City of Westminster
Local Flood Risk
Management Strategy
(2015-2021)
Consultation Draft April 2015.
Picture credit – Evening Standard
Contents
Executive Summary
Introduction
Local Flood Risk Strategy Objectives
Guiding Principles
Why are we doing this?
Geographical context
Background, legislative, policy and guidance context
Flood Risk Regulations
Stakeholders
Flood risk in Westminster
a. History of flooding
b. Sources of flood risk
c. Flooding from surface water run-off, groundwater and
sewers.
d. Flooding from canals, Water bodies and Water mains
10. surface water flood risk assessments
11. Flood Risk Mitigation and Funding
12. Flood risk asset management in Westminster
a. Recording and Maintaining Assets
b. Designation of assets
13. Flood Risk Investigation, Response and Recovery
14. Flood Risk Management through Planning
a. National planning Policy Framework
b. Westminster City Council policy
c. Basement Development in Westminster
15. Strategic Flood Risk Assessment
16. Westminster LFRMS Objectives and Action Plan 2015-2020
17 Funding Strategy
18 Monitoring and Review
19 Sustainable development and consistency with other strategies
20 Timetable and how to comment
Map 1 Surface Water flood Risk Map 1;100 year event for 1:2 year
rainfall event outside Westminster
Map 2 Areas susceptible to elevated groundwater
Map 3 Recorded incidents of sewer flooding in Westminster.
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Appendices
Appendix 1 Roles and responsibilities of organisations
Appendix 2 Local flood risk management strategy environmental report
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Executive Summary
Westminster was fortunate to avoid the national floods of 2007. However, after the 2007
floods, the Flood and Water Management Act 2010 was introduced providing legislation for
managing flood risk.
The Flood and Water Management Act 2010 gave the City Council new roles and
responsibilities. Westminster City Council was designated as a Lead Local Flood Authority
(LLFA), with a range of new risk management duties to assess, minimise, mitigate, manage
and monitor flood risk.
In our role as the LLFA, we are required to develop, maintain, apply and monitor a strategy
to manage surface water run-off and groundwater in Westminster. Westminster does not
contain any ordinary watercourses.
This Local Flood Risk Management Strategy (LFRMS) sets out how Westminster, in
partnership with other stakeholders will manage flood risk. It identifies where flood risk is
greatest in Westminster and the responsibilities stakeholders have to manage it. It also sets
out specific actions to reduce the risk of flooding in areas at greatest risk
These objectives and actions are
Its objectives are
To understand and explain the level of risk affecting
Westminster;
To understand the roles of partners, businesses and
residents in Westminster to manage flood risk.
To take a sustainable and holistic approach to flood risk
management; and
To provide an action plan for flood risk management in
the city
The LFRMS has been developed using evidence and analysis of flood risk, through
consultation, and assessment against environmental objectives and assessment sub-criteria.
Table 1 lists the Key Actions for 2015 to 2020 that will help meet the aims and objectives of
the LFRMS.
Table 1: Key Actions for 2015-2020
LFRMS 1 Actions: Tackling sources of flooding from highways
HIGH 1 Publication of most significant flood risk assets in Westminster
HIGH 2 Designation of significant flood risk assets to ensure that they are maintained.
HIGH 3 Manage and Maintain drainage assets
LFRMS 2: Tackling flood risk through planning and development
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DEV 1: Provide Technical advice and promote SUDS through planning and development
DEV 2:Develop flood risk policy to manage, mitigate and adapt to flood risk
DEV 3 Review and Revise Strategic Flood Risk Assessment, as new data becomes available, or
on a 6 yearly cycle, whichever is more appropriate.
DEV 4: Review and revise Local Flood Risk Management Strategy and Flood Risk Management
Plan on a 6 yearly cycle.
DEV 5- Use LFRMS to inform development of Local and Neighbourhood and development plans,
drainage management and maintenance plans and programming: contingency plans and asset
management plans
LFRMS 3 Tackling flood risk through Raising Awareness
AWARE 1 Modelling Surface Water Flood Risk
AWARE 2 Prepare Flood Risk Awareness Communications Plan
AWARE 3 Publish significant flood incident reports
AWARE 4 Publish significant flood risk asset register.
