London
Regional Flood Risk
Appraisal
Draft
December 2017

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Contents

Page

How to give your views

3

Executive Summary4

Chapter 1 - Introduction
1.1 Wider Policy Background
1.2 The London Plan
1.3 The Sequential Test
1.4 How to use this RFRA

5
6
8
9

Chapter 2 - Overview of Flood Risk to London
2.1 Tidal Flood Risk
2.2 Fluvial Flood Risk
2.3 Surface Water Flood Risk
2.4 Foul Sewer Flood Risk
2.5 Groundwater Flood Risk
2.6 Reservoir Flood Risk

10
16
23
26
28
29

Chapter 3 – Spatial Implications of Flood Risk
3.1 Introduction
3.2 Opportunity Areas and Town Centres
3.3 Main Rail Network and Stations
3.4 London Underground & DLR Network
3.5 Main Road Network and Airports
3.6 Hospitals and Emergency Services
3.7 Schools
3.8 Utilities
3.9 Other Sites

32
33
50
50
51
53
54
55
57

Chapter 4 – Conclusions and Look Ahead

58

Appendix 1 List of Monitoring Recommendations
Appendix 2 Abbreviations
Appendix 3 Flood Risk Maps

59
61
62

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HOW TO GIVE YOUR VIEWSThis draft of the Regional Flood Risk Appraisal is published for public consultation
until 2 March 2018.
Please send your comments:
online:https://www.london.gov.uk/what-we-do/planning/london-plan/new-london-plan/
draft-new-london-plan/by post:London Plan TeamFirst Review of the Regional Flood Risk Appraisal
PP 18 – Greater London Authority
FREEPOST LON15799
City Hall
The Queen’s Walk
London SE1 2AA
by email:londonplan@london.gov.uk with ‘Draft Regional Flood Risk Appraisal consultation’ inthe subject box
If you send an email it is not necessary for you to also send in a hard copy.

Any representations made in relation to this consultation draft will be made available forpublic inspection.

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Executive Summary
The Mayor is aware that flood risk is a major issue for London, and the probability offlooding is increasing with climate change. The potential consequences of flooding
could also increase as London’s population continues to grow. The Regional Flood Risk
Appraisal (RFRA) provides an overview of all sources of flooding in London andaddresses its probability and consequences.
This draft RFRA•••

has been prepared by GLA officers in close cooperation with the Environment
Agency. Transport for London, London Resilience, and Thames Water have also
been involved. It builds on and updates the version that was published in August
2014 to support the Further Alteration to the London Plan
represents important evidence to underpin the new draft London Plan. The levelof detail of data used and the resulting mapping has been greatly improved
compared to the previous RFRA, providing better information and evidence for
Local Plans, Opportunity Area Planning Frameworks, and infrastructure
providers
includes a revised set of monitoring recommendations, which will be used toensure regular checks on broad mitigation measures.

Currently 6 per cent of London is at high risk of tidal, river or surface water flooding and
11 per cent at medium risk. At the centre of the RFRA is the spatial analysis of tidal,
fluvial and surface water flood risk against a number of different receptors of flood risk.
Looking at the outcomes for Opportunity Areas, Earls Court & West Kensington, the Isleof Dogs and Kensal Canalside have the highest proportion of land in high flood risk
areas (all just over 15 per cent) and for Town Centres it is Kingston (34 per cent) and
Woolwich (27 per cent). For all Opportunity Areas individually this RFRA includes
potential mitigation measures and also raise relevant flood risk issues for all Town
Centres to be addressed locally.
The highest percentages in terms of the number of strategic infrastructure assets in highflood risk areas apply to utility sites (44 per cent of 587 sites), hospitals (43 per cent of
191 sites) and waste sites (34 per cent of 312 sites). But it should be recognised that
this is a precautionary approach. Sites in the central/inner London Thames tidal
floodplain have a high degree of tidal flood protection. Also, many of these sites arelarge complex building structures, and without further analysis it is very difficult toknow, if important parts that could put people or the operation of the infrastructure at
risk might be affected. In many cases it may only be small areas. All other infrastructure
assets such as transport routes and stations, emergency services and schools have lower
proportions for high flood risk.
The flood risk and drainage policies in the new draft London Plan are to a large degree
focused on the mitigation of flood risk. They require to sustainably manage flood risk
through new development, e.g. through improved management of surface water,
setting development back from the waterways and allowing space for future
maintenance and upgrade of flood defences. Policy SI12 also includes a specificreference expecting that utility services should be designed to remain operational underflood conditions and that buildings should be designed for quick recovery following aflood.
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Chapter 1 - Introduction
1.
Chapter 1 deals with the strategic overview of flood risk in London with particularreference to the London Plan. Chapter 2 deals with a more detailed analysis of the risk
from all six types of flooding that could affect London. Chapter 3 then examines floodrisk in relation to particular locations, boroughs and important infrastructure. Appendix
3 provides the related maps and detailed statistics.
1.1

Wider Policy Background

2. The issue of flood risk has become increasingly recognised over recent years withmuch publicised floods in winter 2014, late summer 2015 and early summer 2016.
3. One of the key elements of Planning Policy Statement 25 (PPS 25) and its Practice
Guide introduced in 2006 was a flood risk appraisal hierarchy, with
developers/landowners producing site-specific Flood Risk Assessments (FRAs) and local
authorities producing Strategic Flood Risk Assessments (SFRAs). These are currently
being updated by many London boroughs. For Greater London, with its 33 local
authorities, a Regional Flood Risk Appraisal (RFRA) with a broad consideration of floodrisk across London’s borough boundaries represents important evidence to underpin the
London Plan and should also inform local-level flood risk assessments and Local Plans.
As flood risk is a strategic issue, the RFRA also facilitates the application of the Duty to
Cooperate beyond London’s boundaries including the authorities upstream along theRiver Thames and downstream of London in the Thames Estuary.
4. The National Planning Policy Framework (NPPF) 1 and the Planning PracticeGuidance on Flood Risk and Coastal Change 2 set out the currently relevant planningrequirements at national level. They retain the importance of flood risk management
considerations that had been introduced through the PPS25.
5. In London, the boroughs are Lead Local Flood Authorities (LLFAs) and are
responsible, in particular, for local surface water flood risk management and formaintaining a register of flood risk. They identify areas of flood risk to help inform
appropriate locations for development. The GLA-led Drain London project has overrecent years significantly improved the understanding of surface water flood risk acrossLondon.
6. The Environment Agency’s Thames River Basin District Flood Risk Management
Plan 3 is part of a collaborative and integrated approach to catchment planning forwater. It has drawn on evidence set out in the Thames Catchment Flood Management
Plan 4. Making space for water when considering development proposals is particularly
important where there is significant exposure to flood risk along tributaries and at the
tidal-fluvial interface.

1 www.gov.uk/government/uploads/system/uploads/attachment_data/file/6077/2116950.pdf - see inparticular paragraphs 100 - 104
2 www.gov.uk/guidance/flood-risk-and-coastal-change
3 For details see www.gov.uk/government/publications/thames-river-basin-district-flood-riskmanagement-plan
4 For details See Section 2.2 on fluvial flood risk
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7. The Thames Estuary 2100 Plan (TE 2100) was published by the Environment
Agency and endorsed by Government in November 2012. It addresses flood risk
specifically from the tidal Thames and requires the ability to maintain and raise sometidal walls and embankments. The Environment Agency undertook a five-year Interim
Review of the TE2100 Plan in 2016 and found it to be broadly on target 5. A morecomprehensive ten-year Review will commence in 2018 and published in 2020. The
TE2100 Plan introduces the concept of Riverside Stratgies to improve flood risk
management in the vicinity of the river, create better access to and along the riverside,and improve the riverside environment. These will be collaborative documents and the
GLA will support their production.
8. This review deliberately crosses the boundary between land use planning andemergency planning. This recognises the need for close liaison between the two
disciplines. The London Resilience Team has published its London Resilience
Partnership Strategy 6 in 2016. This seeks to co-ordinate emergency services andemergency planners across London in the event of a major flood. In addition, in 2015
the London Strategic Flood Response Framework 7 was updated and includes greater
consideration of social drivers of vulnerability to flooding (not just modelling data) anda more proactive response arrangement across the resilience partnership.
9. The scale and distribution of flood risk is shown on Map 1 included in Appendix
3: Currently 6 per cent of London is at risk of tidal, river and surface water flooding for a
1 in 30 year event 8 (high risk) and 11 per cent for a 1 in 100 year event 9 (medium risk).
In chapter 3 these flood risk areas will be intersected with a number of different
receptors of flood risk, including growth areas, infrastructure assets and services. The
underlying Environment Agency data combine flood risk from rivers, the sea and surface
water. Further updates of the surface water flood risk component will be included when
new local data from LLFAs become available.
10. In spring 2016 the Government published revised climate change allowances 10.
They consider the lifetime, vulnerability and location of a development. Therefore, theassessment of London’s Opportunity Areas, as key locations for future growth, does not
only consider 1 in 30 and 1 in 100 year events (high and medium risk), but also 1 in1000 year events (low risk). This precautious approach was agreed with theEnvironment Agency as an appropriate reflection of the revised allowances.
1.2

The London Plan

11. The RFRA represents important evidence to underpin the new draft London Plan.
Flood risk should be recognised as an important consideration as part of all
development proposals and in combination with the NPPF and its associated Guidance,
Policy SI12 sets out the following strategic approach in London.
5 For details see

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/558630/TE2100_5_Y
ear_Review.pdf
6 For details see
www.london.gov.uk/sites/default/files/london_resilience_partnership_strategy_2016.pdf
7 For details see www.london.gov.uk/about-us/organisations-we-work/london-prepared/planningemergencies-capital#acc-i-43126
8 Greater than 3.3 per cent chance of flooding in any year
9 Greater than 1 per cent chance of flooding in any year
10 For details see www.gov.uk/guidance/flood-risk-assessments-climate-change-allowances
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Policy SI12 Flood risk management
A Current and expected flood risk from all sources across London should bemanaged in a sustainable and cost effective way in collaboration with theEnvironment Agency, the Lead Local Flood Authorities, developers andinfrastructure providers.
B Development Plans should use the Mayor’s Regional Flood Risk Appraisal andtheir Strategic Flood Risk Assessment as well as Surface Water Management
Plan, where necessary, to identify areas where particular flood risk issues exist
and develop actions and policy approaches aimed at reducing these risks.
Boroughs should co-operate and jointly address cross-boundary flood risk issues
including with authorities outside London.
C Development proposals which require specific flood risk assessments should
ensure that flood risk is minimised and mitigated, and that residual risk isaddressed. This should include, where possible, making space for water andaiming for development to be set back from the banks of watercourses.
D Developments Plans and development proposals should contribute to thedelivery of the measures set out in Thames Estuary 2100 Plan. The Mayor will
work with the Environment Agency and relevant local planning authorities,
including authorities outside London, to safeguard an appropriate location for a
new Thames Barrier.
E Development proposals for utility services should be designed to remain
operational under flood conditions and buildings should be designed for quick
recovery following a flood.
F Development proposals adjacent to flood defences will be required to protect
the integrity of flood defences and allow access for future maintenance andupgrading. Where possible, development proposals should set permanent built
development back from flood defences to allow for any foreseeable future
upgrades.
12. As a significant measure to address in particular surface water flooding Policy SI13
on Sustainable Drainage is quoted below as well. The well-established Drainage
Hierarchy is at its centre the policy It will help to reduce the rate and volume of surface
water run-off. Rainwater should be managed as close to the top of the hierarchy as
possible. The role of blue roofs is specifically highlighted in the new policy. They can begreen roofs engineered to retain water or attenuation tanks at roof or podium level. The
combination of a blue and green roof is particularly beneficial as the attenuated water isused to irrigate the green roof.
13. Over recent years the scale of sustainable surface water management measures inmajor planning applications in line with this policy has increased significantly. Manysuch applications achieve the greenfield run-off rate the policy is aiming at. It is
expected that relevant measures are less common on smaller scale developments but arebecoming more commonplace as LLFAs are now well established in their roles.

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Policy SI13 Sustainable drainage
A Lead Local Flood Authorities should identify – through their Local Flood Risk
Management Strategies and Surface Water Management Plans – areas where
there are particular surface water management issues and aim to reduce theserisks.
B Development proposals should aim to achieve greenfield run-off rates andensure that surface water run-off is managed as close to its source as possible inline with the following drainage hierarchy:1) rainwater harvesting (including a combination of green and blue roofs)
2) infiltration techniques and green roofs3) rainwater attenuation in open water features for gradual release4) rainwater discharge direct to a watercourse (unless not appropriate)5) rainwater attenuation above ground (including blue roofs)
6) rainwater attenuation below ground*7) rainwater discharge to a surface water sewer or drain8) rainwater discharge to a combined sewer.
C Development proposals for impermeable paving should be refused whereappropriate, including on small surfaces such as front gardens and driveways.
D Drainage should be designed and implemented in ways that address issues ofwater use efficiency, river water quality, biodiversity, amenity and recreation.
* The benefit of attenuation above compared to below ground or in a basement is that pumping
is normally not required to empty the attenuation tank.

14. Other draft London Plan policies are also relevant, including Policy SI5 about Water
Infrastructure. Its supporting text says that Integrated Water Management
Strategies should be considered for major development locations such as Opportunity
Areas, where flood risk alongside water-related constraints require an integrated
approach to the provision of infrastructure and management of risk.
15. A Water Advisory Group has been established to advise the Mayor on strategic
water and flood risk management issues.
1.3

The Sequential Test

16. The NPPF contains a Sequential Test 11 to ensure that development takes place inthe areas available at lowest flood risk.
17. London is heavily built up with a tightly drawn administrative boundary. The
delineation of the Green Belt and the other protected open spaces in London mean thatthe scope for new development on land other than brownfield redevelopment land is
extremely limited. Over recent years the vast majority of new development has takenplace on brownfield land 12. This trend is expected to continue. Many of London’s
11 Para 101

12 For details see Key Performance Indicator 1 of the Annual Monitoring Report

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remaining large brownfield areas are either substantially or partially at risk of flooding,including some Opportunity Areas 13.
18. The latest Strategic Housing Land Availability Assessment (SHLAA) 14
examined the potential housing capacity within London to inform the London Plan.
Flood risk was considered as an important environmental constraint, and this approachreflects a strategic approach to the sequential test. Sites with a known flood risk had
their capacity reduced depending upon the severity of the risk. In the SHLAA
methodology Flood Zone 3b sites were considered to be unsuitable and by default tohave zero probability for housing. Sites in Flood Zone 3a had their probability reducedby 10 or 5 per cent respectively depending on the existence of flood defences. The
boroughs had then the opportunity to adjust the probability reduction based on their
SFRAs, any specific surface water flood risk issues and potential mitigation measures.
19. The anticipated growth is planned to be accommodated in particular in London’smajor development locations and town centres, where individual risks will have to belooked at by the London boroughs in more detail. They and developers will still need toapply the sequential test locally and consider flood risk assessments at a more detailed
level when allocating uses or applying for planning permission. It will also remain
important to place more vulnerable uses in areas with lower flood risk in order to meet
the Sequential Test at a local level.
20. For development that cannot be located in lower flood risk areas, the Exceptions
Test can be applied 15. It requires that a development can demonstrate wider
sustainability benefits and is safe over its lifetime.
1.4

How to use the RFRA

21. The RFRA is a strategic overview of flood risk across London. It does not represent
a detailed analysis of flood risk in relation to any particular areas or sites. It contains aseries of maps to illustrate flood risk spatially (see Appendix 3).
22. It also includes a series of recommendations (see Appendix 1), for example related
to improvements to local flood risk policies and Drain London activities. The
recommendations are meant as a monitoring tool and progress against them willcontinue to be reported annually in the London Plan Annual Monitoring Report.
23. Future updates of the RFRA should take place approximately every five years orafter a major flooding incident or a major policy shift.
24. The RFRA should be useful to spatial planners, developers, infrastructure and utility
operators and emergency planners. It is a specific aim of this RFRA to give spatialplanners and emergency planners a shared understanding and common baseline of
information.

13 For details see Map 2
14 The full SHLAA is available on the London Plan Evidence website https://www.london.gov.uk/what-

we-do/planning/london-plan/london-plan-full-review/full-review-evidence-base
15 See para 102 of the NPPF
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Chapter 2 - Overview of Flood Risk
25. London is exposed to six different potential sources of flooding. These are analysed
below, each has different spatial impacts on London and requires a different set of
responses. Some responses relate to the land use planning system, whilst others relate
to broader spatial matters or operational considerations for a range of organisations.
26. Each type of flooding is analysed by examining:
•
•
•
•
•
•

Nature of the risk
Development locations that may be affected
Information available
Broad flood risk management options
The likely impact of climate change
Strategic recommendations

27. Chapter 3 goes on to consider flood risk in relation to key locations andinfrastructure in London. In this way the RFRA represents an examination of both thepotential future flood risk issues and the existing flood risk issues that affect London.
By doing this it can make recommendations that fulfil one of two functions. Firstly,
how to ensure that future flood risk is minimised and any residual flood risks aremanaged appropriately. Secondly, to promote new development that will help toreduce and manage existing flood risks. This approach is in line with the NPPF.
2.1

Tidal Flood Risk

Nature of Risk
28. The River Thames and the lower reaches of some of the tributary rivers are affectedby the tide. The River Thames has a very large tidal range, in excess of 7 metres onspring tides. The tide’s influence reaches to Teddington Lock on the Thames and up
several tributaries, for example as far as the Prescott Channel structure on the River Lee.
29. Without the current river walls many areas of London alongside the Thames andalong the tidal stretches of the tributaries would be inundated twice a day through thenormal tidal cycle. River walls have been steadily built up since Roman times to giveincreasing levels of flood protection and to enable urban development.
30. The particular threat that has remained is from tidal surges. These occur when acombination of high tide, easterly winds and a weather system depression over the
North Sea can cause the tide levels to increase significantly above the normal tidal
range. Previous incidents of this type of flood risk date back to 1236. More recently, in
1928, 14 people were drowned in Westminster; this was the last time that central
London suffered tidal flooding. In 1953 London was largely spared the impacts of adevastating tidal flood that cost the lives of over 300 people in the East of England. The
most recent tidal surge in 2013/14 particularly affected the outer Thames Estuary. If
any of those floods had funnelled further up the Thames, the results for the capital
could have been even more disastrous.

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31. As a result of the 1953 flood, a system of flood defences was constructed. The
most iconic element of this is the Thames Barrier, which has been operational since1982. There are also around 400 smaller barriers and movable flood gates downstreamof the Thames Barrier and over 300 km of river walls and embankments stretching into
Essex and Kent that have been raised by 2 metres to give additional protection fromstorm surges. Upstream of the Thames Barrier river walls are still necessary to preventthe normal range of high tides from flooding parts of inner and central London. Thissystem of tidal flood defences made allowance for sea level rise and London is therefore
protected to a very high level. It is estimated that further measures will be needed after
2030 to maintain a 1 in 1000 year risk level.
32. Since its completion in 1982, the Thames Barrier has been closed 179 times toprevent flooding 16. Of these closures, 92 were to protect against tidal flooding and 87
were to protect against combined tidal/fluvial flooding. Diagram 1 indicates that the
number of closures per year is fairly variable. However, there is a general increase in thenumber of closures with a recent peak in the winter 2013/14, which saw a record
number of 50 closures and triggered an investigation by the Environment Agency. It
concluded that it is too early to identify whether or not this peak was part of an
emerging longer-term trend, but it is not part of an existing trend 17. The Environment
Agency continues to estimate that a new Thames Barrier is likely to be required towards
the end of the century. Potential sites will be needed in Kent and/or Essex requiring
close partnership working with the relevant local authorities.
33. It should be noted that closures of the Thames Barrier also necessitates closure ofother barriers and flood gates, and it prevents navigation through the Barrier.

