Innovative ‘tree catcher’ reduces flood risk to hundreds of Cardiff residents

Tree catcher poles across the River Ely in Cardiff

Natural Resources Wales (NRW) has completed a scheme to reduce the risk of flooding to 490 properties in the Ely and Fairwater areas of Cardiff.

The scheme involved constructing a ‘tree catcher’ upstream of where the River Ely passes under Cowbridge Road West (A48) to reduce the chance of trees and other large objects getting trapped under the bridge.

The bridge is a known pinch point and partial blockage of the structure could lead to flood water backing up and overtopping the riverbanks, which has previously contributed to the flooding of homes and businesses in the area.

The tree catcher consists of seven poles staggered across the river, spaced widely to target large debris that would otherwise be trapped at the bridge.

As water levels rise during heavy rain, debris trapped by the poles will float on the surface, allowing water to pass beneath and continue downstream.

By trapping debris at a safe location upstream of the bridge, the risk of flooding is reduced.

Michael Evans, NRW’s Head of Operations South Wales Central, said:

“The tree catcher is an innovative way to reduce the risk of flooding to the residents of Cardiff.
“We’ve all seen the recent devastation that flooding has caused to people’s lives across Wales. Two years on from the devastating February 2020 storms, the impacts of the floods were felt right across Wales and are still etched in our minds.
“Climate change will bring more frequent extreme weather and flood events. While we can never prevent all flooding, we will continue to invest the funding we receive from Welsh Government to manage Wales’ flood risk in the best possible way, working closely with local communities to identify the best combination of measures that tackle the specific threats.”

An access ramp and processing area has also been constructed on the riverbank next to the tree catcher to make it easier to remove the blockages and cut them up for disposal. The build-up of debris will be monitored using a CCTV camera.

A fence secures the processing area, and trees and shrubs have been planted to screen it from the adjacent foot and cycle path.

A secondary access ramp has also been built next to the bridge to help clear any build-up of debris, sediment and stone from under the bridge if required.

The scheme cost £957,000 and was funded by Welsh Government.

Climate Change Minister Julie James said:

“I am pleased construction of the Ely Tree Catcher flood alleviation project has been completed and would like to thank Natural Resources Wales and their contractors for their hard work with delivering this work.”
“This innovative project will assist in reducing the risk of flooding to hundreds of nearby homes at times when flows on the River Ely are at a heightened level.
“The Ely Tree Catcher is just one of hundreds of flood alleviation projects which will benefit from Welsh Government investment during the current government term, helping to protect more than 45,000 homes.
“Over the next three years and working in partnership with local authorities and Natural Resources Wales, the Welsh Government plans to invest a record £238 million to deliver our flood and coastal erosion commitments set out in the Programme for Government.”

For more information visit the Ely Bridge Flood Risk Management page.