London:
The height of flooding in towns can be reduced by up to 20 per cent by planting trees around rivers, according to new research.
Scientists from Birmingham University and Southampton University in the UK conducted a study for the Environment Agency which found that trees round a feeder stream can slow the rush of rainwater and save properties from flooding.
However, they warned that natural flood prevention methods do not always work and urged a strategic approach because foresting a whole catchment would be counter-productive, ‘BBC News’ reported.
With increased building on flood plains and climate change increasing the risk of heavy rain, many places cannot be completely protected by walls of concrete, researchers said.
There has been a lot of interest in natural methods - planting trees and creating leaky dams which attempt to delay the flow of water by creating mini-floods upstream.
But researchers suggest that most successful natural methods are likely to be on a much larger scale than currently in operation.
They advise a strategic approach - taking a tributary stream to a main river then foresting the area round it, allowing the stream to make its own meanders, and letting dead wood from the forest to block the stream where it will.
According to researchers, a drop of up to 20 per cent in flood maximum can be achieved by doing this over 25-40 per cent of the main catchment.
That is because the forested area will release its water to the main stream later than water running off pastureland, they said.
“Where its possible to do more extensive planting than we’re doing we really need to do it. It is a bit of a no-brainer,” said Simon Dixon from Birmingham University.
Foresting even 10-15 per cent of a catchment could prevent some flooding, he said.
