London
Regional Flood Risk
AppraisalFirst Review
August 2014

Contents

Page

Updating the January 2014 Consultation Draft

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
15
23
27
28
29

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

32
33
47
48
49
51
52
53
55

Chapter 4 – Conclusions and Look Ahead

56

Appendix 1 List of Monitoring Recommendations
Appendix 2 Glossary
Appendix 3 Utility Infrastructure within Flood Risk Zones
Appendix 4 Comparison of Flood Risk Data with 2009 RFRA

57
59
60
66

Appendix 5 Flood Risk Maps

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Separate
Document

Updating the January 2014 Consultation Draft
This document represents an update of the draft, that was published in January 2014,
in the light of a three-month consultation.
Alongside further assistance by the Environment Agency, this final version of the First
Review was also informed by responses the Mayor received from TfL as well as the
London Boroughs of Richmond, Havering and Southwark (see Statement ofConsultation provided separately). Some factual changes and updates were also made.

Further Information
For further information please contact:by post:Jörn Peters
First 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:jornpeters@london.gov.uk with ‘Regional Flood Risk Appraisal consultation’ in thesubject box.

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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 First Review of the RFRA has been prepared by officers in close cooperation with
the Environment Agency. It builds on and updates the original version that was
published in October 2009 to support the preparation of the Replacement London Plan,
which was published in 2011. In 2012 the Environment Agency’s the Thames Estuary
2100 Plan was endorsed by Government. The GLA-led Drain London project has also
progressed since 2009 and significantly improved the understanding of surface water
flood risk across London. These represent key changes reflected in this First Review.
14 % of London is at risk of tidal and fluvial flooding, and 3 % at risk of surface water
flooding. It is the impact of surface water flood risk which represents the key change inthis RFRA compared with the 2009 version. 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, including major development locations, key infrastructure assets
and services.
This RFRA represents important evidence to underpin the Further Alterations to the
London Plan (FALP), which are currently being developed. It demonstrates that with thecontinued spatial focus on urban concentration spatial flood risk probability in London
is not expected to increase significantly as a consequence of the anticipated levels of
growth. The better understanding of surface water flood risk gained since 2009 provides
a more robust baseline and opportunity to better monitor and manage flood risk fromkey sources of flooding. 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.
The application of the relevant London Plan policies – in particular Policies 5.12 and5.13 – will be required to sustainably manage flood risk through new development. New
development represents one of the key opportunities to reduce overall flood risk,
notably through improved management of surface water and allowing space for future
maintenance and upgrade of flood defences. The planning of the major development
locations and town centres, where the majority of the anticipated growth will belocated, which increases the potential consequences of flood events, will have toaddress flood risk in more detail. This RFRA provides an updated overview of broad
flood risk issues in each of these 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 and services this RFRA illustrates these risks spatially andidentifies mechanisms to investigate, monitor and address flood risk of current and new
infrastructure and services in cooperation with relevant partners.

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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
5 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 during the 1990s and early part of the 21st century including
recent floods this winter (Dec 2013 / January 2014)1. This has followed a long period
when major floods did not affect London and when, consequently, flooding had notreceived a high profile in matters relating to land use planning. Previous notable floods
occurred in 1947, 1953 and 1968, each of which resulted in responses to increase flood
protection through capital projects. The publication of PPG25 in 2001 marked a stepchange in the approach to flood risk management in the planning system. This was
replaced by PPS25, published in 2006, and its Practice Guide, published in 2008,
continued to raise the profile of flood risk management amongst land use and planningconsiderations.
3. Also in 2008 the Pitt Review was published. It examined all aspects of flood risk
management from forecasting and warning, to flood event management andevacuation/rescue to recovery and rehabilitation. The Pitt Review was triggered by aseries of major floods across England in 2007, particularly affecting Gloucestershire,
Humberside and parts of Yorkshire. Whilst London was not significantly affected then, it
has to be prepared for significant flooding events in the future.
4. One of the key elements PPS25 and its Practice Guide introduced is a flood risk
appraisal hierarchy, with developers/landowners producing site-specific Flood Risk
Assessments (FRAs) and local authorities producing Strategic Flood Risk Assessments(SFRAs). For Greater London, with its 33 local authorities, a Regional Flood Risk
Appraisal (RFRA) with a broad consideration of flood risk across London’s boroughboundaries represents important evidence to underpin the Spatial Development
Strategy, the London Plan. It also facilitates the application of the more recently
introduced Duty to Cooperate within London but also beyond London’s boundaries
including the authorities in the Thames Estuary.
5. This First Review of the RFRA builds on and updates the original RFRA that was
published in October 2009. It has been undertaken with the assistance of theEnvironment Agency, and the Mayor would like to thank the Environment Agency for
their assistance in preparing this document. This is particularly important in the light of
the Agency’s new strategic overview role ensuring that the risk of flooding from all
sources is properly managed alongside operational responsibilities for managing the riskof flooding from main rivers, reservoirs, estuaries and the sea.
6. This review deliberately crosses again the boundary between land use planning andemergency planning. This has been done as the Mayor recognises that there is not
1

Different strands in terms of learning lessons from these floods are currently being pursued by theEnvironment Agency including a ‘winter readiness statement’ in collaboration with Defra.

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always close liaison between the two disciplines and it will be important to stimulate
greater links between them. The London Resilience Team has published its London
Strategic Flood Framework in May 20122. This seeks to co-ordinate emergency services
and emergency planners across London in the event of a major flood.
7. Since the publication of the 2009 RFRA a number of changes have taken place: The
Flood and Water Management Act 2010 (F&WM Act 2010) has come into force
reflecting a range of recommendations from the Pitt Review. The Flood Risk
Regulations 2009 were introduced and set out requirements to manage flood risk fromall sources in order to reduce the consequence of flooding on human health, economic
activity and the environment. The National Planning Policy Framework (NPPF) and theassociated Technical Guidance on flood risk were published in 2012. They retain theimportance of flood risk management considerations that had been introduced through
PPG25/PPS25. The Thames Estuary 2100 Plan was published by the Environment
Agency and endorsed by Government in November 2012. It addresses flood risk fromthe tidal Thames. Catchment Flood Management Plans addressing fluvial flood risk were
published in 2009. Finally, the GLA-led Drain London project has also progressed since2009 and significantly improved the understanding of surface water flood risk acrossLondon, and the Environment Agency has produced reservoir flood maps.
8. The 2009 RFRA included a range of recommendations. Progress against these has
been monitored annually in the London Plan Annual Monitoring Report. Since 2009
progress against the recommendations reflects in particular the actions of Drain London
in terms of the improved understanding of surface water flood risk. It also confirms the
improvements to local flood risk policies based on completed Strategic Flood Risk
Assessments (SFRAs).
9. The current scale and distribution of flood risk is shown through the first two maps
included in Appendix 5: Map 1 illustrates that 14% of Greater London has someextent of known tidal and/or fluvial flood risk (extent of Flood Zones 2 and 3). Map 2
illustrates that 3 % of the area is at some risk from surface water flooding. Table 1
combines the extent of tidal/fluvial and surface water flooding. In chapter 3 these
combined flood risk areas will be compared with a number of different receptors offlood risk, including growth areas, infrastructure assets and services.
Table 1: Tidal/fluvial and Surface Water Flood Risk in London
RegionGreater London

1.2

Hectares inFlood Area

Hectares outof Flood Area

Total
HectaresPortion at Risk
of Flooding

25,802

133,668

159,470

16%

The London Plan

10. The findings of the 2009 RFRA have shaped the policies within the current London
Plan. Flood risk is recognised as an important consideration for all developments and incombination with the NPPF and its associated Technical Guidance, Policy 5.12 sets out
the strategic approach in London.

2

An update is expect in 2015.

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POLICY 5.12 FLOOD RISK MANAGEMENT
Strategic
A The Mayor will work with all relevant agencies including the Environment
Agency to address current and future flood issues and minimise risks in asustainable and cost effective way.
Planning decisions
B Development proposals must comply with the flood risk assessment andmanagement requirements set out in the NPPF and the associatedtechnical Guidance on flood risk [footnote: Technical Guidance to the
National Planning Policy Framework, Department for Communities andLocal Government, March 2012 or any subsequent guidance on flood risk
issued in support of the NPPF] over the lifetime of the development andhave regard to measures proposed in Thames Estuary 2100 (TE2100 –see paragraph 5.55) and Catchment Flood Management Plans.
C Developments which are required to pass the Exceptions Test set out in
the NPPF and the Technical Guidance will need to address flood resilient
design and emergency planning by demonstrating that:a the development will remain safe and operational under flood
conditionsb a strategy of either safe evacuation and/or safely remaining in thebuilding is followed under flood conditions
c key services including electricity, water etc will continue to be provided
under flood conditions
d buildings are designed for quick recovery following a flood.
D Development adjacent to flood defences will be required to protect the
integrity of existing flood defences and wherever possible should aim to be
set back from the banks of watercourses and those defences to allow their
management, maintenance and upgrading to be undertaken in asustainable and cost effective way.
LDF preparation
E In line with the NPPF and the Technical Guidance, boroughs should, when
preparing LDFs, utilise Strategic Flood Risk Assessments to identify areas
where particular flood risk issues exist and develop actions and policy
approaches aimed at reducing these risks, particularly throughredevelopment of sites at risk of flooding and identifying specificopportunities for flood risk management measures.

11. As a significant measure to address in particular surface water flooding Policy 5.13
on Sustainable Drainage is quoted below as well. Over recent years the scale ofsustainable surface water management measures in major planning applications in linewith this policy has increased significantly. Many such applications achieve theGreenfield run-off rate the policy is aiming at. It is expected that relevant measures are
far less common on smaller scale developments but should become more widespreadwith the enactment of SuDS Approval Bodies expected in 2015.
POLICY 5.13 SUSTAINABLE DRAINAGE
Planning decisions
A Development should utilise sustainable urban drainage systems (SUDS)
unless there are practical reasons for not doing so, and should aim to
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achieve greenfield run-off rates and ensure that surface water run-off ismanaged as close to its source as possible in line with the following
drainage hierarchy:
1 store rainwater for later use
2 use infiltration techniques, such as porous surfaces in non-clay areas
3 attenuate rainwater in ponds or open water features for gradualrelease
4 attenuate rainwater by storing in tanks or sealed water features forgradual release
5 discharge rainwater direct to a watercourse
6 discharge rainwater to a surface water sewer/drain
7 discharge rainwater to the combined sewer.
Drainage should be designed and implemented in ways that deliver otherpolicy objectives of this Plan, including water use efficiency and quality,
biodiversity, amenity and recreation.
LDF preparation
B Within LDFs boroughs should, in line with the Flood and Water
Management Act 2010, utilise Surface Water Management Plans to
identify areas where there are particular surface water management issues
and develop actions and policy approaches aimed at reducing these risks.

