The draft London Sustainable Drainage Action Plan was opened for consultation on 29 October. It recommends the use of sustainable drainage such as swales and roof gardens to alleviate flooding.
BALI has labelled the plan "impressive". A spokesperson said it highlights the many ways SUDS techniques can alleviate London's drainage issues, both in new-build and retrofitting buildings. "The knowledge and experience of professional landscape contractors who work with and understand SUDS will, therefore, continue to be in demand." BALI will call on members to contribute to its consultation submission.
Green roof expert Dusty Gedge said the renewed emphasis on SUDS would be great for both the city and the landscape industry. He approved of the plan to create targeted measures for each sector, and possible mechanisms to finance retrofitting. But he said it would be interesting to see where the money comes from as the scheme evolves. "Personally (I think) really the utility should be funding major retrofit."
While large-scale sustainability schemes often brush over the parts played by individuals, the new plan "is really positive because it recognises that citizens can do their bit too - and it also lays out in this part of the action plan proposals to see how this can be financed", Gedge added.
Paul Shaffer, associate at construction research group CIRIA, said the plan is "a nice bold ambition" and the partnership approach with Thames Water is also a positive step.
While planning policy has expectations of sustainable drainage happening, retrofitting is more challenging, added Shaffer. Ensuring the plan joins up with other grey infrastructure plans will be necessary if the programme is to succeed.
The plan - Aiming to reduce level of surface water in the capital
The draft London Sustainable Drainage Action Plan, released on 29 October by London mayor Boris Johnson, outlines plans to cut surface water in London by one per cent each year until 2040, primarily using SUDS measures including green roofs, green walls and rain gardens.
Planning rules already require new developments to include SUDS, but the new plan focuses on retrofitting existing structures. It outlines targets for each sector — from office buildings to schools and hospitals — and suggests ways they could be incentivised to retrofit SUDS. To keep costs low the plan also recommends waiting to carry out the works until building repairs are needed.
Individuals are also encouraged to retrofit SUDS at home, with possible incentives such as cost-reflective charging for waste water removal considered in the plan. Utility company Thames Water also announced that it will commit £20m to transforming at least 20ha of impermeable surfaces across London into sustainable drainage projects by 2020.
Consultation on the plan runs until 15 January. See http://beta.london.gov.uk/what-we-do/environment/environment-publications/draft-lsdap.