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Planning and Consultation

Planning Process

Background and Council Reports

The CSST project is the result of an extensive planning process, including an Environmental Assessment study. During this study, a wide range of conceptual alternatives were considered, a formal screening and evaluation process was developed and followed, and a preferred alternative was identified. This process also provided a range of public consultation opportunities, including Public Open Houses held as part of the Ottawa River Action Plan (ORAP) in late 2009, as well as several more public consultations in 2010 and 2012. The results of the Environmental Assessment study were received by Committee and Council in 2013 (include link: City Council – ORAP Status Update and CSST Environmental Assessment).

Recognizing the importance of the health of the Ottawa River, Council and Committee confirmed the project as a Term of Council Strategic Initiative (SI) in the City’s 2015-2018 City Strategic Plan on July 8, 2015.

Further to a procurement process, Dragados Tomlinson Joint Venture was selected to construct the Construction of the Combined Sewage Storage Tunnel. Implementation officially began in the summer of 2016 at Site 10 (intersection of Kent Street and Chamberlain Avenue), which is the location of the portal for the North-South Tunnel (NST) where the Tunnel Boring Machine will be launched in 2017.

As the project moves into implementation, efforts will continue to ensure that residents, the public and all key stakeholders are informed and engaged throughout construction and in advance of any major construction activities.

In addition to this webpage, residents looking for additional information on the CSST project can access:

Regularly distributed e-newsletter with updates on construction activities, impacts, and progress. Residents can sign up to receive updates automatically at

Email address (link sends e-mail) for inquiries

To date, three public information sessions have been held in advance of site specific construction activities: one at Site 10 (June 27, 2016), and two for Site 5 (October 27 and November 16, 2016). Further sessions are anticipated as construction progresses, and dates and locations will be posted on the website.

Environmental Study Report (ESR) – Addendum – 3 April 2014

Combined Sewer Overflow (CSO) Storage Environmental Assessment and Functional Design Project

Like most municipalities, the City of Ottawa has combined sewers in older areas of the City, which transport sewage and stormwater runoff in the same pipe. These older systems were designed to overflow when it rains to prevent flooding and basement backups.

The City of Ottawa has completed an Environmental Assessment (EA) and Functional Design to identify and develop a preferred solution that will provide additional storage of combined sewage in the combined sewer area and thereby reduce combined sewer overflows (CSOs) to the Ottawa River. This is one of seventeen projects included in the City’s Ottawa River Action Plan. It is being conducted under the Municipal Class EA process.

When implemented, the project will help to:   

  • Reduce CSOs from the Ultimate Combined Sewer Area;
  • Improve water quality in the Ottawa River; and,
  • Become fully compliant with Ministry of Environment’s Procedure F-5-5

Why is the project needed?

Currently, CSOs to the Ottawa River do not meet all provincial CSO control targets. The City’s Combined Sewer Area Pollution Prevention and Control Plan (PPCP) has identified that storage within the Ultimate Combined Sewer Area is the most cost effective way of further reducing CSO beyond the minimum regulatory requirements.

The Process

This project followed Schedule C project of the Municipal Class Environmental Assessment process. Public consultation was carried out throughout the project, including three series public open houses held on the following dates:

  • Spring of 2009
  • June 2010 and
  • June 2012

The Environmental Study Report (ESR) has been completed and has been placed on record January 25 2013 for public and agency review for a 30-day period. Subject to comments received as a result of this Notice and the receipt of necessary approvals, the City intends to proceed with the detailed design of this project in 2013.

The Environmental Study Report (ESR) is available on-line; alternatively, hard copies can be reviewed at the following branches of the Ottawa Public Library:

  • Hazeldean: 50 Castlefrank Road
  • Ruth E. Dickinson: 100 Malvern Drive
  • Main: 120 Metcalfe Street
  • Orléans: 1705 Orléans Boulevard

Interested persons are encouraged to review the ESR and provide comments within the 30 day review period to the City of Ottawa Project Manager listed below. If after consulting with the City of Ottawa, you have unresolved concerns, you have the right to request the Minister of the Environment (135 St. Clair Avenue West, 12th Floor, Toronto, Ontario, M4V 1P5) to “bump-up” (i.e. make a Part II Order for) this project. A Part II Order may lead to preparation of an individual environmental assessment. A written copy of the “bump-up” request must be received by the Minister of Environment by Monday 25 February 2013 at the address indicated above. A copy of the request should also be sent to the City of Ottawa Project Manager at the address indicated below. If there are no outstanding concerns after Monday 25 February 2013, the project will be considered to have met the requirements of the Class EA and the project will proceed with detailed design and construction as presented in the planning document.

Information will be collected in accordance with the Freedom of Information and Protection of Privacy Act.