12. This RFRA represents important evidence to underpin the Further Alterations to the
London Plan (FALP), which are currently being developed. It is not proposed to change
Policies 5.12 or 5.13, but their Supporting Text is proposed to be updated to reflect theGovernment’s endorsement of TE2100 and the better understanding of surface water
flood risk through the Drain London project. In terms of the preparation of the FALP
flood risk is an important constraint in identifying capacity for housing in London
through the latest Strategic Housing Land Availability Assessment (SHLAA) that informs
the FALP. Sites with a known flood risk have their capacity reduced depending upon theseverity of the risk and no sites within the functional floodplain (Flood Zone 3b) or
greenfield sites in Flood Zone 3a were identified as having housing capacity. With thecontinued spatial focus on urban concentration proposed in the FALP, the anticipatedgrowth is planned to be accommodated in particular in London’s major development
locations and town centres, where individual risks will have to be looked at by the
London boroughs in more detail.
13. The Mayor published a Sustainable Design and Construction SPG in April 20143. In
its section 3.4 it gives guidance for the implementation of Policies 5.12 and 5.13
addressing different sources of flooding including surface water flooding; sustainabledrainage; resilience, resistance and safety including basement developments; and flood
defences.
1.3

The Sequential Test

14. The NPPF contains a Sequential Test (paragraph 101) to ensure that development
takes place in the areas available at lowest flood risk. London is a unique city in the UK.
It is heavily built up with a tightly drawn administrative boundary. The Green Belt policy
is now long standing and has been largely successful in its aims of preventing London
from spreading, preventing the coalescence of peripheral settlements and protecting
3

The SPG can be accessed via: http://www.london.gov.uk/priorities/planning/consultations/draftsustainable-design-and-construction

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open countryside. This success is now reaping the additional benefit of promoting there-use and regeneration of brownfield land which is widely seen as an importantelement in achieving sustainable development. In some places that were generally
undeveloped in the middle of the 20th Century, the Green Belt extends into London, forexample in the Lee Valley. Other significant open spaces are also protected by the land
use planning system with various levels of policy; for example, Metropolitan Open Land
(MOL) provides a similar level of protection to Green Belt.
15. The delineation of the Green Belt and the other protected open spaces in London
mean that the scope for new development on land other than brownfieldredevelopment land is extremely limited. Over recent years the vast majority of new
development has taken place on brownfield land4. This trend is expected to continue.
16. Many of London’s remaining large brownfield areas are either substantially or
partially within Flood Zones 2 and 3. Map 3 demonstrates that 37% of the area ofOpportunity Areas and 28% of the area of Intensification Areas are within these Flood
Zones. However alternative sites for large scale development within London do notexist without encroaching into Green Belt, MOL or other protected spaces.
17. The latest SHLAA examines the potential housing capacity of over 9,000 sites within
London. Flood Zone 3b and greenfield sites in Flood Zone 3a were excluded as a
strategic approach to the sequential test. However, consideration has been given tobrownfield sites in Flood Zone 3a to help address London’s housing need.
18. Therefore from a strategic perspective, the sequential test permits the considerationof these sites for development. It will still be necessary for boroughs and developers 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 still remain
important to place more vulnerable uses in areas with lower flood risk in order to meet
the Sequential Test at a local level.
1.4

How to use the RFRA

19. 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 5) and a series of revised
recommendations (see Appendix 1), which are either London wide, applicable toboroughs in undertaking their SFRAs or apply to utility/service providers. These
recommendations are meant as a monitoring tool and progress against them willcontinue to be reported annually in the London Plan Annual Monitoring Report.
20. The RFRA will remain a live document with regular updates to reflect the changing
position in relation to both climate change and development pressure and policy
responses. This is the First Review and future reviews should take place approximately
every five years or after a major flooding incident.
21. 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.
4

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

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Chapter 2 - Overview of Flood Risk
22. 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.
23. 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

24. 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
(paragraph 100).
2.1

Tidal Flood Risk

Nature of Risk
25. 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 Lea Bridge on the River Lee.
26. 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.
27. 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. If
that flood had funnelled further up the Thames the results could have been even moredisastrous.
28. The area at risk of tidal flooding, including from storm surges, approximates to the 5
metre contour line and is shown on Map 1. The area of London below the normal highLondon Regional Flood Risk Appraisal – First Review – August 2014
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tide range is approximately 6200ha and affects parts of 12 London boroughs. The areathat could potentially be affected by a storm surge of the same magnitude as the 1953
flood covers 11 600ha and affects parts of 20 London boroughs.
29. 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 300km 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 the level of protection will reduce
down to a standard of 1 in a 1000 (0.1% chance per year) by 2030 and this willcontinue to decline if no further measures are taken.
30. Since its completion in 1982, the Thames Barrier has been closed 175 times toprevent flooding. Diagram 1 below indicates that the number of closures per year isfairly variable; however, there is a general increase in the number of closures. This ties
in with climate change observations. Closure of the Thames Barrier also necessitatesclosure of other barriers and flood gates, and prevents navigation through the Barrier.
This winter has seen a record number of 50 closures, which has triggered aninvestigation by the Environment Agency, which is currently underway. If there were to
be 50 barrier closures year on year, the Environment Agency indicates that a review of
relevant policies and plans (see TE2100 - paragraph 39) may have to be considered.
31. 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.

32. The likelihood of such residual risks are 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.

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Diagram 1: Thames Barrier Closures

Source: Environment Agency

Locations
33. 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 uses for centuries, it is not
surprising that there is a lot of infrastructure already in place there although it isprotected to a high standard by the combination of the river walls and the Thames
Barrier.
34. 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. Despite their derelict, underused or industrial nature these areas
are also protected from flooding to a high standard.
Information available
35. The 1 in 1000 (0.1%) tidal flood envelope is shown on Map 1 and covers a wide
area. It is closely related to the 5m land contour. This area is currently defended to ahigh standard by the combination of flood walls and embankments and the Thames
Barrier and other movable gates and barriers.
36. The condition of flood defences is held on a database by the Environment Agency
which carries out regular inspections to update condition surveys and take appropriate
action either directly or through riparian owners to ensure that structures are in a soundcondition. The vast majority of flood defences along the Tidal Thames are in a goodstructural condition.

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Flood Risk Management Options
37. 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 defences were constructed through the1970s and 1980s in response to the tidal surge of 1953 and include the Thames Barrier.
There are also many other flood gates and moveable structures that make up the
defence system. This system of tidal flood defences was designed with knowledge ofsea level rise and it made allowances for this. Therefore protection up to a 1 in 1000
(0.1%) event is estimated to be provided by the Thames Tidal Defences until 2030,
after which the level of protection will decline below 1 in 1000 (0.1%) unless othermeasures are taken.
38. The Environment Agency has completed the Thames Estuary 2100 (TE2100)
project. The plan was endorsed by Government and published in November 2012. Thisis the first time that planning for future flood risk management is taking place inanticipation of future flood risk rather than in response to a flood event. This RFRA
takes account of its policy initiatives.
39. TE2100 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:2012 – 2035:• Work with Local Authorities and the construction industry to ensure that existing andnew 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 theEstuary• 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 end of theCentury 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
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40. 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 todeliver them in collaboration with its partners. The Environment Agency has also
identified four broad areas (Reaches) of the Thames and have 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)
41. 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)
42. 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)
43. 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.
44. 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)
45. This is outside London but options sited here could protect London. This area may
provide environmental mitigation and compensation for impacts inside London.
Confluences
46. Particular care will be needed when examining the confluences of tributary rivers
with the Tidal Thames given the interaction between the different systems. In particular
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 andtherefore these areas share high levels of flood protection.
The Likely Impact of Climate Change
47. 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 predictions for
how quickly sea level will rise vary considerably depending on the assumptions used
about emissions and climate modelling. The TE2100 Plan has considered a range ofclimate change derived sea level rises from 0.9m (Defra 2006 Climate Change Scenario)
to 4.2m (High++ Level where all conceivable sea level rise contributions up to 2100
occur).

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48. Up to 2030, there are limited differences between predictions and existing flood risk
management options can continue to provide appropriate risk management for tidal
flooding. Beyond 2030 there is more variation in the projections. However it is clearthat by starting to plan for these changes now, the ability to cope with more extreme
situations will be improved.
2.2

Fluvial Flood Risk

Nature of Risk
49. London has many tributary rivers leading to the River Thames and the Thames itself
is a fluvial river upstream of Teddington Lock. These are shown on Map 1. As with any
river system there is a possibility that any of these rivers could flood. This could comefrom either particularly intense rainfall within the catchment or from a blockage or
restriction to flow within the river channel.
50. The Environment Agency has produced Catchment Flood Management Plans(CFMP) 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
North Kent Rivers CFMP – September 2008

51. 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.
52. The urbanised river environment also contains many bridges, tunnels and culvert
structures. These culverts are often underneath roads or railways but sometimes flow
under substantial areas of land. These form potential flood risks as they can become
blocked or restricted through litter or more likely larger debris such as shopping trolleys,
mattresses or even vehicles. Culverts present a particular difficulty in that it is difficultand expensive to determine their condition and to carry out maintenance and repairs. It
can also be difficult to ascertain ownership and maintenance responsibility for someculverts. It is also known that there are a significant number of illegal mis-connectionsof foul sewers to surface water culverts, these lead to ongoing pollution of rivers. In
general opportunities to remove and open up culverts should be taken on
environmental and aesthetic grounds as well as improving flood risk management. Thisis also addressed in London Plan policy 7.28.
53. 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.

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54. Such urban rivers respond very rapidly to rainfall and the opportunity for flood
warnings to be issued is limited to as little as one half to two hours in many cases.
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
55. 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 alongside the Colne
Valley and the River Lee Navigation are both linked to large fluvial catchments and may
convey flood waters from fluvial sources. A further consideration is that any canalwhich is on land higher than the surrounding land has the potential for a breach.
Therefore, consideration of flood risks from canals needs to be factored into SFRAs and
FRAs.
Locations
56. 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 is more localised than tidal flooding. Fluvial flooding has been more
frequent than tidal flooding meaning that many areas of floodplain have been left undeveloped, often forming parks within the wider urban setting, the most prominent
example being the Lee Valley Regional Park.
Information available
57. The Flood Zones are shown on Map 1. The Environment Agency also has detailed
floodplain modelling for some of the tributaries. Most tributaries have been modified toreduce the likelihood of flooding. In many cases these consist of raised river walls andwidened channels. In the case of the River Lee an entire new flood relief channel wasconstructed 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.
58. The CFMPs classify flood plains into 6 broad types:







Undeveloped natural flood plain
Developed flood plain with no built defences
Developed flood plain with built defences
Developed flood plain with typically concrete river channels
Major urban expansion in or close to flood plains
Narrow flood plains and mixed use land

59. The CFMPs then identify five policy options to manage flood risk and the key
messages that are relevant to each of these approaches.
60. 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:
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those that help to reduce the likelihood of flooding occurring and those addressing theconsequences if a flood does happen.
61. 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)
62. Each tributary river system in London has different attributes, these are described
below:
River Lee - Boroughs affected: Barnet, Enfield, W Forest, Haringey, Hackney, Tower
Hamlets, Newham
63. 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 flood plain and the fact that there are considerable development
proposals both within and outside London.
64. 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 started the construction of a flood alleviation
scheme for Salmons Brook that will, together with maintenance of the existing river
structures, reduce the risk of flooding to a 1.3% standard of protection (1 in 75 year;
1.3% chance of flooding in any year) for 1167 properties.
65. 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.
66. 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.5
5

For further details please see http://www.environmentagency.gov.uk/research/library/consultations/54262.aspx
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River Roding - Boroughs affected: Barking & Dagenham, Redbridge, Newham
67. 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
catchment6.
68. 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
69. 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.
70. 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
71. 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.
72. 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
73. The River Brent and its various tributaries have suffered localised flooding,particularly in the upstream catchments of Harrow and Barnet. The Environment Agency
is examining options in partnership with the London Boroughs of Brent and Harrow andThames 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 LDD policies, updates to Strategic Flood Risk Assessments anddevelopment of Local Flood Risk Management Strategies. The Brent flows throughextensive park areas offering opportunities for flood risk management as well as
potential for enhancement of the river corridor.
6

For further details please see http://www.environmentagency.gov.uk/homeandleisure/floods/148706.aspx
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74. 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
75. 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.
76. 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
77. 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.
78. 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 thePinn 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
79. 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.
80. 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.
81. 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.
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82. 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.
83. The downstream area of this river catchment runs through a heavily built up areawith flood plain covering significant areas of already developed land. Some upstream
areas south of Mitcham are more open with some storage of floodwater possible.
84. 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
85. 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.
86. 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
87. 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
88. 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.
89. 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.
90. 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.

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Fluvial River Thames- boroughs affected: Kingston, Richmond, Spelthorne, Elmbridge
91. 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. The Environment Agency is developing the River Thames Scheme (formerly Lower
Thames Flood Risk Management Strategy).
92. This River Thames Scheme (Datchet to Teddington) aims to reduce flood risk to
15,000 properties, which are currently at risk of a 1 in 100 (1% chance of flooding inany given year). The strategy combines a range of measures to reduce flood risk in thearea, including building three flood diversion channels, capacity improvements to threeweirs and individual property protection measures.
93. The CFMP recommends an approach to take further action to reduce the risk offlooding.
Flood Risk Management Options
94. Now that the CFMP policy approaches have been determined, there needs to becontinued work to ensure that these policy approaches are implemented. The actual
detail of how these need to be implemented will require careful consideration of thelocal river and its flood plain characteristics. London Plan policy 5.12 sets out thestrategic policy of managing flood risk through new development. In many cases setting
development back from river edges will enable a range of flood risk management
options to be used. This should enable the most sustainable, aesthetically pleasing andcost effective options to be selected.
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 identifying such opportunities. In some cases
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 improve flood risk management. Such measures will 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. Most predictions estimatethat peak flows will increase by 20% beyond 2050 with the possibility of up to 40%
increases in peak flows.

