Going with the flow – Why rewilding waterways is the way ahead
Water has its own path, and centuries of human control through redirection, channelling and irrigation have sent it off kilter. The result is increased flood risk, erosion, pollution and devastating loss of biodiversity. What if we let water go its own way again?
Dutch water engineering is admired around the globe – and such expertise is increasingly sought after as the extreme weather associated with climate change means more countries have to plan for floods.
But now The Netherlands’ world-renowned management of water is being confounded by a new impetus to do precisely the reverse – and allow rivers to flow back to where they want to be.
The Meuse River Floodplain project is releasing 50km of river from 500 years of engineered constraint. Freeing it to wind and meander as it would have centuries ago is a nature-based solution to multiple problems. It encourages biodiversity (bird, fish and insect numbers are already increasing, along with mammals… including otters, beavers and even wolves).
Natural river courses and wetlands not only conserve water and protect nearby communities from flood risk, they also filter pollutants – from soil residues, fertilisers and pesticides to oils, fats, heavy metals, plastics and excessive organic matter that can choke off oxygen.
Unlike man made channels that encourage fast water flow, slower moving freshwater has time to clean itself.
Stretching from Maastricht to Roosteren, the recovering Meuse River and its attendant wetlands have also been a catalyst for funding and revenue – with €550 million invested mostly by related industry and the resultant eco-tourism bringing in an estimated €1 billion a year across the region.
In the UK, since 2000, more than 27km of London’s riverways have been improved with landscaping, the removal of concrete culverts and the planting of new reed beds and water margins.
And some particularly skilled wetland engineers are being deployed across the country – beavers. While human-built dams fight with natural water courses, beaver-built dams complement them, creating ponds and lakes and slowing flow to ease downstream flood risk and promote biodiversity.
Around 1,500 beavers are now living in the wild or thriving on conservation areas throughout the UK, literally beavering away to help wetlands bounce back.
Beavers are also among the solutions suggested to restore the Colorado River – America’s sixth longest, which flows through 8% of the lower 48 states. Climate change is depleting snowfall at its headwaters in the Rocky Mountains, which means the Colorado’s flow could ebb by up to 31% by 2050.
Tackling pressures on water
The biggest pressure comes from the irrigation of 5.7 million acres of farmland. Agriculture sucks up 80% of the Colorado River Basin water – mostly to grow hay and alfalfa for livestock feed. Livestock beleaguers the river further when cattle and horses congregate along streams, compacting soils and reducing their absorption ability, and breaking apart banks which leads to shallower, more erodible, watercourses.
In a paper published by BioScience in August 2022 ecologists proposed protected reserves where livestock grazing is eliminated, beavers are sited and – crucially – the grey wolf is reintroduced.
Wolves, it turns out, help water. Their packs require large scale habitat and the presence of this apex predator scares elk and other ruminants deeper into the forest and away from vulnerable shrubs along fragile stream banks.
River and wetland rewilding is largely a natural process – leave nature alone and it will take care of much of the work.
But repairing the damage of centuries of water exploitation will take careful planning, funding, execution and stewardship.
Given the right support and funding, humans, beavers and wolves are set to be saving water together for the foreseeable future.