16 For further details see www.gov.uk/guidance/the-thames-barrier
17 TE2100 5 Year Review (Environment Agency), page 4

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/558631/TE2100_5_Y
ear_Review_Non_Technical_Summary.pdf
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Diagram 1

Source: Environment Agency

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34. There are residual risks even given the high standard of flood risk management
measures that are in place. These risks are:••from an overtopping of the defences, i.e. a larger event than has been planned for,orfrom a breach in the defences, i.e. a failure, either accidental or deliberate, of the
defences.

35. The likelihood of such residual risks is very small. However, the scale ofconsequences from rapid inundation and deep water in heavily urbanised areas meanthat these residual risks must be considered. Management and mitigation of residual
risks in defended parts of London along the tidal Thames are a notable component ofsite-specific FRAs, with the approach to residual risk depending largely on surrounding
ground levels and the type of land use proposed.
Locations
36. The tidal flood risk area through London affects areas to the north and south of theThames and up some of the tributary rivers. Given that much of the land alongside theThames in central and inner London has been in active urban use for centuries, there
is a lot of infrastructure already in place, and protection is of a high standard throughthe combination of flood walls and embankments, the Thames Barrier and othermovable gates and barriers.
37. In north east and south east London there are large areas of derelict or under-used
land forming the Thames Gateway. These areas have mostly been in industrial uses,
many of which have now ceased or are declining. These areas make up some of the
major opportunities for London to accommodate its own growth pressures. Being
alongside the river it is to be expected that many of these areas will have an associatedelement of flood risk.
Information available
38. The Environment Agency Flood Zone mapping is integrated into a mapping toolon the Environment Agency website18. It includes the 1 in 1000 (0.1%) tidal flood riskenvelope and covers a wide area and is closely related to the 5m land contour.
39. The condition of flood defences is held on a database by the Environment
Agency which carries out regular visual inspections to update condition surveys and takeappropriate action either directly or through riparian owners to ensure that structures
are in a sound condition. The vast majority of flood defences along the Tidal Thames
are in a good structural condition.
40. It should be noted that shortly before this RFRA was published, comprehensive
breach modelling was released by the Environment Agency for the tidal Thames
between Teddington and the Thames Barrier. It was not possible to include this within
the current RFRA but should be used when completing a detailed analysis of flood riskin relation to any particular areas or sites. The Environment Agency are also in the
18 See https://flood-warning-information.service.gov.uk/long-term-flood-risk/map, and more detailed

tool for planning applications,which e.g. also includes areas benefitting from flood defences and flood
storage areas https://flood-map-for-planning.service.gov.uk/
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process of reviewing the breach modelling for the area downstream of the Thames
Barrier, and this will be published in early 2018.
Flood Risk Management Options
41. Flood defences for the Thames Estuary have been built up over hundreds of years
and have tended to respond to flood events by successively raising the height of flood
defences walls and embankments. The current system of defences were last upgradedbased on the knowledge of sea-level rise in the 1970s and 1980s and in response to thetidal surge of 1953 and includes the Thames Barrier. The TE2100 Plan, which for the
first time plans for future flood risk management in anticipation of future flood riskrather than in response to a flood event, indicates that the present system of flood risk
management for tidal flooding can continue to provide an acceptable level of risk
management up to 2030 without major alterations. Beyond 2030 more actions will
be needed to maintain the 1 in 1000 year risk (0.1%). Some further details from theEnvironment Agency’s TE2100 Plan are set out below:
2012 – 2035:• Work with Local Authorities and the construction industry to ensure thatexisting and new development is safe through spatial planning and local
resilience measures• Prepare joint riverside strategies establishing a shared vision for the riverside• Continue to maintain, enhance, improve or replace existing flood management
systems• Work with Local Authorities and communities on the future use of the Thames
Barrier in managing fluvial flooding in West London• Continue flood forecasting and emergency planning activities• Commence the creation of new inter-tidal habitat in the Lower Estuary which is
being lost as sea levels rise2035 – 2070:• Maintain, improve or replace the walls, embankments, barriers and gates along
the Estuary• Work with Local Authorities and communities on enhancing and revitalising theThames riverside• Continue flood forecasting and emergency planning activities• Continue replacing areas of inter-tidal habitats as sea-levels continue to rise
• Decide on and construct the option to manage increasing flood risk for the endof the Century and beyond
2070 – 2100:• End of the century option operational (see 2035-2070).
• Further raising and adaptation of defences where required to keep new Barrier
closures to within operational arrangements• Continue programme of maintenance replacement and repair of upstream anddownstream defences• Continue flood forecasting and emergency planning activities
42. These actions will be easier, more affordable and more sustainably delivered, if they
are planned for from today. So, the Environment Agency is beginning to explore how to

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deliver them in collaboration with its partners 19. The Environment Agency has also
identified four broad areas (Reaches) of the Thames and has outlined the following
general spatial options. It will be important for SFRAs and new developments to identify
methods of implementing these options:West London Reach (Teddington Lock to Hammersmith Bridge)
43. Pursue alternative responses to managing fluvial risk such as flood resiliencemeasures (e.g. flood gates) or potentially safeguarding land for future flood storage on
the fluvial tributaries and setting back of development from river walls to enable riverwalls to be modified, raised and maintained in a sustainable, environmentally acceptable
and cost effective way.
City Reach (Hammersmith Bridge to Thames Barrier)
44. Pursue options for small scale set back of development from river walls to enableriver walls to be modified, raised and maintained in a more sustainable, environmentally
acceptable and cost effective way.
Regeneration Reach (Thames Barrier to Tilbury Docks)
45. Pursue options for small scale set back of development from river walls to enableriver walls to be modified, raised and maintained in a more sustainable, environmentally
acceptable and cost effective way. In some cases there may be opportunities for larger
scale set back as part of development in the Thames Gateway.
46. Large areas of currently undeveloped land such as Rainham/Wennington Marshes,
Erith Marshes and Dartford/Crayford Marshes could potentially be used as strategic
locations to increase available flood storage. It may be appropriate to consider ways tosafeguard such land for future flood risk management uses or habitat creation.
Lower Estuary Reach (Tilbury Docks to Southend)
47. This is outside London but options sited here could protect London. This area may
provide environmental mitigation and compensation for impacts inside London.
Confluences
48. Particular care will be needed when examining the confluences of tributary rivers
with the Tidal Thames given the interaction between the different systems 20. There may
be particularly severe effects when a high tide combines with peak fluvial flows. In
general the flood defences have been built to a very high standard and therefore theseareas share high levels of flood protection.
The Likely Impact of Climate Change
49. Climate Change will have a major impact on the tidal flooding threat. The rising sea
level will steadily reduce the level of protection that defences offer. The TE2100 5 Year
Review undertaken by the Environment Agenchy in 2016 confirmed that sea level rise istaking place ‘within the bounds’ of what the TE2100 Plan expected 21. The predictions
for how quickly sea level will rise vary considerably depending on the assumptions used
19 For further details about the TE2100 Implementation Plan please contact te2100@environment-

agency.gov.uk
20 This influence can stretch several miles upstream of the confluence
21 For details see
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/558630/TE2100_5_Y
ear_Review.pdf
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about emissions and climate modelling: Up to 2030 there are limited differences
between predictions, and existing flood risk management options can continue toprovide appropriate risk management for tidal flooding. Beyond 2030 there is morevariation in the projections, and it is important that the close monitoring of sea level rise
continues.
Recommendation 1 – Tidal Flood Risk
The London boroughs should address relevant tidal flood risk mitigation measures set
out in the Thames Estuary 2100 Plan in their Local Plans. They include setting backdevelopment and defences from the banks of watercourses, flood storage and floodgates.
The delivery of Riverside Strategies through Thames Estuary 2100 should be supported.
2.2

Fluvial Flood Risk

Nature of Risk
50. London has many tributary rivers leading to the River Thames and the Thames itself
is a fluvial river upstream of Teddington Lock. As with any river system there is apossibility that any of these rivers could flood. This could come from either particularly
intense rainfall within the catchment or from a blockage or restriction to flow within theriver channel.
51. The Environment Agency has produced Catchment Flood Management Plans(CFMPs) for fluvial rivers in England and Wales. These CFMPs examine thecharacteristics of rivers, current and future flood risk and potential flood risk
management measures and set out a long-term view of flood risk (50-100 years). The
CFMPs relevant to London are:••Thames CFMP – December 2009 22
North Kent Rivers CFMP – September 2008

52. As a predominantly urban area London’s rivers are often heavily modified from theirnatural state. This means that rivers have been straightened, deepened, widened andconstructed from materials such as concrete. These changes have often been madespecifically to reduce the risk of flooding by either increasing the physical size of theriver channel or increasing the rate at which it can convey water.
53. The urbanised river environment also contains many bridges, tunnels and culvert
structures. These culverts are often underneath roads or railways but sometimes also
flow under substantial areas of built up land. These form potential flood risks as they
can become blocked or restricted through fallen tree branches, litter or larger debris
such as shopping trolleys, mattresses or even vehicles. Culverts present a particulardifficulty in that it is difficult and expensive to determine their condition and to carryout maintenance and repairs. It can also be difficult to ascertain ownership andmaintenance responsibility for some culverts. It is also known that there are a significant
number of illegal mis-connections of foul sewers to surface water drains, which lead toongoing pollution of rivers. In general, opportunities to remove and open up culverts
should be taken on environmental and aesthetic grounds as well as in order to improve
22 The Thames Flood Risk Management Plan, which was produced more recently in March 2016, has
drawn on the evidence and proposals set out in this CFMP, but has not replaced it.

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flood risk management. This is also addressed in the new draft London Plan Policy SI17
on waterways protection.
54. In London the rate at which rainwater enters urban rivers is significantly higher thannormally occurs naturally. This is because a larger proportion of London’s surface iscovered by hard impermeable surfaces, which are positively drained via surface water
sewers into local watercourses and then to larger tributaries. This also increases theabsolute volume of rainwater that reaches rivers because there is less chance for water
to soak into the ground, be taken up by vegetation or evaporate.
55. Such urban rivers respond very rapidly to rainfall and the opportunity for flood
warnings can be as short as 30 minutes. Some larger rivers such as the Lee or the fluvial
Thames have much bigger upstream catchments so flood flows can be detected several
hours or even days in advance, allowing for reasonable flood warnings to be issued.
Canals
56. London has many miles of canals. In general, canals pose a low flood risk, as they
have limited surface water inputs. However, the Grand Union Canal is linked to large
fluvial catchments - including the Colne Valley, the River Lee Navigation, and the River
Brent - and may convey flood waters from fluvial sources. A further consideration is thatany canal, which is on land higher than the surrounding land, has the potential for abreach. Therefore, consideration of flood risks from canals needs to be factored into
SFRAs and FRAs.
Locations
57. Fluvial flooding affects parts of most London boroughs. As such it affects a numberof Opportunity Areas, town centres and strategic infrastructure across the city. In
general, the scale of risk is more localised than for tidal flooding. Fluvial flooding has
been more frequent than tidal flooding meaning that many areas of floodplain havebeen left un-developed, often forming parks within the wider urban setting, whichshould be protected. The most prominent example is the Lee Valley Regional Park.
Information available
58. The Environment Agency produced and regularly updates its Flood Zone maps,
which are integrated into the mapping tool on the Environment Agency website 23. There
are also detailed floodplain modelling for some of the tributaries. Most tributaries havebeen modified to reduce the likelihood and severity of flooding. In many cases these
consist of raised river walls and widened channels. In the case of the River Lee an entire
new flood relief channel was constructed along the east side of the Lee Valley in the
1970s. These channel modifications have generally resulted in a reduction of
biodiversity value and amenity value and an increased maintenance requirement.
59. The CFMPs classify floodplains into 6 broad types:•

Undeveloped natural floodplain

23 See https://flood-warning-information.service.gov.uk/long-term-flood-risk/map, and more detailed

tool for planning applications,which e.g. also includes areas benefitting from flood defences and flood
storage areas https://flood-map-for-planning.service.gov.uk/
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•
•
•
•
•

Developed floodplain with no built defences
Developed floodplain with built defences
Developed floodplain with typically concrete river channels
Major urban expansion in or close to floodplains
Narrow floodplains and mixed use land

60. The CFMPs then identify five policy options to manage flood risk and the key
messages that are relevant to each of these approaches.
61. These approaches are applied to policy units (sub-regional areas) that have been
identified by geography, floodplain characteristics and land use types. More detailed
actions for each policy unit, reflecting the relevant approach, have been identified to
manage flood risk, today and in the future. These actions can be split into two types:
those that help to reduce the likelihood of flooding occurring and those addressing theconsequences if a flood does happen.
62. Three of the five policy options are used in London and they are specified below inrelation to each of the catchments. SFRAs and FRAs should consider how to implement
these policy approaches in local circumstances.
London Catchments (local authorities in italics are outside London but relevant to the
management of the catchment)
63. Each tributary river system in London has different attributes, these are described
below:
River Lee - Boroughs affected: Barnet, Enfield, Waltham Forest, Haringey, Hackney,
Tower Hamlets, Newham
64. The River Lee catchment is a mixture of relatively small urban tributaries with very
fast reaction times to flood and the main River Lee channel which has a large andsubstantially rural upstream catchment. The River Lee suffered extensive flooding in1947 as a result of rapid snowmelt. In the 1970s the River Lee Flood Relief Channel wascompleted to reduce the risk of flooding through the Lee valley. It is known that thedesign specification for the River Lee Flood Channel was to accommodate a 1 in 75
flood (1.3% chance of flooding in any year). This is below the level of protection that is
now required for development under the NPPF. Furthermore the level of protection is
likely to have been reduced further by the extensive development in the Hertfordshire
and west Essex upper catchment of the River Lee. It will therefore be important for thecurrent level of flood protection through the Lee Valley to be re-assessed. This isparticularly relevant given the extent of built development (including raised reservoirs)in the natural floodplain and the fact that there are considerable development proposals
both within and outside London.
65. The Lee catchment also includes several tributaries which have experienced localised
flooding, notably Salmons Brook, Ching Brook, Turkey Brook and Pymmes Brook. These
are all highly urbanised catchments where flood risk needs to be addressed strategically.
The Environment Agency has recently completed the construction of a flood alleviation
scheme for Salmons Brook that, together with maintenance of the existing river
structures, reduces the risk of flooding significantly.

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66. The CFMP recommends an approach to take further action to reduce the risk offlooding for the main River Lee river channels. For the tributaries of the Lee the CFMP
recommends taking action to increase the frequency of flooding on open spaces todeliver benefits locally or elsewhere, which may constitute an overall flood risk
reduction.
67. The Environment Agency has published a document summarising the findings of theLower Lee Flood Risk Management Strategy. This covers the fluvial River Lee from
Hertford to the Queen Elizabeth Olympic Park, including the tributaries of the River
Lee, and outlines the proposals for managing fluvial flood risk in the catchment. 24
River Roding - Boroughs affected: Barking & Dagenham, Redbridge, Newham
68. The river here was extensively re-engineered during the 1980s and 1990s in
conjunction with the construction of the North Circular Road and M11 and theintroduction of a semi-tidal barrage in Barking. There has been localised flooding within
London in recent years although most regular flooding occurs on agricultural land northof the London boundary. The Environment Agency’s River Roding Flood Risk
Management Scheme provides a strategic perspective on flood risk in the Roding
catchment 25.
69. For the London reaches of the River Roding, the CFMP recommends an approach totake further action to sustain current scale of flood risk into the future (responding topotential increases in flood risk from urban development, land use change, and climatechange).
River Rom/Beam - Boroughs affected: Barking & Dagenham, Havering
70. There has been limited localised flooding in this catchment and the Beam wetlands
serve as a strategic flood storage area. Development proposals will still need to consider
their flood risk.
71. The CFMP recommends an approach to take further action to sustain current scaleof flood risk into the future (responding to potential increases in flood risk from urban
development, land use change, and climate change).
River Ingrebourne - Boroughs affected: Havering, Brentwood
72. There has been some localised flooding to properties in Upminster and otherflooding on open spaces through the river valley of this relatively natural tributary.
There is also the tidal interaction where the southern part of the river becomestidelocked at high tide.
73. The CFMP recommends an approach to take further action to sustain current scaleof flood risk into the future (responding to potential increases in flood risk from urban
development, land use change, and climate change).
River Brent - Boroughs affected: Barnet, Brent, Harrow, Ealing, Hounslow

24 For details see www.environment-agency.gov.uk/research/library/consultations/54262.aspx
25 For details see www.environment-agency.gov.uk/homeandleisure/floods/148706.aspx

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74. The River Brent and its various tributaries have suffered localised flooding,particularly in the upstream catchments of Harrow, Brent and Barnet. The Environment
Agency is examining options in partnership with the London boroughs of Brent andHarrow and Thames Water to address this. These options will then be examined andrecommendations will be taken forward by the partners. These recommendations willneed to inform local policy objectives to reduce and store surface water run-off. Thiscan be achieved through Local Plan policies, updates to SFRAs and development ofLocal Flood Risk Management Strategies. The Brent flows through extensive park areas
offering opportunities for flood risk management and the enhancement of the rivercorridor. The Wealdstone Brook and the Colindale Flood Alleviation Schemes areinvestigating options to alleviate the risk of flooding in these areas in particular 26.
75. The CFMP recommends an approach to take further action to sustain current scaleof flood risk into the future (responding to potential increases in flood risk from urban
development, land use change, and climate change).
River Crane - Boroughs affected: Harrow, Hillingdon, Ealing, Richmond, Hounslow
76. This river has historically suffered flooding problems in its lower reaches. The upper
Reaches, known as the Yeading Brook, flow through considerable lengths of parks andopen spaces giving some less sensitive areas for floodwater to be accommodated.
Nevertheless a strategic examination of options for sustainable surface water
management, bearing in mind climate change predictions, should be used to influence
future development decisions and considerations of the management of the riverside
open spaces.
77. The CFMP recommends an approach to take further action to sustain current scaleof flood risk into the future (responding to potential increases in flood risk from urban
development, land use change, and climate change).
River Colne and Pinn - Boroughs affected: Harrow, Hillingdon, Spelthorne
78. The Colne is a large tributary which in places forms London’s western boundary. It
has suffered extensive flooding in the past, although mostly of undeveloped land. Floodalleviation works have been undertaken. The River Pinn has had several recorded
localised floods over recent years. There are Environment Agency projects investigating
options to alleviate the risk of flooding on the River Pinn and the Lower Colne 27.
79. For the River Colne, the CFMP recommends an approach to take further action tosustain current scale of flood risk into the future (responding to potential increases inflood risk from urban development, land use change, and climate change) and for the
26 The Wealdstone Brook Scheme is a partnership project between the London Borough of Harrow,

