London Sustainable Drainage Action Plan

1. The SuDS Opportunity Map was commissioned through the Drain London project and was delivered by Atkins using their SuDS Studio product. This project looked to highlight the locations where opportunities for Sustainable Drainage Systems (SuDS) are located across London. The raw outputs of the modelling are currently available for all boroughs. However, given the complex nature of the results, and the potential for them to be misinterpreted, it was deemed that it would be beneficial to develop a web tool to allow users to visualise the results in the same manner. Work has been undertaken to translate the results from the modelling into a web tool to enable Local Authorities to easily view and make best use of the data generated without the need for advanced GIS skills. A beta version of this web tool was trialled during the summer of 2018 by two boroughs (Sutton and Enfield) and feedback was gathered around user experience and usefulness of data. The web tool was then launched in December 2018 to all 33 London Boroughs, Environment Agency, Transport for London and Thames Water. A series of training events will be provided on the web tool and data in 2019, following initial feedback from users.
   
   
   
   Note: the results of the SuDS Opportunity Map are only available for Local Authorities and related Risk Management Authorities through password protected access to the web tool, it will not be made available for public use at this time.
   
2. Officers from the GLA continuously promote the need for and benefits of SuDS to a wide range of audiences through a wide variety of means, from presentations at conferences to attending small project workshops across all sectors. The London Environment Strategy Proposal 8.2.3b specifically refers to the implementation of the actions within the LSDAP and sets an aspiration for London to alter 200 hectares of currently conventionally drained land to drain to SuDS by 2030. Collaboration has occurred with a number of different teams within the GLA, including Air Quality, Regeneration and Green Infrastructure. The Mayor’s Greener City Fund has heavily promoted the integration of SuDS within its strategic green infrastructure projects as well as through its Community Greenspace Grants.
   
3. In 2020 funding was provided for community based schemes that incorporated SuDS via the Grow Back Greener grant scheme. The Drain London project previously provided funding contributions towards a number of schemes that integrated SuDS. Summaries of these schemes can be found here. Thames Water have delivered programmes of SuDS delivery both withi their previous Asset Management Period (AMP) 2015-2020 named ‘Twenty 4 Twenty’ and their current one (2020-2025). For further details see Thames Water. A number of other successful projects that have incorporated SuDS have been delivered across London by a mixture of bodies ranging from communities to the private sector. A map with the location of some of these can be found here. Please note that this is a live map so we welcome submissions of projects not currently included on this map.

The London Strategic SuDS Pilot (LSSPS) is a project developed by the London Drainage Engineers Group (LoDEG) alongside a number of key partners (Environment Agency, London Councils, Thames Flood Advisors, Thames Water, Transport for London and the GLA) to address a common issue faced by Lead Local Flood Authorities (LLFAs) across London: their struggle to obtain central government flood funding, Flood Defence Grant in Aid (FDGiA) or Local Levy, for small scale SuDS schemes as a result of the current funding mechanisms. The long-term intention is to develop a strategy for SuDS delivery across London that could be subsequently rolled out within discrete catchments. This approach can potentially provide cumulative flood risk protection that meets the economic benefits test required to release FDGiA and Thames Regional Flood and Coastal Committee (TRFCC) Local Levy funding. The inclusion of the multiple benefits will help to strengthen the business case and create opportunities to access additional funding.

The LSSPS has five key objectives:

• hydraulic modelling to determine flood risk benefits of strategically dispersed SuDS (using SuDS Opportunity Mapping)
• provision of feedback to influence DEFRA’s National Review of the existing Partnership Funding Calculator
• delivery of a number of SuDS measures within up to six boroughs
• performance monitoring of said measures
• the development of a long-term programme for SuDS implementation to facilitate alignment with other public works programmes.