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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 applies not only to development in or 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 1
All Thames-side planning authorities should consider in their SFRAs and put in place
Local Plan policies to promote the setting back of development from the edge of theThames and tidal tributaries to enable sustainable and cost effective upgrade of riverwalls/embankments in line with Policy 5.12, CFMPs, TE2100 and advice from theEnvironment Agency.
Recommendation 2
The London Boroughs of Richmond, Kingston, Hounslow and Wandsworth should put inplace policies to ensure alternative responses to managing fluvial risk such as flood
resilience measures (e.g. flood gates) or potentially safeguarding land for future flood
storage or, on the fluvial tributaries, setting back local defences or any resiliencemeasures between Teddington Lock and Hammersmith Bridge in line with TE2100
findings.
Recommendation 3
The London Boroughs of Newham and Greenwich should work with the Environment
Agency on issues such as the potential safeguarding of potential land needs around theexisting Thames Barrier, and the London Borough of Bexley should work with theEnvironment Agency on future flood risk management options in line with TE2100
findings.
Recommendation 4
Boroughs at confluences of tributary rivers with the River Thames should ensure Flood
Risk Assessments (FRAs) include an assessment of the interaction of all forms offlooding, but fluvial and tidal flood risks in particular. These are the London Boroughsof Havering, Barking & Dagenham, Newham, Tower Hamlets, Greenwich, Lewisham,Wandsworth, Hounslow, Richmond and Kingston.
Recommendation 5
Regeneration and redevelopment of London’s fluvial river corridors offer a crucial
opportunity to reduce flood risk. SFRAs and policies should focus on making the mostof this opportunity through appropriate location, layout and design of development as
set out in the Thames CFMP. In particular opportunities should be sought to: Set back development from the river edge to enable sustainable and cost effective
flood risk management options
 Ensure that developments at residual flood risk are designed to be flood compatible
and/or flood resilient Maximise the use of open spaces within developments which have a residual floodrisk to make space for flood water.

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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 modelling suggest thatit 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 for action forparticularly sensitive sites/uses. Since the 2009 RFRA significant work has been
undertaken to assess, map and understand surface water risks. This is true nationally
but in London has been given a particular focus through the Drain London project.
101. 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 Boroughand has funded detailed studies into over 20 high flood risk areas. The project also
produced an initial assessment of groundwater flood risk – see groundwater flood risk
section below. The project has been funded by Defra and has broadened its remit to
support Community Flood Plans and research into household level measures that
individuals can undertake to improve flood resilience at an individual property level.
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. It is impractical andexpensive to construct surface drainage networks that will cope with much higher storm
return periods.
103. Within the F&WM Act 2010 there is a provision for the establishment of SUDS
Approval Bodies (SABs). These will be run by the Lead Local Flood Authority and willcontrol, permit and maintain SUDS on new development. These SABs are expected to
be enacted in 2015, with a staged phasing-in of different scales of development thatwill require SAB Approval. It is anticipated that SABs will operate in a similar way to
Building Control as a parallel process to planning permission. It is also anticipated that
this requirement will result in a step change in the number of SUDS being implemented.
The Drain London Forum will facilitate the information exchange between the boroughson their experience of operating as SABs, and more widely it is anticipated that it willcontinue to assist boroughs as Lead Local Flood Authorities in sharing good practice inthe delivery of these new duties.
Locations104. The Drain London project has produced the first comprehensive series of surface
water risk maps for London and these have been accompanied by a Surface Water
Management Plan (SWMP) for each London Borough.
105. 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 impossible
to predict precisely where the risks will lie. Details such as the height of kerbs or level
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and construction of boundary walls can determine whether surface water flows one way
or another. Therefore any London wide or borough wide mapping must only be taken
as a general indication of risk areas (see Map 2).
106. There are some general points that emerge from the analysis of the mapping. In
central and inner London, where the natural drainage systems have been largely
removed and built over, surface water flood risk tends to occur in lots of small, localized
areas representing slightly lower ground than the surrounding land. Basement
properties and entrances to sub surface car parks, servicing yards etc. can be atparticular risk of ingress of water. It should be noted that such basements often house
important utilities such as electrical sub stations/meters, lift motors/control gear, backup power generators or computer servers. It should be remembered that thecircumstances under which surface water flooding is likely to occur are heavy rain whenmost places will be wet already. Often smaller natural drainage features such as
tributary streams and ditches have been built over during the centuries of development,
whilst the land may remain at a slightly lower level, thereby being likely to be subject tosurface 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.
107. 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 thosebuildings may lie within risk areas. Away from those river corridors surface water will
pond in lower lying areas.
108. Buildings with large roof areas, such as mainline rail termini, 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 programme there
are projects which are examining those risks and seeking ways to demonstrate how to
retrofit more sustainable drainage to reduce the risks.
109. 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 more sustainably.
The implementation of London Plan Policy 5.13 (Sustainable Drainage) and theemerging Sustainable Design and Construction SPG is therefore important across all ofLondon and not just in identified risk areas.
Information available
110. The Drain London project has produced surface water flood risk maps for eachLondon Borough covering the following return periods: 1 in 30, 1 in 75, 1 in 100, 1in
100 + Climate change) and 1 in 200. This modelling is “intermediate” level modellingand made a general allowance of 6.5mm of rainfall per hour being absorbed by thedrainage network. For a selection of high risk areas, Drain London has undertaken“detailed” level modelling in partnership with the relevant boroughs. This has generally
shown that the extent of flood risk in the London-wide intermediate level modelling has
been slightly over estimated. This is mainly because the 6.5mm/hour drainage

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allowance has been a conservative estimate. The detailed level of work has enabledboroughs to determine whether they should progress with risk management works.
111. The mapping used in this RFRA shows the Drain London flood risk areas withdeeper than 0.3m (300mm) of modelled flooding (see Appendix 5). This has been
selected to increase the confidence in the mapping. For some flood risk receptors suchas rail stations and emergency services manual screening of the Drain London data wasundertaken to improve the reliability of the data further. For example in cases wheresites/facilities do have some level of modelled flood risk, these may have still been
excluded if these risks were assessed to be not significant.
112. In December 2013 the Environment Agency published updated surface water
flood risk mapping for England. This has utilised advances in computer modelling
power to generate flood risk maps, using some similar methodology to that of the Drain
London project, for the whole country. The EA modelling technique tends to channel
more surface water into identifiable features such as roads, thus suggesting greater
impacts on the highway network but lower impacts on properties. If an area has an
identified surface water flood risk, then more detailed site specific analysis is
recommended.
113. There are still relatively few well documented records of surface water flooding.
The nature of surface water flooding is often that it occurs and then dissipates quickly,
usually within a few hours. Whilst historically this has made it difficult to make a reliable
record of such an event, the prevalence of camera phones, social media and CCTV now
makes it possible to build up an accurate picture of such events and in future events arelikely to be recorded on a much more consistent basis. Furthermore, the London
boroughs as Lead Local Flood Authorities now have a duty under the F&WM Act 2010
to maintain a register of any significant flood events.
Flood Risk Management Options
114. As mentioned before, it is often impossible to manage surface water flood risk at
the locations where that risk is present and it is therefore important to apply London
Plan Policy 5.13 across the whole of London. Drain London is also working on several
retrofit projects to deliver sustainable drainage solutions where new development is not
the primary driver.
115. Where development proposals are on brownfield sites, there are real benefits to
be gained 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/brown 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.
116. 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

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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.
117. The Drain London project is now working with partners to broaden the delivery ofsustainable drainage. It will be developing a London Sustainable Drainage Action Plan
during 20147. It will examine ways of encouraging and incentivising the retrofitting ofsustainable drainage measures into the existing urban environment. Such measures will
investigate how existing maintenance budgets for public and private buildings candeliver more sustainable drainage measures, how improvements to the road system,
public realm and public transport network can be designed to incorporate moresustainable management of rainwater and how private individuals could be encouraged
to adopt more sustainable rainwater management on their own properties.
118. 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 themost sustainable option. London Plan policy 5.13 promotes this option.
119. There is also emerging evidence on rainwater management that even relatively
extensive green roofs, as encouraged by London Plan Policy 5.11, can have a significant
effect in reducing surface water run-off, particularly with the lower intensity rainfall
events.
120. Drain London is working to deliver “Greenstreets” pilot projects across London.
These are local projects to demonstrate how to manage surface water in a moresustainable way working with communities to bring additional benefits to theappearance and amenity of streets and individual properties. Thames Water is leadingwith three streets in the Counters Creek sewer catchment of Hammersmith & Fulham
and Kensington and Chelsea; the Environment Agency is delivering a project in Beckton;
and LB Newham, the GLA and the Environment Agency are working with LB Haringey toidentify suitable measures. The lessons learnt from these pilots will help to shape future
work under the London Sustainable Drainage Action Plan.
The Likely Impact of Climate Change
121. Current predictions anticipate that the intensity of storms is likely to increase.
This will mean that both the likelihood of surface water flooding will increase and theconsequences will increase as flood waters may be deeper given the higher volumes ofrainwater. The application of the sustainable drainage hierarchy (Policy 5.13) and theLondon Sustainable Drainage Action Plan should improve the ability of the urban area
as a whole to cope with such storm events but individual locations will still be affected.
Recommendation 6
Developments all across London should reduce surface water discharge in line with the
Sustainable Drainage Hierarchy set out in Policy 5.13 of the London Plan, the emerging
Sustainable Design and Construction SPG and the emerging London Sustainable
Drainage Action Plan.

7

A consultation draft is expected to be published in late 2014 and a final plan in the middle of 2015.

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2.4

Foul Sewer Flood Risk

Nature of Risk
122. 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.
Sewer flooding is clearly particularly unpleasant and distressing as its contents are highly
contaminated. At present Thames Water estimates that there are over 10,000
properties which are vulnerable to sewer flooding across the whole of Thames Water’s
operational area.
123. Thames Water is investing over £300million between 2010-2015 to combat sewer
flooding at 2,500 properties. The aim is to eradicate the problem in the foreseeable
future.
124. There will also be some potential synergies with the Drain London project,particularly within the Combined Sewer areas of London.
125. 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. The proposed Thames
Tideway Tunnels will intercept overflows and transfer the flows for treatment at
Beckton Sewage Treatment Works. London Plan policy 5.14 supports this project inprinciple. It will prevent the discharge of millions of tonnes of untreated sewage andrainwater to the Thames.
Locations126. The locations affected tend to be small discrete sub-catchments on the sewer
network rather than any specific patterns or particular locations.
Information available
127. 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
128. 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
over £120,000 per property for the programme between 2010-2015.
129. Future developments should be catered for by ensuring that the appropriate on
and off site sewerage infrastructure is planned and delivered to fit in with proposeddevelopment. In line with London Plan Policy 5.13 it is important to promote that
surface water is not discharged into the foul water system, thereby surcharging its
capacity.

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The Likely Impact of Climate Change
130. 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 should be largely overcome through the completion of the Thames
Tideway Tunnels8. In parallel, it will be important that developments follow the London
Plan Sustainable Drainage Hierarchy (Policy 5.13) in order to ensure the continued
effectiveness of the sewer system and to prevent gradual increases in the number andscale of overflows to the new Thames Tideway Tunnel, in particular as climate change
will have more impact later in the century.
Recommendation 7
Thames Water should continue the programme of addressing foul sewer flooding.
2.5

Groundwater Flood Risk

Nature of Risk
131. 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 around 50 properties affected in particular in Croydon andBromley.
132. 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.
133. This problem has been addressed by the General Aquifer Research Development
and Investigation Team (GARDIT). Through increased abstraction of the groundwater,
notably by Thames Water, groundwater levels are now relatively stable and theEnvironment Agency is maintaining a regular monitoring regime.
8

The Secretary of State is expected to make a decision on Thames Water’s Development Consent
Order in Sept 2014.

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Major Development Locations
134. There are no known 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.
135. 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 sites specific assessments are important, particularly where deep
excavation is involved or where there is an indication that the groundwater levels may
be elevated. The areas highlighted in the IPEG map are generally quite sporadic acrossLondon. See Map 12 for an illustration of the IPEG.
Information available
136. 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
137. 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 Change138. 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 8
The groundwater flood risk in identified locations (see IPEG map) should be consideredin FRAs and SFRAs to ensure that its impacts do not increase.
2.6

Reservoir Flood Risk

Nature of Risk
139. 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
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happen with little or no warning. The resulting high consequence of flooding means
that, although flooding from reservoirs is considered to be of very low likelihood, therisk should be considered in SFRAs and FRA.
Major Development Locations
140. 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.
Information available
141. Reservoir flood maps were introcuced by the Environment Agency only after the2009 RFRA. They are now available via the following website:
http://maps.environmentagency.gov.uk/wiyby/wiybyController?ep=maptopics&lang=_e 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
142. 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 size9. The Environment Agency has started to review all reservoirs todetermine their level of risk.
143. 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:





9

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.