Environment Agency and Thames Water. There are historical flooding issues, particularly due to thefoul sewerage system backing up as a consequence of being overloaded with surface water. The
project is looking at the scope of opening up a culvert and creating flood storage as part of adevelopment site in the Wealdstone Brook catchment, but it is also looking at other options such aflood storage areas. The current estimated completion date for this project is 2022. The Colindale
Scheme is looking at options for local flood storage areas aiming to be completed in 2025.
27 The project for the River Pinn catchment is looking at the effect that maintenance of vegetation has
on river flows, also to increase the resistance and resilience of the communities in the catchment. The
project is expected to be completed by 2023. Along the Lower Colne there are a range of projects
looking at maintenance and potential flood storage areas.
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Pinn it recommends taking action to increase the frequency of flooding on open spaces
to deliver benefits locally or elsewhere, which may constitute an overall flood risk
reduction.
Hogsmill River - Boroughs affected: Kingston, Epsom & Ewell
80. Some localised flooding has occurred on this river, notably through Kingston Town
Centre. Most of the route of the river flows through open spaces and parts of the Green
Belt. The Hogsmill is characterised by a developed floodplain with typically concreteriver channels. The risk of flooding in these areas is relatively high and it is likely that
this will increase in the future. Flooding caused by surface water, overflowing drainage
systems, and the systems themselves, are the responsibility of several organisations.
81. The CFMP recommends taking action to increase the frequency of flooding on open
spaces to deliver benefits locally or elsewhere, which may constitute an overall flood risk
reduction.
Beverley Brook - Boroughs affected: Richmond, Wandsworth, Kingston, Merton.
82. Many parts of the floodplain remain as open space, notably through Richmond Park,
although the Raynes Park area is identified as having an extensive floodplain. This
coincides with the confluence of two tributaries and the river passing underneathseveral major road and railway structures.
83. The CFMP recommends an approach to take further action to sustain current scaleof flood risk into the future (responding to potential increases in flood risk from urban
development, land use change, and climate change).
River Wandle - Boroughs affected: Wandsworth, Merton, Sutton, Croydon.
84. The downstream area of this river catchment runs through a heavily built up areawith floodplain covering significant areas of already developed land. Some upstream
areas south of Mitcham are more open with some storage of floodwater possible.
85. The CFMP recommends an approach to take further action to sustain current scaleof flood risk into the future (responding to potential increases in flood risk from urban
development, land use change, and climate change).
River Ravensbourne - Boroughs affected: Lewisham, Bromley, Greenwich
86. This is a relatively large river with several tributaries. In the downstream reaches theriver is tightly confined by urban development although in the more southerly upstream
reaches the river and its tributaries often flow through open spaces. Parts of the river
system have benefited from river restoration projects in recent years, which have also
improved flood risk management. The Environment Agency is also investigating a flood
defence scheme in the Catford/Lewisham reaches of this river.
87. The CFMP recommends an approach to take further action to prevent an increase inflood risk into the future (responding to potential increases in flood risk from urban
development, land use change, and climate change).
River Cray/Darent - Boroughs affected: Bexley, Bromley, Greenwich, Dartford
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88. The upstream reaches stretch out into the Green Belt. Through much of the middle
reaches the river runs through a mix of built up areas and open space and in the lower
reaches there are extensive areas of floodplain and the interaction with the tidal Thamespresents a further flood risk although the Dartford Barrier controls this risk with
Dartford and Crayford Marshes providing large areas of flood storage upstream of theBarrier
89. These catchments are covered by the North Kent Rivers CFMP which recommends
an approach to take further action to reduce the risk of flooding.
Marsh Dykes – boroughs affected: Bexley, Greenwich.
90. There are a number of modified and natural rivers in the Thamesmead/Belvedere
area which are unusual in that they are below the height of Thames flood defences andrely on a system of lakes, canals and pumping stations to manage their discharge to thetidal Thames.
91. TE2100 recommends an approach to take further action to sustain current scale offlood risk into the future (responding to potential increases in flood risk from urban
development, land use change, and climate change). Furthermore it recommends
careful consideration of new development given the particular risks of this low lying area
and the difficulties in managing surface water following heavy rainfall events.
Fluvial River Thames- boroughs affected: Kingston, Richmond, Spelthorne, Elmbridge
92. The fluvial reaches of the Thames are prone to large flood events from its extensive
upstream catchment. There are no built flood defences and this stretch of the river isparticularly noted for its historic and cultural value. Given the large upstream catchment
close co-operation is needed with flood risk management approaches further to thewest.
93. The Environment Agency is developing the River Thames Scheme 28 (formerly
Lower Thames Flood Risk Management Strategy). Between 2020 and 2025 theEnvironment Agency will build a new flood channel alongside the River Thames toreduce flood risk to 15,000 properties and 2,400 businesses in communities in Datchet,
Wraysbury, Egham, Staines, Chertsey, Shepperton, Weybridge, Sunbury, Molesey,
Thames Ditton, Kingston and Teddington. More than half of the funding required forthe construction of the scheme has been identified, and the Environment Agency is
working with partners to secure the additional funding needed.
Flood Risk Management Options
94. There needs to be continued work to ensure that the recommended policy
approaches are implemented. The actual detail will require careful consideration of therivers locally and their floodplain characteristics. In many cases setting development
back from river edges will enable a range of flood risk management options to be used.
This measure is referred to in the draft London Plan Policy SI12 and should enable themost sustainable, aesthetical and cost effective options to be selected.

28 For details see www.gov.uk/riverthamesscheme

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95. Boroughs and individual developments will need to consider the Sequential Test andthe allocation of more vulnerable land uses to those areas at lowest risk.
96. Open spaces within development can be designed to accommodate flood waters.
The Green Grid concept is a good example of identifying such opportunities. In somecases the flood risk is such that upstream flood storage may prove to be the most
realistic option. Efforts to restore damaged river environments also present good
opportunities to incorporate natural flood management techniques, which can
improve flood risk management and bring other benefits, such as increased biodiversity.
In October 2017 the Environment Agency published evidence on working with naturalprocesses to reduce flood risk 29. Such measures may need to be considered inconjunction with neighbouring local authorities.
97. Where a residual flood risk remains, flood risk assessments should consider what
would happen to the development and its users/occupants if a flood were to occur andhow the development would recover from the flooding.
The Likely Impact of Climate Change
98. Climate change predictions suggest that there will be an increased risk of flooding
on tributary rivers due to more intense patterns of rainfall.
99. This gives added emphasis to the need to consider the above range of flood risk
management options and the Environment Agency’s recommendations from CFMPs.
Furthermore methods of reducing surface water run off from urban development areimportant. This is the responsibility of the LLFAs and applies not only to development inor near to a floodplain or river but across London. For those rivers whose headwaters
originate outside London, the GLA will seek to work with the relevant authorities.
Recommendation 2 – Fluvial Flood Risk
Regeneration and redevelopment on London’s river corridors offer a crucial opportunity
to reduce fluvial flood risk. Strategic Flood Risk Assessments (SFRAs) and planningpolicies should focus on making the most of this opportunity through appropriate
location, layout and design of development as set out in the Thames Catchment FloodManagement Plan (CFMP). In particular opportunities should be sought to set backdevelopment from the river edge; ensure that developments with residual flood risk aredesigned to be flood compatible and/or flood resilient; and maximise the use of open
spaces to make space for flood water.
2.3

Surface Water Flood Risk

Nature of Risk
100. This section deals with rainfall that overwhelms the drainage system or is of suchintensity that it flows over land. This kind of flooding can happen in very localised
areas as a result of particularly intense storm cells and as such it is hard to predict.
Some recent developments in radar technology and improved weather modellingsuggest that it may be possible to predict these storm events more accurately in the
future. However, even if these storms can be predicted, there is likely to be only scope
29 For details see www.gov.uk/government/publications/working-with-natural-processes-to-reduce-

flood-risk

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for action for particularly sensitive sites/uses. Since the 2009 RFRA significant work has
been undertaken to assess, map and understand surface water risks.
101. This is true nationally but in London has been given a particular focus through theDrain London project. Drain London is a partnership led by the Mayor, Environment
Agency, Thames Water and London Councils. It has been successful in producing
surface water flood risk mapping and Surface Water Management Plans (SWMPs) for
every London Borough and has funded detailed studies into over 20 high flood risk
areas. The project has been funded by Defra and broadened its remit more recently toinvestigate how more sustainable drainage can be implemented across London. This has
led to the publication of the London Sustainable Drainage Action Plan (LSDAP) in
Dec 2016 30. There is also the London Drainage Engineers Group (LoDEG), a joint forum
to help and facilitate collaboration between the 33 LLFAs within London and otherstrategic risk management authorities with regards to surface water flood risk anddrainage issues.
102. Surface water flooding can be caused or exacerbated by blockages to the drainage
network. New surface water drainage networks are normally designed to cope withstorms of a 1 in 30 year intensity, however many existing systems may be constructed todifferent standards. It is to be expected that events above the design intensity will
occur from time to time and will lead to surface water flooding.
Locations103. Surface water flood risks occur in lower lying areas of all London boroughs. Given
the complexity of the land form, topography and the drainage network it is very
difficult to predict precisely where the risks will lie. Details such as the height ofkerbs or level and construction of boundary walls can determine whether surface waterflows one way or another. Therefore any London wide or borough wide mapping must
only be taken as a general indication of risk areas.
104. However, in central and inner London, where the natural drainage systems havebeen largely removed and built over, surface water flood risk tends to occur in lots ofsmall, localized areas representing slightly lower ground than the surrounding land.
Basement properties and entrances to sub surface car parks, servicing yards etc. can beat particular risk of ingress of water. It should be noted that such basements oftenhouse important utilities such as electrical sub stations/meters, lift motors/control gear,back up power generators or computer servers. Often smaller natural drainage features
such as tributary streams and ditches have been built over during the centuries ofdevelopment, whilst the land may remain at a slightly lower level, thereby being likely tobe subject to surface water flooding. Any blockages or failures of the drainage network
will exacerbate such flooding and may even cause flooding in circumstances where thedrainage system would otherwise have coped.
105. In the rest of London where the natural drainage system of rivers and streams
remains, surface water flooding is often directed to the valleys of those streams which
form the naturally lower land areas. Many of these urban rivers are immediately
adjacent to built development or even underneath buildings and in such cases those

30 For details see https://www.london.gov.uk/WHAT-WE-DO/environment/environment-

publications/london-sustainable-drainage-action-plan

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buildings may lie within risk areas. Away from those river corridors surface water will
pond in lower lying areas.
106. Buildings with large roof areas, such as mainline rail terminals, hospitals,
schools, retail warehouses are particularly prone to surface water risks under heavy
rainfall situations. For such buildings it will be important to ensure that any new
development proposals reduce those risks. Additionally, through the Drain London
project, those risks have been examined and opportunities for retrofitting moresustainable drainage to reduce risks have been indentified.
107. It will often be unfeasible to address surface water risks at the specific location
where the risk of flooding exists. Therefore it is important that steps are taken in thesurrounding contributory catchment areas to manage surface water moresustainably. The implementation of draft London Plan Policy SI13 (Sustainable
Drainage) and the LSDAP are therefore important across all of London and not just in
identified risk areas.
Information available
108. This RFRA uses the Environment Agency’s updated flood map for surface water.
This is also integrated into the mapping tool on the Environment Agency website31. If an
area has an identified significant surface water flood risk, then more detailed site
specific analysis is recommended.
109. Lead Local Flood Authorities have a Duty under the F&WM Act 2010 to maintaina register of any significant flood events. There are still only relatively few welldocumented records of surface water flooding. It often occurs and then dissipatesquickly, usually within a few hours. Whilst historically this has made it difficult to make areliable record of such an event, the prevalence of camera phones, social media and
CCTV now makes it possible to build up a more accurate picture of such events andin future events are likely to be recorded on a much more consistent basis.
Flood Risk Management Options
110. There are a number of good practice examples of both site specific and morestrategic scale sustainable drainage projects32.
111. Where development proposals are on brownfield sites, there are real benefits to begained by making a substantial reduction in the amount of surface water run-off
generated through the redevelopment of the site. In cases where sites were used for
predominantly industrial purposes the proportion of drained area is often close to 100%of the site. A residential development is likely to be in the range of 40-80% positively
drained, leading to a reduction in surface water run-off. Adding in measures such as
porous road and parking surfaces, green/blue roofs, storage ponds/tanks, swales andsoakaways could reduce run-off to an estimated 20-50% of previous levels, and in somecases may be close to the natural (greenfield) run-off rate. This should be the aim of asustainable approach to urban drainage.

31 For details see https://flood-warning-information.service.gov.uk/long-term-flood-risk/map
32 For details see www.london.gov.uk/what-we-do/environment/climate-change-weather-and-water/surface-water/sustainable-drainage-london

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112. In some specific locations, for example where basements are at risk, there may be
options to raise the threshold entrance to those basements. Additionally, as is often
recommended for developments within the defended Flood Zone 3a, which meet the
Exceptions Test, placing important infrastructure, such as electrical supplies, lift motors,
computer servers, within a flood proof room or enclosure may be a viable option.
113. The LSDAP aims to encourage and incentivise the retrofitting of sustainabledrainage measures into the existing urban environment. The key aim of the Action Plan
is to provide guidance, advice and support to bring forward sustainable drainage
measures as part of any maintenance/improvement projects planned for existingbuildings/sites. The LSDAP will also consider how private individuals could be
encouraged to adopt more sustainable rainwater management on their own properties.
114. It should also be remembered that for development close to tidal rivers, docks andpotentially other water bodies, a direct discharge of clean rainwater to these may be
the most sustainable option. Draft London Plan Policy SI13 promotes this option
accompanied by suitable pollution prevention measures. However, in some cases directdischarge will not be appropriate, for example discharge into a small stream at the
headwaters of a catchment, which may cause flooding.
115. There is also emerging evidence on rainwater management that relatively
extensive green roofs, can have a significant effect in reducing surface water run-off,particularly for lower intensity rainfall events. More recently there have beendevelopments which have used blue roofs. These can be green roofs engineered toretain water or attenuation tanks at roof level. By retaining water at roof level,
opportunities for rainwater harvesting are increased, and there is also potential for theblue roof tank to provide irrigation to any green roof.
The Likely Impact of Climate Change
116. Current predictions anticipate that the intensity of storms is likely to increase.
This will mean that both the likelihood and consequences of surface water flooding will
increase as flood waters may be deeper given the higher volumes of rainwater. The
application of the Drainage Hierarchy and the LSDAP should improve the ability of theurban area as a whole to cope with such storm events but individual locations will still
be affected.
Recommendation 3 – Surface Water Flood Risk
Developments all across London should reduce surface water discharge in line with the
Sustainable Drainage Hierarchy set out in Policy SI13 of the London Plan, and theactions in the London Sustainable Drainage Action Plan (LSDAP) should also taken.
2.4

Foul Sewer Flood Risk

Nature of Risk
117. Foul sewer flooding occurs where sewers become blocked or overloaded andproperties connected to the sewer system are located at a level below the hydraulic levelof the sewage flow. These are often basement flats or premises in low lying areas orwhere carriageway surcharging floods a property indirectly. Sewer flooding is clearlyparticularly unpleasant and distressing as its contents are highly contaminated. At
present Thames Water estimates that there are over 10,000 properties which arevulnerable to sewer flooding across the whole of Thames Water’s operational area.
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118. Thames Water is planning to invest over £350million between 2015-2020 tocombat sewer flooding at 2,000 properties. This includes their Counters Creek
proposals for a large-scale sewer relief tunnel in the LB Hammersmith & Fulham and LB
Kensington & Chelsea area. Some consultation has been undertaken, however,proposals are expected to be reviewed in early 2018. There will also be some potential
for sustainable drainage measures, particularly within the combined sewer areas of
London.
119. In most of central and inner London the surface water and sewerage networks are
combined in ‘Combined Sewers’. During periods of heavy rain the combined sewage
and rainwater is diverted to the River Thames via combined sewer overflows to prevent
significant flooding of homes, businesses, streets and gardens.
120. The Thames Tideway Tunnel, currently under construction, will intercept
overflows and transfer the flows for treatment at Beckton Sewage Treatment Works. It
will prevent the discharge of millions of tonnes of untreated sewage and rainwater tothe Thames.
Locations121. The locations affected tend to be small discrete sub-catchments on the sewer
network rather than any specific patterns or particular locations.
122. However, at a larger scale Thames Water has produced the Brent & Harrow
Catchment Study 33 between 2015 and 2017. Jointly with LB Harrow, LB Brent, and theEnvironment Agency, they investigated the root causes of flooding and potential ways
to reduce them across the catchment.
Information available
123. Detailed records of locations where sewer flooding has been recorded either
within a property or within the grounds of a property are held by Thames Water. The
locations are generally very sporadic and not suited to mapping on a London-wide basis.
Flood Risk Management Options
124. The nature of the problem dictates that the most effective solution is for Thames
Water to carry out direct works to those parts of the sewer network linked to theaffected property or group of properties. This is an expensive operation – averaging
around £150,000 per property for the programme between 2015-2020.
125. Future developments should be catered for by ensuring that the appropriate on
and off-site sewerage infrastructure is planned and delivered to serve proposeddevelopment (see also draft London Plan Policy SI5). In line with London Plan’s
Drainage Hierarchy (Policy SI13), it is also important that surface water is notdischarged into the foul water system, thereby limiting its capacity.

33 For details see https://corporate.thameswater.co.uk/About-us/Investing-in-our-network/Sewerage-

catchment-studies/Brent-and-Harrow

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The Likely Impact of Climate Change
126. In theory climate change should not make a substantial difference to this problem.
However, in practice, as surface water drains are often wrongly connected to the foulsystem, the expected increase in intensity of storm events will increase the likelihood ofsewer flooding. Similarly, within the combined sewer area of London, increases inrainfall will trigger additional combined sewer discharges to the Thames. In central
London this problem will be largely overcome through the completion of the Thames
Tideway Tunnel. In parallel, it will be important that new development follows theDrainage Hierarchy and that retrofitting is undertaken by implementing the LSDAP. Thisshould ensure the continued effectiveness of the sewer system and prevent gradualincreases in the number and scale of overflows to the new Thames Tideway Tunnel, inparticular in the light of the likely incease in frequency of heavy rainfall events.
Recommendation 4 – Sewer Flood Risk
Thames Water should continue the programme of addressing foul sewer flooding, also
working with other risk management authorities such as local authorities and theEnvironment Agency.
2.5

Groundwater Flood Risk

Nature of Risk
127. Groundwater flows out of the ground at the point where the water table meetsthe surface. This acts as the source of many rivers and is also a valuable source ofdrinking water. Heavy rainfall can infiltrate the ground causing saturation. Surplus
water will then flow out to rivers or onto land potentially causing flooding. Groundwater
tends to respond slowly to rainfall, so when groundwater flooding occurs it can persist
for some time. Within London there have only been very few recorded groundwater
flooding events, although it may be possible for groundwater to cause elevated baseflows into some of the rivers entering London as a result of increased groundwater flows
from the surrounding hills of the Chilterns or the North Downs. In February 2014 someSouth London boroughs were affected by groundwater flooding, with the Kenley Water
Treatment Works and ca 50 properties affected in particular in Croydon and Bromley.
128. London had an issue over the past 20 or so years with rising groundwater. Thishas occurred because the majority of London, including much of its undergroundinfrastructure such as tube lines and foundations for large buildings, was built at a time
when the natural groundwater was suppressed due to large scale abstraction by
manufacturing industry. With the steady reduction of industrial activity in London
during the second half of the 20th century, groundwater levels began recovering to theirnatural levels thereby threatening to inundate the underground infrastructure or destabilize the ground surrounding the structures.
129. This problem was addressed by the General Aquifer Research Development
and Investigation Team (GARDIT) 34. Through increased abstraction of thegroundwater, notably by Thames Water, groundwater levels are now relatively stable
and the Environment Agency is maintaining a regular monitoring regime.