LFRMS 4 Tackling flood risk through Partnership working
PART 1: Work in partnership with other flood risk management authorities, stakeholders and
relevant departments to address flood when it happens, and ensure contingency plans is
appropriate.
PART 2: Work with Thames Water and other key stakeholders to mitigate and manage flood risk
from surface water and manhole surcharge in Westminster,
Part 3 :Organise, attend and participate in flood risk management meetings such as Drain
London/LoDeg, London Central North Flood Risk Group and Westminster City Council’s flood risk
management group
LFRMS 5:Flood Risk Management and Maintenance
RISK 1: Seek opportunities for Sustainable Drainage Systems across the city
RISK 2: Implementation of LFRMS and action plan
RISK 3 Identify and prioritise programme of flood risk management projects and funding for 20152020 and provide multiple benefits in terms of biodiversity, amenity, health and wellbeing.
The Flood and Water Management Act 2010 identifies the City Council, the Environment
Agency and Thames Water Utilities Limited as the major risk management authorities for
Westminster with new responsibilities.
Additionally, the following other stakeholders have also been identified as key stakeholders
in Westminster.
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Residents and businesses
Greater London Authority/Transport for London
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Neighbouring London Boroughs
Network Rail
Canal and River Trust.
These key stakeholders and the public will be consulted on the draft strategy and comments
received will be considered when finalising the strategy.
The Strategy is a ‘living’ document, and will evolve as new evidence is produced and
understanding increases. The action plan will be monitored and reviewed annually as part of
the annual monitoring report and will be fully reviewed every 6 years.
Environmental assessment of the strategic objectives and actions are presented in the
Environmental Report (Appendix 2). Significant beneficial effects on implementation of the
strategy are
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Improved flood risk management for local residents, businesses, workers and
recreational users, and tourists and reduced flood risk to critical infrastructure.
Encourages partnership working
Improves understanding, preparedness and response and recovery from flooding
and potentially reduce fear of the flooding.
Provides opportunities to deliver wider environmental and social benefits in terms of
biodiversitiy, amenity etc.
Although it is uncertain what impacts new flood risk management schemes will have on the
historic environment or townscape and public realm, until detailed designs have been
completed
We are now consulting on the draft strategy and it is available online at
https://www.westminster.gov.uk/council-open-consultations
The strategy is available for consultation from April 27th to June 5th 2015.
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1 Introduction
1.1 The Flood and Water Management Act 2010, gave the city council strategic
responsibility for managing flood risk from surface water, groundwater and ordinary
watercourses.
1.2 This Local Flood Risk Management Strategy (LFRMS) sets out how Westminster, in
partnership with other stakeholders will manage flood risk. It identifies where flood risk is
greatest in Westminster and the responsibilities stakeholders have to manage it. It also sets
out specific actions to reduce the risk of flooding in areas at greatest risk.
1.3 The work identified in this strategy will help to reduce flood risk but cannot stop floods
happening. All stakeholders will need to work together to reduce the likelihood of flooding
and the impact of flooding if it were to happen. This is why it is important that all residents,
businesses and other institutions are aware of their roles and responsibilities (Appendix 1).
2 Local Flood Risk Management Strategy Objectives
2.1 The LFRMS objectives are
1. To understand and explain the level of risk affecting Westminster;
2. To understand the roles of partners, businesses and residents in Westminster to
manage flood risk.
3. To take a sustainable and holistic approach to flood risk management; and
4. To provide an action plan for flood risk management in the city
3 Guiding principles
3.1 The following guiding principles inform Westminster’s overall approach to managing
flood risk.
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Flooding is a natural event that will sometimes occur despite all efforts to prevent it. It
is important therefore, to focus on installing flood resistance and resilience measures.
Effective flood risk management can reduce long term flood damage costs and is a
worthwhile investment for both the public and private sector.
Decisions on where local resources will be focussed are evidence based
Improving knowledge and understanding of flood risk is vital for all
No single organisation can effectively manage flood risk alone, co-operation is
necessary from public and private sectors and residents.