Previously only applied to large raised reservoirs over 25,000 m3.

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The Likely Impact of Climate Change
144 It is very unlikely that climate change will have a significant impact on reservoir
flooding. However, this will be monitored through the above mentioned strict
management arrangements.
Recommendation 9
The reservoir flood risk in identified locations (see reservoir flood maps) should beconsidered in FRAs and SFRAs to ensure its impacts do not increase.

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Chapter 3– Spatial Implications of Flood Risk
3.1 Introduction
144. 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 particular locations, boroughs and important infrastructure. Appendix
5 provides the related maps and detailed statistics, and Appendix 4 represents a broad
comparison of flood risk data with the 2009 RFRA.
London Boroughs – Strategic Flood Risk Appraisals (SFRAs)
145. Most London boroughs have some extent of identified flood risk; see Maps 1 and2. 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.
146. All boroughs have now completed their SFRAs. These will need to be kept up todate and reviewed approximately every 3-5 years or as and when significant new data
becomes available. For specific strategic purposes joint SFRAs have been produced,
including one for East London and one for North London to support the North London
Waste Plan.
147. 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.
148. 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.

149. 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.
150. Complementing this planning specific tool, as Lead Local Lead Flood Authorities
the London boroughs also have to produce Local Flood Risk Management Strategies
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based on the F&WM Act 2010 requirements with measures to address local flood risk intheir areas. All boroughs are currently in the process of developing these Strategies.
They also have to maintain a register of Flood Risk Management Assets and must
investigate reports of flooding.
3.2

Specific Development Areas

Major Development Locations
152. The London Plan contains two categories of major development location;
Opportunity Areas and Intensification Areas. These are the places where London willaccommodate the majority of its anticipated significant 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 promotesustainable development.
153. 33 of the 45 areas have some form of identified tidal or fluvial flood risk, whilst
surface water flooding is much more dispersed (see Map 3). Table 2 provides an
overview of the current flood risk from these sources (for clarity the surface water floodrisk element is provided in red) for the individual major development locations, andtherefore a flood risk framework for more detailed investigations at the level of theindividual 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 more sustainable 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 of operating the sewerage system. Furthermore, if planned acrosslarge scale developments such measures can reduce development costs compared withthe provision of conventional drainage infrastructure.
154. 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
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.

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Table 2: Flood Risk in Major Development Locations
Current flood risk
characteristics

Potential flood risk mitigation
measuresOpportunity Areas

BexleyRiverside

Current Flood Risk Characteristics
Downstream of the Thames Barrier
protected from storm surges byraised river walls. Contains several
shipping-related industries requiring
operational access to the river. Also
contains parts of the Darent flood
plain which is protected by tidal
defences.
There are some surface water floodrisk areas particularly where there isa dominance of large impermeable
areas. Some areas rely on pumped
drainage.

Bromley

Identified 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.

CanadaWater

Intensively developed, protected fromdaily flooding by river walls and fromtidal surges by the Thames Barrier.
Relatively minor surface water flood
risks focused on London Overgroundlines around Surrey Quays station
and Rotherhithe Tunnel approach
road.

Future Flood Risk Considerations
Located in the Thamesmead and Dartford
and Erith TE2100 policy units. Raising riverwalls and embankments required by 2040
for normal tides and tidal surges. Openspaces to be retained for potential flood
storage and work to flood defences in future.
Need to consider future of Darent Industrial
Estate and potential use of Crayford
Marshes for tidal storage. Outputs from theRiver Cray flood risk management asset
study should be considered.
Measures to reduce surface water run-off
will be important. 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.
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.
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.
Located in Wandsworth to Deptford TE2100
policy unit. Raising river walls required by
2065. Set development back from riversedge 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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Charlton
Riverside

Current flood risk
characteristics

Potential flood risk mitigation
measures

Straddling the Thames Barrier,protected from storm surges byraised river walls but with land lying
significantly below high tide levels.

Located in the Greenwich TE2100 policy
unit. Raising river walls and embankments
required by 2065 for normal tides and tidal
surges. Open spaces to be retained forpotential flood storage and work to flood
defences in future.

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

Intensively developed, protected fromdaily flooding by river walls and fromtidal 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.

Colindale /Burnt Oak

Cricklewood/ Brent Cross

CroydonRelatively small proportion of area
within flood plain but contains Silk
Stream, a River 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.
Small proportion of area is withinfloodplain. Some local flood history
on the River Brent.
There are some surface water floodrisk areas particularly along the River
Brent corridor, the A406 where it
passes under the A41, the A41 southof the A406, Cricklewood Lane near
Crickelwood Station and around
Prayle Grove.
Small area within flood plain of theRiver Wandle.
Extensive areas of surface water
flood risk along the route of thelargely buried River Wandle. Drain
London has funded an initial study
into this risk area.

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.
Located in the London City TE2100 policy
unit. Raising river walls required by 2065 fornormal tides and tidal surges. Open spaces
to be retained for potential flood storage andwork 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.
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.
Set development back from rivers edge toenable a range of flood risk management
options. Investigate opportunities to restore
culverted watercourses.
New development is a good opportunity tointroduce more sustainable rainwater
management there should be good scopefor sustainable drainage options to achievegreenfield run-off rates and reduce thecurrent risks.
Investigate opportunities to reduce flood risk
for the Caterham Bourne.
Measures to reduce surface water run-off
will be important. New development is agood opportunity to introduce moresustainable rainwater management there
should be good scope for sustainabledrainage options to achieve substantial
reduction in run-off rates and reduce thecurrent risks.

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Deptford
Creek /
GreenwichRiverside

Current flood risk
characteristics

Potential flood risk mitigation
measures

Intensively developed, protected fromdaily tidal flooding and fluvial flooding
from the 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, setting
development back from rivers edge toenable a range of flood 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

Elephant
and Castle

Protected from storm surges byraised river walls.
Documented surface water flood risk
areas and known capacity problems
in the Counters Creek catchment,
below ground level London
Overground and Underground raillines at risk and areas close to large
footprint buildings. It is notable thatmost older properties in the area
have basements which will be at ahigher risk of overflow from thehighway network.
Intensively developed, protected fromdaily flooding by river walls and fromtidal surges by the Thames Barrier.
Relatively minor surface water floodrisk present focus on the public
highway network.

EustonNo flood plain 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.
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.
Located in Wandsworth to Deptford TE2100
policy unit. Raising river walls required by
2065. Set development back from riversedge 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.
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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Greenwich
Peninsula

Current flood risk
characteristics

Potential flood risk mitigation
measures

Intensively developed, protected fromdaily flooding by river walls and fromtidal surges by the Thames Barrier.
Contains many shipping relatedindustries requiring operational
access to river.

Located in Greenwich TE2100 policy unit.
Raising river walls required by 2065. Set
development back from rivers edge toenable a range of flood risk management
options.

There are likely to be some surface
water flood risk areas particularly
where there is a dominance of large
impermeable areas and there is aparticular risk to the Blackwall Tunnel
approach road.
Harrow andWealdstone

Heathrow

Small area located in the Wealdstone
Brook floodplain. The Brook flows
through the 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.
Relatively small proportion of areas
within fluvial flood risk zones.
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

Very small proportion of area withinRiver Roding flood plain.
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.
Intensively developed, protected fromdaily flooding by river walls and fromtidal surges by the Thames Barrier.
Relatively minor surface water flood
risks, mainly focused on the public
highway network and aroundWestferry Circus.

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,notably to the Blackwall Tunnel approachroads. Development close to the Thames
can discharge directly to the river.
Set development back from culverts. Look atopportunities to reduce 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.
Set development back from rivers 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.
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 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.

Raising river walls beyond 2030. 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.
Development close to the Thames anddocks can discharge directly to the river.

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KensalCanalside

Current flood risk
characteristics

Potential flood risk mitigation
measuresNo identified flood plain. Grand Union
Canal runs alongside the site.

Set development back from canal edge toenable a range of flood risk management
options.

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

Kings Cross– St Pancras

No flood plain identified. Grand Union
Canal runs through the site.
Relatively minor surface water flood
risks, mainly focused on the public
highway network and sub surface
National Rail lines.

Lewisham /Catford /New Cross

Located in the floodplains of theRavensbourne, Quaggy and Thamesrivers. Catford and Lewisham havethe river Ravensbourne and its
tributaries running through them withlocally recorded flooding. Intensively
developed area protected from daily
tidal flooding by river walls and fromtidal surges by the Thames Barrier.
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.

LondonBridge,Borough &Bankside

Intensively developed protected fromdaily flooding by river walls and fromtidal surges by the Thames Barrier.
Relatively minor surface water flood
risks, mainly focused on the public
highway network.

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 theGrand Union Canal may be able todischarge directly to the canal.
Set development back 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 mainline station.
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.
Need to consider the role of multipurpose
open spaces within the wider developmentareas. Development to be set back fromriver edges to enable a range of flood risk
management measures. Safeguarding land
potentially required for future flood risk
management measures on fluvial
watercourses. Comply with therecommendations of the River
Ravensbourne river corridor improvementplan.
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.
Located in Wandsworth to Deptford TE2100
policy unit. Raising river walls required by
2065. Set development back from riversedge 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.

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LondonRiverside

Current flood risk
characteristics

Potential flood risk mitigation
measures

Downstream of the Thames Barrier,protected from daily flooding andstorm surges by raised river walls.
Contains many shipping-relatedindustries requiring operational
access to river. Tributary rivers ofRainham Creek, Rom/Beam, Gores
Brook and River Roding. Relatively
few incidences of flooding in the past.

Located in Barking and Dagenham andRainham Marshes TE2100 policy units.
Raising river walls and embankments
required by 2040 for normal tides and tidal
surges. Open spaces to be retained forpotential flood storage. Set development
back from rivers edge to enable a range offlood risk management options. The area
may have a role for strategic flood storage –notably when tributaries become tide locked.

Relatively minor surface water flood
risks, mainly focused on the public
highway network and around existingwater features.

Lower Lee
Valley,including
Stratford

Intensively developed protected fromdaily tidal flooding and fluvial flooding
by river walls and from tidal surges
by the Thames Barrier. River Lee
and various tributaries flow throughthe Opportunity Area.
Some significant areas of surface
water flood risk in Hackney Wick andWick Road area, around Oliver Road,
and on parts of the highway network
including lower parts of the Blackwall
A102M and A12 and parts of the
Jubilee Line/DLR corridor between
Stratford and Canning Town.

Old Kent
Road

Intensively developed, protected fromdaily flooding by river walls and fromtidal 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.

Old OakCommonNo flood plain identified, Grand Union
Canal runs through the site.
Surface water risks generally
localised and small scale, althoughsome rail cuttings and roadunderpasses identified as at risk.

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.
Located in Royal Docks and Isle of Dogs
and Lee Valley TE2100 policy units. Raising
river walls required by 2065. Set
development back from rivers edge toenable a range of flood risk management
options. Interaction of tidal and fluvial floodrisk will need consideration. Comply with theLower Lee Flood Risk Management Strategy
recommendations.
New development is a good opportunity tointroduce more sustainable rainwater
management and should readily be able toachieve greenfield run-off rates especially inareas that contribute to identified risk areas
and reduce those current risks.
Development close to the tidal River Lee
and Bow Creek can discharge directly to theriver.
Located in Wandsworth to Deptford TE2100
policy unit. Raising river walls required by
2065. Set development back from riversedge 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 risksboth within and just outside the easternedge of the Opportunity Area.
Set development back 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.

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Paddington

Park Royal

Current flood risk
characteristics

Potential flood risk mitigation
measures

No flood plain identified. Grand Union
Canal runs through the site.

Set back development from canal edge.

Relatively minor surface water flood
risks. It is notable that most older
properties in the area havebasements which will be at a higher
risk of overflow from the highway
network.
Only identified flood plain lies along
the River Brent to the west of North
Circular. Grand Union Canal runs
through the site.
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.

