Upgrade of Hemlock Pumping Station

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.


Proponent Contact

City of Ottawa
Jeff de Laat, Project Manager
100 Constellation Drive, Ottawa, ON K2G 6J8
Telephone: 613-580-2424, ext. 21916




Latest update

September 1st 2021 - The assessment decision statement has been issued to the proponent.


Key documents

Key documents
Document Number Document Title File Date
2 Notice of Determination - September 1, 2021
1 Upgrade of Hemlock Pumping Station - February 25, 2021


National Capital Commission
Environmental Assessment
40 Elgin Street
Ottawa, Ontario K1P 5A8
Email: IA-EI@ncc-ccn.ca

  • Location

    • Hemlock Pumping Station (Ontario)
  • Nature of Activity

    • Water Management
  • Assessment Status

  • Start Date

  • Proponent

    City of Ottawa
  • Authorities

    • National Capital Commission
  • Assessment Type

    Project on federal lands
  • Reference Number


This map is for illustrative purposes. The markers represent the approximate locations based on available data. More than one marker may be identified for a given assessment.


Nearby assessments

...within 200 kilometres
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