly before the Hamilton Spectator published a story based on confidential reports about the spill.

A call for more 'more rigorous checks'

The city explained that like many other "older cities" Hamilton has a combined sewer system that's used to collect both storm water runoff and sewage from homes — both of which were leaked into the creek.

The waterway flows into Cootes Paradise, a marsh that a variety of agencies have spent millions trying to restore and clean up over many years.

Lukasik pointed out that the combined sewer overflow (CSO) tanks are an important part of that massive rehabilitation effort. 

They work by collecting sewage and runoff during the spring melt or extreme rain events and storing it, so it can be processed later. But the leak meant one of the tanks that was supposed to be saving the waterfront from damage was actually storing up harmful material only to release it directly into the water it was supposed to protect.

"That sure as heck is not what that tank is designed to do," she explained. "It says to me that there's obviously a need for more rigorous checks and balances at these CSO tanks to make sure this kind of thing doesn't happen."

In response to the spill the city says it has taken several actions including retaining an external consultant to review the environmental impacts of the leak and make recommendations about how to remediate the creek.

The city says that expert's work was peer-reviewed by a second consultant, but that both people believe more investigation is required.

Staff have also carried out enhanced inspections of all sewage overflow facilities and an inventory of all valves and control points and reviewed the procedures for the city's response to spills.

City says E. coli levels have dropped

The city describes Chedoke Creek as an "urban watercourse," meaning it already collects runoff and sewage discharge during large storms. Therefore, public health officials are recommending against using any waterways linked to it for things like canoeing or fishing. Signs warning people to stay away are in place and will remain there "indefinitely" says the city.

"Since this came to the attention of the City, staff have continued to monitor water quality in impacted areas of Chedoke Creek," said the city in its press release, adding that work has shown improvements in water quality and odour within weeks of stopping the spill. "Sample results show a dramatic decrease in E.coli levels for the parameters tested, and the results were similar to the levels before the discharge within weeks of stopping the discharge."

The city is also promising to provide updates to council and the public on the MECP investigation.