‘FROM GREY TO GREEN’

NEW RAIN GARDENS IN CENTRAL LONDON TO IMPROVE TRANSPORT NETWORK AND CLIMATE RESILIENCE 

The new Marylebone Flyover rain gardens are the largest sustainable drainage systems (SuDS) in central London. Equivalent to the size of 10 New Routemaster buses and with more than 3,500 square metres of water collection area, this project will boost biodiversity, improve surface drainage, and make the network more resilient to climate change and flooding. Mete Coban, Deputy Mayor for Environment and Energy said, “addressing the important issue of surface water flooding is one of many ways we are working with partners like TfL to make London more climate resilient, creating a fairer, greener city for all”.

The planted gardens can be seen on three corners of the road within the Marylebone Flyover underpass and are about 300 square metres when combined. They have been planted with 11 trees, 95 shrubs, more than 1,100 perennial plants and almost 2,300 bulbs in total. All have been chosen to support pollinating insects and can thrive in local climate and soil conditions so require minimal maintenance.

Londoners can spot flowering species like pink geraniums, orange-coloured Kniphofia and blue wood-aster in full bloom, adding colour and life to the urban streets. 

Porous rain gardens such as this are vital when significant storms occur by helping to prevent flooding on busy roads. The Marylebone rain garden scheme is a collaboration between TfL, the Greater London Authority (GLA) and Thames Water, with the Marble Arch London BID committed to fund and run the maintenance work on the gardens. It was part funded by Thames Water and the GLA under the Green Infrastructure Fund programme where £1 million was allocated for greening projects on the TfL Road Network. TfL’s most recent Business Plan sets out their plans to invest £6 million, between now and 2027/8, to improve its understanding of the impacts of climate change, as well as help supplement existing projects to add additional green infrastructure and SuDS. 

TfL’s highways-based SuDS will not only reduce flooding risks but also support biodiversity and improve water quality in London’s rivers, supporting the Mayor’s ambition to achieve swimmable rivers in the capital by 2034. More sustainable drainage is a key part of TfL’s plans to make the capital more resilient and biodiverse, and the completed Marylebone Flyover rain gardens have enabled TfL to reach more than 70 per cent of its current annual target.

Craig Boorman, Principal Environmental Engineer at Thames Water stated, “this unique regeneration project shows how sustainable drainage can help our capital city to adapt to the impacts of more intense rainfall, while also being beautiful and enhancing for local communities- the solution is to turn our landscape from grey to green.”