Thames Water has launched a £20 million campaign to invest in sustainable urban drainage systems via its Twenty 4 Twenty initiative.

Over the next five years, the Twenty 4 Twenty initiative will see at least 20 hectares of hard, impermeable surfaces transformed into sustainable drainage projects, aimed at slowing rain water down before it enters the sewers or letting it drain away naturally into the ground.

It builds on existing SUDS (sustainable urban drainage systems) which Thames Water has been involved in, including the award-winning Dulwich Park scheme which it funded in partnership with Southwark Council. The project was completed in 2014 and has reduced the risk of sewer flooding at more than 100 properties in the area.

By easing pressure on the sewer network, the work will help reduce the risk of sewer flooding and pollution following heavy rainfall.

Areas dominated by concrete and asphalt will be turned into rain gardens and natural drainage areas and concrete pathways will be replaced with permeable paving, able to allow water to filter through and soak away into the ground or enter the sewer network much more slowly.

Twenty 4 Twenty will focus on communities served by ‘combined sewers’, which collect both waste water from toilets and sinks, and rain water from streets, roofs and driveways.

While preparing the new campaign, Thames Water wrote to all 33 London boroughs for information about SUDS projects that are already being developed across the capital.

Thames Water director Richard Aylard commented:

“We work really hard to make sure our sewers are as empty as possible whenever heavy rain is expected but it’s important we also look at how to reduce surface water getting into them in the first place.”

“We’ve set aside £20m to help support new and exciting sustainable drainage projects across our patch over the next five years. Our aim is to help create at least 20 hectares, equivalent to about 30 football pitches, of green infrastructure to capture rainwater by 2020.”