Sewage tunnel project 6 months behind schedule, city says

A massive downtown tunnel project intended to keep sewage overflows from spilling into the Ottawa River is running roughly six months behind schedule, the City of Ottawa says.

Construction on the $232.3-million Combined Sewage Storage Tunnel was expected to wrap up by 2019 but will now extend into 2020, according to a memo from Alain Gonthier, the city's director of infrastructure services.

The delay is partly due to "challenges" encountered while commissioning and assembling the tunnel boring machine that will carry out the digging, Gonthier said.

"As with any complex constructionproject, opportunities to recover and/or mitigate this construction delay over the next 24months are being pursued and evaluated," he said.

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Construction started 2 years ago

During major rainfalls, the tunnels will hold up to 43 million litres of surface runoff and wastewater as much as approximately 18 Olympic-sized pools.

Once the rainfall subsides, the water willbe treated before being returned to the Ottawa River.

Work began in June 2016 on a shaft that would grant access to the tunnel at the intersection of Kent Street and Chamberlain Avenue.

Last October, the city announced the 23-metre deep shaft was complete, and that work to assemble the boring machine underground was underway.

Partially finished

Over the next few months, Gonthier said, crews will begin work at a number of other sites:

• McLeod Street and Kent Street.
• Catherine Street and Kent Street.
• Cumberland Street and Wilbrod Street.

In addition tothe delays related tothe tunnel boring machine, the excavation of the Kent Street shaft and starter tunnel also took longer than expected,Gonthiersaid.

Gonthiersaidthe machine is now in operation, and is boring northward underKent Street at roughly 20 metres perday, five days a week.

Approximately 500 metres' worth of tunnel have already been installed, he added.

The project which isbeing funded by the city, provincial and federal governments remains on budget, Gonthier said.