The LSSPS project is jointly funded by the TRFCC Local Levy and Thames Water and is due for completion in April 2021. The key headlines from the study are:

• the current FCERM funding system is not suited to recognising the benefits of multiple SuDS working together
• current flood funding isn’t flexible enough to align with other funding streams
• simpler method of calculating flood funding for small SuDS is possible
• distributed SuDS can be highly effective at reducing flood risk in urban areas but hydraulic modelling is needed to identify the best locations to maximise those flood benefits
• distributed SuDS can help free up significant capacity within the sewer to enable growth
• natural capital benefits of highway SuDS are less influenced by location
• the wider benefits of Green Infrastructure increase the overall BCR by 4 times with public health and wellbeing outweighing all other benefits
• integrating SuDS into other public realm projects reduces costs and increases funding opportunities.

The project has led to the unlocking of £1million of Local Levy to contribute towards further delivery of distributed SuDS and ultimately demonstrate how changes to the existing funding mechanism can unlock greater delivery.

4. The new London Plan will be published on the 3 March 2021. Within Chapter 9 of the new London Plan, Sustainable Infrastructure Policy 13 (SI13) specifically addresses sustainable drainage. This policy has been altered slightly from Policy 5.13 in the current London Plan, with updates made to the wording within the drainage hierarchy and a stronger stance taken on the use of impermeable surfacing. There are various other policies throughout the Plan that link to SuDS as well, in particular: G1, G5, G6 and SI5. Since 2018 the GLA has committed additional resources to review and monitor referable planning applications for flood risk, drainage and water use. The data from this is being collated and will help provide a greater understanding of how these policies are being interpreted as well as providing an insight into their impact over time.

5. The GLA have produced a London-wide SuDS planning proforma to help London’s 33 Lead Local Flood Authorities (LLFAs) and Local Planning Authorities (LPAs) in assessing planning applications in relation to SuDS and drainage. The main aim of this is to provide consistency across London in the information provided on SuDS for all major developments. Through the use of this proforma, data can then be gathered on the SuDS delivered through the planning system on an annual basis across London. The proforma was consulted on with the LLFAs and LPAs in late 2018, receiving an overwhelmingly positive response from the majority of LLFAs. Through the project steering group, with representatives from the LLFAs and GLA, was then finalised in March 2019. As of 1 April 2019 all major planning applications within London have been required to complete the proforma.

6. The GLA have provided strategic SuDS and drainage advice related to a number of major development areas across London, most notably at Old Oak Common & Park Royal, Thamesmead and Old Kent Road. These have included input into SuDS Offsetting policies, input into SuDS strategy workshops and contributions to Supplementary Planning Guidance documents.

7. Several Integrated Water Management Strategies (IWMS) have been developed for Mayoral opportunity areas (Isle of Dogs, Vauxhall Nine Elms, Old Oak & Park Royal Development Corporation, Charlton to Bexley Riverside and Old Kent Road). Plans are in place to deliver further IWMSs in partnership with Thames Water and the corresponding Local Authorities over the coming years, most notably in the Royal Docks.

8. Guidance has been developed that provides clear and concise sector specific guidance designed to capture the attention of those involved in routine maintenance and capital projects within the education sector. It is not the intention for these documents to provide comprehensive guidance on how to design and install SuDS. Instead, the guidance alerts the reader to the potential benefits that can be unlocked through the implementation of SuDS. It provides the reader with the key information they need to form a decision as to whether SuDS are applicable to their specific project and signpost them to where further information is available. Importantly the guidance also includes relevant sector-specific case studies. The Reimagining Rainwater in Schools guidance can be found on the GLA website.
9. Off the back of The Mayor’s School Air Quality Audit Programme, conducted in summer 2018, the GLA have helped to make the LLFAs aware of the green infrastructure interventions proposed as mitigating solutions for air quality within the audits and encourage the integration of SuDS. There is potential to efficiently deliver SuDS within these 50 primary schools that can help reduce surface water flood risk, enhance biodiversity and amenity, whilst also helping to address air quality issues. The South East Rivers Trust and Sutton Council are working in partnership on the SuDS in Sutton’s Schools (SiSS) project. The SiSS project has installed SuDS at the council’s Denmark Road offices and seven schools in Carshalton. The SuDS at these eight sites will help to reduce flood risk in the local area. There are many other good examples of SuDS being integrated into schools across London. Programmes including SuDS for Schools, which was run by the Wildfowl and Wetlands Trust in partnership with the EA and Thames Water, have previously been undertaken that identified the large scale of opportunities for SuDS within schoolyards.

