“Greener” grass drainage for motorways

Grass could soon start replacing the concrete lining Britain's motorways, after a new "green" drainage system designed to cut pollution and flooding successfully passed tests.

The Highways Agency tried out the new system, which uses V-shaped grass-lined channels to drain water off roads, on the M2 in Kent, and said it will now promote its use on motorways and trunk roads across Britain.

Grass has many advantages over concrete, the HA said. The new system encourages sedimentation, thus preventing pollutants that drain off roads from entering water courses.

It also provides a more effective buffer zone for excess water draining off roads, helping prevent floods, as grass slows down and evens out the flow.

The Highways Agency also praised the aesthetic qualities of grass as a roadside drainage alternative.

Santi Santhalingam, principal specialist in drainage and water quality for the Highways Agency said: “We wanted to use a green solution, not only for the benefits to the environment, but also because this system is more pleasing to look at.

“With climate change in mind, the channels are also designed to cope with heavier than normal rain.”

“We are now recommending the use of the v-shaped grass channels in our design manuals.”

Phil Chatfield, policy adviser for pollution prevention at the Environment Agency said: “We are promoting more sustainable drainage systems, known as SUDS, which protect water quality, reduce flood risk and improve amenity.

“These grass channels are a welcome innovation which should help to reduce the risk of road drainage damaging our rivers and groundwaters.”

Goska Romanowicz

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