Why & How Are We Restoring Burns Bog?
The City of Delta, Metro Vancouver, the Province of British Columbia and Canada are working together to carry out a 100-year management plan for Burns Bog that will preserve and restore the ecosystem.
Why?
The ecological integrity of Burns Bog faces a range of challenges resulting from many decades of peat extraction, drainage, filling, conversion to agriculture, and adjacent urban and industrial uses. Drainage ditches and survey lines were cut through Burns Bog in the early 1900s, but the most significant drainage activity is associated with peat extraction (1930s-1980s).
Before peat extraction and farming activities, Burns Bog covered about 48 km2. During the 20th century, the Bog’s area was reduced to about 30 km2.
Drainage caused a lower water table in the bog. These drier conditions allow trees to take over and remove even more water from the bog. Drier peat also means a greater risk of fire. In response to a large bog fire in 2005, the City of Delta developed the Burns Bog Fire Management Plan, which is updated annually. Delta also worked with Metro Vancouver to put staff protocols in place to minimize the risk of fire caused by human error.
Fighting Fire in Burns Bog (June 17, 2014)
Fire in Burns Bog is a real threat. Peat provides the perfect methane environment for a fire to burn underground for weeks. Metro Vancouver works closely with Delta Fire to ensure fires are fought with a united approach using the latest technology.
How?
The main goal is to keep the water table high so that bog plants can grow. Drainage ditches are being blocked to retain more precipitation in the summer months. Ditches have been blocked with peat dams, wood dams and steel weirs, as well as naturally occurring beaver dams. The dams are then filled with peat dug from a nearby borrow-pit. As of 2019, almost 500 dams had been built in the ditches of Burns Bog by Delta’s ditch blocking crews.
Delta and Metro Vancouver have also been experimenting with tree seedling removal. In the areas burned by large fires in 2005 and 2016, extensive tree seedling establishment has taken place. Dense forests are detrimental to Burns Bog because trees capture and use more water than typical bog plants. To address this, Metro Vancouver is working to remove tree seedlings in high priority areas before they can establish into a mature forest. This, along with ditch blocking, will encourage the restoration of bog plant communities in disturbed areas.
Burns Bog Fire Rehabilitation (Dec 13, 2021)
Fires in a bog are very different than fires in a forest. Years after fire damaged parts of Burns Bog Ecological Conservancy Area in Delta, Metro Vancouver continues to rehabilitate the bog; a job that's done both on the ground, and in the air.
Working with Beavers
Beavers have been instrumental in blocking many of the ditches throughout Burns Bog. Most of the time, we are very happy with their work. Sometimes the dams are built in ditches near roads and adjacent lands, which can cause flooding and damage to access routes and property. In these cases, our crews will maintain the dams at a level that retains water in the bog areas, while allowing excess water to flow through the dam and prevent flooding.