Objectives have been set taking account of local knowledge, modelling and mapping
and evidence gathering, as set out in SFRA 2010, enhanced surface water flood risk
modelling, and calibrated sewer modelling of critical drainage hotspots in
Westminster 2014/15, along with the Westminster’s vision of a City for All,
Westminster City Council’s Strategic Policies and Integrated Impact Assessment It
also takes account of the need to integrate our role as a Lead Local Flood Authority
with our roles as Local Planning Authority, Highways Authority, Contingency
Planning, Asset Management and Policy, Performance and Communication
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4 Why are we doing this?
4.1 Westminster was fortunate to avoid the national floods of 2007. However, after the 2007
floods, the Flood and Water Management Act 2010 was introduced providing legislation for
managing flood risk.
4.2 The Flood and Water Management Act 2010 gave the City Council new roles and
responsibilities. Westminster City Council was designated as a Lead Local Flood Authority
(LLFA), with a range of new risk management duties to assess, minimise, mitigate, manage
and monitor flood risk.
4.3 In our role as the LLFA, we are required to develop, maintain, apply and monitor a
strategy to manage surface water run-off and groundwater in Westminster. Westminster
does not contain any ordinary watercourses.
4.4 A review of this strategy will take place by June 2020 in consultation with key
stakeholders. A fuller review, with public consultation will then take place on the National
Flood Risk Management Plan 2021. In the event of either a major flooding incident or a
significant change in legislation, the timing of this may be reviewed.
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5 Geographical Context
5.1 The City of Westminster is located in north London and covers approximately 21.5km2
(Map 1) . It sits between the London borough of Brent to the north, City of London and
London Borough of Camden to the east, the tidal Thames to the south and the Royal
Borough of Kensington and Chelsea to the west.
6 Background; Legislative, Policy and Guidance
International, National, Regional and Local Plans and Programmes
6.1 Relevant international, national, regional and local plans and programmes have been
identified and considered in the preparation of this strategy. The key relevant plans are listed
in Table 1 below and a full list of releveant plans and programmes can be found in the SEA
Environmental Report Appendix B.
Table 1 – Relevant Plans and programmes .
International
Floods Directive 2007/60/EC
Water Framework Directive 2000/60/EC
Groundwater Directive 2006/118/EC
Strategic Environmental Assessment (SEA) Directive 2001/42/EC
Habitats Directive 1992/43/EC
National
Flood and Water Management Act 2010
Flood Risk Regulations 2009
National flood and Coastal Erosion Management (FCERM) Strategy for England 2011 (EA&
DEFRA)
National Planning Policy Framework (NPPF) 2012 (DCLG)
Technical Guidance on National Planning Policy Framework 2012 (DCLG)
National Planning Practice Guidance 2013 to NPPF
Draft SUDs National Standards.
Regional
The London Plan 2011
The Mayor’s Water Strategy 2011
The Mayor’s Climate Change Adaptation Strategy 2011
Thames Estuary 2100 2012
Thames River Basin Management Plan 2009
Local
City of Westminster Strategic Flood Risk Assessment 2010
City of Westminster Preliminary Flood Risk Assessment 2011
Westminster City Plan – Strategic Policies 2014
6.2 The Floods Directive requires Member states to assess the risk of flooding and to identify
measures in place to reduce that risk. The Water Framework Directive requires protection of
water bodies, including the River Thames with the aim of achieving ‘good’ water quality
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status by 2015. The Groundwater Directive sets the framework for the protection and
conservation of groundwater. The SEA and Habitats Directive requires the assessment of
impacts of plans and programmes to identity their effects on the Environment and
Designated European sites.
6.3 Nationally, the Flood And Water Management Act (FWMA)2010 , designated the City of
Westminster as a Lead Local Flood Authority (LLFA), responsible for managing local flood
risk from surface water, groundwater and ordinary watercourses. The Environment Agency
retained responsibility for managing flood risk from the sea, main rivers and reservoirs.
6.4 LLFA’s duties include,
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Strategic management of local flood risk
Power to request information related to flood incidents and flood risk
to investigate and publish flood incident records
the designation of flood management assets and maintenance and publication of
flood risk asset register
powers to do works to manage surface water and ground water flood risk; and
the production of a Local Flood Risk Management Strategy.
