Restoration of previously drained or damaged peatlands, including the Burns Bog Conservation Area in Delta, has been found to successfully revert them back to carbon sinks.
That’s what a report to Metro Vancouver’s Climate Action Committee noted in an outline of ongoing greenhouse gas (GHG) reduction initiatives, including emissions from peat decomposition during excavation.
Earlier this year, the committee received a report on Metro Vancouver’s air quality regulatory role, and subsequently discussed opportunities to reduce GHG emissions from landscaping equipment and the impacts on air quality during excavation processes.
Staff were requested to report back on GHG emissions associated with decomposition of peat during excavation processes.
Peatlands are classified as a terrestrial wetland ecosystem, where waterlogged conditions prevent the total decomposition of plant matter. While the conditions can result in methane production, peatlands are also a large natural terrestrial carbon sink.
The report also notes that the excavation of peatlands has been found to cause relatively low levels of direct, immediate GHG emissions, even when considering emissions from excavation equipment. However, ongoing peatland excavation could lead to a longer-term net increase of GHG emissions, which can be attributed to a combination of increased carbon dioxide production and the reduced ability of the peatland to sequester carbon.
Restoration of the previously drained or damaged peatlands in Burns Bog has been found to successfully revert it back to carbon sinks, so they have been the subject of several Sustainability Innovation Fund projects.
Meanwhile, the City of Delta is hoping to raise the water table in an area of Burns Bog.
A request for bids was recently issued for a qualified consultant experienced in wetland hydrology and ecological restoration to prepare a conceptual restoration plan for a section located in the southeast corner of the ecological conservancy area, west of 96 Street.
The area includes an agricultural drainage ditch, which the city notes has lowered the water table over decades, resulting in a change from the natural bog plant community to a birch forest with a salal understory.
The water table is now substantially lower compared to undrained areas in the bog, so the goal is to raise the water table in the birch forest area, restore bog plant communities, as well as restart the peat-forming processes while also providing the appropriate conditions for the bog to develop a transitional lagg plant community and accompanying hydrological functions.
A Delta staff report last year noted that a review of water level data from the bog’s interior determined that, despite. summer drought impacts from climate change, water levels are high and stable enough to pause the interior ditch blocking program. The goal is to give Delta and Metro Vancouver enough time to consider an overall restoration plan and priorities for the bog ecosystem.
However, the report also noted that the Burns Bog management team and the scientific advisory panel have agreed that the bog’s edge remains too dry in many areas as a result of perimeter drainage ditches and is a priority for hydrological restoration.
In 2004, four partners - federal, provincial, regional and municipal government - jointly purchased 2,042 hectares (5,045 acres) of Burns Bog to be protected as an ecological conservancy area.
The partners, wanting to make sure the site was maintained using the best science available, agreed to come up with an overall management strategy.
Metro Vancouver’s Burns Bog Scientific Advisory Panel was established in 2005 to provide scientific and technical advice on hydrology and bog ecology to a management team, while an Ecological Conservancy Area Management Plan was completed in 2007.
Delta, specifically responsible for the bog’s hydrology and wildfire management, has undertaken a series of projects, including internal ditch dams to ensure the environmentally sensitive wetland doesn’t dry up.
