Local residents in Perth are on a mission to save one of the city’s most treasured rivers.
Alexei MacKay is a team leader at Armadale Gosnells Landcare Group, which has dedicated decades to conserving the Canning river, a major tributary of the Swan River.
He says the riverbanks at Astley Street River Park, on the southeast fringe of Perth, have changed drastically since colonisation.
“Pre-colonial times, these river systems would have been big meandering wetland chains. Since they’ve damned it all, there’s no habitat and there’s no wetland space around,” he says.
Volunteers are working to restore degraded riverbanks at Astley Street River Park, which forms part of the floodplain of the Canning River.
The AGLG is made up of local environmental representatives and volunteers who meet to discuss environmental issues and strategies. In the colder months, they run planting events along the riverbanks to try to restore and stabilise the land.
AGLG Chairperson Pat Hart says the group is restoring the ecosystem.
“What we are doing simply is repairing the land. Riverbanks are what hold the trees and vegetation in place, it’s part of the whole ecosystem,” she says.
Ms Hart says erosion and sedimentation are natural processes but because of excessive land use and a lack of land management, the process has accelerated.
This is what is happening at Astley Street River Park along Canning River, which is called Djarlgarra in Nyoongar language.
To try turn this around, volunteers are using at technique called fringing, which is the stabilisation of riverbanks by planting vegetation along the shoreline. This decreases erosive power by creating slow-moving river streams and helps to prevent water runoff.
Mr Mackay says not only do planting events restore the riverbanks, they also help with habitat restoration.
“A lot of what we do is take the weeds that are here which would destroy the habitat, then we come in and plant new vegetation to restore habitats,” he says.
The erosion of the Swan and Canning rivers has a cultural impact on First Nation Australians.
According to culture, the rivers were created by the Waugal, a Dreamtime Spirit that took the form of a snake. The rivers are connected to the well-being of the Waugal and the health and healing of the Nyoongar peoples’s cultural identity.
It is believed if the Waugal is killed or leaves, the rivers will dry up and the process of rejuvenation will not occur.
There are growing calls to learn from traditional knowledge to restore Australia’s rivers and ecosystems.
Dr Cristina Estima Ramalho specialises in researching cross-culture and urban ecology as well as conservation planning.
Dr Ramalho, who is a research fellow at the University of Western Australia, says there needs to be more cross-cultural research between Indigenous and western science.
“There is not enough cross-culture restoration, so much more can be done,” she says.
“We could have more co-design of restoration projects.
“We need to have co-design for places of healing, places which have been affected by colonisation.
“We should have gardens dedicated Nyoongar bush routes, all of this done by Nyoongar and working together for better management, to highlight and celebrate cultural heritage.”
The State of Environment Report 2021 found that rivers will not improve unless there is human intervention.
It projects that, over the coming decades, Australia will see continued warning and a decrease in cool-season rainfall, which will ultimately impact hydrology by reducing streamflow.
Ms Hart says the straightening and deepening of waterways for flood control as well as the building of bridges and dams has caused erosion, while the removal of vegetation has caused excessive sedimentation and a lack of stabilisation within the waterways.
Western Australia’s government has offered $1.5 million in funding to different restoration projects across the state. According to the Minister for Environment, Reece Whitby, the State Government has invested $25 million in the past decade toward river restoration.
In a statement, Mr Whitby says the state remains committed to supporting river restoration.
“Last year’s funding round saw 21 foreshore restoration projects funded including foreshore planning, erosion control, revegetation, weed control, enhanced foreshore and river access, and creating native animal habitats.”
Ms Hart says she’s heartened more people are attending planting events each year.
“Schools and young people are coming down, planting and learning,” she says.
“What we are doing is for the future generations to restore the rivers.
“The more and more people that join us, the better the outcome.”