Royal Docksand Beckton
Waterfront

Straddles the Thames Barrier so ispartially protected 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.

Southall

Close to flood plain of Yeading
Brook. Grand Union Canal runs
alongside the site.
Relatively minor surface water flood
risks, mainly focused on the public
highway network.

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.
Set development back from river Brent andcanal edges 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 greenfield run-off rates and reduce
current risks. Development close to theGrand Union Canal may be able todischarge directly to the canal. It is also
important to consider the role ofmultipurpose open spaces and additional
drainage attenuation from large
roof/hardstanding areas.
Located in Royal Docks TE2100 policy unit.
Raising river walls and embankments
required by 2040 for normal tides and tidal
surges. Open spaces to be retained forpotential flood storage.
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.

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Thamesmea
d and Abbey
Wood

Current flood risk
characteristics

Potential flood risk mitigation
measures

Within tidal Thames floodplain withlarge areas significantly below hightide level. Parts of the areas are
dependent 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 for normal tides and tidal
surges. New development needs carefulconsideration, particularly of residual risks
and emergency measures. Set development
back from rivers 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
ValleyNo floodplain identified.
Relatively minor surface water flood
risks. It is notable that most 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. 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.

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.
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 rivers edge toenable a range of flood risk management
options. Need to consider the role ofmultipurpose open spaces within the wider
development area. Should be considered inassociation with measures across London’sboundaries in Herts and Essex. Comply with
the Lower Lee Flood Risk Management
Strategy recommendations.
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.

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Vauxhall /Nine Elms /Battersea

Current flood risk
characteristics

Potential flood risk mitigation
measures

Intensively developed, protected fromdaily flooding by river walls and fromtidal surges by the Thames Barrier.
Contains several shipping relatedindustries requiring operational
access to river.

Located in Wandsworth to Deptford TE2100
policy unit. Raising river walls required by
2065, setting development back from rivers
edge. Climate change is expected toincrease the residual risks posed bybreaches in the tidal defences and it isimportant that developments take account of
this residual risk when considering thesafety of proposed developments.

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

Intensively developed protected fromdaily flooding by river walls and fromtidal surges by the Thames Barrier.
Relatively minor surface water flood
risks, mainly focused on the public
highway network and the National
Rail lines into Victoria Station. It isalso notable that most older
properties in the area havebasements which will be at a higher
risk of overflow from the highway
network.
Intensively developed, protected fromdaily flooding by river walls and fromtidal surges by the Thames Barrier.
Relatively minor surface water flood
risks, mainly focused on the public
highway network with a concentration
around Waterloo Station.

Wembley

Relatively small proportion of area
within flood risk zones. River Brentflows through the area.
Relatively minor surface water flood
risks focused on the Wealdstone
Brook corridor and areas close tolarge footprint buildings.

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.
See also the Water Strategy of theOpportunity Area Planning Framework Technical Appendix 7.
Located in London City TE2100 policy unit.
Raising river walls required by 2065 on river
frontage section. Set development backfrom rivers 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, inparticular around mainline station.
Located in Wandsworth to Deptford TE2100
policy unit. Raising river walls required by
2065. Set development back from riversedge 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, inparticular around mainline station.
Development close to the Thames candischarge directly to the river.
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 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.

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White City

Woolwich

Current flood risk
characteristics

Potential flood risk mitigation
measuresVery small area of River Thames
tidal floodplain.

Located partially within Hammersmith
TE2100 policy unit.

Documented surface water flood risk
areas and known capacity problems
in the Counters Creek catchment,
below ground level London
Overground and Underground raillines at risk.

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. It is also
important to consider the role ofmultipurpose open spaces and additional
drainage attenuation from large
roof/hardstanding areas.
Located in Thamesmead TE2100 policy unit.
Raising river walls and embankments
required by 2040 for normal tides and tidal
surges. Open spaces to be retained forpotential flood storage. Set development
back from rivers edge to enable a range offlood risk management options.

Downstream of the Thames Barrier,protected from storm surges byraised river walls 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 a substantial reduction on current
run-off rates and reduce the current risks.

Intensification Area

Farringdon /Smithfield

HaringeyHeartlands /Wood Green

Current flood risk characteristics
No floodplain identified.
Some localised surface water flood
risks that should be investigated in
more detail at a site specific level.
Other risk areas focused on the
below ground level LU and National
Rail lines around Farringdon Stationand the lower sections of Farringdon
Ave around Holborn Viaduct.
No flood plain identified, 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.

Future flood risk considerations
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 culverts. Look atopportunities to reduce flood risk 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.

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Holborn

Current flood risk
characteristics

Potential flood risk mitigation
measures

No floodplain identified. Regent’s
Canal culverted watercourse flows
through the site.

Set development back from culverts.

Some localised surface water flood
risks that should be investigated in
more detail at a site specific level.

Kidbrooke

Substantial area within the River
Quaggy and Kid Brook floodplains.
Some surface water flood risk areas
mainly focused on the highway
network. Sutcliffe Park acts as aflood storage area.

Mill Hill EastSouth
Wimbledon /Colliers
Wood

West
HampsteadInterchange

No floodplain identified.
Relatively minor surface water flood
risks, mainly focused on the public
highway network and the Dollis
Brook corridor to the south east is anotable flood risk area.
Substantial proportion of area iswithin the Wandle Valley floodplain.
Some localised surface water flood
risks that should be investigated in
more detail at a site specific level andgeneral risk areas along the route of
the River Wandle.
No floodplain identified.
Relatively minor surface water flood
risks, mainly focused on the public
highway network with the exceptionof some more significant risks to low
lying parts of the rail network.

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
Wealdstone Brook.
Need to consider the role of multipurpose
open spaces within the wider developmentarea. Setting development back from riversedge to enable a range of flood risk
management options.
Measures to reduce surface water run-off
will be particularly important. 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 elsewhere in thecatchment such as at Lewisham.
Measures to reduce surface water run-off
will be particularly important. 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.
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.
Measures to reduce surface water run-off
will be important. 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.

Town Centres and the Central Activities Zone
155. 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.

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156. Given that development at 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. Map 4 illustrates the location of
tidal/fluvial and surface water flood risk of the Metropolitan (18%) and Major Town
Centre (28%) areas, and Table 3 provides an overview of the current flood risk in theindividual Town Centres.
157. 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.
158. 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.
Table 3: Flood Risk in Town Centres
Metropolitan centres

Flood Risk Issues
Bromley

CroydonEalingHarrow
Hounslow

Small proportion within the River Ravensbourne flood plain andsignificant surface water risk areas co-inciding with the Ravensbourne
floodplain and flowpath from the east passing under Bromley SouthstationPartially within the River Wandle flood plain 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
No identified fluvial flood risk issues but some surface water flood risk
areas have been identified close to LU rail lines

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IlfordKingston
RomfordStratford
Shepherd Bush

SuttonUxbridge

Small proportion within the River Roding flood plain 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 flood plains of the River Thames and the
Hogsmill River and some localised areas of surface water flood risk
Partially within the River Rom flood plain, 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
Partially within the River Lee flood plain, and some localised surface
water risk areas mainly affecting below ground level rail corridors
Small proportion within the River Thames flood plain. Some localised
areas of surface water risk identified, notably along rail lines and in thevicinity of Tadmor St.
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

Major centres

Flood Risk Issues
Angel
Barking
Bexleyheath
BrixtonCamden Town
Canary Wharf
Catford
Chiswick
Clapham Junction

DalstonEast Ham
EdgwareElthamEnfield Town
FulhamHammersmith

Kensington HighStreetCulverted watercourses flow through 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.
Wholly within the Thames tidal flood plain but protected by the Thames
tidal defences
Partially within floodplain of the River Ravensbourne with significant
areas of surface water risk along the the Ravensbourne corridor
Wholly within the River Thames flood plain - both tidal and fluvial floodrisk and some localised surface water risk areas
Small proportion within the River Thames flood plain 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 flood plain 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 surface water flood risks underinvestigation through Drain London and LB Enfield project
Wholly within the Thames tidal flood plain but protected by the Thames
tidal defences, some localised surface water risks
Almost entirely within the Thames tidal flood plain 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

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Kilburn
Kings Road East
LewishamNags Head
Orpington
Queensway/Westbo
urne Grove
PeckhamPutneyRichmond

SouthallStreathamTooting
Walthamstow
Wandsworth

Wembley

Wimbledon
Woolwich

No identified fluvial flood risk issues, but some localised surface water
risks, mainly affecting public highway
Small proportion within the River Thames flood plain
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 flood plain with extensive surface
water flood risk areas along Sevenoaks Rd- Orpington High St corridor
No identified fluvial flood risk issues, but some localised surface water
flood risk areas, notably affecting basements
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 flood plain but protected byThames Tidal Defences including the Thames Barrier
Small proportion within the Thames flood plain, 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 flood plains 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
No identified fluvial flood risk issues, but some risks to below groundlevel railway
Partially within the River Thames flood plain and some significant
surface water risk areas

Recommendation 10
Detailed flood risk assessments should be undertaken at an early stage at the level ofindividual major development locations and town centre development sites, andopportunities to reduce flood risk should be maximised where possible.
3.3

Main Rail Network and Major Stations

159. Map 5 shows that there are a total of 76 mainline stations and 217 km of mainline
rail corridor at risk of tidal/fluvial and/or surface water flooding10. This represents 23%
of London’s stations and 27% of its rail corridor. A key issue will also be thevulnerability of power supplies, signalling and communications equipment to flood risk.
160. Rail lines cross rivers on bridges, viaducts and embankments meaning that theroute is generally at low flood risk. This is demonstrated with the elevated rail lines
10

Total figures for rail lines and stations are based on the Ordinance Survey’s Meridian dataset, 2013.

London Regional Flood Risk Appraisal – First Review – August 2014
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through London Bridge and into Waterloo, Blackfriars and Victoria. Many stations arealso on elevated sections of track and therefore at lower risk. The rail lines into
Liverpool Street and Stratford 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 lines can be expected to have a higher level of flood risk.
161. The High Speed 1 Rail Link is substantially in tunnel through the flood plains of
the tidal Thames and River Lee and parts of the line is at ground level and elevatedthrough tidal flood risk zones in the Dagenham and Rainham areas. It is understoodthat the tunnel portals have been built to a very high standard of flood protection.
162. Surface water is responsible for over half of the rail line and station flood risk.
Appropriate mitigation measures include flood warning and emergency procedures. Rail
services within cuttings or stations with large roof areas may be at particular risk fromsurface water flooding during heavy storms and these are set to increase. Measures tostore or disperse rainwater from heavy storms are therefore particularly important.
3.4

London Underground & DLR Networks

163. Map 6 shows that 30% of the London Underground and DLR stations and 27% of
the lines are at risk of tidal/fluvial and/or surface water flooding11. The majority ofthese are within the tidal Thames floodplain through central London. The stations on
the DLR branch to Stratford and Jubilee line from Stratford to Canning town are also
within the River Lee Fluvial floodplain, although most of the DLR network at flood risk
is elevated on raised tracks. There are also some outlying stations and tracks which arein the flood plain and/or at risk of surface water flooding. However, notable sections of
the tube network are also on raised tracks including for example parts of the District
Line (Hammersmith to Acton, Putney Bridge to Wimbledon, around West Ham) as wellas Outer London parts of the Central, Piccadilly, Northern and Metropolitan Line.
164. 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 4 have tunnel portals within floodplains:
Table 4: 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

Flood plain
River Lee
Tidal Thames
Tidal ThamesRiver Lee
Tidal Thames
Tidal Thames

165. It is acknowledged that the underground location of stations and tracks meansthat the flood risk may not necessarily be highest in the corresponding overground11

Total figure for lines and stations are based on TfL and GLA data.