34 Informal partnership originally led by Thames Water, London Underground and the Environment
Agency oversee a programme of action to stabilise groundwater levels

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Major Development Locations
130. There are no known mayor development locations where groundwater flooding
has been a problem. The rising groundwater was mostly related to central and inner
London, although this is now being managed.
131. The Drain London project undertook a London-wide assessment of groundwater
flood risks. This combined several existing datasets to produce a map of ‘indicative
Potential for Elevated Groundwater’ (IPEG), which provides a starting point for
further investigations. Detailed site-specific assessments are important, particularly
where deep excavation is involved or where there is an indication that the groundwaterlevels may be elevated. The areas highlighted in the IPEG map are generally quite
sporadic across London. See Map 12 for an illustration of the IPEG.
Information available
132. The Environment Agency keeps detailed records of groundwater levels through acomprehensive monitoring regime. All boroughs with historic groundwater flooding
records have incorporated them into their SFRAs. In addition, the IPEG maps can beused to highlight areas where there may be an increased potential for groundwater torise sufficiently to cause flooding denoting where further, site-specific, assessment may
be required as part of an FRA.
Flood Risk Management Options
133. The continued abstraction of water by Thames Water is important to manage
groundwater levels in the foreseeable future. This is expected to continue.
The Likely Impact of Climate Change
134. Increased groundwater levels are normally the result of prolonged rainfall with adegree of delay built in as water percolates through the ground. It is not yet clear
whether the increased amount of winter rainfall will increase this risk or, as the total
amount of rainfall is expected to remain relatively unchanged (just fall in moreconcentrated periods), the effect upon groundwater patterns and flows may remain
stable. This needs to be kept under review.
Recommendation 5 – Groundwater Flood Risk
The groundwater flood risk in identified locations (see IPEG map) should be consideredin Strategic Flood Risk Assessments (SFRAs) and Flood Risk Assessments (FRAs).
2.6

Reservoir Flood Risk

Nature of Risk
135. Reservoir flooding is extremely unlikely to happen. There has been no loss of lifein the UK from reservoir flooding since 1925. Specific reservoirs must be inspected andsupervised by reservoir panel engineers. As the enforcement authority for the Reservoirs
Act 1975 in England, the Environment Agency ensures that reservoirs are inspected
regularly and essential safety work is carried out. However, in the unlikely event that areservoir dam failed, a large volume of water would escape at once and flooding could
happen with little or no warning. The resulting high consequence of flooding means
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that, although flooding from reservoirs is considered to be of very low likelihood, therisk should be considered in SFRAs and FRAs.
Major Development Locations
136. The reservoirs in the Lower Lee Valley are the largest reservoir area within the
GLA boundaries. They are well maintained and monitored. In the unlikely event of areservoir flood, the Lower Lee Valley downstream from the reservoirs could besignificantly affected. Similarly the large reservoirs to the west of London are wellmaintained, but in the unlikely event of a failure, parts of west London could be
affected. There are a number of other smaller reservoirs, whose areas of potential
inundation are shown on Environment Agency mapping (see below).
Information available
137. Reservoir flood maps, which are included in the Envionrment Agency mapping
tool on their website 35, were introduced after the 2009 RFRA. An extract covering
London is included as illustration as Map 13. Reservoir maps display information forlarge reservoirs holding over 25,000 cubic meters of water. They show the largest areathat might be flooded, if a reservoir were to fail and release the water it holds. They do
not display information about how likely any area is to be flooded or about the depth or
speed of the flood waters.
Flood Risk Management Options
138. The Water Act 2003 amended the Reservoirs Act 1975 and introduced arequirement for reservoir flood plans. Since August 2013 requirements are based on risk
and not on size 36. The Environment Agency has therefore designated specific reservoirs
as High Risk. Some of these designations are under review.
139. The Reservoirs Act requires that reservoir owners undertake all necessary steps toprevent breaches from occurring following regular inspection and reporting. The
likelihood of breaching is very low, and therefore , when considering flood risk to new
development it is unlikely that any particular mitigation measures will be required,
unless a high vulnerability development was proposed immediately downstream of ahigh risk reservoir. There may also be implications for emergency planning and it may
be necessary to incorporate the following aspects of the relevant reservoir safety
plan, which represents an element of the reservoir flood plan and includes the three
aspects below, into emergency plans for new developments:•••a reservoir flood map by the Environment Agency which identifies the extent andseverity of flooding which could result from an uncontrolled release of water;
an on-site reservoir emergency plan by the reservoir owner setting out what would
be done in an emergency to try to contain and limit the effects of the incident. It
will include a plan for communicating with external organisations, mainly the
emergency services but also for example transport network operation centres;
an off-site reservoir emergency plan by the Local Resilience Forum (LRF) setting out
what the emergency services will do to warn and protect people and property
downstream in the event of an incident which could lead to dam failure.

35 For details see https://flood-warning-information.service.gov.uk/long-term-flood-risk/map
36 The Act applies to reservoirs over 25,000 m3 in England.

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The Likely Impact of Climate Change
144 For offline reservoirs (ie reservoirs where water has to be pumped or diverted into
the reservoir) it is unlikely that climate change will have a significant impact on reservoir
floodrisk. For online reservoirs (ie reservoirs which have watercourses flowing into andout of them) there could be an increased risk of flooding due to higher inflows. In
either case this will be monitored through the above mentioned strict management
arrangements, including other possible risk factors such as drought or waterlogging
reducing the stability of reservoir embankments.
Recommendation 6 – Reservoir Flood Risk
The reservoir flood risk in identified locations (see reservoir flood map) should beconsidered in Strategic Flood Risk Assessments (SFRAs) and Flood Risk Assessments(FRAs).

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Chapter 3– Spatial Implications of Flood Risk
3.1 Introduction140. Chapter 1 dealt with the strategic overview of flood risk in London with particularreference to the London Plan. Chapter 2 dealt with a more detailed analysis of the risk
from the six types of flooding that could affect London. Chapter 3 now examines floodrisk in relation to strategic growth locations (Opportunity Areas and Town Centres) andinfrastructure assets. Appendix 3 provides the related maps and detailed statistics.
Further information in terms of relevant definitions and assumptions are provided
directly on the maps themselves.
London Boroughs – Strategic Flood Risk Appraisals (SFRAs)
141. Most London boroughs have some extent of identified flood risk; see Map 1. For
some this is limited to small areas along tributary streams, for others it includes large
areas with potential for tidal flooding across a large proportion of the borough.
142. All boroughs have SFRAs in place, but these will need to be kept up to date andreviewed approximately every 3-5 years or as and when significant new data becomes
available. Many London boroughs are currently updating their SFRAs. For specificstrategic purposes joint SFRAs have been produced, including one for East London and
one for North London to support the North London Waste Plan.
143. It is important for SFRAs to identify areas where there are particular flood risks.
For example, some low lying areas of land will be susceptible to ponding of water, inother areas there may be particular risks of a breach of flood defences or rapid
inundation of flood waters with high velocities. This type of analysis will assist in
determining locations where development may have to be constrained or altered to
avoid particularly high risks.
144. The SFRAs represent a baseline study of flood risk for each borough and havegenerated detailed descriptions of prevailing flood risk. When the SFRAs are
updated, they should consider further;••

Where appropriate, taking forward key recommendations into flood risk
management policies within the Local Plans.
Using the characterisation of risk to identify areas where redevelopment could be an
opportunity to reduce flood risk. Where redevelopment is likely and capable ofcontributing to a reduction in flood risk (reducing probability and/or consequence),
this could be achieved for example through relocating buildings, improving layout
and design (designing in resistance), removing certain vulnerable land uses orproviding flood compatible open spaces.

145. These issues may require design considerations at the masterplan or community
scale and a SFRA could identify where this type of planning is required. Some SFRAs
have started to present this analysis through identification of character areas, others
have started to link spatial planning policy to enhancement of emergency planningcapability.

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146. Complementing this planning specific tool, the London boroughs also have to
produce – in their role as LLFAs - Local Flood Risk Management Strategies basedon the F&WM Act 2010 requirements with measures to address local flood risk in theirareas. All boroughs have at least draft strategies in place. They also have to maintain aregister of Flood Risk Management Assets and must investigate reports of flooding.
3.2

Specific Development Areas

Opportunity Areas
152. The new draft London Plan continues to designate Opportunity Areas as major
development locations. These are the places where London will accommodate asignificant share of its anticipated growth and where large scale development is
expected to take place over the Plan period. Each of these will involve up to several
thousand new dwellings and/or employment space for up to several thousand people
and frequently a mix of many different land uses to promote sustainable development.
153. All 50 Opportunity Areas, including ten emerging ones 37, have some form ofidentified flood risk. Map 2 illustrates that Earls Court, the Isle of Dogs and Kensal
Canalside have the highest proportion of high flood risk areas (17, 16 and 15 percent respectively). The Royal Docks, London Riverside, Kingston Town Centre, Victoria
and the Upper Lea Valley follow with ten or more percent. On average seven per cent ofOpportunity Areas are at high risk of flooding. All individual Opportunity Area risk
figures are provided alongside Map 2. The assessment of the Opportunity Areas, as key
locations for future growth, does not only consider 1 in 30 and 1 in 100 year events(high and medium risk), but also 1 in 1000 year events (low risk). This precautious
approach was agreed with the Environment Agency as an appropriate reflection of therevised allowances.
154. Integrated Water Management Strategies should be considered for
Opportunity Areas, where an integrated approach to the management of risk and waterrelated infrastructure is required.
155. A brief overview of current flood risk characteristics and potential mitigation
measures for all of them is included in Table 1. For better distinction between river/tidal
and surface water flood risk issue, the latter element is included in red, and theemerging new Opportunity Areas are on a blue background. The table represents a
broad flood risk framework for more detailed investigations at the level of the individual
location. In terms of surface water flood risk these major development locations offer
opportunities to divert surface water away from the existing drainage network into moresustainable rainwater use or disposal techniques. This is especially important in areas
served by the combined sewer network, as the benefits will also reduce the costs ofoperating the sewerage system. Furthermore, if planned across large scale developments
such measures can reduce development costs compared with the provision of
conventional drainage infrastructure.
156. The presence of an element of flood risk is something that needs to beunderstood, planned and managed. Appropriate development can still come forwardand may actually result in a reduction of flood risk both on site and for surrounding
37 Hays, Great West Corridor, Wood Green, New Southgate, Romford, Poplar Riverside, Sutton, Kingston,Wimbledon, and Clapham Junction

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areas. A further consideration in these important locations is to ensure that criticalinfrastructure is either located away from flood risk areas or has a high standard ofprotection.
Table 1: Flood Risk in Opportunity Areas

BexleyRiverside

Current flood risk
characteristics

Potential flood risk mitigation
measures

Mainly within Flood Zone 3,
downstream of the Thames Barrier,with a high level of protection fromstorm surges by raised river walls.
Contains several shipping-relatedindustries requiring operational
access to the river. Also contains
parts of the Darent floodplain with ahigh level of protection by tidal
defences.

Located in the Thamesmead and Dartford
and Erith TE2100 policy units. Raising riverwalls and embankments required by 2040 tokeep up with climate change and keep floodrisk at current levels. Open spaces to beretained for potential flood storage and work
to flood defences in future. Need to consider
future of Darent Industrial Estate andpotential use of Crayford Marshes for tidal
storage. Outputs from the River Cray floodrisk management asset study should beconsidered.

There are some surface water floodrisk areas particularly where there isa dominance of large impermeable
areas. Some areas rely on pumped
drainage.

Bromley

Partially within Flood Zones 2 and 3
with fluvial flood risks along River
Ravensbourne to the west of town
centre and a tributary watercourse
running close to Bromley South
Station.
Surface water risks broadly follows
fluvial floodplains with some areas at
risk of deep surface water flooding in
extreme events.

An Integrated Water Management Strategy
has been produced. Measures to reducesurface water run-off will be important. New
development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve Greenfield run-off rates and reducethe current risks. Development close to theThames can discharge directly to the river.
Investigate opportunities to reduce flood risk
from River Ravensbourne. Set development
back from river’s edge to enable a range offlood risk management options.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks.
Given the identified flood risk the control ofsurface water is particularly important for thedevelopment of the area. It is also important
to consider the role of multipurpose open
spaces and additional drainage attenuationfrom large roof/hardstanding areas.

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CanadaWater

Current flood risk
characteristics

Potential flood risk mitigation
measures

Wholly within Flood Zone 3 and witha high level of protection from daily
flooding by river walls and from tidal
surges by the Thames Barrier.

Located in Wandsworth to Deptford TE2100
policy unit. Raising river walls required by
2065 to keep up with climate change andreduce flood risk further. Set development
back from river’s edge to enable a range offlood risk management options.

Relatively minor surface water flood
risks focused on London Overgroundlines around Surrey Quays station
and Rotherhithe Tunnel approach
road.

Charlton
Riverside

Mainly within Flood Zone 3 andstraddling the Thames Barrier, with ahigh level of protection from storm
surges by raised river walls but withland lying significantly below high tidelevels.
There are notable areas of surface
water flood risk around Horn Lane,
Westmoor – Eastmoor Streets and at
the low point on Bugsbys Way under
the freight rail bridge.

City Fringe /Tech City

Mainly within Flood Zone 1, thesouthern extremes have a high levelof protection from daily flooding by
river walls and from tidal surges by
the Thames Barrier.
Relatively minor surface water flood
risks mainly focused on the public
highway network and the sub surface
National Rail lines north of Liverpool
St Station.

New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks.
Existing water spaces and nearby green
infrastructure will provide good opportunities
for sustainable drainage.
Located in the Greenwich TE2100 policy
unit. Raising river walls and embankments
required by 2065 to keep up with climatechange and reduce flood risk further. Openspaces to be retained for potential flood
storage and work to flood defences in future.
An Integrated Water Management Strategy
has been produced. New development is agood opportunity to introduce moresustainable rainwater management andshould readily be able to achieve Greenfieldrun-off rates and reduce the current risks.
Development close to the Thames candischarge directly to the river.
Located in the London City TE2100 policy
unit. Raising river walls required by 2065 tokeep up with climate change and reduce
flood risk further. Open spaces to beretained for potential flood storage and work
to flood defences required in future.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks.

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Claphamjunction

Current flood risk
characteristics

Potential flood risk mitigation
measures

Mainly within Flood Zone 3 but with ahigh level of protection from daily
flooding by river walls and from tidal
surges by the Thames Barrier.

Located in Wandsworth to Deptford TE2100
policy unit. Raising river walls required by
2065 to keep up with climate change andreduce flood risk further; also setting
development back from river’s edge. Climatechange is expected to increase the residual
risks posed by breaches in the tidal
defences and it is important thatdevelopments take account of this residual
risk when considering the safety of proposeddevelopments.

Some areas of significant surface
water flood risk, notably to the northof Clapham Jcn station.

Colindale /Burnt Oak

Cricklewood/ Brent Cross

Part of the area is within Flood Zones
2 and 3 and contains Silk Stream, aRiver Brent tributary where localised
flooding has been recorded.
Some surface water flood risk areas
notably along tributary river corridors,
especially in the vicinity of Burnt Oak
LU Station.
A small proportion of area is within
Flood Zones 2 and 3 with some local
flood history on the River Brent.
There are some surface water floodrisk areas with recently recorded
flooding history particularly along theRiver Brent corridor, the A406 where
it passes under the A41, the A41
south of the A406, Cricklewood Lane
near Crickelwood Station and around
Prayle Grove.

CroydonPart of the area is within Flood Zones
2 and 3 of the River Wandle.
Extensive areas of surface water
flood risk along the route of thelargely buried River Wandle. Drain
London/LB Croydon have funded an
initial study into this risk area.
Groundwater flood risk is also an
issue.

New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks.
Given the extent of surface water risks,
there may be merit in delivering a strategic
drainage solution.
Set development back from river’s edge toenable a range of flood risk management
options.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks.
Set development back from river’s edge toenable a range of flood risk management
options. Investigate opportunities to reduce
flood risk from River Brent including
opportunities to restore canalised/culverted
watercourses.
New development is a good opportunity tointroduce more sustainable rainwater
management and there should be good
scope for sustainable drainage options toachieve greenfield run-off rates and reducethe current risks.
Investigate opportunities to reduce flood risk
for the River Wandle/Caterham Bourne.
Measures to reduce surface water run-off
will be important. New development is agood opportunity to introduce moresustainable rainwater management andthere should be good scope for sustainabledrainage options to achieve substantial
reduction in run-off rates and reduce thecurrent risks.
The Caterham Bourne Flood Alleviation
Scheme is being considered also to address
groundwater flood risk.

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Deptford
Creek /
GreenwichRiverside

Current flood risk
characteristics

Potential flood risk mitigation
measures

Mainly within Flood Zone 3, with ahigh level of protection from daily
tidal flooding and fluvial flooding fromthe River Ravensbourne by riverwalls and from tidal surges by theThames Barrier.

Located in the Greenwich and Wandsworth
to Deptford TE2100 policy units. Raising
river walls required by 2065 to keep up withclimate change and reduce flood risk further.
Investigate opportunities to reduce flood risk
from River Ravensbourne. Set development
back from river’s edge to enable a range offlood risk management options.

Localised areas of surface water
flood risk with some particular risk
areas along the national rail lines
through Greenwich Town Centre.

Earls Court
and West
Kensington

Partially within Flood Zone 3 and witha high level of protection from storm
surges by raised river walls.
Documented surface water/sewer
flood risk areas and known capacity
problems in the Counters Creek
catchment affecting thousands ofproperties. London Overground andUnderground rail lines at risk andareas close to large footprint
buildings. It is notable that manyolder properties in the area havebasements which will be at a higher
risk of overflow from the highway
network.

Elephant
and Castle

Wholly within Flood Zone 3 and witha high level of protection from daily
flooding by river walls and from tidal
surges by the Thames Barrier.
Relatively minor surface water floodrisk present focus on the public
highway network.

EustonWithin Flood Zone 1 with nofloodplain identified.
Relatively minor surface water flood
risks, mainly focused on the public
highway network with the exceptionof more significant risks to the sub
surface National Rail lines north of
Euston Station and Euston Rd
underpass.

New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks.
Development close to the Thames candischarge directly to the River
thames/Deptford Creek.
Located in the Hammersmith TE2100 policy
unit. Need to consider the role ofmultipurpose open spaces for flood risk
management and management of surface
water.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks, as
has been achieved at Westfield with
substantial rainwater storage.
Thames Water is developing the Counters
Creek sewer flood relief tunnel project within
this area.
Located in Wandsworth to Deptford TE2100
policy unit. Raising river walls required by
2065 to keep up with climate change andreduce flood risk further. Set development
back from rivers edge to enable a range offlood risk management options.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks.
HS2 and Euston development need to fully
consider flood risks in the area.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks.

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Great West
Corridor/Gol
den Mile

Current flood risk
characteristics

Potential flood risk mitigation
measures

Mainly Flood Zone 1 although
eastern parts include Flood Zone 3
from tidal Thames and River Brent
floodplains.

Set development back from river’s edge toenable a range of flood risk management
options and deliver TE2100
recommendations where appropriate.
Investigate opportunities to reduce flood risk
from River Brent.

Some areas have significant surface
water flood risks, mainly to the southof Great West Road.

GreenwichPeninsula

Wholly within Flood Zone 3 and witha high level of protection from daily
flooding by river walls and from tidal
surges by the Thames Barrier.
Contains several shipping relatedindustries requiring operational
access to river.
Some surface water flood risk areas
notably along existing highways.

HaringeyHeartlands /Wood Green

Flood Zone 1 although includes
upper reaches of Moselle brook in
culvert.
Relatively minor surface water flood
risks, mainly focused on the public
highway network with higher risk
areas to the west of the National Raillines.

Harrow andWealdstone

Some areas are located in Flood
Zone 3 of the Wealdstone Brook
floodplain. The Brook flows throughthe site in culvert.
Some surface water flood risk areas
particularly to the highway network
including low lying parts of the HighSt, Masons Ave and around
Kenmore Ave.
The combination of surface water,
sewer and fluvial flooding are ofconcern.

New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks.
New development in areas of significant
surface water flood risk may also needspecific mitigation measures.
Located in Greenwich TE2100 policy unit.
Raising river walls required by 2065 to keep
up with climate change and reduce flood risk
further. Set development back from river’s
edge to enable a range of flood risk
management options.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks,Development close to the Thames candischarge directly to the river and much of
the rest of the peninsula can connect into asurface water drainage system thatdischarges to the Thames.
Set development back from culverts.
Consider opportunities to reduce floodrisk/open the culvert for the Moselle Brook.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks
and in particular the discharge to theMoselle Brook.
Set development back from culverts andseek opportunities to open up culverted
sections of the river. Look at opportunities toreduce flood risk for the Wealdstone Brook.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a greenfield run-off rates andreduce the current risks in the area anddownstream, where there are particularly
acute risks.

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HayesCurrent flood risk
characteristics

Potential flood risk mitigation
measures

Mainly Flood Zone 1.

