Toronto launches $3B project to improve water quality in Lake Ontario and city's waterways.

The first phase of the five-phase project — the Coxwell Bypass Tunnel — will see a 10.5 kilometre long and 6.3 metre wide tunnel built at a cost of $400 million. The overall project is expected to cost $3 billion.
https://www.cbc.ca/news/canada/toronto/toronto-storm-water-wastewater-management-program-1.5396886