Derbyshire Street
A range of sustainable drainage measures have been installed in Derbyshire Street pocket park, Tower Hamlets. These include green roofs, permeable paving, swales and rain gardens.

London Sustainable Drainage Action Plan

Date published: 
13 December 2016

Why do we need an action plan for sustainable drainage?

London is outgrowing its drains and sewers.  The combined sewer system originally built over 150 years ago by Joseph Bazalgette has served us well, but it was designed for a smaller city with more green surfaces.  The combined challenges of London’s growing population, changing land uses and changing climate mean that if we continue to rely on our current drains and sewers, we face an increasing risk of flooding.

To make the most effective use of our existing and planned drainage infrastructure and avoid increased flood risk, we need to change how London’s drainage system operates. Rainwater should be managed as a valuable resource rather than a waste product.  We need to roll back the tide of impermeable surfaces.  They should be replaced with ‘sustainable drainage’ systems that mimic the ways that nature manages rainwater and add to the services provided by our existing drains and sewers.  The need for more sustainable drainage is now widely recognised internationally and embedded in our national and local planning systems including in the Mayor’s London Plan. 

What are we doing about it?

The London Sustainable Drainage Action Plan addresses a specific need to promote the awareness, and the retrofitting, of sustainable drainage systems right across London. It contains a series of actions to make our drainage system work in a more natural way which will bring a wide range of benefits including:

  • steadily reducing flood risks by easing the burden on our drains and sewers
  • reducing pollution of our tributary rivers and streams
  • creating more pleasant landscapes, streets and settings for London’s buildings
  • providing opportunities to save water
  • providing opportunities for school activities and studies related to the water cycle

The main focus of the action plan is on the retrofitting of sustainable drainage to existing buildings, land and infrastructure.  It is recognised that funding pressures mean there will not be funds specifically for a large-scale drainage improvement programme.  Instead the key is to identify when and where other planned maintenance, repair or improvement works are scheduled and then to identify opportunities to retrofit sustainable drainage as part of those works.  This way sustainable drainage can be introduced at a much lower cost.  In some cases these measures can save money, for example where ‘harvested’ rainwater replaces large scale water supplies used for irrigation, toilet flushing or vehicle/plant cleaning.

The action plan aims to set the direction for the next 20 years, but includes 40 actions specifically for the next five years.  These actions will be implemented, in part by City Hall staff, and in part by others, and include a commitment to measure and report progress annually.  It is also important that the awareness of rainwater management is spread more broadly across London’s institutions and individual Londoners – we can all make a contribution to the vision.

Progress made to date

The London Sustainable Drainage Action Plan (LSDAP) originally included expected commencement/delivery dates for each of the 40 identified actions. Following significant delays encountered in the launching of the document and in the subsequent recruitment of a project manager a review was undertaken into these dates and they have been subsequently amended to reflect delays and opportunities that arose over the past 18 months. The final action within the LSDAP relates to the delivery of an annual monitoring report to provide an update on progress. To provide a more comprehensive and ‘live’ update, this page provides a progress report from July 2017 through to 2019, that will be continuously updated as further work occurs on individual actions.

The LSDAP breaks the actions down to the following 15 sections for which a progress update has been provided for each:

London Wide Actions

No.

Actions

1

Publish the results of the London-wide Sustainable Drainage Opportunity Model

2

Raise Awareness of the need for, benefits of and delivery of sustainable drainage within London

3

Deliver a programme of sustainable drainage demonstration projects

 

  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.

  1. 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.

  2. The Drain London project previously provided funding contributions toward a number of schemes that integrated SuDS. Summaries of these schemes can be found here. Thames Water has also embarked on a programme of SuDS delivery for this current Asset Management Period (AMP) 2015-2020 named ‘Twenty 4 Twenty’ and are proposing to scale up this programme for their next AMP (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);
  • creation of an Urban Partnership Funding Calculator 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; and
  • 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 by April 2021.

The London Plan

No.

Action

4

Maintain a strong London Plan policy to support sustainable drainage in new development

5

Collate information on sustainable drainage delivered through the planning system

6

Provide strategic guidance on sustainable drainage requirements for major development locations

7

Provide detailed Integrated Water Management Plans for specific opportunity areas

 

  1. The draft new London Plan was placed out for consultation in January 2018. A number of consultation responses were received, and edits were subsequently made. The document is currently with the Planning Inspectorate for review. 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. In 2018 the GLA 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.

  2. 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 1st April 2019 all major planning applications within London will be required to complete the proforma.