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flood risk areas. This is why the portals are highlighted, and there may also be otherpotential flood routes including emergency access points and ventilation shafts.
166. Risk management measures could include physical barriers (e.g. flood gates, vent
covers); flood warning systems; the relocation of sensitive equipment (e.g.
electrical/telecommunications equipment); or the provision of sump areas to facilitatethat flood water can be pumped out after the event. London Underground is currently
undertaking a review of flood risk from all sources that may affect its lines, stations,depots and other infrastructure. Its outcomes are expected to be available in 2015.
3.5

Main Road Network and Airports

167. The road network is a critical element of London’s infrastructure. The bus
network transports around 6 million people per day12 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 of
the Highways Agency 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.
168. This RFRA has made an initial scoping of locations on the TLRN where flooding
may present a potential risk. Map 7 shows that 26% of the TLRN are at risk, themajority of which is 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 andimplement remedial measures. In terms of surface water flood risk Drain London isinvestigating several high risk sections of the highway network, notably underpasses on
the TLRN. TfL will then be encouraged to investigate other specific risk areas.
169. Tunnels under the Thames have a particular risk as their portals are all within the
tidal Thames flood plain. In a similar way to tube tunnels, ventilation shafts or
emergency shafts may also present potential routes for the conveyance of flood water.
Other underpasses are low points within the network and are more likely to be at risk of
surface water flooding although 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 Park12

http://www.tfl.gov.uk/corporate/modesoftransport/1548.aspx

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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 Road
170. Highways flood management measures could include the provision of pumping
stations – they already exist for most underpasses – and possible improvements to theirflood resilience (e.g. back-up power supply) as well as flood warning systems anddiversionary routes.
Bus Depots
171. There are 76 bus garages13 serving London’s bus operators. Some of these arewithin 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.
172. Bus depot flood management measures could include green roofs, attenuation
measures, flood warning systems, as well as locating vulnerable equipment andpotentially polluting materials (e.g. fuel and oils) above potential flood levels. There aregood practice examples of green roofs at bus depots, such as at West Ham, where also
rainwater is captured for use in vehicle washing.
Airports
173. 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.
174. London City Airport is wholly within the floodplain of the tidal Thames. It is in anarea that is close to the Thames Barrier. It is protected by the existing flood defences toa standard of at least 1 in 1000 years.
Recommendation 11
Relevant transport authorities and operators should examine and regularly review theirinfrastructure including their networks, stations, depots, underpasses and tunnels forpotential flooding locations and flood risk reduction measures. For large stations anddepots, solutions should be sought to store or disperse rainwater from heavy storms.

13

http://londonbusesbyadam.zenfolio.com/london-bus-garages

London Regional Flood Risk Appraisal – First Review – August 2014
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3.6

Emergency Services

175. The London Resilience Partnership has published in May 2012 its London
Strategic Flood Framework. It is important for emergency services to remain operable
during major flood events. Localised flooding events should be able to be managed byother supporting 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 carried out an initial examination to identify whether
there are any potentially vulnerable concentrations of emergency service facilities withinflood risk areas.
Main Hospitals
176. NHS London data from May 2012 were used14 as basis for the investigation of
main hospitals. There are 15 hospitals at risk of tidal/fluvial and/or surface water floodrisk, see Map 8. The 8 hospitals in a flood zone are all upstream of the Thames Barrier
and therefore protected to a high standard in particular from tidal flooding. 4 of these
hospitals are in the floodplains of tributary rivers.
177. 12 hospitals are at risk of surface water flooding. 5 of them are also at risk offluvial/tidal flooding. Drain London has commissioned more detailed reviews. This work
is currently on-going but initial results indicate that they are generally able to manage
their risks at an acceptable level. For Edgware Hospital a detailed flood risk assessment
has already been undertaken and mitigation works necessary to ensure that the hospitalcan continue to operate in the event of a flood on the Silk Stream have been identified.
Fire Stations
178. Fire stations are likely to be important bases during flood events. Map 9 indicatesthat 26 fire stations from a total of 11215 within London (23%) are at risk of fluvial/tidal
and/or surface water flooding. The majority of these are in 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.
179. Drain London has identified 8 fire stations at risk of surface water flooding andhas commissioned more detailed reviews of those stations and their risks. The work iscurrently on-going and the results will be shared with London Fire Brigade.
Ambulance Stations
180. Map 9 also indicates that 13 of London’s 7016 ambulance stations (19%) are at
risk of fluvial/tidal and/or surface water flooding. The significant majority of these arein central/inner London Thames tidal floodplain and as such have a high degree offlood protection in particular from tidal flooding. They are also generally well coveredby other ambulance stations just outside the flood zone.
14‘Walk in Centres’ and ‘Minor Injury Units’ were excluded. The total number of hospitals is with 86
instead of 112 lower compared to the 2009 RFRA.
15
Data source – London Fire Brigade
16
Data source updated with London Ambulance Service, July 2013 - total of 63 stations only in 2009
RFRA.
London Regional Flood Risk Appraisal – First Review – August 2014
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181. Drain London is currently considering whether to commission more detailed
reviews of those stations specifically at risk of surface water flooding.
Police Stations
182. Map 9 also indicates that 23 of London’s 16717 police stations (14%) are at risk offluvial/tidal and/or surface water flooding. The majority of these are again incentral/inner London Thames tidal flood plain and as such have a high degree of flood
protection in particular from tidal flooding. They are also generally well covered byother police stations just outside the flood zone. The Metropolitan Police Service is in
the process of re-organising their estate through their Estate Strategy 2010 - 2014. Thisis likely to mean that some back office functions will be moved away from traditional
police stations. Care will be needed to ensure that this does not reduce the resilience ofthe service through a lack of back-up options that are at low flood risk.
183. Drain London is currently considering whether to commission more detailed
reviews of those stations specifically at risk of surface water flooding.
Prisons184. London has 9 prisons/detention centres. Only the collocated prisons Belmarsh, Isisand Thameside in Greenwich are at risk of flooding. They are within the tidal Thames
floodplain but currently protected to a standard of 1 in 1000 years by the existing flood
defences. Nevertheless, this presents particular challenges in the event of a flood as
issues of safety and security will arise. Therefore, detailed emergency plans should be inplace for the event of a flood.
Recommendation 12
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 flood risk areas are in place and regularly reviewed so that they can cope inthe event of a major flood. These plans should put in place cover arrangements throughother suitable facilities.
3.7

Schools

185. Schools need to serve their local population. Map 10 indicates that 445 of
London’s 3,14318 schools (14%) 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, for example within playing fields. The majority of schools affected are incentral/inner London part of the Thames tidal floodplain and as such have a highdegree of flood protection. However, a flood would represent a direct risk to the pupils
and staff at schools and would cause longer-term disruption whilst any repairs are
made. The analysis has examined public sector and private schools, further and higher

17

Figure updated by Metropolitan Police Service in April 2013 (includes premises open to the public
including Front Counters and Contact Points – total significantly lower than 2009 RFRA figure of 215
18‘Edubase’ database (Department of Education), Sept 2013 – total figure included in the 2009 RFRA
was lower with 3,064 schools.
London Regional Flood Risk Appraisal – First Review – August 2014
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education facilities, but not pre-schools and nurseries. Free schools represent the mostsignificant addition to the total number of schools included in the 2009 RFRA.
186. 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.
187. Drain London has examined secondary schools across London and has identified
21 secondary schools at highest risk of surface water flooding and has commissioned
more detailed reviews of those schools and their risks. The work is currently on-going
and will be shared with the schools/local education authorities.
Recommendation 13
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

188. This section covers a wide range of utility installations. Appendix 3 provides an
overview of known installations over 1000m2 and related to energy, water and waste
management as well as telecommunications that are at risk from fluvial/tidal flooding.
This should serve as a resource and initial input for the London boroughs to pursue theirown investigations into flood risk of their most important utilities. Map 11 provides a
spatial overview showing 448 sites at risk of flooding. As the underlying data set is not
up-to-date, this will require further investigation as part of the next review.
Major Electrical Installations
189. 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
have some energy generation capability and also has many switching and transformer
stations. Major installations are listed in Table 5.
Table 5: Electrical Installations in Floodplain
Installation
Brimsdown Power Station
Barking Power Station
Greenwich Power Station
Park Royal Power Station
Hayes Power Station
City Road Switching Station
St Johns Wood Switching Station
Croydon/Beddington Switching Station
Edmonton Waste to Energy
SELCHP Waste to Energy
Belvedere Waste to Energy

Flood Risk Zone
Adjacent to River Lee floodplain
Wholly within the Thames Tidal flood plain
Wholly within the Thames Tidal flood plain
Not within a flood zone
Not within a flood zone
Not within a flood zone
Not within a flood zone
Partially within River Wandle floodplain
Wholly within River Lee floodplain
Wholly within the Thames Tidal flood plain
Wholly within the Thames Tidal flood plain

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Major Gas Installations
190. 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
191. The nature of water and sewage treatment plants is that they are located close to
major rivers in order to abstract water from them and discharge sewage effluent tothem. It is therefore to be expected that these plants will have a certain level of floodrisk.
192. A significant flood at a water treatment plant could result in the contamination ofdrinking 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 means that water supplies can be flexibly managed andsupplies derived from several works, and given the geographical spread of the works aslisted in Table 6 they are unlikely all to be affected by one flood. In addition, the fourwater companies supplying London with drinking water all have operational plans tocope with flooding.
Table 6: Water Treatment Plants in Floodplain
Water treatment plant
HamptonCoppermills
Hornsey
Walton (outside London but supplying
parts of London)
Chigwell (outside London but
supplying parts of London)

Flood Risk Zone
Substantially within River Thames floodplain
Partially within River Lee floodplain
Not within a flood zone
Partially within River Thames floodplain
Not within a flood zone

193. Thames Water operates all the sewage treatment works included in Table 7 andhas 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 untreatedor partially treated sewage and effluent from the works. The operation of the works
may also be affected by ancillary power losses.
Table 7: Sewage Treatment Plants in Floodplain
Sewage Works
BecktonCrossness
MogdenRiverside
Deephams
Beddington Farm
Hogsmill

Flood Risk Zone
Wholly within the Thames Tidal flood plain
Wholly within the Thames Tidal flood plain
Not within a flood zone
Wholly within the Thames Tidal flood plain
Substantially within River Lee floodplain
Partially within River Wandle floodplain
Substantially within Hogsmill Brook
floodplain

London Regional Flood Risk Appraisal – First Review – August 2014
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Sewage Works
Luxborough Lane (outside London but
treats sewage from parts of London)
Long Reach (outside London but treats
sewage from parts of London)

Flood Risk Zone
Wholly within River Roding floodplain
Wholly within the Thames Tidal flood plain

194. In addition to the listed water treatment and sewage works there may also be
pumping stations and other installations that relate to water infrastructure (seeAppendix 3). There are also a number of pumping stations to manage surface water.
These are particularly relevant to low lying areas such as Thamesmead.
Waste Management Sites
195. Waste management sites are also included in Appendix 3. In addition, waste
licencing data from the Environment Agency have been used to generate a more
specific overview of the scale of flood risk of waste sites (see Table 8). The 105 sites
specifically identified by the Environment Agency for this purpose include operational
treatment plants plus a selection of other types of sites such as transfer stations andmetal recovery facilities. Almost half of the sites are at risk of flooding, and appropriate
mitigation measures include flood warning and emergency procedures.
Table 8: Waste Sites in Flood Risk Areas

Flood area

Number in
Flood area

NumberOutside Floodarea

Total Number
in Greater
LondonPortion in
Flood area

EA flood zone 2&3

45

60

105

43%

Drain London > 0.3m

10

95

105

10%

Combined flood area

49

56

105

47%

Recommendation 14
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 secondary
flood defences.
3.9

Other Sites

196. This RFRA is not intended to provide a comprehensive list of all vulnerable
infrastructure. Some of the other vulnerable land uses include nursing homes where thesafety and ability to evacuate residents may be difficult and council/benefits offices
where closure would have an immediate impact on the welfare of local communities,
particularly the most vulnerable. COMAH sites, petrol stations and other sources ofpollution are also particular risks as flood water may liberate and spread polluting
and/or dangerous substances that will have further impacts over and above the physicalimpacts of the flood waters.