New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks.
New development in areas of significant
surface water flood risk may also needspecific mitigation measures.
Set development back from river’s edge toenable a range of flood risk management
options. Need to consider the role ofmultipurpose open spaces for flood risk
management and management of surface
water.

Some areas have significant surface
water flood risks, mainly aroundHayes town Centre.

Heathrow

Relatively small proportion of thearea within Flood Zones 2 and 3.
Relatively minor surface water flood
risks, although potentially risks to sub
surface roads/rail. Heathrow benefits
from the presence of surface waterbalancing ponds.

IlfordIsle of Dogs

Mainly Flood Zone 1 but a very small
proportion of area within Flood Zone
3 of the River Roding.
Relatively minor surface water flood
risks, mainly focused on the public
highway network with the exceptionof the Cranbrook corridor along partsof Northbrook Road and parts of the
National Rail lines east of Ilford
Station where risks are moresignificant.
Mainly within Flood Zone 3 but with ahigh level of protection from daily
flooding by river walls and from tidal
surges by the Thames Barrier.
Some localised surface water flood
risks, mainly focused on the public
highway network.

KensalCanalside

Flood Zone 1. Grand Union Canalruns alongside the site.
Some localised surface water flood
risks, and the area contributes to thealready overloaded Counters Creek
combined sewer catchment.

New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve greenfield run-off rates and reducethe current risks.
Set development back from river’s edge toenable a range of flood risk management
options.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks.

Raising river walls by 2065 to keep up withclimate change and reduce flood risk further.
Set development back from river’s edge toenable a range of flood risk management
options.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks.
Development close to the Thames anddocks can discharge directly to the river.
Set development back from canal edge toenable a range of flood risk management
options.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve greenfield run-off rates and reducethe current risks and discharge rates into the
combined sewer system. Development close
to the Grand Union Canal may be able todischarge directly to the canal.

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Kings Cross– St Pancras

Current flood risk
characteristics

Potential flood risk mitigation
measures

Flood Zone 1. Grand Union Canalruns through the site.

Set development back from canal edge.

Relatively minor surface water floodrisk, mainly focused on the public
highway network and sub surface
National Rail lines.
Kingston –New Malden

Mainly Flood Zone 1 with somesignificant areas of Flood Zones 2
and 3, notably around Kingston Town
centre and along the Hogsmill River.
Some areas have significant surface
water flood risks, mainly to the northof Kingston Town centre and north of
new Malden.

New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks, inparticular around mainline station.
Set development back from river’s edge toenable a range of flood risk management
options. Environment Agency investigating a
Lower Thames Flood Defence scheme, newdevelopment should allow for any
appropriate interventions. Investigate
opportunities to reduce flood risk from
Hogsmill River.
New development in areas of significant
surface water flood risk may need specificmitigation measures.

Lewisham /Catford /New CrossSignificant areas located within Flood
Zones 2 and 3 within the floodplainsof the Ravensbourne, Quaggy andThames rivers. Catford andLewisham have the River
Ravensbourne and its tributaries
running through them with locallyrecorded flooding. There is a highlevel of protection from daily tidal
flooding by river walls and from tidal
surges by the Thames Barrier. A
fluvial flood risk defence scheme isunder consideration by theEnvironment Agency.
Extensive areas of surface water
flood risk along the tributary rivers
through Catford and Lewisham Town
Centres, some of these areas are at
risk of deep surface water flooding in
extreme events.

New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks.
New development in areas of significant
surface water flood risk may also needspecific mitigation measures.
Part of the Opportunity Area is located in the
Wandsworth to Deptford and Greenwich
TE2100 policy units. Defence raising
required on the Thames frontage by 2065 tokeep up with climate change and reduce
flood risk further. Need to consider the roleof multipurpose open spaces within thewider development areas. Development tobe set back from tributary river edges toenable a range of flood risk management
measures. Safeguarding land potentiallyrequired for future flood risk management
measures on fluvial watercourses. Comply
with the recommendations of the River
Ravensbourne river corridor improvement
plan and Environment Agency requirements
for improving flood risk management.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks.
Given the spread and depth of flood risk thecontrol of surface water within this area andits contributing catchment is particularly
important.

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LondonBridge,Borough &Bankside

Current flood risk
characteristics

Potential flood risk mitigation
measures

Wholly within Flood Zone 3 and witha high level of protection from daily
flooding by river walls and from tidal
surges by the Thames Barrier.

Located in Wandsworth to Deptford TE2100
policy unit. Raising river walls required by
2065 to keep up with climate change andreduce flood risk further. Set development
back from river’s edge to enable a range offlood risk management options.

Relatively minor surface water flood
risks, mainly focused on the public
highway network.

LondonRiverside

Mainly within Flood Zone 3,
downstream of the Thames Barrier
and with a high level of protection
from daily flooding and storm surges
by raised river walls. Contains many
shipping-related industries requiring
operational access to river. Tributary
rivers of Rainham Creek, Rom/Beam,
Gores Brook and River Roding.
Relatively few incidences of floodingin the past.
Relatively minor surface water flood
risks, mainly focused on the public
highway network and around existingwater features.

NewSouthgate

Mainly Flood Zone 1 with somelocalised areas of Flood Zones 2 and
3, along Strawberry Vale Brook.
Some areas have significant surface
water flood risks, notably affecting
the North Circular Road.

Old Kent
Road

Mainly within Flood Zone 3 and witha high level of protection from daily
flooding by river walls and from tidal
surges by the Thames Barrier.
Mostly relatively minor surface water
flood risks but more extensive risk
areas in the eastern part of the area
close to Ilderton Rd and just outside
the Opportunity Area to the south of
Old Kent Rd.

New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks.
Development close to the Thames candischarge directly to the river.
Located in Barking and Dagenham andRainham Marshes TE2100 policy units.
Raising river walls and embankments
required by 2040 to keep up with climatechange and keep flood risk at current levels.
Open spaces to be retained for potential
flood storage. Set development back fromriver’s edge to enable a range of flood risk
management options. The area may have arole for strategic flood storage – notably
when tributaries become tide locked.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve greenfield run-off rates and reduce
current risks. Development close to theThames can discharge directly to the river.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks ofboth surface and fluvial flood risk. Potential
to utilise large areas of open space forstrategic surface water/flood storage.
Located in Wandsworth to Deptford TE2100
policy unit. Raising river walls required by
2065 to keep up with climate change andreduce flood risk further. Set development
back from rivers edge to enable a range offlood risk management options.
An Integrated Water Management Strategy
has been produced. New development is agood opportunity to introduce moresustainable rainwater management andshould readily be able to achieve asubstantial reduction on current run-off rates
and reduce the current risks both within andjust outside the eastern edge of theOpportunity Area.

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Old OakCommonPaddington

Current flood risk
characteristics

Potential flood risk mitigation
measures

Wholly within Flood Zone 1, Grand
Union Canal runs through the site.

Set development back from canal edge.

Surface water risks generally
localised and small scale, althoughsome rail cuttings and roadunderpasses identified as at risk.
The area drains to the alreadyoverloaded Counters Creek
Catchment.
Wholly within Flood Zone 1. Grand
Union Canal/Paddington Basin runs
through the site.
Relatively minor surface water flood
risks. It is notable that many older
properties in the area havebasements which will be at a higher
risk of overflow from the highway
network.

Park RoyalPart of the area lies along the River
Brent to the west of North Circularand is within Flood Zones 2 and 3.
Grand Union Canal runs through thesite.
Some areas of localised surface
water flood risks focused in areas
close to large footprint buildings,
A406 underpasses and lower
stretches of the rail network.

PoplarRiverside

Mainly Flood Zone 3 from tidal
Thames and River Lee floodplains
but with a high level of protection
from daily flooding by river walls andfrom tidal surges by the Thames
Barrier.
Generally low to medium risks ofsurface water flooding.

An Integrated Water Management Strategy
has been produced. New development is agood opportunity to introduce moresustainable rainwater management andshould readily be able to achieve asubstantial reduction on current run-off rates
and reduce the current risks and discharge
rates into the local combined sewer network.
Set back development from canal edge.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks, inparticular around the main line station.
Development close to the Paddington Basinshould be able to discharge rainwater to thebasin.
Investigate opportunities to reduce flood risk
from River Brent. Set development backfrom river and canal edges to enable arange of flood risk management options.
An Integrated Water Management Strategy
has been produced. New development is agood opportunity to introduce moresustainable rainwater management andshould readily be able to achieve greenfieldrun-off rates and reduce current risks.
Development close to the Grand Union
Canal may be able to discharge directly tothe canal. It is also important to consider therole of multipurpose open spaces andadditional drainage attenuation from large
roof/hardstanding areas.
Raising river walls by 2065 to keep up withclimate change and reduce flood risk further.
Set development back from river’s edge toenable a range of flood risk management
options. Investigate opportunities to reduce
flood risk from River Lee.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks.
Opportunities to divert rainwater directly to
the River Lee and River Thames.

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Romford

Current flood risk
characteristics

Potential flood risk mitigation
measures

Mainly Flood Zone 1 with somelocalised areas of Flood Zones 2 and3.

New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks.
New development in areas of significant
surface water flood risk may also needspecific mitigation measures including
investigation of opportunities to de-culvert
and naturalise the River Rom and Black
Brook.
Located in Royal Docks TE2100 policy unit.
Raising river walls and embankments
required by 2040.

Some areas have significant surface
water flood risks, notably aroundRomford Town centre.

Royal Docksand Beckton
Waterfront

Southall

Almost entirely within Flood Zone 3,
the area straddles the Thames
Barrier so has a high level ofprotection from storm surges by the
Barrier and by raised walls
downstream. Various watercourses
flow through the site.
Relatively minor surface water flood
risks, mainly focused on the public
highway network including parts ofNorth Woolwich Road and lower
parts of Royal Albert Way and lowers
DLR lines along Royal Albert Way.
Flood Zone 1 but close to floodplainof Yeading Brook. Grand Union
Canal runs alongside the site.
Some localised surface water flood
risks, mainly focused on the public
highway network.

SuttonFlood Zone 1
Some areas have significant surface
water flood risks, mainly to the southof Sutton Town centre.

New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve greenfield run-off rates and reduce
current risks. Development close to theThames and docks can discharge directly tothe river.

Need to ensure that development does notincrease flood risk. Set back developmentfrom canal edge.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve greenfield run-off rates and reduce
current risks. Development close to theGrand Union Canal may be able todischarge directly to the canal.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks.
New development in areas of significant
surface water flood risk may also needspecific mitigation measures.

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Thamesmea
d and Abbey
Wood

Current flood risk
characteristics

Potential flood risk mitigation
measures

Almost entirely within Flood Zone 3
within the tidal Thames floodplain
with large areas significantly below
high tide level. Parts of the area aredependent on pumping stations andstorage reservoirs for continuous
flood risk management. Various
watercourses flow through the site.

Located in Thamesmead TE2100 policy unit.
Raising river walls and embankments
required by 2040 to keep up with climatechange and keep flood risk at current levels.
New development needs carefulconsideration, particularly of residual risks
and emergency measures. Set development
back from river’s edge to enable a range offlood risk management options.

There are some surface water floodrisk areas particularly where the
National Rail line embankment acts
as an informal flood barrier. There
are surface water features within
Thamesmead and some areas relyon pumped drainage.

Tottenham
Court Road

Upper Lee
ValleyFlood Zone 1.
Relatively minor surface water flood
risks. It is notable that many older
properties in the area havebasements which will be at a higher
risk of overflow from the highway
network.
Includes extensive areas of Lee
Valley floodplain and contains areasof Flood Zone 2 and 3. River Lee andtributaries flow through the area.
Some notable surface water risk
areas around Tottenham Hale and
SW of Northumberland Park, Hall
Lane and industrial estates close to
the A406 and some low lying parts of
the River Lee floodplain.

An Integrated Water Management Strategy
has been produced. New development is agood opportunity to introduce moresustainable rainwater management andshould readily be able to achieve asubstantial reduction on current run-off rates
and reduce the current risks. Development
close to the Thames can discharge directly
to the river.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks.

Investigate opportunities to reduce flood risk
from River Lee. Set development back fromriver’s edge to enable a range of flood risk
management options. Need to consider therole of multipurpose open spaces within thewider development area. Should beconsidered in association with measuresacross London’s boundaries in Herts andEssex.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks. In
areas close to the Lee Valley greenfield runoff rates should be achievable with options
for discharges to the River Lee.

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Vauxhall /Nine Elms /Battersea

Current flood risk
characteristics

Potential flood risk mitigation
measures

Mainly Flood Zone 3 and with a highlevel of protection from daily flooding
by river walls and from tidal surges
by the Thames Barrier. Contains
several shipping related industries
requiring operational access to river.

Located in Wandsworth to Deptford TE2100
policy unit. Raising river walls required by
2065 to keep up with climate change andreduce flood risk further. Set development
back from river’s edge. Climate change is
expected to increase the residual risks
posed by breaches in the tidal defences andit is important that developments takeaccount of this residual risk when
considering the safety of proposeddevelopments.

Relatively minor surface water flood
risks, mainly focused on the public
highway network with the exceptionof more significant risks on streets tothe north west of Wandsworth Road.
The access road into New Covent
Garden under the railway lines isshown at particular risk and should
be investigated.

Victoria

Waterloo

Partially within Flood Zone 3 and witha high level of protection from daily
flooding by river walls and from tidal
surges by the Thames Barrier.
Some significant surface water floodrisk, mainly focused on the public
highway network and the National
Rail lines into Victoria Station. It isalso notable that many older
properties in the area havebasements which will be at a higher
risk of overflow from the highway
network.
Wholly within Flood Zone 3 and witha high level of protection from daily
flooding by river walls and from tidal
surges by the Thames Barrier.
Relatively minor surface water flood
risks, mainly focused on the public
highway network with a concentration
around Waterloo Station.

An Integrated Water Management Strategy
has been produced. New development is agood opportunity to introduce moresustainable rainwater management andshould readily be able to achieve greenfieldrun-off rates and reduce the current risks.
Development close to the Thames candischarge directly to the river and Thames
Water is investing in new surface water
infrastructure to enable more clean water todischarge to the river.
Located in London City TE2100 policy unit.
Raising river walls required by 2065 on river
frontage section to keep up with climatechange and reduce flood risk further. Set
development back from rivers edge toenable a range of flood risk management
options.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks, inparticular around mainline station.
Located in Wandsworth to Deptford TE2100
policy unit. Raising river walls required by
2065 to keep up with climate change andreduce flood risk further. Set development
back from river’s edge to enable a range offlood risk management options.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks, inparticular around mainline station.
Development close to the Thames candischarge directly to the river.

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Wembley

Current flood risk
characteristics

Potential flood risk mitigation
measures

Some areas are within Flood Zones 2
and 3 of the Wealstone Brook/River
Brent, which flow through the area.

Investigate opportunities to reduce flood risk
from River Brent. Set development backfrom river’s edge to enable a range of floodrisk management options.

Relatively minor surface water flood
risks focused on the Wealdstone
Brook corridor and areas close tolarge footprint buildings.

White City

Small part of the area is within Flood
Zone 3 and with a high level ofprotection from daily flooding by riverwalls and from tidal surges by theThames Barrier.
Some significant surface water risk
areas in/close to the area. The areadrains to the already overloaded
Counters Creek Catchment.

Wimbledon

Mainly Flood Zone 1 with somesignificant areas of Flood Zones 2
and 3, along the River Wandle
corridor.
Some areas have significant surface
water flood risks, mainly to the south
west of Wimbledon Chase.

Woolwich

Mainly within Flood Zone 3,
downstream of the Thames Barrier
and with a high level of protection
from storm surges by raised riverwalls but with land lying significantly
below high tide levels.
Some parts of Woolwich Town
Centre, notably the national rail lines
are at risk of surface water floodingwith flows running off the ridgeline tothe south.

New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve greenfield run-off rates and reduce
current risks. It is also important to consider
the role of multipurpose open spaces andadditional drainage attenuation from large
roof/hardstanding areas.
Located partially within Hammersmith
TE2100 policy unit.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks
and reduce discharge rates into the local
combined sewer system, as has beenachieved at Westfield with substantial
rainwater storage. It is also important toconsider the role of multipurpose open
spaces and additional drainage attenuationfrom large roof/hardstanding areas.
Investigate opportunities to reduce flood risk
from River Wandle. Set development backfrom river’s edge to enable a range of floodrisk management options.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks.
New development in areas of significant
surface water flood risk may also needspecific mitigation measures.
Located in Thamesmead TE2100 policy unit.
Raising river walls and embankments
required by 2040 to keep up with climatechange and keep flood risk at current levels.
Open spaces to be retained for potential
flood storage. Set development back fromriver’s edge to enable a range of flood risk
management options.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve a substantial reduction on current
run-off rates and reduce the current risks.

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Town Centres and the Central Activities Zone
157. Intensification of development at Town Centre locations is generally sustainable,
given the high levels of public transport accessibility and concentration of facilities.
New development will still need to be accompanied by a Flood Risk Assessment whererequired as set out in the NPPF.
158. Given that development in town centres tends to be high density, there are likely
to be high run-off rates and limited scope for floodwater or rainwater attenuation in theimmediate vicinity. In addition, many new developments will come forward in apiecemeal manner. Therefore, surface water management in constrained town centre
sites needs to be considered particularly early in the design process so it can besatisfactorily accommodated and managed.
159. Map 3 illustrates that Kingston and Woolwich have the highest proportion of their
town centres in areas of high flood risk (34 and 27 per cent respectively).
Hammersmith (23 per cent), Canary Wharf (22 per cent) and Lewisham (19 per cent)follow. On average 13 per cent of Metropolitan and 9 per cent of Major town centres
are at high risk of flooding. All individual town centre risk figures are provided alongside
Map 3 and a brief overview of flood risk issues for all of them is included in Table 2.
160. The Central Activities Zone (CAZ), which includes both the West End andKnightsbridge International Town Centres as well as a number of Opportunity Areas andAreas of Intensification, is at risk of tidal flooding from the Thames, which flows
through the CAZ. Flood risk to the south of the Thames and in particular in the
Pimlico/Victoria area is quite extensive. However, the area is defended to a very highstandard by a combination of the Thames Barrier and the Thames tidal flood defences.
Particular attention should nevertheless be paid to the layout and design ofdevelopment close to the River itself in order to allow for the appropriate maintenanceand potential upgrade of the flood walls. Setting development back from the existing
walls will generally be desirable in order to enable a range of flood risk management
options. Consideration should also be given to the residual risk should the defences failor be breached. This includes locating significant infrastructure and more vulnerable
types of development in areas at lowest risk or implementing flood resilience measures.
In addition developments with basements should consider the safety, continuity ofservices and recovery from a flood, should one occur.
161. Surface water flood risks are relatively minor for the majority of the CAZ but
particular attention should be paid to flood risk management for any specific low lying
areas and to buildings with basements. Sustainable Drainage techniques should bedelivered wherever is reasonably practical and there is increasing evidence of suchtechniques being implemented in high density CAZ locations to achieve significant
reductions in rainwater discharge rates. Green roofs and rainwater harvesting systems
can be economically viable for commercial and even residential development within the
CAZ. Locations close to the Thames may be able to discharge clean rainwater direct to
the Thames without the need for any other attenuation measures.