There are more opportunities to be explored within 2021 and beyond for the education sector.

14. SuDS in London: A Guide has been produced by TfL and shows how SuDS can be incorporated into London's streets and wider public areas. Revised and updated in November 2016, the guidance highlights potential opportunities and constraints, aimed at encouraging the relevant authorities across London, including the boroughs, to consider their streetscape and the possibilities of successfully integrating SuDS.
15. Design guidance, rather than standards, has been developed within TfL for the retrofitting of green infrastructure. The document provides advice on green infrastructure installation requirements on the unique and sensitive environment of the transport network. The Mayor’s Transport Strategy, released in March 2018, includes specific reference to encouraging SuDS. Proposal 44 sets a target of five hectares per year of impermeable surface to be adapted to drain to SuDS.
16. A significant amount of work has been done on this sector to date to try and encourage greater integration of SuDS within London’s transport network through input into the creation of guidance materials, the creation of policies, addition of SuDS specific items to framework contracts and through influencing major transport projects across London. Through promotion of SuDS within highway schemes, a number of TfL major projects have now explored the potential for SuDS inclusion within their designs. Of particular note are works occurring at Old Street and Edgware Road where significant SuDS are being installed including green roofs, permeable paving and the repurposing of disused subway ramps into rain gardens that accept runoff from the adjacent highway. The GLA and TfL have developed bespoke SuDS training modules for highway officers and have been delivering this through Urban Design London since 2019, training over 300 highways officers from across London to date. These aim to improve the levels of knowledge and understanding of SuDS within the highway authorities whilst ensuring consistency in application.
17. TfL’s Liveable Neighbourhoods Programme actively encourages the integration of SuDS and green infrastructure within proposals from boroughs within their guidance for submissions document (para 4.51) and support to the individual projects with regards to SuDS has been offered. TfL’s Local Implementation Plan, which is a major source of funding for borough highways, stating within its guidance that “Boroughs are encouraged to consider in new schemes the role of green infrastructure (such as street trees and green roofs/walls) to help deliver improvements in line with the Healthy Street indicators, and sustainable drainage systems (SuDS) to reduce flood risk and increase resilience.” The GLA have also undertaken work with Transport for London, Environment Agency, Thames21, Middlesex University and ZSL to identify road runoff pollution hotspots across London. This study provides information on the predicted pollutant concentrations within road runoff from all roads in Outer London (separate sewers) and identifies the worse polluters. Further work will be published shortly that identifies the types of SuDS interventions (both at roadside and further downstream) that can help to improve the health of London’s watercourses.

18. Guidance has been developed that provides clear and concise sector specific guidance designed to capture the attention of those involved in routine maintenance and capital projects within the hospital sector. It is not the intention for these documents to provide comprehensive guidance on how to design and install SuDS. Instead, the guidance alerts the reader to the potential benefits that can be unlocked through the implementation of SuDS. It provides the reader with the key information they need to form a decision as to whether SuDS are applicable to their specific project and signpost them to where further information is available. Importantly the guidance also includes relevant sector-specific case studies. The Reimagining Rainwater in Hospitals guidance can be found on the GLA website.
19. Examples of SuDS within the health sector in London are few and far between at present. Green Infrastructure Audits undertaken by some of the Business Improvement Districts (BIDs) where health centres are located have often identified SuDS opportunities, although there is little evidence to suggest that many of these have been subsequently delivered. Work within this sector has been halted due to the pandemic but will likely continue as restrictions ease and hospital estates are looking at undertaking works to their estates.

21. Guidance has been developed that provides clear and concise sector specific guidance designed to capture the attention of those involved in routine maintenance and capital projects within the retail sector. It is not the intention for these documents to provide comprehensive guidance on how to design and install SuDS. Instead, the guidance alerts the reader to the potential benefits that can be unlocked through the implementation of SuDS. It provides the reader with the key information they need to form a decision as to whether SuDS are applicable to their specific project and signpost them to where further information is available. Importantly the guidance also includes relevant sector-specific case studies. The Reimagining Rainwater in Retail guidance can be found on the GLA website.
22. Work within the retail sector has not yet commenced and is programmed for 2021-22.