London Regional Flood Risk Appraisal – First Review – August 2014
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Chapter 4 – Conclusions and Look Ahead
197. Flood Risk is a serious consideration for London. It is important that London’s
future is planned for and delivered in the fullest knowledge of flood risk and how it islikely to change in future. That knowledge is advancing rapidly and it will be importantto keep this RFRA under regular review.
198. This RFRA demonstrates that with the continued spatial focus on urban
concentration flood risk in London is not expected to increase significantly as aconsequence of the anticipated levels of growth. The better understanding of surface
water flood risk gained since 2009 provides a more robust baseline and opportunity tobetter monitor and manage flood risk from key sources of flooding.
199. The application of the relevant London Plan policies – in particular Policies 5.12
and 5.13 – will be required to sustainably manage flood risk through new development.
New development represents one of the key opportunities to reduce overall flood risk,
notably through improved management of surface water and allowing space for future
maintenance and upgrade of flood defences. The planning of the major development
locations and town centres, where the majority of the anticipated growth will belocated, which increases the potential consequences of flood events, will have toaddress flood risk in more detail. This RFRA provides an updated overview of broad
flood risk issues in each of these 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 and services this RFRA illustrates these risks spatially andidentifies mechanisms to investigate, monitor and address flood risk of current and new
infrastructure and services in cooperation with relevant partners.
200. 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 annually in the London Plan Annual Monitoring Report. Since thepublication of the 2009 RFRA progress against the original recommendations reflects inparticular the actions of Drain London in terms of the improved understanding of
surface water flood risk. It also confirms the improvements to local flood risk policies
based on completed Strategic Flood Risk Assessments (SFRAs).
201. Finally, it should be noted that the Mayor has recently published a long-term
London Infrastructure Plan 2050 for consultation. It addresses a wide range ofinfrastructure needs and challenges for London including drainage and flood risk. It
highlights, for example, the emerging Sustainable Drainage Action Plan and promotes
the idea of long-term (25 years) climate resilient, multi-source, flood risk management
and investment plans for each of London’s catchments covering all sources of flooding.
The Environment Agency would work through seven strategic Flood Risk Partnerships in
London to develop and monitor this long-term plan. It would integrate the actions
identified in the boroughs’, water companies’ and GLA’s flood risk and water
management plans. It would also identify synergies with planning policy, regeneration
and redevelopment19.

19

The draft London Infrastructure Plan 2050 and its background documents are available via
http://www.london.gov.uk/priorities/business-economy/vision-and-strategy/infrastructure-plan-2050

London Regional Flood Risk Appraisal – First Review – August 2014
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202. Appendix 1
List of Monitoring Recommendations
Recommendation 1
All Thames-side planning authorities should consider in their SFRAs and put in place
Local Plan policies to promote the setting back of development from the edge of theThames and tidal tributaries to enable sustainable and cost effective upgrade of riverwalls/embankments in line with Policy 5.12, CFMPs, TE2100 and advice from theEnvironment Agency.
Recommendation 2
The London Boroughs of Richmond, Kingston, Hounslow and Wandsworth should put inplace policies to ensure alternative responses to managing fluvial risk such as flood
resilience measures (e.g. flood gates) or potentially safeguarding land for future flood
storage or, on the fluvial tributaries, setting back local defences or any resiliencemeasures between Teddington Lock and Hammersmith Bridge in line with TE2100
findings.
Recommendation 3
The London Boroughs of Newham and Greenwich should work with the Environment
Agency on issues such as the potential safeguarding of potential land needs around theexisting Thames Barrier, and the London Borough of Bexley should work with theEnvironment Agency on future flood risk management options in line with TE2100
findings.
Recommendation 4
Boroughs at confluences of tributary rivers with the River Thames should ensure Flood
Risk Assessments (FRAs) include an assessment of the interaction of all forms offlooding, but fluvial and tidal flood risks in particular. These are the London Boroughsof Havering, Barking & Dagenham, Newham, Tower Hamlets, Greenwich, Lewisham,Wandsworth, Hounslow, Richmond and Kingston.
Recommendation 5
Regeneration and redevelopment of London’s fluvial river corridors offer a crucial
opportunity to reduce flood risk. SFRAs and policies should focus on making the mostof this opportunity through appropriate location, layout and design of development as
set out in the Thames CFMP. In particular opportunities should be sought to: Set back development from the river edge to enable sustainable and cost effective
flood risk management options
 Ensure that developments at residual flood risk are designed to be flood compatible
and/or flood resilient Maximise the use of open spaces within developments which have a residual floodrisk to make space for flood water.
Recommendation 6
Developments all across London should reduce surface water discharge in line with the
Sustainable Drainage Hierarchy set out in Policy 5.13 of the London Plan, the emerging
Sustainable Design and Construction SPG and the emerging London Sustainable
Drainage Action Plan.

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Recommendation 7
Thames Water should continue its programme of addressing foul sewer flooding.
Recommendation 8
The groundwater flood risk in identified locations (see IPEG map) should be consideredin FRAs and SFRAs to ensure that its impacts do not increase.
Recommendation 9
The reservoir flood risk in identified locations (see reservoir flood maps) should be inconsidered in FRAs and SFRAs to ensure its impacts do not increase.
Recommendation 10
Detailed flood risk assessments should be undertaken at an early stage at the level ofindividual major development locations and town centre development sites, andopportunities to reduce flood risk should be maximised where possible.
Recommendation 11
Relevant transport authorities and operators should examine and regularly review theirinfrastructure including their networks, stations, depots, underpasses and tunnels forpotential flooding locations and flood risk reduction measures. For large stations anddepots, solutions should be sought to store or disperse rainwater from heavy storms.
Recommendation 12
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 flood risk areas are in place and regularly reviewed so that they can cope inthe event of a major flood. These plans should put in place cover arrangements throughother suitable facilities.
Recommendation 13
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 14
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 secondary
flood defences.

London Regional Flood Risk Appraisal – First Review – August 2014
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Appendix 2
Glossary
CAZ
CFMP
EA
F&WM Act
FALP
FRA
GLA
IPEG
LB
LSFP
NPPF
PLA
PPG/PPS25
RFRA
SAB
SFRA
SHLAA
SUDS
SWMP
TE2100TfL
TLRN

Central Activities Zone
Catchment Flood Management Plan
Environment Agency
Flood and Water Management Act
Further Alteration to the London Plan
Flood Risk Assessment
Greater London Authority
Indicative Potential for Elevated Groundwater
London borough(s)London Strategic Flood Plan
National Planning Policy Framework
Port of London Authority
Planning Policy Guidance/Statement 25
Development and Flood Risk
Regional Flood Risk Appraisal
SUDS Approval Body
Strategic Flood Risk Assessment
Strategic Housing Land Availability Assessment
Sustainable Urban Drainage System
Surface Water Management PlanThames Estuary 2100 projectTransport for London
Transport for London Road Network

London Regional Flood Risk Appraisal – First Review – August 2014
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Appendix 3 - Utility Infrastructure within Flood Risk Zones

Barking & Dagenham
Barking & Dagenham
BarnetBexleyPost
Ref Street
Code
Merrielands
1 Crescent
RM9
2 Chequers Lane
RM9
3 Chequers Lane
RM9
4 Hindmans Way
RM9
5 River Road
IG11
6 Rewick Road
IG11
7 Barking Barrier East IG11
8 Kingsbridge Road IG11
west of Northern
Relief Road,
9 Barking
IG11
10 Hertford Road
IG11
0 None found
1 Belvedere Road
SE2

BexleyBexleyBexleyBexleyBexleyBexley

2
3
4
5
6
7

BexleyBexleyBexley8910Bexley11

Bexley12

BexleyBexleyBexleyBexleyBrent
Bromley
Bromley
Bromley
Bromley
Bromley

13
14
15
16
0
1
2
3
4
5

Bromley

6

Bromley

7

Bromley

8

Bromley

9

BoroughBarking & Dagenham
Barking & Dagenham
Barking & Dagenham
Barking & Dagenham
Barking & Dagenham
Barking & Dagenham
Barking & Dagenham
Barking & Dagenham

Norman Road
DA17
Norman Road
DA17
Yarnton Way
DA17
Station Road North DA17
Crabtree Manorway DA17
Viking Way
DA8West Street/Maxim
Road
DA8Slade Green Road DA8Hollywood Way
DA8Industrial estate,north of River Cray DA1South of Thames
Road
DA1
South of Thames
Road
DA1
Station Road
DA1
Weir Road
DA5Riverside Road
DA14
None found
Beck Lane
BR3
Kelsey Park Road BR3
Valley Road
BR2
Liddon Road
BR1
Coates Hill Road
BR1
Bridge Rd/Cray
AvenueBR5
Orpington HighStreetBR6
Tower
Road/Sevenoaks
RoadBR6
north of Sevenoaks
Road/A21
TN14

Type

Comment

unknown
Electricity
Fuel
Fuel
unknown
Electricity
Flood Defence
SewageBarking Power Station
Oil Storage Depot
Oil Storage Depot
Apparently disused site
former Power Station/sub station
Tidal barrier
Gascoigne Road Pumping Station

Drainage
Unknown

Pumping Station

SewageCrossness Sewage Treatment Works
Belvedere Sub station note Disused
Belvedere Power Station/proposed waste toenergy plant not included yet
Likely Fuel/gas use

Electricity
unknownGas
unknown
unknown
unknown

possible telecommunications

unknown
unknown
unknown

possible electricity
possible pumping station

unknown

possible waste/council depot

unknown
unknown
Drainage
unknown
Water

Pumping Station
Pumping Station and covered reservoir

Council
unknown
DrainageGas
unknown

Council Depot
possible telecommunications
Pumping Station

Electricity

Sub station

Post

Sorting Office

Drainage

Pumping station

unknown

possible drainage use

possible telecommunications

London Regional Flood Risk Appraisal – First Review – August 2014
page 60 of 66

Post
Ref Street
Code
0 None found0 None found
1 Godstone RoadCR8
2 Factory Road
CR0
3 Factory Road
CR0
1 Ruislip Road East W7
2 Warple Way
W3
1 Leeside RoadN18
2 Albany Road
N18
3 Bolton Road
N18
4 Balham RoadN9
5 Lee Park Way
N18
6 Picketts Lock Lane N9
7 Woodhall Road
EN3
8 Edison RoadEN3
9 Brancroft Way
EN3
Lee Valley
10 Reservoirs
EN3
11 Brancroft Way
EN3
12 Hadley RoadEN2
13 Station RoadN11
14 Dendridge Close
EN3
1 Borthwick Street
SE8
2 Stowage
SE8
3
Maze
Hill/Greenwich Park
4 Street
SE10
5 Boord Street
SE10
6 Barrier Approach
SE7
7 White Hart Road
SE18
Nathan8 Way/Eastern Way SE28
9 Nathan Way
SE28
10 Sewell RoadSE2
11 west of Wilton Road SE2
12 Thamesmere
SE28
13 Old Woolwich Rd SE10

BoroughCamdenCity
CroydonCroydonCroydonEalingEalingEnfield
Enfield
Enfield
Enfield
Enfield
Enfield
Enfield
Enfield
Enfield
Enfield
Enfield
Enfield
Enfield
Enfield
Greenwich
Greenwich
Greenwich
Greenwich
Greenwich
Greenwich
Greenwich
Greenwich
Greenwich
Greenwich
Greenwich
Greenwich
Greenwich
GreenwichHackney
Hackney
Hammersmith andFulhamHammersmith andFulhamHammersmith andFulhamHammersmith andFulham14 Greenwich High Rd SE10
1 Millfields Road
E5
2 Millfields Road
E5
west of Weltje
Road/great West
1 RoadW6
south of Riverside
2 Gardens
W634

Chancellor Road
north of Yeldham
Road

Type

unknown
Gas
Electricity
Drainage
SewageGas
Gas
unknown
unknown
Waste
SewageGas
Electricity
Electricity
Water
Electricity
DrainageGas
unknown
Electricity
Electricity

Telecomms
Gas
Flood Defence
unknown
Council officeCouncil depot
Electricity
unknown
Drainage
Electricity
Generation
Water
Electricity
Waste

Comment

Sub Station
Pumping Station
Acton Pumping Station

North London Waste to Energy
Deephams Sewage Treatment Works

Brimsdown Power Station
Reservoirs including pumping stations
Sub Station
Pumping Station

Deptford Grid
Disused ?
DeletedTraining and exchange on upper
floorsThames Barrier
possible waste use

unknown
possible telecommunications
pumping station
Greenwich Power Station - Back up to
London Underground and gridThames Water Pumping Station

unknown
unknown

W6

unknown

W6

unknown

London Regional Flood Risk Appraisal – First Review – August 2014
page 61 of 66

BoroughHammersmith andFulhamHammersmith andFulhamHammersmith andFulhamHammersmith andFulhamHammersmith andFulhamHammersmith andFulhamHammersmith andFulhamHaringey
Haringey
Haringey
HarrowHarrow

Ref Street
south of Thaxton
5 Road

Post
Code

Type

W6

unknown

SW6

Post

6

Pulton Place

7

Peterborough Road SW6
Townmead Rd adj
Swedish Wharf
SW6south of Townmead
Rd, west of
superstore
SW6

