Minable oil sands are located in the Regional Municipality of Wood Buffalo (RMWB), with an active mining footprint that covers about 844 square kilometres. The most common wetland type in the RMWB is called a fen. They cover about 50 per cent of the landscape. Fens are peat-forming wetlands, similar to bogs; however, they are fed primarily by groundwater rather than surface water.
Peat-forming wetlands – or wetlands that accumulate organic matter – are ecologically important because they accumulate and store carbon. They also provide a very specific habitat for wildlife and plant species, many of which are of cultural significance to Aboriginal communities.
COSIA member companies with oil sands mining operations have committed to returning the landscape to an equivalent capacity at the end of a mine’s life. This includes reclaiming wetlands such as fens and marshes.
In 2013, Suncor Energy, with the help of joint industry project (JIP) partners Imperial Oil Limited and Shell Canada, completed construction of a three-hectare fen, named the Nikanotee Fen (pronounced Nee-ga-no-tee; Cree word for “future”). This achievement established Suncor as one of the first companies in the world to complete reconstruction of this type of wetland in co-operation with a number of university researchers and consultants from across the continent.
“Construction of the fen was based on research undertaken at the University of Waterloo,” says Joshua Martin, Suncor’s Wetland Reclamation R&D Coordinator. “Their research provided us with a model, complete with the design and material properties we needed to build a fen.”
Fens, unlike other peat-forming wetlands, are fed primarily by groundwater, rather than surface water. In order to construct a fen, the groundwater system needs to lie at or just below the surface – less than 20 centimetres.
“In order to meet these specifications, Suncor constructed the watershed to supply the fen with groundwater using materials available on the mine site, including tailings sand and coke,” Joshua explains.
The 2.9-hectare fen is supplied with groundwater discharging from the 7.7 hectares constructed upland, which is set within a basin surrounded by both natural and reclaimed hill slopes. The total watershed area is just over 32 hectares.
Learn more about how the groundwater system was engineered
“To build a fen, you can’t just dig a hole and allow the water to build up,” Joshua says. “You need the water to flow and filter through the ground, which in turn creates a very specific water quality and chemistry for fen vegetation.”
To achieve this, Suncor used sand from their tailings facilities and coke from their upgrader. The tailings sand was used to create the aquifer, which the groundwater flows through to get to the fen. Coke was then used to create an underdrain for the peat. It was placed on top of the tailings sand and a two-metre layer of peat was then placed on top of the coke.
When water lands on the upland soil around the fen, it percolates into the tailings sand aquifer and rises up through the coke and into the peat and fen. This creates the appropriate water chemistry needed for a fen ecosystem.
With the groundwater system constructed, Suncor is now focused on developing methods for vegetating the fen.
“The fen has been divided into plots so that a number of different planting methods can be tried and compared to one another,” says Josh.
Eight different plant species have been planted in the fen – as both seeds and seedlings. Some areas of the fen have also been left alone to see how quickly plants will grow on their own.
In addition to the different planting methods, Suncor has treated parts of the fen with moss, cultivated from other fens in the region, to assess its impact on seed germination and moss growth. Other sections of the fen have been treated with wood straw to assess its ability to control weed growth and retain soil moisture for optimal plant growth.
“So far, the fen is very lush but we are seeing that certain combinations work better than others. We will continue to monitor the different treatments so we can determine which planting methods to use when we construct our next fen,” says Joshua.
One challenge that has been identified with the fen is that the water table is below design level in the upland, due in part to low infiltration rates through the upland soils. However, the water table is expected to rise over time, and with the water level only just below the surface in the fen, the project is still achieving its objectives. The fen has only been monitored under normal conditions; the real test for the fen will be withstanding a drought, which has not been experienced in the RMWB since the fen was constructed.
Learn more about the different plant species in the fen
Suncor planted eight species in the Nikanotee Fen as both seeds and seedlings:
- Water Sedge, Carex aquatilis
- Northern Reed Grass, Calamagrostis inexpansa
- Seaside Arrowgrass, Triglochlin maritima
- Wire Rush, Junctus balticus
- Dwarf Birch, Betula pumila
- Small Bog Cranberry, Oxycoccus microcarpus
- Purple Pitcher plant, Sarracena purpurea
- Round-leaved Sundew, Drosera rotundifolia
Monitoring over the first year is showing that the fen is remaining wet through the seasonal weather cycles, water quality is good and plants are growing and spreading naturally.
All aspects of the constructed Nikanotee Fen are being monitored and compared against monitoring results from natural fens in the region. This will allow Suncor to understand whether over time, the constructed fen will continue to behave like a natural one.
The research being conducted in the Nikanotee Fen will provide industry with the information they need to effectively reclaim the most common wetland type in the RMWB. It will also enhance industry’s understanding of how to establish peat-forming plant communities that naturally capture and store carbon.
“Our ability to reconstruct fens will increase diversity in post-mine landscapes and through that increase the diversity of vegetation and wildlife in the region,” says COSIA’s Land EPA Director, Jenna Dunlop.
Construction and monitoring of the Nikanotee Fen is being led by Suncor. Shell Canada and Imperial joined the project in 2011, during the fen’s construction. They supported research on natural fens and, later, compared these reference areas to the constructed site once it was complete. A number of reclamation methods and best practices developed at the JIP partners’ operations were incorporated into the design of Nikanotee Fen. Canadian Natural took on Shell Canada’s role in the project in 2017.
This is a legacy Canadian Oil Sands Network for Research and Development (CONRAD) Environmental Reclamation Research Group JIP, which was contributed by Suncor to other members of the COSIA Land EPA in late 2013 to support ongoing monitoring and research.