  3. 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.

  4. Several Integrated Water Management Strategies (IWMS) have been developed for Mayoral opportunity areas (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 Isle of Dogs and Thamesmead.

Education

No.

Action

8

Produce guidance and good practice examples of sustainable drainage applicable to the education sector

9

Identify opportunities and funding for sustainable drainage retrofit at the same time as planned maintenance, repair and improvement of public sector schools

10

Identify opportunities and funding for sustainable drainage retrofit at the same time as planned maintenance, repair and improvement works in higher education establishments

11

Identify opportunities and funding for sustainable drainage retrofit at the same time as planned maintenance, repair and improvement works in private sector schools

 

  1. Guidance is currently being developed that will provide 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 will alert the reader to the potential benefits that can be unlocked through the implementation of SuDS. It will provide 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 will also include relevant sector-specific case studies. The education sector guidance is due to be published in July 2019.<br />
  2. 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 will be installing 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 2019 and beyond for the education sector

Transport

No.

Action

14

Produce guidance that includes good practice examples of sustainable drainage in the streetscape public realm

15

Prepare a standard for retrofitting green infrastructure

16

Identify opportunities and funding for sustainable drainage retrofit at the same time as planned maintenance, repair and improvement works within TfL owned/managed transport assets

17

Identify opportunities and funding for sustainable drainage retrofit at the same time as planned maintenance, repair and improvement works within other highway authorities’ transport assets

 

  1. 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.
  2. 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 document has been finalised and is now awaiting the necessary internal approvals prior to being published in 2019. 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.
  3. 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 is a London Strategic SuDS Pilot Study project at Edgware Road that will repurpose disused subway ramps into rain gardens that accept runoff from the adjacent highway.  GLA and TfL are developing bespoke SuDS training modules for highway officers within TfL and the boroughs through Urban Design London to help identify the potential opportunities to include SuDS in the design process. These aim to improve the levels of knowledge and understanding of SuDS within the highway authorities whilst ensuring consistency in application.  Work is also underway to create a set of Concept Design Statements of the most common SuDS components implemented within the highway for use by all highways authorities. 
  4. 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, now states within its 2018/19 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 are currently working with Transport for London, Environment Agency, Thames21, Middlesex University and ZSL to identify road runoff pollution hotspots across London. The approach uses ‘big data’ from road traffic systems to inform the level of pollution. This work will be finalised in April 2019 and will ultimately help authorities target SuDS interventions to improve the health of London’s watercourses. 
Health Sector

No.

Action

18

Produce guidance and good practice examples of sustainable drainage applicable to the health sector

19

Identify opportunities and funding for sustainable drainage retrofit at the same time as planned maintenance, repair and improvement works within the NHS estate

20

Identify opportunities and funding for sustainable drainage retrofit at the same time as planned maintenance, repair and improvement works within the private sector health providers’ estate

 

  1. Guidance is currently being developed that will provide clear and concise sector specific guidance designed to capture the attention of those involved in routine maintenance and capital projects within the health sector. It is not the intention for these documents to provide comprehensive guidance on how to design and install SuDS. Instead, the guidance will alert the reader to the potential benefits that can be unlocked through the implementation of SuDS. It will provide 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 will also include relevant sector-specific case studies. The health sector guidance is due to be published in October 2019.
  2. Work within the health sector has not yet commenced and is programmed for 2019/20.  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.
Retail Sector

No.

Action

21

Produce guidance and good practice examples of sustainable drainage applicable to the retail sector

22

Identify opportunities and funding for sustainable drainage retrofit at the same time as planned maintenance, repair and improvement works within the major supermarkets estates

23

Identify opportunities and funding for sustainable drainage retrofit at the same time as planned maintenance, repair and improvement works within DIY and other large format retailers’ estates

24

Identify opportunities and funding for sustainable drainage retrofit at the same time as planned maintenance, repair and improvement works within retail estate owners’ proposals

 

  1. Guidance is currently being developed that will provide 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 will alert the reader to the potential benefits that can be unlocked through the implementation of SuDS. It will provide 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 will also include relevant sector-specific case studies. The retail sector guidance is due to be published in December 2019.
  2. Work within the retail sector has not yet commenced and is programmed for 2020/21. 
Recreational Land / Other Open Space

No.

