Could new trees help protect flood-prone fields and rivers?
7:00 a.m. January 15, 2022
Planting trees and hedges along the River Waveney could help alleviate the twin problems of flooding and water pollution.
Last weekend the river overflowed its banks after prolonged wet weather and high spring tides, causing widespread flooding around Geldeston – captured by aerial photographer Mike Page.
Such flooding is becoming more frequent in a warming climate, adding to ongoing river pollution problems.
Those concerns were raised again this week in a worrying report by the government’s Environmental Audit Committee, which said only 14% of England’s rivers were in good ecological condition.
But conservationists in the Waveney Valley hope that planting new trees and new hedgerows could be part of the long-term solution to both problems.
The River Waveney Trust has started its winter planting season, working with the Environment Agency on a scheme to plant 276 trees and 90m of hedges along the banks of the river.
The project, funded by Defra’s Aquatic Environment Improvement Fund, aims to create food and habitats for wildlife, while capturing carbon and intercepting runoff and pollutants from the land.
But the roots will also stabilize the banks and improve the soil’s ability to absorb excess water.
Dr Emily Winter, River Waveney Trust Catchment Manager, said: “A lot of what we’re talking about in terms of flood prevention and drought resilience, we’re talking about the same interventions to address those two issues.
“Things like planting trees can help protect against flooding because they themselves will absorb a lot of water and you build organic matter in the soil and help the water seep deeper into the soil. floor.
“In terms of heavy rainfall, the water holding capacity of the soil will be greater, and in terms of drought, it will give a slower release into the river. So we are building resilience in both directions.
“When it comes to water quality and stopping things from getting into the river, the best thing people can do is get to the source of the pollution.
“What we are doing by planting trees and hedges is intercepting the path, we are not attacking the source. So farmers and land managers can do that by managing the amount of nutrients on the land , being careful with the chemicals they put in, and not spraying near watercourses.”
The trees planted are a mix of native species including alder, willow, hawthorn, hazel, oak and black poplar.
“Black poplar is interesting because it has suffered a big decline in recent decades, but it is a typical floodplain species and we particularly try to use locally sourced black poplar, taken from cuttings in the valley. of Waveney,” Dr. Winter said.
She added that this was a long-term project, with trees taking up to a decade to reach semi-mature and some needing to be fenced off to avoid livestock damage as they grow.
“The issues we face in terms of land use change, climate change and general soil deterioration – these have changed the landscape over a long period of time, so we are looking at longer term solutions.
“We are improving the health of our soil, we want the soil to act more like a sponge, rather than a barrier to water infiltration – and more trees and more hedgerows, all of that helps water to penetrate the ground.
Dr Winter said reconnecting rivers with their floodplains is also important – and the recent flood in Geldeston was an example of a working floodplain in action.
“Many banks have been raised due to dredging,” she said. “This flooded land in Geldeston is a natural floodplain, so we should expect to see this land flooded regularly.
“The flooding of rivers is a natural process and it’s not necessarily a bad thing to see, as it provides a lot of sediment and nutrients to the surrounding land. Historically this would have provided very fertile land along the river. .
“If we can find a way to maintain that with all of our businesses and homes that we’ve built on the floodplains, we’ll go a long way to improving the ecology of the rivers.”