City of Ottawa has announced that the tunnel boring machine (TBM) working on its CAN$232M (£137M) Combined Sewage Storage Tunnel project has achieved breakthrough on the north-south tunnel.
The new sewer network is formed by two 3m diameter tunnels and will add sewage storage capacity to reduce overflows into the Ottawa River and minimise the risk of basement flooding in low-lying city centre areas.
The Herrenknecht TBM driving the north-south tunnel was launched by joint venture contractors Dragados and Tomlinson from Chamberlain Avenue in December last year. The TBM has completed a 2km long drive through limestone and shale to emerge at the Ottawa River behind the Supreme Court of Canada.
The TBM is now being dismantled and will be used to drive the 4km east-west tunnel from New Edinburgh to LeBreton Flats later this year.
Construction started in 2016 and the project is expected to become operational by 2020.