25. Guidance has been developed that provides clear and concise sector specific guidance designed to capture the attention of those involved in routine maintenance and capital projects within parks and green spaces. It is not the intention for these documents to provide comprehensive guidance on how to design and install SuDS. Instead, the guidance alerts the reader to the potential benefits that can be unlocked through the implementation of SuDS. It provides the reader with the key information they need to form a decision as to whether SuDS are applicable to their specific project and signpost them to where further information is available. Importantly the guidance also includes relevant sector-specific case studies. The Reimagining Rainwater in Parks and Green Spaces guidance can be found on the GLA website.
26. There are some great examples of SuDS being incorporated within this sector across London, particularly in the outer London boroughs (see Enfield, Harrow and Haringey). Works are ongoing with the Greenspace Commission to identify potential routes to further encourage delivery.

27. Work within public sector buildings has not yet commenced, mainly due to the pandemic, and is currently programmed for 2022-23.

29. Guidance has been developed that provides clear and concise sector specific guidance designed to capture the attention of those involved in routine maintenance and capital projects within commercial offices. It is not the intention for these documents to provide comprehensive guidance on how to design and install SuDS. Instead, the guidance alerts the reader to the potential benefits that can be unlocked through the implementation of SuDS. It provides the reader with the key information they need to form a decision as to whether SuDS are applicable to their specific project and signpost them to where further information is available. Importantly the guidance also includes relevant sector-specific case studies. The Reimagining Rainwater in the Office Sector guidance can be found on the GLA website. Further work is required to encourage take up of SuDS within this sector however significant changes have occurred within this sector brought about by the pandemic and therefore work within this sector has been postponed fr the time being.

30. Guidance has not been produced to date but is being discussed with key partners.
31. Work within the Industrial sector has not yet commenced and is currently programmed for 2021-22.

35. Work within the Agricultural sector has not yet commenced and is programmed for 2022-23.

36. There are already a number of useful guidance documents that focus on individual homeowners, such as Living with Rainwater. In addition to this, the GLA produced a Grey to Green Guide to encourage community depaving activities.
37. Following the release of the Grey to Green Guide a grant scheme for small community groups was established via the Our Space Awards which helped fund 21 projects across London, with over half of these including SuDS or a form of depaving to help the spaces better adapt to climate change. The Greener City and recent Grow Back Greener Funds have contributed over £13m since 2016 in green infrastructure which help London adapt to the impacts of climate change, £1.8m of which has funded over 40 projects that have specifically addressed surface water flood risk. These green infrastruture grants programmes actively encourage the integration of SuDS into projects applying for its funding.

38. Work is underway to look at potential investment models and financial incentives to encourage greater SuDS uptake. One area that could offer a financial incentive is through the charging of premises for the discharging of their surface water. This currently forms part of the wastewater charge for all London water bill payers based on the rateable value of the property. An alternative method is to charge premises on the basis of the area draining to the sewer, this is commonly known as Area Based Charging. This method was recommended for the billing of commercial premises by Ofwat in 2003, yet Thames Water have not proceeded down this route. By charging for surface water on an area basis, there is an opportunity for billpayers to decrease their charges by reducing the area that drains to the sewer through the implementation of SuDS. The GLA has been and will continue to make recommendations to Thames Water to change to an Area Based Charging method for surface water for both commercial and residential premises.
39. SuDS are now appropriately included within funding criteria associated with TfL programmes and the GLA’s Grow Back Greener Fund. Work is still ongoing with some of the other GLA Group funding streams to specifically require that SuDS be included within funding applications.

40. The action in this section relates to the production of this webpage. The decision was made to update the action to a live website. This has been done so that progress can be monitored closer to real-time and so anyone can see the SuDS retrofit activities currently underway and recently completed. Progress has also been made on developing a method of monitoring the uptake of SuDS across London, through the revision of the SuDS Map, the development of the SuDS proforma and through continual close working with borough officers, TfL, EA, TWUL and NGOs