Action

25

Produce guidance and good practice examples of sustainable drainage applicable to the open space/recreational sector

26

Identify opportunities and funding for sustainable drainage retrofit at the same time as planned maintenance, repair and improvement works in parks and open spaces

 

  1. Guidance is currently being developed that will provide clear and concise sector specific guidance designed to capture the attention of those involved in routine maintenance and capital projects within the recreational land and open space sector. It is not the intention for these documents to provide comprehensive guidance on how to design and install SuDS. Instead, the guidance will alert the reader to the potential benefits that can be unlocked through the implementation of SuDS. It will provide 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 will also include relevant sector-specific case studies. The recreational land and open space sector guidance is due to be published in October 2019.
  2. Work within the recreational land and other open space sector has not yet commenced and is programmed for 2019/20. There are already some great examples of this taking place in London, particularly in the outer London boroughs (see Enfield, Harrow and Haringey).
Other Public Sector Buildings

No.

Action

27

Examine local authority development proposals, capital and revenue programmes for sustainable drainage opportunities

28

Identify opportunities and funding for sustainable drainage retrofit at the same time as planned maintenance, repair and improvement works within the central government departmental and quango estates

 

  1. Work within public sector buildings has not yet commenced and is currently programmed for 2019/20.
Commercial Offices

No.

Action

29

Identify opportunities and funding for sustainable drainage retrofit at the same time as planned maintenance, repair and improvement works with major office owners/occupiers

 

  1. Work within the Commercial Offices sector has not yet commenced and is programmed for 2019/20. 
Industrial and Major Utilities

No.

Action

30

Produce guidance and good practice examples of sustainable drainage applicable to the industrial sector

31

Identify opportunities and funding for sustainable drainage retrofit at the same time as planned maintenance, repair and improvement works within Thames Water’s estate

32

Identify opportunities and funding for sustainable drainage retrofit at the same time as planned maintenance, repair and improvement works within energy companies’ estates

33

Identify opportunities and funding for sustainable drainage retrofit at the same time as planned maintenance, repair and improvement works within telecoms companies’ estates

34

Identify opportunities and funding for sustainable drainage retrofit at the same time as planned maintenance, repair and improvement works within the Environment Agency’s estate

 

  1. Guidance is currently being developed that will provide clear and concise sector specific guidance designed to capture the attention of those involved in routine maintenance and capital projects within the industrial sector. It is not the intention for these documents to provide comprehensive guidance on how to design and install SuDS. Instead, the guidance will alert the reader to the potential benefits that can be unlocked through the implementation of SuDS. It will provide 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 will also include relevant sector-specific case studies. The industrial sector guidance is due to be published in December 2019.
  2. Work within the Industrial sector has not yet commenced and is currently programmed for 2019/20. 
Agriculture

No.

Action

35

Identify opportunities and funding for sustainable drainage retrofit at the same time as planned maintenance, repair and improvement works within agricultural estates

 

  1. Work within the Agricultural sector has not yet commenced and is programmed for 2020/21. 
Individuals

No.

Action

36

Produce guidance and good practice examples of sustainable drainage applicable to the individual homes, small apartment blocks or local neighbourhoods

37

 

Consider a grant/incentive scheme to encourage individuals or local communities to implement their own sustainable drainage scheme

 

  1. 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 have recently embarked on a project with Groundwork London and two local communities to deliver de-paving schemes. The project aims to gather important evidence to support the creation of suitable guidance that will help to encourage greater de-paving across London in the future. The outcomes of the project will include Social Impact Studies and a Grey to Green Guide, which will be available from April 2019.
  2. Subject to the outcomes of this de-paving project, there is potential for a grant scheme to be setup to encourage individual homeowners and small community groups to apply for funding for de-paving projects that focus on managing surface water. At present, the Greener City Fund’s Community Tree Planting and Green Space Grants, £5 million during this Mayoral term to help Londoners plant trees and make our city greener, actively encourages the integration of SuDS into projects applying for its funding. The Groundwork London-managed Our Space Award, which aims to help Londoners green their city through active community engagement and participation, also encourages applicants to consider the management of surface water within their projects.
Funding

No.

Action

38

Examine methods of encouraging more sustainable drainage take-up through adjusting water bill incentives and Thames Water investment

39

Lobby for sustainable drainage to be included in project funding criteria

 

  1. 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.
  2. SuDS are now appropriately included within funding criteria associated with TfL Local Implementation Plans (LIP) and Liveable Neighbourhoods schemes. They are also recommended for inclusion within the GLA’s Greener City Fund Grants. Work is still ongoing with some of the other GLA Group funding streams to specifically require that SuDS be included within funding applications.
Monitoring

No.

Action

40

Produce an annual monitoring report

 

  1. 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