LONDON SUSTAINABLE DRAINAGE ACTION PLAN Kevin Reid Principal Programme Manager Greater London Authority 11 May 2015

Content 1.Flood Risk in London 2.Drain London Project 3. London Sustainable Drainage Action Plan (LSDAP)

Tidal & Fluvial Flood Risk Flood Zone 3 Flood Zone 2

Flood Risk in London Surface water – Until 2007 poorly understood with unclear responsibilities and lack of records London Regional Flood Risk Appraisal Summer 2007 Floods

Drain London Project – Drain London Delivered: 33 Flood risk maps 33 Flood Hazard Maps 33 Surface Water Management Plans

Drain London Project

– Drain London Delivered: 33 Flood risk maps 33 Flood Hazard Maps 33 Surface Water Management Plans All to same standards, return periods, layouts etc Drain London began to build a partnership across the 33 Boroughs, Environment Agency, Thames Water, Transport for London and GLA.

Drain London Project detailed studies into high risk areas Critical infrastructure Demonstration Projects

London Sustainable Drainage Action Plan To deliver a Step Change in sustainable rainwater management in London over next 20 years Learn from international experience, such as New York, Philadelphia, Portland, Melbourne, Singapore

10 But what about all the new development ?

m 2m 3m 4m 5m 6m 7m 8m 9m 10m 11m Population has just exceeded previous (1939) peak of 8.6m POPULATION GROWTH

New development = Opportunity London Plan Policy 5:13

New development = Opportunity London Plan Policy 5:13 …unless there are practical reasons for not doing so, and should aim to achieve greenfield run-off rates … 1 store rainwater for later use 2 use infiltration techniques 3 attenuate rainwater in ponds or open water features 4 attenuate rainwater in tanks or sealed features 5 discharge rainwater direct to a watercourse 6 discharge rainwater to a surface water sewer/drain 7 discharge rainwater to the combined sewer.

New development = Opportunity London Plan Policy 5:13 Most planning applications referred to the Mayor propose at least a 50% reduction Many achieve or close to greenfield run-off

New development = Opportunity Need to roll out a similar approach on major planning applications (>10 homes) Greenroofs Raingardens Permeable surfaces Water butts

London Sustainable Drainage Action Plan 1.Examine new buildings 2.Advise and Lobby for SUDS retrofit when undertaking: Repairs Renovation Expansion

Housing Sector Landscaping Roof, pavement, parking repairs Mayor, Councils, Housing Associations

Education Sector Roof, playground, parking repairs Mayor, Councils

Commercial Sector Supermarkets/DIY Stores Car park re-surfacing Roof repairs Landscaping Limited control

Private residential Advice Incentives

Transport Sector Some positive TfL Projects West Ham Bus Depot, Ruislip Gardens Re-surfacing Drainage works Street trees Upgrades to divert drainage TfL, Councils

Street Trees

Road side drainage

Dropped kerbs

Rainwater gardens

Highways Should some highways be designed to temporarily store flood water ?

THANK YOU Kevin Reid Principal Programme Manager Greater London Authority 11 May 2015