Public Notice

February 25th, 2021- The National Capital Commission must determine, as lead authority, whether the proposed upgrade of the Hemlock Pumping Station, located on lands partially owned by the National Capital Commission in Ottawa, Ontario, is likely to cause significant adverse environmental effects.


To help inform this decision, the National Capital Commission is inviting comments from the public on the project and its potential effects on the environment. All comments received will be considered public. For more information, individuals should consult the Privacy Notice on the Registry website.


Written comments must be submitted by March 26th, 2021, referencing project name and registry number.


Contact Information
The National Capital Commission
Environmental Assessment
40 Elgin, 5th floor
Ottawa (Ontario) K1P 1C7


The National Capital Commission thanks you for your comments, which will be considered in the project determination. Please note that responses may not be provided.


General Inquiries
613-239-5000 or 1-800-465-1867 (toll-free)
TTY: 613-239-5090 or 1-866-661-3530 (toll-free)


The Proposed Project


The Hemlock Pumping Station is located at 751 Hillsdale Road, Ottawa, Ontario. The City of Ottawa owns and manages the Hemlock Pumping Station. The City plans to undertake improvements to the Hemlock Pumping Station to prevent potential sewage overflows into the Ottawa River.


The site is located next to a forested area and near private residences. Rockcliffe Park and McKay Lake are approximately 42 m south of the site. As the Hemlock Pumping Station is located partially on NCC land, the upgrade project is subject to Federal Land Use Approval. Additionally, an Environmental Effects Evaluation will be undertaken to determine whether any positive or negative environmental effects are expected to result from the project. An initial screening of impacts has determined that some vegetation may be impacted. The City will undertake replanting to compensate for any tree removals from NCC land at a ratio of 2:1 (two replacement trees planted for every tree removed).


The scope of work for the Project on NCC property includes:

  • Excavation and installation of a new bypass chamber containing a new submersible pump (to permit future pump station and wet well maintenance);
  • Installation of temporary overland or underground piping from the new bypass chamber to the existing chamber (to permit bypass operations);
  • Excavation and installation of a new east chamber for a 900mm sluice gate on an overflow pipe (to isolate overflows and permit bypass pumping operations);
  • Installation of a new backflow valve (to prevent high level river flow from entering the site);
  • Replacement of ladders and platforms in five chambers (accessibility and safety requirements);
  • Installation of a new sluice gate in an existing chamber (to permit bypass operations);
  • Replacement of an existing large flume chamber cover and hatch with three smaller hatches (accessibility and safety requirements); and,
  • Concrete structural repairs in existing chambers.


A portion of the east side of the NCC Ottawa River Pathway will be closed during construction. A temporary detour pathway will be established and maintained at all times.

No impacts are expected to residential water service during the works.

Construction is proposed to begin in August 2021 and be completed in January 2022.

Document Reference Number: 1

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