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Table 2: Flood Risk in Town Centres
Metropolitan centres

Flood Risk Issues
Bromley

CroydonEalingHarrow

Hounslow
IlfordKingston
RomfordShepherd Bush

Stratford
SuttonUxbridge

Wood Green

Small proportion within the River Ravensbourne floodplain andsignificant surface water risk areas co-inciding with the Ravensbourne
floodplain and flow path from the east passing under Bromley SouthstationPartially within the River Wandle floodplain and close to culverted
sections of the river and significant surface water risk areas co-inciding
with the former course of the River Wandle
No identified fluvial flood risk issues but surface water flood risk areas
have been identified along rail lines
No identified fluvial flood risk issues but surface water flood risk areas
have been identified along rail lines and the Town Centre is upstream ofan area that suffers significant flood risk
No identified fluvial flood risk issues but some surface water flood risk
areas have been identified close to LU rail lines
Small proportion within the River Roding floodplain and some relatively
minor surface water risks affecting rail lines to the east of the town
centre and Northbrook Road to the north
Substantially within the floodplains of the River Thames and the
Hogsmill River and some localised areas of surface water flood risk
Partially within the River Rom floodplain, river flows through the Town
Centre in a culvert and significant surface water risks following the River
Rom and River Ravensbourne corridors through the Town Centre
Small proportion within the River Thames floodplain which is welldefended. Some localised areas of surface water risk identified, notably
along rail lines and in the vicinity of Tadmor St.
Partially within the River Lee floodplain, and some localised surface
water risk areas mainly affecting below ground level rail corridors
No identified fluvial flood risk issues but surface water flood risk on flow
path from the south west with risk areas to the south of the station andon Langley Park Rd under rail lines
Small proportion within the floodplains of the Frays River, River Colne
and Grand Union Canal which flow through the Town Centre. Somelocalised areas of surface water risk identified, notably along rail lines
just outside Station
Particular flood risk from Moselle Brook culvert. Relatively minor surface
water flood risks, mainly focused on the public highway network withhigher risk areas to the west of the National Rail lines

Major centres

Flood Risk Issues
Angel
Barking
Bexleyheath
BrixtonCamden Town

Canary Wharf

Regents Canal flows in a tunnel under the Town Centre. No identified
fluvial flood risk issues but some localised surface water risks.
No identified fluvial flood risk issues, but some localised surface waterrisks
No identified fluvial flood risk issues, but some localised surface water
risks to the west of the town centre
Significant surface water flood risk identified through the town centre
along the course of the Lost River Effra and continuing north along
Brixton Road
Grand Union Canal flows through the Town Centre. No identified fluvial
flood risk issues but some localised surface water risks. Opportunities todischarge surface water to the canalWholly within the Thames tidal floodplain but protected by the Thames
tidal defences. Opportunities to discharge surface water to the docks.

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Catford
Chiswick
Clapham Junction

DalstonEast Ham
EdgwareElthamEnfield Town
FulhamHammersmith

Kensington HighStreetKilburn
Kings Road East
LewishamNags Head
Orpington
PeckhamPutneyQueensway/Westbo
urne Grove
Richmond

SouthallStreathamTooting
Walthamstow
Wandsworth

Wembley

Partially within floodplain of the River Ravensbourne with significant
areas of surface water risk along the Ravensbourne corridor
Wholly within the River Thames floodplain - both tidal and fluvial floodrisk and some localised surface water risk areas
Small proportion within the River Thames floodplain and significant
surface water flood risk identified through the town centre along
Northcote Rd, St Johns Rd, under railway and affecting a large area tothe north of rail lines
No identified fluvial flood risk issues, but some localised surface water
risks, notably the sub-surface London Overground rail lines
No identified flood risk issues
Partially within the Silk Stream floodplain with some significant surface
water risk areas following the corridors of small local tributary rivers
No identified fluvial flood risk issues, but some surface water risks
around Well Hall Parade and risks to the A2 below the town centre
No identified fluvial flood risk issues, but some significant surface water
flood risks
Wholly within the Thames tidal floodplain but protected by the Thames
tidal defences, some localised surface water risks
Almost entirely within the Thames tidal floodplain but protected by theThames tidal defences, some areas of surface water flood risk, notably
on roads under rail to the north of King St.
No identified flood risk issues
No identified fluvial flood risk issues, but some localised surface water
risks, mainly affecting public highway
Small proportion within the River Thames floodplain but well defended
Substantially within the floodplains of the Rivers Ravensbourne andQuaggy with significant areas of surface water risk along the floodplains
No identified fluvial flood risk issues, but some localised surface waterrisk areas
Significantly within the River Cray floodplain with extensive surface
water flood risk areas along Sevenoaks Rd- Orpington High St corridor
No identified fluvial flood risk issues, but some significant surface water
risks, notably to the east of the town centre along the Copeland RdClayton Rd corridor
Small proportion within the Thames tidal floodplain but protected byThames Tidal Defences including the Thames Barrier
No identified fluvial flood risk issues, but some localised surface water
flood risk areas, notably affecting basements
Small proportion within the Thames floodplain, some localised surface
water risk areas around The Quadrant and affecting the sub surface rail
stationNo identified fluvial flood risk issues, but some localised surface waterrisk areas
No identified fluvial flood risk issues, but a significant area of surface
water flood risk to the north east of Streatham Station
No identified fluvial flood risk issues, but some localised surface water
risks, possibly focused on the route of the River Graveney
No identified fluvial flood risk issues, but some localised surface water
flood risk areas
Significantly within the tidal Thames and River Wandle floodplains andthe River Wandle flows through the Town Centre and some significant
surface water risk areas focused on the Wandle Floodplain and roads
passing under the railway
No identified fluvial flood risk issues. Wembley Brook flows in a culvert
under part of the Town Centre and some localised surface water risks
notably to the east of Lancelot Rd

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Wimbledon
Woolwich

No identified fluvial flood risk issues, but some risks to below groundlevel railway
Partially within the River Thames floodplain and some significant surface
water risk areas

Recommendation 7 – Flood Risk to Opportunity Areas and Town Centres
Where required, detailed flood risk assessments for individual major development
locations and town centre development sites should be undertaken by developers at an
early stage. Opportunities to reduce flood risk should be maximised where possible.
3.3

Main Rail Network and Major Stations

162. Map 4 shows that there are a total of 85 mainline stations and 87 km of mainline
rail corridor at high risk of tidal/fluvial and/or surface water flooding. This represents 24
per cent of London’s stations and 11 per cent of its rail corridor. A key issue is also thevulnerability of power supplies, signalling and communications equipment to flood risk.
163. Rail lines cross rivers on bridges, viaducts and embankments. Here the routes are
generally at low flood risk. Examples include the elevated rail lines through London
Bridge and into Waterloo, Blackfriars and Victoria. Many stations are also on elevatedsections of track and therefore at lower risk. The rail lines into Liverpool Street andStratford along the Lee Valley and the C2C lines east of Barking travel through the River
Lee and Thames floodplains respectively often at ground level. These have a higher
level of flood risk. Rail services within cuttings or stations with large roof areas may be
at particular risk from surface water flooding during heavy storms and these are set toincrease.
3.4

London Underground & DLR Networks

164. Map 5 shows that 4 per cent of the London Underground and DLR stations and 9
per cent of the lines are at risk of tidal/fluvial and/or surface water flooding. The
majority of high-risk stations are within the tidal Thames floodplain through central
London and westwards. The stations on the DLR branch to Stratford and Jubilee linefrom Stratford to Canning town are also within the River Lee Fluvial floodplain.
However, most of the DLR network at flood risk is elevated on raised tracks. There arealso some outlying stations and tracks, which are in the floodplain and/or at risk of
surface water flooding. However, notable sections of the tube network are also onraised tracks including for example parts of the District Line (Hammersmith to Acton,
Putney Bridge to Wimbledon, around West Ham) as well as Outer London parts of theCentral, Piccadilly, Northern and Metropolitan Line.
165. Flood water getting into underground stations presents a particular hazard and amajor engineering problem if the flood waters were to enter tube tunnels. This risk isextended geographically as tunnel portals could act as a conveyance route for flood
water from a wide variety of locations, especially in the event of a tidal flood. The tube
and DLR lines listed in Table 3 have tunnel portals within floodplains:

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Table 3: Tunnel Portals in Floodplain
Tube LineCentral Line
London Overground
Jubilee Line
Victoria LineDLR Lewisham branch
DLR Woolwich branch

Tunnel Portal
Eastern Portal
Southern Portal
Eastern Portal
Northern Portal
Thames Tunnel both portals
Thames tunnel both portals

Floodplain
River Lee
Tidal Thames
Tidal ThamesRiver Lee
Tidal Thames
Tidal Thames

166. It is acknowledged that the underground location of stations and tracks meansthat the flood risk may not necessarily be highest in the corresponding flood risk areasof the ground. This is why the portals are highlighted, and there may also be otherpotential flood routes including emergency access points and ventilation shafts.
167. London Underground has undertaken a review of flood risk from all sources that
may affect its lines, stations, depots and other infrastructure. London Underground isusing the results of this work to prioritise appropriate flood risk mitigation works overthe coming years. They have also identified measures to mitigate the risks andconsequences of burst water mains.
168. In addition, TfL is preparing a work programme related to improving theunderstanding of transport resilience in London. A Transport Sector working group is
being established, also in line with related draft policies set out in the draft London
Environment Strategy 38 and Mayor’s Transport Strategy 39.
3.5

Main Road Network and Airports

169. The road network is a critical element of London’s infrastructure. The bus network
provides around 6.5 million journey stages per day 40 and much of the network is heavily
used by private passenger and goods vehicles. The road network is also of criticalimportance to emergency services. The road network is managed by a combination ofHighways England for motorways and some trunk roads, TfL for the Transport for
London road network (TLRN) and local boroughs for local roads. The density of theroad network in London is likely to mean that alternative routes will be available inlocalised flood situations. However the volume of traffic is likely to lead to significant
congestion.
170. Map 6 shows that 11 per cent of the TLRN are at high risk, the majority of whichis in the tidal floodplain. However, some important road sections including parts of the
A13 and the North Circular are elevated, and TfL has a pro-active monitoring
programme of its network to report on flooding incidents, assess risks and implement
remedial measures.
171. Tunnels under the Thames have a particular risk as their portals are all within
the tidal Thames floodplain. In a similar way to tube tunnels, ventilation shafts or
emergency shafts may also present potential routes for the conveyance of flood water.

38 Policy 8.1.1
39 Policy 8 and Proposals 44 and 45

40 For details see https://tfl.gov.uk/corporate/publications-and-reports/travel-in-london-reports

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Other underpasses are low points within the road network and are more likely to be atrisk of surface water flooding, and a few are also within a Flood Zone.
Subterranean river crossings (road and pedestrian)
Rotherhithe Tunnel
Limehouse Link Tunnel
Greenwich Foot Tunnel
Blackwall Tunnel x2
Woolwich Foot Tunnel
Proposed: Silvertown Crossing
Road Underpasses
A501 Euston Road
A406 Edmonton – River Lee Floodplain
A406 Stonebridge Park
A406 Crooked Billet
A12 Wanstead/Green Man junction
A102/A11 Bow – River Lee Floodplain
A13 Movers Lane – River Thames Floodplain
A113/A1400 Charlie Browns Roundabout – River Roding Floodplain
A4088 Neasden Lane /A406 underpass
A4 Hyde Park Corner underpass
A214 Trinity Road/East Hill Underpass
A3 Tibbetts Corner underpass
A3 Tolworth Underpass
A3 Hook Road underpass
Heathrow Access RoadBus Depots
172. Some of the bus garages serving London’s bus operators are within flood risk
areas. A flood affecting a garage may have the direct impact of making buses unusable
or may have other indirect impacts for example the loss of electricity supply rendering
fuel pumps inactive or employees who are unable to reach work.
173. Bus depot flood management measures could include ideally a combination ofgreen and blue roofs. There is a good practice example at West Ham, where also
rainwater is captured for use in vehicle washing.
Airports
174. Heathrow Airport is largely free from flood risk, although some of the peripheral
areas to the west of the airport could be affected by large floods on the River Colnesystem. The airport has large surface water attenuation areas.
175. London City Airport is wholly within the floodplain of the tidal Thames. It is in
an area that is close to the Thames Barrier. It is protected by the existing flood defences
to a standard of at least 1 in 1000 years.

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Recommendation 8 – Flood Risk to Transport Infrastructure
Relevant transport authorities and operators should examine and regularly review theirinfrastructure assets including their networks, stations, depots, underpasses and tunnels
for potential flooding locations and flood risk reduction measures.
Appropriate mitigation measures include flood warning systems, emergency procedures,
sustainable drainage systems, temporary flood storage areas, pumping stations, back-up
power supply and the relocation of sensitive electrical/telecommunications equipment
and potentially polluting materials (e.g. fuel and oils) above potential flood levels.
For large stations and depots, solutions should be sought to attenuate or disperse
rainwater from heavy storms including in particular a comination of green and blue
roofs.
Highways flood management measures should also include diversionary routes.
For tunnel portals and ventilation shafts physical barriers such as flood gates and vent
covers should be considered.
3.6

Hospitals and Emergency Services

176. The London Resilience Partnership updated in 2015 its London Strategic Flood
Response Framework 41. It is important for emergency services to remain operable during
major flood events. Localised flooding events should be able to be managed by othersupporting emergency services. Major flood events affecting either the tidal Thames or
the major tributaries will need consideration and co-operation between several services.
This RFRA has identified potentially vulnerable concentrations of emergency service
facilities within flood risk areas.
Main Hospitals
177. 43 per cent of the 191 hospitals are at high risk of tidal/fluvial and/or surface
water flood risk (see Map 7). This is a high proportion, and therefore mitigation
measures such as those included in Recommendation 9, are important. But it should
also be recognised that this is a precautionary approach. Many hospitals are large
complex building structures, and without further analysis it is very difficult to know, if
important parts that could put people or the running of the hospitals at risk might beaffected. In many cases it may only be small areas.
178. Drain London commissioned some more detailed reviews of surface water risk tohospitals. This work demomstrated that they were generally able to manage their risks
at an acceptable level.
Fire Stations
179. Fire stations are likely to be important bases during flood events. Map 8 indicatesthat 28 fire stations from a total of 118 within London (24 per cent) are at high risk offluvial/tidal and/or surface water flooding. Several are in the central/inner London
Thames tidal floodplain and as such have a high degree of flood protection in particularfrom tidal flooding. They are also generally well covered by other fire stations justoutside the Flood Zone.

41 For details see www.london.gov.uk/about-us/organisations-we-work/london-prepared/planning-

emergencies-capital#acc-i-43126

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180. Drain London identified eight fire stations at risk of surface water flooding andcommissioned more detailed reviews of those stations and their risks. The more detailed
work revealed that two fire stations had a significant risk of surface water flooding, andthis information has been shared with London Fire Brigade.
Ambulance Stations
181. Map 8 also indicates that 12 of London’s 64 ambulance stations (19 per cent) are
at high risk of fluvial/tidal and/or surface water flooding. Several are in thecentral/inner London Thames tidal floodplain and as such have a high degree of flood
protection in particular from tidal flooding. They are also generally well covered byother ambulance stations just outside the Flood Zone.
182. Drain London identified three ambulance stations with a potentially significant
risk of surface water flooding.
Police Stations
183. Map 8 also indicates that 58 of London’s 235 police stations (25 per cent) are athigh risk of fluvial/tidal and/or surface water flooding. They are generally well coveredby other police stations just outside the Flood Zone.
184. Drain London identified three police stations with a potentially significant risk of
surface water flooding.
Prisons
185. Finally, Map 8 also indicates that 3 of London’s 39 prisons (8 per cent) are at highrisk of fluvial/tidal and/or surface water flooding. Several are within the tidal Thames
floodplain and as such have a high degree of flood protection in particular from tidal
flooding. However, in the event of a flood issues of safety and security would arise, andtherefore detailed emergency plans should be in place for the event of a flood.
Recommendation 9 – Flood Risk to Emergency Services
Emergency service authorities and operators covering hospitals, ambulance, fire andpolice stations as well as prisons should ensure that emergency plans in particular for
facilities in high flood risk areas are in place and regularly reviewed, so that they cancope in the event of a major flood. These plans should put in place cover arrangements
through other suitable facilities.
3.7

Schools

186. Schools need to serve their local population. Map 9 indicates that 643 of London’s
2,895 schools 42 (22 per cent) are either wholly or partially at risk of fluvial/tidal and/or
surface water flooding, although for some of them it may only be to a minor extent, forexample within playing fields. Many of schools affected are in central/inner London
part of the Thames tidal floodplain and as such have a high degree of flood protection.
However, a flood could represent a direct risk to the pupils and staff at schools andcould cause longer-term disruption whilst any repairs are made.
42 Types of schools include Primary, Secondary, All Through, and 16 Plus.

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187. Schools are also important in terms of managing civil emergencies as they areoften used as emergency shelter, food and supply bases. If the emergency is a flood,then this may mean that the school cannot fulfil this function.
188. Drain London examined secondary schools across London and identified 21
secondary schools at significant risk of surface water flooding. Consultants investigatedthese risks in more detail and found that ten sites had the most significant risks. For
each of these sites the consultants discussed potential mitigation option with theschools and presented a range of relatively low impact proposals.
Recommendation 10 – Flood Risk to Schools
Education authorities should ensure that emergency plans in particular for facilities inflood risk areas are in place and regularly reviewed so that they can cope in the event ofa major flood. These plans should put in place cover arrangements through othersuitable facilities.
3.8

Utilities

189. This section covers a wide range of utility installations including electricity
supply, gas supply, telecommunications, sewage disposal, and water supply. The data
about utilities is much more accurate and up-to-date compared to the previous RFRA.
Map 10 provides a spatial overview showing 261 of 587 sites (44 per cent) at high riskof flooding. This is a relatively significant proportion, and therefore mitigation measures
such as those included in Recommendation 11, are important. But it should also berecognised that many different types of utilities are included and several sites are likely
to be large complex structures. Without further analysis it is very difficult to know, if
important parts that could put their operation at risk might be affected.
190. It should also be noted that the flood risk Policy SI12 in the new draft London
Plan explicitly includes the following clause E: ‘Development proposals for utility
services should be designed to remain operational under flood conditions and buildings
should be designed for quick recovery following a flood.’
191.

The following sections address individual utilities in more detail.

Major Electrical Installations
192. Many power generation plants are located near rivers or the sea as they requirelarge volumes of water for cooling purposes. Therefore, they have an associated floodrisk. Most of London’s electricity supply is generated outside London and transmitted to
London via high voltage power lines, either on pylons or underground. London does
still have some energy generation capability and also many switching and transformer
stations. Major installations in floodplains, potentially affected by flooding from rivers
and/or the sea, are listed in Table 4.

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Table 4: Electrical Installations in Floodplain
Installation
Brimsdown Power Station
Barking Power Station
Greenwich Power Station
Croydon/Beddington Switching Station
Edmonton Waste to Energy
SELCHP Waste to Energy
Belvedere Waste to Energy

Floodplain
Adjacent to River Lee floodplain
Wholly within the Thames Tidal floodplain
Wholly within the Thames Tidal floodplain
Partially within River Wandle floodplain
Wholly within River Lee floodplain
Wholly within the Thames Tidal floodplain
Wholly within the Thames Tidal floodplain

Major Gas Installations
193. Gasholders and pipelines are unlikely to be directly affected by a flood given thatthey are gas tight containers and therefore will not let water in. However, in the unlikely
event of water entering a gasholder, drying it out again is a difficult and costly process.
There may also be issues around ancillary power and access to gas sites.
Water and Sewage Treatment Plants
194. Water and sewage treatment plants are naturally located close to major rivers inorder to abstract water from them and discharge treated sewage effluent into them. It istherefore to be expected that these plants are exposed to a certain level of flood risk.
195. A significant flood at a water treatment plant could result in the contaminationof drinking water supplies by flood water. This risk may trigger the shutting down of theplant. The operation of the plant may also be affected by ancillary power losses.
However, the London Ring Main ensures that water supplies can be flexibly managed
and supplies derived from several works. Given the geographical spread of the works,
they are unlikely all to be affected by one flood. In addition, the four water companies
supplying London with drinking water all have operational plans to cope with flooding.
Major plants in floodplains, potentially affected by flooding from rivers and/or the sea,
are listed in Table 5.
Table 5: Water Treatment Plants in Floodplain
Water treatment plant
HamptonCoppermills
Walton (outside London but supplying
parts of London)

Flood Risk Zone
Substantially within River Thames floodplain
Partially within River Lee floodplain
Partially within River Thames floodplain

196. Thames Water operates all the sewage treatment works in London and has
operational plans to cope with flooding. A significant flood at a sewage treatment plant
could result in the contamination of rivers and land as the flood spreads untreated or
partially treated sewage and effluent from the works. The operation of the works may
also be affected by ancillary power losses. Major plants in floodplains, potentiallyaffected by flooding from rivers and/or the sea, are listed in Table 6.

