View of the Ottawa River from Ontario, looking over the Portage Bridge.

Project Update

Combined Sewage Storage Tunnel (CSST)

The Combined Sewage Storage Tunnel (CSST) project will help protect the Ottawa River for future generations. Read on to find out how construction is progressing.

Construction Forecast - Sites on your radar

The map below identifies construction sites for the CSST project within the City of Ottawa. Construction has either started or activities are imminent at the sites indicated in green. The red dots indicate future construction sites. Site 7, identified with the grey dot, was eliminated during the design phase of the project.
Tunneling activities for the North-South Tunnel are anticipated to start at Site 10 by mid 2017. 
Below is information regarding project sites that are currently active:
Map of the CSST sites numbers 1 to 10. Sites 5, 6 and 10 are green, site 7 is grey and all other sites are red

Site 5: East West Tunnel Outlet/Rideau River Collector Diversion – Stanley Park/New Edinburgh Park

Construction activity will begin in New Edinburgh the week of March 20, 2017 to support the construction of CSST access shafts in Stanley Park (to launch the tunnelling operation for the East-West Tunnel) and at River Lane/Queen Victoria.
 An interim truck route will be in place to support these activities and will remain in place until a decision is made on the preferred truck route(s).  This interim route, which is a mix of the routes "N1" and "S1" presented at the CSST Open House (February 22, 2017), provides separate access and egress (exit) for construction vehicles. Specifically, the interim route in the figure below includes:
  • Route N1 functioning as access (enter): Trucks will enter New Edinburgh from Sussex Drive at Stanley Avenue, then access Stanley Park via Queen Victoria 
  • Route S1 functioning as egress (exit): Trucks will exit the construction site along the multi-use pathway (MUP) then leave Stanley Park at Stanley Avenue near Dufferin Road. Trucks will then continue on Dufferin Road to Crichton Street and exit the community westbound at St. Patrick
Implementation of this interim route will involve some temporary improvements where the MUP meets Stanley Avenue at Dufferin Road. The temporary improvements will provide improved safety to the public at that location.

The final report, with the recommended preferred truck routes that incorporate feedback from the open house, will be available to the community the week of March 20.
Interim trucking route
Interim trucking route

Site 6: North South Tunnel (NST) Overflow/Kent Street Outfall - Ottawa River Pathway

This site will be the exit point for the tunnel boring machine traveling northward from Site 10 (Kent and Chamberlain). It will also be a permanent access point to the CSST once complete.
Tree clearing in the area has been completed. The trees were removed early in the year so that the work occurs outside of the general nesting period for breeding birds.
Further to the tree removal, construction activities at this site are anticipated to begin in June 2017.
Tree and brush clearing activities in preparation for construction work
Tree and brush clearing activities in preparation for construction work

Site 10: Chamberlain Shaft – Kent and Chamberlain Street

This site will be the access point for the tunnel boring machine; a shaft is being constructed to launch the tunnelling operation for the North-South Tunnel to the Ottawa River.
Temporary site services (site trailer and electrical power) remain on site.
Controlled blasting continues inside the access shaft to facilitate rock excavation.  Mining of the tail tunnel for the tunnel boring machine will begin in early April under Chamberlain Street.
Rock excavation activities (including controlled blasting) and mining have not affected vehicle or pedestrian traffic. Notices were previously sent to nearby residents informing them of blasting and excavation activities.
Access shaft secured perimeter
Access shaft secured perimeter

Excavation activities at Site 10 in close proximity to homes and businesses


Excavation activities at Site 10 in close proximity to homes and businesses

Mobility & You

Stay informed about capital infrastructure projects. Check out the City's interactive traffic map and traffic report or call 3-1-1 for updates about when and where construction is happening.

Contact Us

Visit us on the web at or email the project team at Note that the website is continuously updated with information on Open Houses, Public Information Sessions, and materials distributed at these events. Please continue to visit for updated information.

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