A new online tool which highlights where the opportunities are to install nature-based solutions, such as wetlands, to tackle road runoff pollution before it ends up in London’s rivers has gone live.

The nation’s rivers are polluted. Along with sewer overflows, littering and misconnected drains, pollution from our roads adds to this cocktail of pollution. Road runoff occurs when pollutants that settle on the surface of the road – such as residue from oil spills, as well as tyre and brake wear from vehicles. These build up during dry weather and are then washed into rivers and streams when it rains.

The online tool will help decision makers to prioritise the right water quality improvement interventions:

• in greenspaces that lie between the road and the river,
• at road locations in Outer London where surface water drains to the rivers; and
• on London’s main strategic road network (includes Transport for London’s roads and some sections of National Highways’ and local authority roads).

The development of the tool builds on years of research by environmental charity Thames21 and its partners Middlesex University and the South East Rivers Trust. The charity started its initial road runoff project identifying key polluting London roads in 2019, with help of funding from the Mayor of London, Transport for London, and the Environment Agency. The British Geological Survey built the online decision support tool ‘Road Pollution Solutions’ and provided some additional support through the UKRI NERC-funded CAMELLIA project.

Modelling has shown that 2,415 road sections covering a total of 451.43km of London’s roads that were modelled pose a high risk of causing road runoff and are therefore a priority for treatment to help prevent pollution entering rivers. Roads where heavy goods vehicles regularly apply their brakes are often the worst affected.

John Bryden, Head of Improving Rivers at Thames21, said: “Pollutants from road runoff are having a devastating impact on aquatic wildlife, including killing off fish. As more people look to London’s rivers for recreation, we all need to up our game.”

To read more about the project, read full press release here.