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Table 6: Sewage Treatment Plants in Floodplain
Sewage Works
BecktonCrossness
Riverside
Deephams
Beddington Farm
Hogsmill
Luxborough Lane (outside London but
treats sewage from parts of London)
Long Reach (outside London but treats
sewage from parts of London)

Floodplain
Wholly within the Thames Tidal floodplain
Wholly within the Thames Tidal floodplain
Wholly within the Thames Tidal floodplain
Substantially within River Lee floodplain
Partially within River Wandle floodplain
Substantially within Hogsmill Brook
floodplain
Wholly within River Roding floodplain
Wholly within the Thames Tidal floodplain

197. In addition to the listed water treatment and sewage works there may also be
pumping stations and other installations that relate to water infrastructure. There arealso a number of pumping stations to manage surface water. These are particularly
relevant to low lying areas such as Thamesmead.
Waste Management Sites
198. As London has a high number of waste management sites and as a specificonline tool is available (the London Waste Map 43), waste management has been
separated from the other utitilies. Map 11 is based on the London Waste Map andshows 164 of 312 sites (34 per cent) at high risk of flooding. This is a relatively
significant proportion, and therefore mitigation measures such as those included in
Recommendation 11, are important. But it should also be recognised that this is aprecautionary approach. Many different types of waste management are included andseveral sites are likely to be large complex structures. Without further analysis it is very
difficult to know, if important parts that could put their operation at risk might beaffected. In many cases it may only be small areas.
Recommendation 11 – Flood Risk to Utility Infrastructure
Operators of electricity, gas, water, sewerage, and waste utility sites should maintain an
up to date assessment of the flood risk to their installations and, considering the likely
impacts of failure, establish any necessary protection measures including flood warning,
emergency procedures, sustainable drainage systems and secondary flood defences.
3.9

Other Sites

199. This RFRA is not intended to provide a comprehensive list of all vulnerable assets.
Other vulnerable land uses include nursing homes, where the safety and ability toevacuate residents may be difficult, and council/benefits offices, where closure
would have an immediate impact on the welfare of local communities, particularly themost vulnerable. COMAH sites, petrol stations and other sources of pollution are
also particular risks, as flood water may liberate and spread polluting and/or dangerous
substances that could have further impacts over and above the physical impacts of theflood waters.
43 For details see https://maps.london.gov.uk/waste/

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Chapter 4 – Conclusions and Look Ahead
200. Flood Risk is a serious issue for London. It is important that the capital’s future isplanned for and delivered in the fullest knowledge of flood risk and how it is likely tochange in future. That knowledge is advancing rapidly and it will be important to keep
this RFRA under regular review.
201. The application of the relevant draft London Plan policies – in particular Policies
SI12 and SI13 – will be required to sustainably manage flood risk through newdevelopment. New development represents one of the key opportunities to reduceoverall flood risk, notably through improved management of surface water, setting
development back from the waterways and allowing space for future maintenance andupgrade of flood defences. The planning of the major development locations and town
centres, where the majority of the anticipated growth will be located, which increases
the potential consequences of flood events, will have to address flood risk in moredetail. This RFRA provides an updated overview of broad flood risk issues in each ofthese locations and a framework of potential mitigation measures on which the relevant
partners can build locally. In terms of flood risk for London’s key infrastructure andservices this RFRA illustrates these risks spatially and identifies mechanisms toinvestigate, monitor and address flood risk of current and new infrastructure andservices in cooperation with relevant partners.
202. This RFRA includes a revised set of monitoring recommendations, which will be
used to keep the information up-to-date and to ensure regular checks on broad
mitigation measures. This will also help to focus attention on the strategic issues
relating to flood risk in London. Progress against the recommendations will continue tobe monitored in the London Plan Annual Monitoring Report. Since the publication of
the original 2009 RFRA progress against the recommendations reflects in particular theactions of Drain London in terms of the improved understanding of surface water floodrisk. Improvements to local flood risk policies based on completed and updated
Strategic Flood Risk Assessments (SFRAs) are also apparent. More widely, the London
Climate Change Partnership is working on climate change adaptation indicators for
London and a sector-based assessment of how the capital is coping with the challenge.
203. It should also be noted that the Mayor has established a new Water Advisory
Group to provide advice on water management issues in London including:••••water resources/supplies and use
flood risk and drainage
sewerage and water quality
integration across these areas, resilience and innovation.

204. Its remit includes the coordination of activities between key stakeholders and tomaintain awareness of potential water management risks (such as floods, droughts,
major pollution incidents) and to help coordinate action in response to the lead up,
management and recovery from such events.
205. This draft of the Regional Flood Risk Appraisal is published for public
consultation until 2 March 2018. Consultees are particularly invited to review andadd strategic area-specific information to ensure local accuracy. Following consultation,
the GIS layers for the risk receptors will also be placed on the London Datastore.
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Appendix 1 List of Monitoring Recommendations
Recommendation 1 – Tidal Flood Risk
The London boroughs should address relevant tidal flood risk mitigation measures set
out in the Thames Estuary 2100 Plan in their Local Plans. They include setting backdevelopment and defences from the banks of watercourses, flood storage and floodgates.
The delivery of Riverside Strategies through Thames Estuary 2100 should be supported.
Recommendation 2 – Fluvial Flood Risk
Regeneration and redevelopment on London’s river corridors offer a crucial opportunity
to reduce fluvial flood risk. Strategic Flood Risk Assessments (SFRA) and planningpolicies should focus on making the most of this opportunity through appropriate
location, layout and design of development as set out in the Thames Catchment FloodManagement Plan (CFMP). In particular opportunities should be sought to set backdevelopment from the river edge; ensure that developments with residual flood risk aredesigned to be flood compatible and/or flood resilient; and maximise the use of open
spaces to make space for flood water.
Recommendation 3 – Surface Water Flood Risk
Developments all across London should reduce surface water discharge in line with the
Sustainable Drainage Hierarchy set out in Policy SI13 of the London Plan, and theactions in the London Sustainable Drainage Action Plan (LSDAP) should also be taken.
Recommendation 4 – Sewer Flood Risk
Thames Water should continue the programme of addressing foul sewer flooding, also
working with other risk management authorities such as local authorities and theEnvironment Agency.
Recommendation 5 – Groundwater Flood Risk
The groundwater flood risk in identified locations (see IPEG map) should be consideredin Strategic Flood Risk Assessments (SFRAs) and Flood Risk Assessments (FRAs).
Recommendation 6 – Reservoir Flood Risk
The reservoir flood risk in identified locations (see reservoir flood map) should beconsidered in Strategic Flood Risk Assessments (SFRAs) and Flood Risk Assessments(FRAs).

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Recommendation 7 – Flood Risk to Opportunity Areas and Town Centres
Where required, detailed flood risk assessments for individual major development
locations and town centre development sites should be undertaken by developers at an
early stage. Opportunities to reduce flood risk should be maximised where possible.
Recommendation 8 – Flood Risk to Transport Infrastructure
Relevant transport authorities and operators should examine and regularly review theirinfrastructure assets including their networks, stations, depots, underpasses and tunnels
for potential flooding locations and flood risk reduction measures.
Appropriate mitigation measures include flood warning systems, emergency procedures,
sustainable drainage systems, temporary flood storage areas, pumping stations, back-up
power supply and the relocation of sensitive electrical/telecommunications equipment
and potentially polluting materials (e.g. fuel and oils) above potential flood levels.
For large stations and depots, solutions should be sought to attenuate or disperse
rainwater from heavy storms including green roofs.
Highways flood management measures should also include diversionary routes.
For tunnel portals and ventilation shafts physical barriers such as flood gates and vent
covers should be considered.
Recommendation 9 – Flood Risk to Emergency Services
Emergency service authorities and operators covering hospitals, ambulance, fire andpolice stations as well as prisons should ensure that emergency plans in particular for
facilities in high flood risk areas are in place and regularly reviewed, so that they cancope in the event of a major flood. These plans should put in place cover arrangements
through other suitable facilities.
Recommendation 10 – Flood Risk to Schools
Education authorities should ensure that emergency plans in particular for facilities inflood risk areas are in place and regularly reviewed so that they can cope in the event ofa major flood. These plans should put in place cover arrangements through othersuitable facilities.
Recommendation 11 – Flood Risk to Utility Infrastructure
Operators of electricity, gas, water, sewerage, and waste utility sites should maintain an
up to date assessment of the flood risk to their installations and, considering the likely
impacts of failure, establish any necessary protection measures including flood warning,
emergency procedures, sustainable drainage systems and secondary flood defences.

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Appendix 2 - Abbreviations
CAZ
CFMP
EA
F&WM Act
FRA
FRMP
GLA
IPEG
LB
LLFA
LSDAP
LSFP
NPPF
PPG
RFRA
SFRA
SHLAA
SuDS
SWMP
TE2100TfL
TLRN

Central Activities Zone
Catchment Flood Management Plan
Environment Agency
Flood and Water Management Act
Flood Risk Assessment
Flood Risk Management Plan
Greater London Authority
Indicative Potential for Elevated Groundwater
London boroughLead Local Flood Authority
London Sustainable Drainage Action Plan
London Strategic Flood Plan
National Planning Policy Framework
Planning Practice Guidance
Regional Flood Risk Appraisal
Strategic Flood Risk Assessment
Strategic Housing Land Availability Assessment
Sustainable Drainage System
Surface Water Management PlanThames Estuary 2100 Plan
Transport for London
Transport for London Road Network

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Appendix 3 – Flood Risk Maps

London Regional Flood Risk Appraisal – Draft - December 2017

page 62 of 64

Appendix 3 – Flood Risk Maps

London Regional Flood Risk Appraisal – Draft - December 2017

page 62 of 64

Map 1 - Environment Agency Flooding From Multiple Sources in Greater London 2017

Enfield

BarnetHarrow

Westminster

H&F

Kingstonupon
Thames1 in 100 year risk
© Crown Copyright and database right 2016. Ordnance
Survey 100032216 GLA
Flood risk data from ©Environment Agency; river and tidal datafrom 2016; surface water flood risk data from 2013, but more recent/ higher-resolution data for LB Hammersmith & Fulham and RB
Kensington & Chelsea included; this does not necessarily meanthat more properties are at risk, although higher resolution may givethat impression on this London-wide map

City

Hackney
Tower
Hamlets

NewhamBarking andDagenham

K&C

Southwark

Hounslow

1 in 30 year risk

Islington

CamdenEalingRichmond
upon Thames

Redbridge
Havering

Brent

Hillingdon

WalthamForestHaringey

Wandsworth

Greenwich

LambethBexleyLewishamMertonBromley
SuttonCroydonHigh (1 in 30 year) and medium (1 in 100 year) risk ofriver, tidal and surface water flooding combined(basis for other maps in this RFRA)

Environment Agency Flooding From Multiple Sources in Greater London 2017
NAME

Barking and Dagenham
BarnetBexleyBrent
Bromley
CamdenCity of London
CroydonEalingEnfield
GreenwichHackney
Hammersmith and Fulham
Haringey
Harrow
Havering
Hillingdon
Hounslow
Islington
Kensington and Chelsea
Kingston upon Thames
LambethLewishamMertonNewhamRedbridge
Richmond upon ThamesSouthwark
SuttonTower Hamlets
Waltham Forest
WandsworthWestminster
TOTALS

Area in 1 in 30 Flood: High Risk (Ha) Area in 1 in 100 Flood: Medium Risk (Ha) TOTAL AREA (Ha) PORTION IN 1 IN 30 FLOOD RISK PORTION IN 1 IN 100 FLOOD RISK

367
396
657
222
401
38
33
199
279
540
502
51
308
95
207
1,089
841
247
24
197
226
119
170
158
488
313
644
233
128
289
311
225
162
10,161© Crown Copyright and database right 2016. Ordnance Survey 100032216 GLA
Flood risk data from ©Environment Agency; river and tidal data from 2016; surface water flood risk data from 2013

620
504
923
450
1,035
98
38
546
524
1,003
626
143
343
264
383
1,692
1,395
406
81
275
429
222
387
392
785
587
891
285
305
345
523
391
261
17,150

3,780
8,675
6,429
4,323
15,013
2,179
315
8,649
5,554
8,220
5,044
1,905
1,715
2,960
5,046
11,446
11,570
5,659
1,486
1,238
3,726
2,725
3,532
3,762
3,858
5,644
5,876
2,991
4,385
2,157
3,881
3,522
2,203
159,470

10%
5%
10%
5%
3%
2%
11%
2%
5%
7%
10%
3%
18%
3%
4%
10%
7%
4%
2%
16%
6%
4%
5%
4%
13%
6%
11%
8%
3%
13%
8%
6%
7%
6%

16%
6%
14%
10%
7%
4%
12%
6%
9%
12%
12%
8%
20%
9%
8%
15%
12%
7%
5%
22%
12%
8%
11%
10%
20%
10%
15%
10%
7%
16%
13%
11%
12%
11%

Map 2 - Opportunity Areas and Flood Risk 2017

8

5

3

1

7

2

4

Opportunity Area Size
0.2 - 3.2 (Ha)
3.2 - 9 (Ha)6

9 - 25 (Ha)25+ (Ha)

1 Earls Court and West Kensington
2 Isle of Dogs
3 Kensal Canalside
4 Royal Docks and Beckton Waterfront
5 London Riverside
6 Kingston town centre/Norbiton/New Malden
7 Victoria
8 Upper Lea Valley
Copyright © and Database rights Environment Agency 2016. All rights reserved© Crown Copyright and database right 2016. Ordnance Survey 100032216 GLA
Opportunity Areas from GLA

Percent for 1 in 30 year risk
0% - 5%5% - 10%
10% -15%
15%+
Corresponding Table also includes data for 1 in 100 and 1 in 1000
year flood risk for each Opportunity Area.

Opportunity Areas and Flood Risk 2017
NAME

Bexley Riverside
Bromley
Canada Water
Charlton Riverside
City Fringe/ Tech City
Clapham Junction
Colindale/Burnt Oak
Cricklewood/Brent Cross
CroydonDeptford Creek/Greenwich Riverside
Earls Court and West Kensington
Elephant and Castle
EustonGolden Mile/ Great West Corridor
Greenford
Greenwich Peninsula
Haringey Heartlands/Wood Green
Harrow & Wealdstone
Hayes HZ
Heathrow
IlfordIsle of Dogs
Kensal Canalside
King's Cross - St Pancras
Kingston town centre/Norbiton/New Malden
Lewisham, Catford & New Cross
London Bridge, Borough & Bankside
London Riverside
Lower Lea Valley
New Southgate
Old Kent Road
Old Oak Common
Olympic Legacy SPG boundary
Paddington
Park Royal
Poplar Riverside
Romford HZRoyal Docks and Beckton Waterfront
SouthallSuttonThamesmead & Abbey Wood
Tottenham Court Road
Upper Lea Valley
Vauxhall, Nine Elms & Battersea
Victoria
Waterloo
WembleyWhite City
Wimbledon
WoolwichTOTAL

Area in 1 in Portion in Area in 1 in Portion in Area in 1 in Portion in Opportunity
1000 (Ha) 1 in 1000 100 (Ha)1 in 100 30 (Ha)1 in 30
Area (Ha)

807
9
33
138
147
38
61
59
33
125
28
87
14
98
32
225
11
31
37
1155
15
463
5
9
129
353
155
1236
161
119
343
252
41
7
68
73
71
1086
76
9
707
2
1808
218
43
78
59
20
4
22
10801

60%
13%
72%
78%
16%
65%
23%
18%
17%
77%
74%
99%
16%
25%
20%
86%
19%
18%
8%
17%
17%
95%
28%
18%
32%
43%
99%
50%
72%
17%
27%
89%
17%
19%
16%
15%
23%
83%
14%
25%
81%
12%
36%
96%
83%
100%
25%
18%
16%
33%
37%

153
5
2
21
49
4
38
18
33
18
7
4
5
57
17
18
6
20
12
490
5
84
4
4
63
145
8
680
45
75
148
21
28
5
35
24
32
316
24
5
61
0
950
25
6
3
27
11
3
6
3821

11%
7%
4%
12%
5%
7%
14%
6%
17%
11%
18%
5%
5%
15%
11%
7%
10%
11%
3%
7%
5%
17%
21%
8%
15%
18%
5%
27%
20%
11%
12%
7%
12%
14%
8%
5%
11%
24%
5%
16%
7%
3%
19%
11%
12%
4%
11%
10%
10%
9%
13%

108
2
2
16
19
3
22
13
10
13
6
3
1
35
8
16
2
10
3
238
1
76
3
2
42
61
8
301
14
36
55
19
20
1
15
14
16
188
7
3
57
0
517
21
5
3
10
7
1
3
2037

8%
2%
4%
9%
2%
5%
8%
4%
5%
8%
17%
4%
2%
9%
5%
6%
4%
6%
1%
4%
1%
16%
15%
3%
10%
7%
5%
12%
6%
5%
4%
7%
8%
4%
4%
3%
5%
14%
1%
9%
6%
0%
10%
9%
10%
3%
4%
7%
3%
5%
7%

1353
69
46
177
898
59
262
324
194
163
38
88
85
391
160
261
60
177
462
6788
85
488
20
53
405
818
156
2474
224
693
1282
282
240
38
415
480
308
1302
523
34
877
19
5024
227
51
78
239
107
29
66
29090

Map 3 - Town Centres and Flood Risk 2017

!

!
!
!

!

!

!

!

!

!

!

!

!
!

!

!

!

!

!

!

!
!

!
!Hammersmith !
!

!Woolwich!

!

!

!Lewisham

!

!

!

!
!

!

!Canary Wharf

!

!
!

!

!

!
!Kingston!

!
percent for 1 in 30 year risk

!

0-8

!

8-16

!

16-24

!

24-34

Copyright © and Database rights Environment Agency 2016. All rights reserved© Crown Copyright and database right 2016. Ordnance Survey 100032216 GLA
Town Centres from GLA Town Centre Health Check!Orpington!