8
9

unknown
unknown
unknown

SW6

Electricity
Gas
Electricity
Drainage
unknown
Electricity
unknown

Hillingdon
Hillingdon

Imperial Road
SW6
Leeside Road
N17
Marsh Lane
N17
Reform Row
N17
Wolverton Road
HA7
Canon Lane
HA5South of1 Coldharbour Lane RM13
2 Manor Way
RM13
Rainham Road opp
3 Dominion Way
RM13
4 Dagenham Road
RM13
5 South Street
RM1
6 Exchange Street
RM1
7 St Mary's Lane
RM14
Cortina Drive, off
8 Thames Avenue
RM9
9 Warley
CM14
Former Perry Oaks
1 Sewage Works
TW6
Bath Road adj Moor
2 Bridge
TW19
Bath Road adj
3 White Hart Pub
TW6
North Hyde4 Gardens
UB3
north of Charvill Rd
5 south of A40
UB10
east of Tavistock
6 RoadUB10
7 Cowley Mill Road UB88 Waterloo Road
UB8
west of Springwell
9 LaneWD3
10 Slough Road
SL0

Hillingdon
Hounslow
Hounslow

11 Maple Lodge Close WD3
1 Heathfield Terrace W42 Sutton Court Road W4

Sewageunknown
unknown

Havering
Havering
Havering
Havering
Havering
Havering
Havering
Havering
Havering
Hillingdon
Hillingdon
Hillingdon
Hillingdon
Hillingdon
Hillingdon
Hillingdon
Hillingdon

10 Townmead Road
11
1
2
3
1
2

Comment

Pumping Station

not the disused gas works

unknown
Sewageappears to be Tilda Rice plantRiverside Sewage Treatment Works

unknown
Drainage
Unknown
Electricity
Sewagepossible telecommunications
Pumping Station
opp Gloucester Road
Sewage Treatment Works Anglian Water

unknown
SewageSewage Treatment Works

Sewagenow disused

unknown

possible pumping station

Electricity
Electricity

sub station

unknown

possible waste use

unknown
Post
Electricity

possible waste use
Also former Gas use

unknown
Electricity

sub station just outside London boundary
Maple Lodge Sewage Treatment Works justoutside London boundary

London Regional Flood Risk Appraisal – First Review – August 2014
page 62 of 66

Borough
Hounslow
Islington
Kensington and
Chelsea

Ref Street
North of Kew
3 Bridge Road
0 None found0

KingstonKingstonKingstonKingstonKingstonKingston

1
2
3
4
5
6

KingstonKingston
Lambeth7
8
1

LambethLewisham
Lewisham
Lewisham

2
1
2
3

Lewisham
Lewisham
Lewisham
Lewisham
Lewisham
Lewisham
Lewisham
LewishamMertonMertonNewhamNewhamNewhamNewhamNewham

4
5
6
7
8
9
10
11
1
2
1
2
3
4
5

Newham6

NewhamNewhamNewhamNewhamNewham

7
8
9
10
11

NewhamNewham12
13

None foundnorth of Kingshill
AvenueLower Marsh Lane
Dawson Road
Ashdown Road
Downhall Road
Skerne Road
Portsmouth Road
opp Grove Road
Portsmouth Road
Vauxhall Street
Kennington Park
Road/Kennington
Way
Chilton Grove
Landmann Way
Copperas Street
Brookmill Road,
opp Stricland St
Beck Close
Armoury Road
Engate Street
Canadian Avenue
Barmeston Road
Callander Road
Selworthy Road
Bye Grove Road
Plough Lane
Jupp Road
Abbey Lane
Abbey Lane
Abbey Lane
Channelsea Island
Crows
Road/CanningRoad
Twelvetrees
Crescent
Stephenson Street
Cody Road
Western Gateway
Coolfin Road
south of North
Woolwich Road
Connaught Road

Post
Code

Type

TW8

unknown

KT17
KT1
KT1
KT1
KT2
KT2

Gas
SewagePost
unknown
Electricity
Gas

KT5
KT5
SE11

unknown
Water
Gas

SE11
SE16
SE14
SE8

unknown
unknown
Waste
unknown

SE8
SE13
SE13
SE13
SE6
SE6
SE6
SE6
SW19
SW17
E15
E15
E15
E15
E15

unknown
unknown
Electricity
unknown
unknown
unknown
unknown
unknown
SewageElectricity
unknown
Gas
Post
Sewageunknown

possible Council Depot

E15

unknown

Apparently disused site

E3
E16
E16
E16
E16

Gas
Post
Electricity
unknown
unknown

Bromley By Bow Gas Works

E16
E16

Flood DefenceElectricity

Thames Barrier

Comment

Motspur Park
Hogsmill Sewage Treatment Works
Sorting Office
Sub station

Seething Wells filter beds
Kennington Gas Works

SELCHP

possible Post use
possible disused sewage site
operational sewage site
Sub Station
possible telecommunications

Abbey Mills Pumping Station
Apparently disused site

Possible Jubilee Line Vent Shaft

London Regional Flood Risk Appraisal – First Review – August 2014
page 63 of 66

Borough
NewhamNewhamNewhamNewhamNewhamNewhamNewhamNewhamNewhamNewhamNewhamNewhamNewhamNewhamRedbridge
Redbridge
Redbridge
Redbridge
Redbridge
Richmond
Richmond
Richmond
SouthwarkSouthwarkSouthwarkSouthwarkSouthwarkSouthwark
SuttonSuttonSuttonSuttonSutton

Post
Code

Type

E16

unknown

15 Factory Road
E16
Woolwich Manor
Way adj Royal
16 Victoria Gdns
E16
Gallions
17 Roundabout
E16
18 Gallions Road
E16
east of Royal Docks
19 RoadE6
20 Alpine Way
E6
Woolwich Manor
Way east of Alpine
21 WayE6
Northern Outfall
22 SewerE6
23 Jenkins Lane
IG11

Drainage

Pumping Station also add adjacent satellite
station as a new site

Drainage

Pumping Station

Drainage
unknown

Pumping StationGas
unknown

Beckton Gas Works

Drainage

Pumping Station

SewageSewage24 Jenkins Lane
IG11
25 Watson Avenue
E6
26 Grantham Road
E12
Barking Barrier
27 West
IG11
Cranbrook
1 Road/The Drive
IG1
2 Royston Gardens IG1
Redbridge Lane
3 WestE11
4 Roding Lane South IG4
5 Snakes Lane East IG8
1 Mellis Avenue
TW9
Mortlake high
2 Street
SW14
Lower Sunbury
3 RoadTW12
1 Old Kent Road
SE15
2 Verney Road
SE16
LyntonRoad/Monnow
3 RoadSE17
4 Dockley RoadSE16
5 Salter RoadSE16
6 Hatfields
SE1
1 Beddington Lane CR0
2 Beddington Lane SM6
3 Water Mead Lane SM5
4 Buckhurst Avenue SM5

Waste
Gas
Electricity

apparently part of NOS
Beckton Sewage Treatment Works
waste Transfer Station and possible Council
Depot

5

unknown

Ref Street
Royal Albert Way
south of Beckton
14 Park DLR

Grove Road

SM1

Flood Defence

Comment

Also former Gas use
Tidal barrier

Telecommunications
Drainage
Pumping Station
unknown
Electricity
Gas
SewageSub Station
Biothane Plant

Electricity

Sub Station

Water
Gas
Electricity

Treatment Plant
South Eastern Gas Works
sub station

Telecommunications
Post
Gas
unknown
Electricity
Switching Station
SewageBeddington Sewage Treatment Works
unknown
possible sewage use
unknown
possible pumping station

possible post use

London Regional Flood Risk Appraisal – First Review – August 2014
page 64 of 66

Waltham Forest
Wandsworth
Wandsworth
Wandsworth
Wandsworth
Wandsworth
Wandsworth

Post
Ref Street
Code
6 Crown Road
SM1
7 Green Lane
KT4
1 Three Colt Street E14
2 Ontario Way
E14West India Dock
3 RoadE14
4 Castor Lane
E14
5 Watts Grove
E3
6 Leven Road
E14
7 Aspen Way
E14
8 Law Street
E14
9 Yabsley Street
E14
10 Stewart Street
E14
1 Westdown RoadE15
2 Osier Way
E10
3 Clementina Road E10
4 South Access Road E17
5 Coppermill Lane
E17South of Lockwood
6 Reservoir
E17
west of Chingford
7 RoadE4
8 May RoadE4
9 Harbert RoadE4
Lee Valley
10 Reservoirs
E4
1 Longmead Road
SW17
2 Lynden Grove
SW18
3 Mapleton RoadSW18
4 Morie Street
SW18
5 Armoury Way
SW18
6 The Causeway
SW18

Wandsworth
Wandsworth

7
8

Borough
SuttonSuttonTower Hamlets
Tower Hamlets
Tower Hamlets
Tower Hamlets
Tower Hamlets
Tower Hamlets
Tower Hamlets
Tower Hamlets
Tower Hamlets
Tower Hamlets
Waltham Forest
Waltham Forest
Waltham Forest
Waltham Forest
Waltham Forest
Waltham Forest
Waltham Forest
Waltham Forest
Waltham Forest

Type
Gas
unknown
unknown
unknown

Comment

unknown
Electricity
unknown
Gas
Vent Shaft
Vent Shaft
Waste
Drainage
unknown
SewageGas
Council Depot
Waterpossible police use

Water

Pumping Station

Electricity
unknown
Water

Pumping Station

Water
unknown
unknown
Electricity
unknown
Gas
Electricity

possible telecommunications

Blackwall Tunnel
Blackwall Tunnel
Northumberland Wharf
Pumping Station
Auckland Road Pumping Station

Coppermills Waterworks

Reservoirs

SW18
SW11

Waste
unknown

Riverside Waste Transfer Station and Council
Depot
Possible Aggregates Depot

SW11

unknown

Within York Gardens

Wandsworth
Wandsworth
Wandsworth

Smugglers Way
Paveley Drive
York Road/Plough
9 RoadPrince of Wales
10 Drive
11 Kirtling Street
12 Stewarts Road

SW8
SW8
SW8

Westminster
Westminster
Westminster

1
2
3

SW1
SW1
SW1

Gas
unknown
Telecommunications
Former Grosvenor Dock waste transfer
unknown
stationunknown
unknown

Wandsworth

Gatliff Road
Ebury Bridge
Francis Street

Source: Cities Revealed Land Use, 2003 – including comments from GLA, 2009, and updates from the London
Boroughs of Richmond and Havering, 2014

London Regional Flood Risk Appraisal – First Review – August 2014
page 65 of 66

Appendix 4
Comparison of Flood Risk Data with 2009 RFRA
Flood Receptor at
risk
Flood Risk Area2009 RFRA (EA
Flood Zone risk)
23,279 ha
15 %
Mayor
OA: 10,345 ha
42 %Development
AoI: 155 ha
Locations24 %Town Centres
Major: 274 ha
26 % (total 980)
Metro: 89 ha
14 % (total 641)
Mainline Rail
Track: 115 km
14 %Network
Stations: 37
12%
Underground and Track: 87.5 km
19 %DLR Network
Stations: 72
24 %TfL Road Network 131 km
22 %Hospitals
8
7 % (total112)
Emergency
Amb 8
13 % (total 63)
Services
Fire 2119 %Police 44
20 % (total 215)
Schools385
13 % (total 3064)
Utilities
223
34 %2013 RFRA (EA
Flood Zone risk)
22,857 ha
14 %OA: 9,169 ha
37 %AoI: 109 ha
28 %Major: 230 ha
24 % (1048)
Metro: 98 ha
13 %(total 739)
Track: 110 km
14 %Stations: 37
11%
Track: 89 km
20 %Stations: 71
24 %126 km22 %
89 % (total 86)
Amb 13
19 % (total 70)
Fire 20
18%
Police 21
13 % (total 167)399
13 % (total 3143)
223
34 %

London Regional Flood Risk Appraisal – First Review – August 2014
page 66 of 66

2013 RFRA (EA
and DL flood risk)
25,802 ha
16 %OA: 9,502 ha
39 %AoI: 125 ha
32 %Major: 275 ha
28 %Metro: 133 ha
18 %Track: 217 km
27 %Stations: 76
23%
Track: 123 km
27 %Stations: 90
30 %150 km26 %15
18 %Amb 1319 %Fire 26
23 %Police 23
14 %
445
14 %
448
68 %