Archived - Replacement of a floating boardwalk segment within the Mer Bleue Bog, Ottawa, Ontario

The Mer Bleue bog floating boardwalk (ON)

Reasons for a Federal Assessment
Project Description
Final Decision

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Reference Numbers

Canadian Environmental Assessment Registry: 10-01-59668
National Capital Commission: CP2218‑191

Environmental Assessment Type

Screening

Responsible or Regulated Authorities

National Capital Commission

Reasons for a Federal Assessment

On December 16, 2010, it was determined that an environmental assessment was required in relation to the project because the National Capital Commission was the proponent for the project, considered providing financial assistance to the proponent and considered providing federal lands.

Project Description (as posted in the Notice of Commencement)


General Introduction:

The National Capital Commission is proposing the replacement of a floating boardwalk segment within the Mer Bleue Bog, Ottawa, Ontario. The segment, which is part of a larger 1.2 km long boardwalk linked to trails 53A and 53 and one of the most popular year-round in the National Capital Region, has deteriorated beyond repair. As a result, it will be removed and replaced with a new floating structure consisting of different materials and features such as a wider deck, safety handrails and universal access ramps. The project will allow recreational users to continue enjoying a close-up view of the Mer Bleue Bog.

General nature and scale of the project:

The project entails the removal of an existing floating boardwalk segment approximately 171.7 m long and 1.78 m wide, and the installation of a new floating structure. Removal will commence from south to north, and installation will proceed from north to south. The new structure will largely preserve the existing alignment except for the final section to the south which will be straightened over a length of 57.4 m. The straightening will require some vegetation removal. The new boardwalk will match the length of the existing one, but will have a slightly greater width: 1.83 m.

The frame of the new segment will consist of anodized aluminum and floaters by "Dockmaster" or approved equivalence. The new decking will consist of untreated red cedar planks fixed to the anodized aluminum frame. A new untreated cedar board railing system comprised of posts will be installed along the edges of the new decking to support safety railing boards.

The north and south end transitions of the boardwalk will be modified to be wheelchair accessible by installing two series II dock ramps. To ensure lateral stability, the new structure will be anchored into the bog at the north and south ends with two aluminum boards at each end. A small excavation will be conducted at the north end to reinforce the sub-base with infill and compacted stone-dust material over a geotextile, and to smooth the transition with the existing stone-dust trail. At the south end, the new section will be attached to an existing crib-supported boardwalk.

Duration of works:

The works are intended to commence and to be completed during the Winter of 2011.

Environmental setting of the project - General:

The segment is located at the southwest of the Mer Bleue Bog Sector of the NCC 1996 Greenbelt Master Plan and is designated as a Core Natural Area (conservation use). The section is the northeastern portion of a loop trail linked to trails 53A and 53 which are accessible from NCC public parking No. 22 located at the east end of Ridge Road.

The Mer Bleue Bog Sector is one of the largest natural areas in the Greenbelt encompassing about 3,500 ha. It is the largest bog and the only one internationally recognized (Ramsar Convention) in the National Capital Region due to its unique ecology more typical of the Arctic than of the Ottawa Valley region. Mer Bleue is also classified as a Class 1 wetland, the highest designation, and as an area of natural and scientific interest (ANSI) by the Ontario Ministry of Natural Resources (MNR).

The Mer Bleue bog is a drainage area for several streams and is surrounded by marshland, agricultural fields and hardwood forests. Its location makes it is a key connector and a corridor for riparian and wooded environments. In turn, this makes it a key player in protecting the diversity of plants and animals of the Ottawa Region. The vast size and broad range of plant species supported by Mer Bleue provide habitat to some endangered, rare and unique animal species. The oxygen depleted nature of the bog has created habitat to insect-eating plants such as sundews and pitcher plants who obtain their nutrients directly from the insects they capture. The Spotted Turtle (Clemmys guttata) and the Least Bittern (Ixobrychus exilis), species respectively designated as endangered and threatened under the Species at Risk Act (SARA), are known to inhabit the area. Sightings of the Monarch Butterfly (Danaus plexippus), a species designated as of special concern under SARA, and the Fletcher's dragonfly (Williamsonia fletcheri), a rare insect known to inhabit only a few places worldwide, have also been reported in the area. Other wildlife found within Mer Bleue includes common mammals, waterfowl, and amphibians.

The boardwalk is located within the most water-saturated area of the bog known as the "sea" which in some part reaches a depth of 6 m. The "sea" is a fish habitat for Bass, Smelt, Capelin, Eel, Carp, Northern Pike, Perch and Pickerel. A mat of heaths growing over a living layer of moss and sedges known to host 16 of the 70+ regionally rare species surrounds the replacement section.

Main environmental issues of concern:

The main environmental issues of concern stem from the potential effects of the replacement activities on the quality of surface water and on the resident fish, amphibians and plants of the bog. Specifically, the potential disturbance of the bog's bed during the removal of vegetation and/or the entry of other deleterious substances waste and fuels, including spills, are the main concerns. The sustainable management of the Mer Bleue Bog Conservation Area is the broader environmental issue of concern.

Human populations potentially affected by the project (positively or negatively):

The recreational users of the trail loop will be temporarily affected in terms of restricted access during the works.

Final Decision

A decision was taken on January 13, 2011 and was that the authority may exercise any power or perform any duty or function with respect to the project because, after taking into consideration the screening report and taking into account the implementation of appropriate mitigation measures, the authority is of the opinion that the project is not likely to cause significant adverse environmental effects.