International, Metropolitan and Major Town Centres includedTown Centres and Flood Risk 2017
NAME

LP2016REF CLASSIFICATION 1 IN 100 RISK AREA (Ha) 1 IN 30 RISK AREA (Ha) TOTAL AREA 2016 (Ha) PERCENT AT RISK 1 IN 30 PERCENT AT RISK 1 IN 100

Knightsbridge

2 International

0.8

0.5

11.2

4.5%

7.0%

West End

1 International

4.9

1.4

104.8

1.3%

4.6%

Bromley

3 Metropolitan

4.8

1.7

69.4

2.4%

6.9%

Croydon4 Metropolitan

16.3

5.5

111.7

4.9%

14.6%

Ealing

5 Metropolitan

5.4

2.6

68.0

3.8%

8.0%

Harrow

8 Metropolitan

1.8

0.8

38.8

2.1%

4.7%

Hounslow

11 Metropolitan

2.3

0.9

34.5

2.5%

6.8%

Ilford14 Metropolitan

2.0

0.7

54.8

1.3%

3.6%

Kingston

12 Metropolitan

31.3

26.8

79.2

33.8%

39.6%

Romford

9 Metropolitan

16.6

9.2

82.0

11.2%

20.2%

Shepherds Bush

6 Metropolitan

4.6

3.3

39.9

8.3%

11.5%

Stratford

13 Metropolitan

5.7

1.5

69.8

2.2%

8.2%

Sutton15 Metropolitan

5.1

2.9

57.9

4.9%

8.8%

Uxbridge

10 Metropolitan

2.9

1.1

51.4

2.1%

5.6%

Wood Green

7 Metropolitan

2.3

0.8

20.9

3.9%

11.1%

Angel

31 Major

1.0

0.3

34.2

0.8%

3.0%

Barking

16 Major

0.9

0.3

25.9

1.0%

3.5%

Bexleyheath

18 Major

1.3

0.4

33.9

1.3%

3.8%

Brixton

35 Major

2.7

1.0

28.7

3.3%

9.3%

Camden Town

22 Major

2.3

1.0

27.9

3.7%

8.2%

Canary Wharf

43 Major

11.8

11.7

52.5

22.3%

22.4%

Catford

37 Major

7.1

1.4

24.9

5.7%

28.5%

Chiswick

30 Major

1.9

1.8

27.4

6.7%

7.0%

Clapham Junction

45 Major

2.3

1.4

22.8

6.2%

10.2%

Dalston

27 Major

1.1

0.4

16.2

2.5%

6.6%

East Ham

40 Major

0.8

0.4

15.6

2.3%

5.1%

Edgware17 Major

3.3

1.8

20.9

8.8%

15.8%

Eltham

25 Major

0.9

0.6

38.7

1.6%

2.3%

Enfield Town

24 Major

1.3

0.5

21.8

2.2%

6.1%

Fulham

28 Major

1.2

1.1

16.5

6.8%

7.3%

Hammersmith

29 Major

8.1

8.0

34.4

23.3%

23.7%

Kensington High Street

33 Major

1.2

0.7

12.4

5.5%

9.5%

Kilburn

20 Major

1.6

0.8

16.6

5.1%

9.5%

King's Road (east)

34 Major

1.1

0.7

10.9

6.4%

10.3%

Lewisham

38 Major

19.1

6.9

36.3

19.1%

52.5%

Nags Head

32 Major

2.6

1.0

17.1

5.8%

15.3%

Orpington

21 Major

8.4

2.9

18.4

16.0%

45.6%

Peckham

42 Major

2.8

1.2

29.6

4.0%

9.5%

Putney46 Major

2.5

1.3

21.4

5.9%

11.7%

Queensway/ Westbourne Grove

49 Major

1.2

0.3

6.6

4.4%

18.1%

Richmond

41 Major

2.2

1.0

28.6

3.6%

7.8%

Southall23 Major

1.8

0.5

38.1

1.4%

4.7%

Streatham

36 Major

1.8

0.9

27.4

3.4%

6.7%

Tooting

47 Major

2.4

1.5

14.9

9.9%

16.0%

Walthamstow

44 Major

2.7

1.0

39.2

2.5%

6.8%

Wandsworth

48 Major

10.5

2.7

23.9

11.3%

44.0%

Wembley

19 Major

3.0

1.3

45.4

2.8%

6.7%

Wimbledon

39 Major

2.8

0.9

28.6

3.1%

9.7%

Woolwich

26 Major

29.9

26.6

100.2

26.6%

29.9%

International

5.6

1.9

116.1

1.6%

4.9%

Metropolitan

101.1

57.7

778.3

13.0%

7.4%

Major

145.6

84.5

958.1

8.8%

15.2%

TOTALS:Map 4 - Mainline Rail Network and Flood Risk 2017
RAIL STATIONS IN RAIL STATIONSTOTAL RAILFLOOD AREAOUTSIDE FLOOD AREA STATIONS

1 IN 30 FLOOD
1 IN 100 FLOOD

!
(

85
106

275
254

RAIL LENGTH IN
RAIL LENGTH OUTSIDEFLOOD AREA (km) FLOOD AREA (km)

!
(
!
(
!
(

1 IN 30 FLOOD
1 IN 100 FLOOD

!
(

87
111

740
715

!
(
!
(
!
(
!
(

!
(

(
!!
(
!
(

!
(
!
(

!
(

!
(

!
(

!
(

!
(

!
(

!
(

!
(

!
(

!
(

!
(

!
(

!
(

!
(

!
(
!
(

!
(

!
( !
(

!
(

!
(
!
(

!
(

(
!
( !

!
(

!
(

!
(

!
(

!
(

!
(

!
(
!
(

!
(

!
(

!
(

!
(

!
(

!
(

!
(
!
(

!
(
!
(

!
(

!
(

!
(

!
(
!
(
!
(

!
(
!
(

!
(

!
(
!
(
!
(

!
(

!
(

!
(

!
(

(
!!
(

!
(

Station in 1 in 30 year risk!
(

Station in 1 in 100 year risk

!
(
!
(

!
(

Railway in 1 in 30 year risk
Railway in 1 in 100 year risk
Elizabeth Line, Crossrail2, HS2
Mainline Rail, Overground, and Tram Lines
Copyright © and Database rights Environment Agency 2016. All rights reserved
Rail from OS Strategy © Crown Copyright and database right 2016. Ordnance Survey 100032216 GLA

!
(
!
(

!
(
!
(
!
(

!
(

!
(
!
(

!
(
!
(!
(
!
(

!
(

!
(

!
(

!
(

!
(

!
(

!
(

!
(
!
(

!
(

!
(

!
(
!
(
!
(

!
(

360
360
TOTAL RAILLENGTH (km)

827
827

PORTION IN
FLOOD ZONE

24%
29%
PORTION IN
FLOOD ZONE

11%
13%

Map 5 - Underground and DLR Networks and Flood Risk 2017
RAIL STATIONS IN RAIL STATIONSTOTAL RAIL PORTION IN
FLOOD AREAOUTSIDE FLOOD AREA STATIONSFLOOD ZONEFLOOD TYPE
1 IN 30 FLOOD
12
285
297
4%
1 IN 100 FLOOD
20
277
297
7%
RAIL LENGTH IN
RAIL LENGTH OUTSIDE TOTAL RAIL PORTION IN
FLOOD AREA (km) FLOOD AREA (km)LENGTH (km) FLOOD ZONEFLOOD TYPE
1 IN 30 FLOOD
40
415
455
9%
1 IN 100 FLOOD
44
411
455
10%
!
(

!
(

!
(
!
(
!
(

!
(

!
(

!
(
!
(

!
(
!
(

!
(
!
(

!
(
!
(

!
(

Underground Lines

Underground Lines in 1 in 30 year risk

Underground Lines in 1 in 100 year risk!
(!
(

Underground Stations in 1 in 30 year risk

Underground Stations in 1 in 100 year risk

Copyright © and Database rights Environment Agency 2016. All rights reserved© Crown Copyright and database right 2016. Ordnance Survey 100032216 GLA

!
(
!
(

!
(!
(

Map 6 - TfL Road Network and Flood Risk 2017
FLOOD TYPEROADS LENGTH IN
FLOOD AREA (Km)1 IN 30 FLOOD
125.2
1 IN 100 FLOOD
163.3*Dual carriageway lengths counted twice

Enfield

ROADS LENGTH OUTSIDE TOTAL ROAD
FLOOD AREA (Km)LENGTH (Km)1007.4969.4

BarnetHarrow

Islington

CamdenEalingWestminster

H&F

Kingstonupon
ThamesTfL Road Network in 1 in 100 year risk
TfL Road Network
Copyright © and Database rights Environment Agency 2016. All rights reserved© Crown Copyright and database right 2016. Ordnance Survey 100032216 GLA
Roads from TfL Network data

Tower
Hamlets

Southwark

Wandsworth

NewhamGreenwich

LambethLewishamMertonBromley
SuttonTfL Road Network in 1 in 30 year risk

City

Hackney

Barking andDagenham

K&C

Hounslow
Richmond
upon Thames

Redbridge
Havering

Brent

Hillingdon

WalthamForestHaringey

CroydonBexley1132.71132.7PORTION IN
FLOOD ZONE

11%
14%

Map 7 - Hospitals and Flood Risk 2017
Flood Area Type

Number in Flood Number Outside
Area
Flood Area

1 IN 30
1 IN 100

GG

82
92

111
101

Total Number inGreater London

Percent inFlood Area

193
193

G

G
G
G

G

G
G

G
G

G
G

G
G G

G

G

G
G

G

G
G

G

G
G

G
G
G
G

G

G

G
G

G
G

G

G
G

G

G
G

G

G

GG

G
G

G

G
G

G
G
G

G

G

G

G
G

GG
G

G

G
GG

G
G

G

G

G G

G

G

G

G
G

G

G

G

G

G

G
G

G

G

G

G
G
G

Hospitals 1 in 30 year riskG

Hospitals 1 in 100 year risk

Copyright © and Database rights Environment Agency 2016. All rights reserved© Crown Copyright and database right 2016. Ordnance Survey 100032216 GLA; Hospitals: UK Map, Geoinformation Group 2016, OS Strat 2015

Only buildings intersectedwith flood risk map

42%
48%

Map 8 - Emergency Services and Flood Risk 2017
Emergency
Building Type

Enfield

Ambulance
Fire Stations
PolicePrisonTOTALS!
&

BarnetHaringey

WalthamForest!
&Redbridge

*
#
*
#

Brent

Camden*#Islington

2
%

*
#
*
#

*
#
#
*

*
! #
&

!
&

*
!#
&

Wandsworth
2
%

*
#

#
*

2
%

#
*

!

#
*
2
%

Fire station
Police station
PrisonEmergency Services in 1 in 100 year risk!
©

Ambulance stations&

Fire station#*

Police station2%

Prison*#Kingston
!
©
&
upon
&
Thames

64
118
235
39
221

19%
24%
25%
8%
23%

20%
27%
29%
18%
27%

!
&

Barking and! Dagenham&

Havering
*
#

#
*

!
&

!
&
!
!
&
©
!
©
©
!
*&
#

*
#

!
&

*
#

*
#

Greenwich

#
*

!
©

%
2
*
#

!
&

Bexley

! #
*
©

*
#
*
#

Merton
*
#
#
*

!
&

*
#
Newham

Lewisham
*
#

*&
#
!
*
#

Emergency Services in 1 in 30 year risk
© Ambulance stations

Hamlets

*
#

!
©

*
#
!

*
#
Tower

City

#
*
#
*
Lambeth

!
&

!
&

!
©
#
*©
Richmond#*
upon Thames

Hackney* * Westminster
#
* #
#
!
*
#
! &
!
&
©
K&C
*
#
#
*
*
#
*
#
!
!#
&
©
*
!
&
*
#
*
#
H&F
!
&
*©
#
!
!
©
*
#
Southwark
!
&
*
#
*
#
!
&

#
*
!
©

!
&

!
&

*
#

Ealing

%
2

*
#

2
%

*
#

!
&

#
*

13
32
68
7
120

!
©
©

*
#

Hounslow&

12
28
58
3
101

Percent in FloodArea 1 in 100*#

Harrow*#

Hillingdon

Number inside Number inside 1 Total Number in Percent in Flood
1 in 30
in 100Greater London Area 1 in 30

*
#

#
*

Bromley#*&#Sutton
*

*
#
*
#

#
Croydon *&*#Emergency Services from UK Map©: Geoinformation Group 2016
Copyright © and Database rights Environment Agency 2016. All rights reserved; © Crown Copyright and database right 2016. Ordnance Survey 100032216 GLA

Only buildings intersected with flood risk map

Map 9 - Schools and Flood Risk 2017
Numberin Flood Number Outside
Flood Area
Area

Flood Area Type

1 IN 30
1 IN 100

!
!
!
!
!!
!!

!
!

!

!

!

!

!

!

!
!

!
!

!

!
!

!

!

!

! !
!
!
!

!!
!

!
!
! !
!
!

!

!
!
!

!

Schools in 1 in 100 year risk!

Schools in 1 in 30 year risk!

!
!

Copyright © and Database rights Environment Agency 2016. All rights reserved© Crown Copyright and database right 2016. Ordnance Survey 100032216 GLA; Buildings: Geoinformation Group UK 2016. Schools from DoE Edubase 2016

!
!

!

! !
!
!
!
!
! !
!
!
!
!
! !
Waltham!
Redbridge
!
! !
!
!! !
!
Haringey
!!
!
!
!
!
!
!
Forest
!
!
!
!
! !!
!
!
!
!
!
!
!
!
!
!
!
!
!
!!
!
!
!
!
!
! !!
!
!
! !
!
!
!
!
!!
!
!
!
!
! !
!
!
!
!
!
!
!
!
!
!
Brent
!
!
!
!!
!
!
!
!Hackney!! ! !
! !
!
!!
!
!
!
!
Islington
!! !
!
!
!
!
!
!
Camden!
!
!
!
Barking and
!
!
!
!
! !
!
!!
!
!!
! !
!
!
!
!
!
!
!
Dagenham
!
!!
!
! !
!
!!
! !
!
!
! !! !
Newham
!
!! !
!
!
Tower
!
!
!
!
!
!!
!
!
!
! !
!
Hillingdon! ! !!
!
!
! !
!!!
! !
!
! !
!
!!
! !
Hamlets!
!
!
! Ealing
!
!
!
!
!
!
!
! !!
! !
!
City ! ! !! !
!!
!
! ! !
!
!!Westminster!
!
! !
! !!! !
!
!
!
!
!!
!
!
!
!
!
!
!
!!
!
!
!
!
!
!
!
!! !
!
!
! !
K&C
!
! !!! !!
! !!
!
!!!
! !
!
!! !
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!! !
! !!
!
!
!
!! H&F!
!
!
!
!
!
! ! ! ! !! ! !
!
!
!
!
!
!
! ! !!! !
!
!
!
! !
!
! !
!
!
!
!
!
! !
!
!
!
!
!
!
!!
! !
! ! Southwark!
! !!
!
!! ! !
!
!
!
!
!
!
!
!
!
!
!
GreenwichHounslow!! ! !!
!
!
! ! !
!
!!
!! !
!
!
!
!!
!
!
!
Bexley!
Lambeth
!
!
!
! !!
!
! !
!
!!
!!
! ! !!
! !
!
!
!
!
!
!
!
! !
! ! ! !! !
!
!!
! !
! ! !
Wandsworth
!
!
!
!
!
!
!
!
Richmond
!
!
!
!
!
!
Lewisham
!
! !
!
! !
! !!
!
!
!
!
!!
!
!
!
!
upon
Thames
!
!
!!
!
!
!
!
!
!
!
!
!!
!! !
!
!
!
!
!
!
!
! !
!
!
!
!
!
! !
!!
!
!
!
!
!
!
!!
!! !
!
!!
!
!
! ! ! ! !! ! ! !
!!
!
!
!
!
!
!
!
Merton
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!!!!
! !
!
! !
! !
!
!
Kingston !!
! !
!
!
!
!
!
!
!
!
!
! !
upon
!
!
! !
!
!
!
!
!
!
!
!
!
! Thames
!
!
!!
!
!
!
!
!
! !
!!
!
!
Bromley
!
!
!
! !!
!
!
!
!!
!
!
!
! !
!
!
!
! ! !
!
!
!
!
! Sutton!!
!
!!
!!
! Croydon
!
!! !
!
!
!
!
!
! !
!
!
!
! !
!
!!
!
!
Harrow
!

22%
27%

!
!

!
!

2895
2895

Enfield!
!

Barnet2252
2114

Percent
in Flood
Area

!
!

!
!

643
781

Total Number
in Greater
London

!
!

!
!

!
!!
!
!

Havering
!

!

! !

!

Types of schools include Primary, Secondary,
All Through, and 16 Plus.
Only buildings intersected with flood risk map.

Map 10 - Utilities Infrastructure and Flood Risk 2017
Flood Area Type

!
!
!

!

!

!
!
Barnet!!
Harrow!

!

!

!

Hillingdon!!

Ealing

!
!
!
!

!
!

!

!
!

! !

!

!

!

Hounslow
!
!
!
!
!
!
!
!
!
!
! ! ! Richmond!
upon Thames

!!
!
!
!

!

!
!!
!!
!!!

!! !
!
Kingston
!!
!
!
!
!
upon
!
!
!
Thames!

!
!
Haringey!
Islington!

Camden! !

!

Utilities in 1 in 100 year risk

!

587
587

44%
49%

! !

!Redbridge!

Sutton!
!

Copyright © and Database rights Environment Agency 2016. All rights reserved© Crown Copyright and database right 2016. Ordnance Survey 100032216 GLA
Utilities from UK Map® copyright by The GeoInformation® Group, 2016 and Crown Copyright © All rights reserved

!
!

!

!
!!
Barking and !
Dagenham!
Newham
!
!
!
!
!
!
!
!
!
!!
! !
!!
!
!
!
! ! !!
!
!
!!!
!
!
!
!
!
!
!
!
!

!

Havering

!

!! !!
! !
Croydon !

!

Bromley

!
!

!

!
!

Bexley

!
!!

!

!

!
! !

!
!

!

!

Utilities in 1 in 30 year risk!

! Waltham!
Forest!!
!
!
!
Hackney

!

!

326
301

!

!
!!
!
City
!
Westminster
!
!
!
!
K&C
!
!
! ! !
H&F
!!
!
!!
!
!
! !
!
!
! Southwark!
! !!!
!
!
!
Greenwich!
!
!
Lambeth
!
!
!
!
!
!
! !
Wandsworth
Lewisham
!
!
!
!
!
!
!!
!
!
!
!
! !!
Merton
! ! !
!!
!
!
!

261
286

!!
! !
!
Tower
Hamlets
!

!

!

!
!
!!
! !
!

!

!
!

!

!

!

!!
Brent

!
!

Utilities Outside
Flood Area

!

!
!
!!
!

1 IN 30 FLOOD
1 IN 100 FLOOD

Enfield!

Utilities inFlood Area

Total Number inGreater London Percent inFlood Area
> 1 kmTypes of utilities include electricity supply,
gas supply, telecommunications, sewage
disposal, and water supply.
Many utilities are collections of buildings andare clustered to together, and those greaterthan 1000 sqm are shown as points, if theyintersect flood risk map; a buffer of 1 km
around GLA boundary is included, as several
utilities cross this boundaryMap 11 - Waste or Treatment Sites and Flood Risk 2017
Number in
Flood Area

Flood Type

1 IN 30
1 IN 100!

Enfield

Number Outside
Flood Area

164
180

312
296

Total Number inGreater London

476
476

Percent in Flood
Area

34%
38%

!

!
!

!

Barnet!
!
!!
! !!!!
!
! !!

!

Harrow

Haringey
!

!
!

Brent

Hillingdon

!

!

!
!

!

H&F

!

Hounslow!
!!

Hackney

K&C!
!

Wandsworth!
! Richmondupon ThamesSouthwark

Barking andDagenham

Newham
!!
!

!

!
!

!!

!

!

!
!
!! !!

!

!
!

!
! ! !!

Greenwich

Lambeth

!

!

!
!
!!
!
!
! !

!!

Bexley!
!
!

!

Lewisham

!

!
!!

!
!

Merton

!
!

!!

!
!

!!

!

Kingston!
upon
ThamesHavering

!

!

!

!

!!

Tower
Hamlets

!

!
!!!

!

Redbridge
!

!
!!

City

Westminster!

!

!
Islington

Camden

!
!

!

!

!
!
! !
!

!
!

! !! !
!

Ealing

!!

!
!

!

!

WalthamForest

!

!!
!
!
!
!

Sutton

!!! !
!
!!!
!
!!
! !

!
!

!

!

Bromley
Croydon!
!
!

!

Waste Sites In 1 in 30 year risk!

Waste Sites In 1 in 100 year risk

Copyright © and Database rights Environment Agency 2016. All rights reserved© Crown Copyright and database right 2016. Ordnance Survey 100032216 GLA; Waste Sites: London Plan GLA Waste Sites 2016

Exact size of waste sites estimated;
includes current and proposed sites

Map 12 – Increased Potential for Elevated Groundwater

Source: GLA

London Regional Flood Risk Appraisal – Draft - December 2017

Map 13 – Environment Agency Reservoir Flood Map – London extract illustration

Source: Environment Agency

London Regional Flood Risk Appraisal – Draft - December 2017