Parliament Hill / Supreme Court Escarpment Rehabilitation

In the early 1970s, the National Capital Commission (NCC) built a manicured shoreline and the Ottawa River multi-use pathway within the river's 100-year flood plain at the base of the Parliament Hill / Supreme Court escarpment. Since then, both the Ottawa River shoreline and pathway have been subject to floods of different volume and intensity.  While the engineered shoreline and escarpment base have withstood flooding to an extent, the manicured shoreline and adjacent pathway were severely eroded and damaged by the flooding of 2017 and 2019.  To address the damage and erosion caused by these major flooding events, the NCC repaired and reinforced the shoreline banks with a combination of riprap and vegetation that would better withstand flooding.  The aim of the Parliament Hill / Supreme Court escarpment rehabilitation project is to restore, stabilize and revegetate the damaged area, and make it safer for users, as well as more resilient to climate change in terms of major flooding and rainfall events.

Prior to the 2017 flood, the Ottawa River shoreline and adjacent multi-use pathway at the base of the escarpment were meticulously maintained by the NCC and had considerable mature tree growth between the pathway and the escarpment.  The 2017 and 2019 flooding adversely affected these areas of mature trees, which the NCC is also responsible for maintaining.  The flood water remained for a considerable time and, as a result, the combined action of the standing water, waves and impact of water flow, both from the flooding and from the top of escarpment, contributed to considerable erosion and damage of shoreline segments, the asphalt pathway and the adjacent mature tree groupings at the escarpment base.  The significant loss of mature trees between the pathway and the escarpment slope led to further deterioration of the shoreline area.  The escarpment consists of limestone shale bedrock, covered with a variable thickness of topsoil and organic matter terraced with wood logs.  The project entails collaboration with Public Services and Procurement Canada (PSPC), which is the owner of the escarpment slope where some project components will be undertaken.  As the owner and manager of the multi-use pathway and manicured areas at the escarpment base, the NCC is the project leader.

Specifically, the Parliament Hill / Supreme Court escarpment rehabilitation project includes the following components:

  • removal of inert human-made debris, rock, concrete and invasive species such as buckthorn and others
  • removal of dead trees, protection of existing native trees and vegetation, and planting of native trees, seeding mixes, shrubs and perennials
  • rehabilitation of approximately 650 m of damaged sections of the escarpment base, through various approaches to address the specific damage of each section, including installation of an erosion-resistant cover (consisting of topsoil, seeding and sodding mixes), toe improvements, construction of armour stone retaining walls, installation of riprap plus vegetation, rock face repairs, and a combination of these approaches in some sections
  • installation of drainage gullies or other drainage devices to control runoff volume and speed from the top of escarpment

The Parliament Hill / Supreme Court escarpment is one of the character-defining elements of the Parliament Buildings National Historic Site of Canada, a designation from Parks Canada's Federal Heritage Buildings Review Office (FHBRO).  According to the FHBRO heritage character statement, the prominent location, multiple viewscapes in all directions surrounding the site and a "wild" aesthetic are among the site's character-defining elements.  The escarpment rehabilitation project is expected to re-create a lively shoreline that will provide the opportunity for interpretation and safe, enhanced public access to the site.

To prevent potential adverse effects on existing, abandoned and/or planned staircases from the base to the top of the escarpment (i.e. the creation of insurmountable or significant obstructions to future plans), the project will be closely coordinated with PSPC and other stakeholders identified throughout the project planning and implementation phases.  Coordination with the Canadian Wildlife Service (CWS) of Environment and Climate Change Canada (ECCC) will also be required, as the CWS would need to issue a permit under the Species at Risk Act to remove and/or adversely affect six butternut trees, and ECCC will make a determination under the Impact Assessment Act to allow the project to proceed.

Disclaimer

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.

 

Latest update

December 4, 2021 The public comment period on the project is closed. The National Capital Commission is considering comments received to help inform its determination on whether the carrying out of the project is likely to cause significant adverse environmental effects..

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Contacts

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


  • Location

    • Ottawa (Ontario)

  • Nature of Activity

    • Other, not otherwise specified

  • Assessment Status

    In progress

  • Start Date

    2021-11-04

  • Proponent

    The National Capital Commission

  • Authorities

    • National Capital Commission

  • Assessment Type

    Project on federal lands

  • Reference Number

    83139

Nearby assessments

..within 200 kilometres
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