6.5 Section 9 of the FWMA 2010 also requires LLFAs to
“develop, maintain, implement and monitor a strategy for local flood risk management in its
area covering surface water runoff, groundwater and ordinary water courses”. The strategy
must specify the following
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the risk management authorities in the area and their flood and coastal erosion risk
management functions
the assessment of flood risk
the objectives for managing local flood risk and measures to achieve those
objectives, including their implementation, cost and benefits and how they will be
paid for:
How and when the Strategy is to be reviewed, and how it contributes to the
achievement of wider environmental objectives.
6.6 The Strategy must be consistent with the Water Framework Directive ( UK Regulations
2003 ), the National Flood and Coastal Erosion Risk Management Strategy for England
(DEFRA 2011) and should be consulted on publically. Consistency with the national strategy
means consistency with the overall aims and objectives, in particular
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community focus and partnership working;
a catchment and coastal “cell” based approach;
sustainability ;
proportionate, risk based approaches (identify the highest risks and the priorities for
taking action);
multiple economic , environmental and social benefits; and
beneficiaries should be allowed and encouraged to invest in local flood risk
management.
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7 Flood Risk Regulations (FRR) 2009 4
7.1 The FRR imposed a duty to prepare and publish a series of flood risk documents
including a Preliminary Flood Risk Assessment, Flood Risk Maps and Flood Risk
Management Plans. The City Council has produced these documents in partnership with the
Environment Agency and Drain London.
7.2 The Strategy also needs to take account of the links with the Civil Contingency Act 2004,
which delivers a single framework for civil protection in the UK, and the planning system.
Through the planning system flood risk will be taken into account when development is
proposed, and from April 6 2015, where appropriate, the implementation of Sustainable
Drainage Solutions will be sought through development planning .
7.3 Other plans, strategies and documents taken into account when preparing this document
were
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WCC Strategic Flood Risk Assessment 2010
WCC enhanced surface flood risk modelling 2015
Framework to assist the development of the Local Strategy for Flood Risk
Management ‘ A living document’ ( Local Government Association 2011)
WCC Preliminary flood risk assessment 2011) ;
London Regional Flood Risk Appraisal First Review ( Greater London Authority 2014)
WCC draft Surface Water Management Plan 2011
Multiagency Flood Plan 2013
WCC strategic policies – City Plan 2013
National Planning Policy Framework 2010
7.4 Flood risk management is an environmental activity and the strategy needs to support
both local and national flood risk management plans and the need for sustainable
development and ensure that it satisfies the needs of today while making sure that future
generations can also look forward to the same quality of life.
7.5 It does this by considering key national plans such as the Water Framework Directive
and Strategic Environmental Assessment (SEA) Directive, as well as local plans such as
Integrated Impact Assessment (IIA). More information on these plans can be found in
Appendix 2 ( Local Flood Risk Management Strategy Environmental Report 2015 )
8 Stakeholders
8.1 The Flood and Water Management Act 2010 identifies the City Council, the Environment
Agency and Thames Water Utilities Limited as the major risk management authorities for
Westminster with new responsibilities.
8.2 Additionally, the following other stakeholders have also been identified:
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Residents and businesses
Greater London Authority/Transport for London
Neighbouring London Boroughs
Network Rail
Canal and River Trust.
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A list of key stakeholders and their roles and responsibilities can be found in Appendix 1
9 Flood Risk in Westminster
History of Flooding
9.1 No major flooding incidents have been recorded in Westminster in recent history.
However,
Westminster is at risk from a number of sources of flooding
Sources of Flood Risk
9.2 The most likely sources of flooding in Westminster are listed below
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Flooding from the River Thames
Flooding from surface water
Flooding from sewers
Flooding from groundwater
Flooding from canals, water features and water bodies
9.3 Flooding from the River Thames and from surface water has been identified as posing
the most likely risks in Westminster. This strategy takes account of the risk from surface
water, ground water, sewers, canals, water features and water bodies.
Flooding from Surface Water Runoff, groundwater and sewers
9.4 As a Lead Local Flood Authority we are tasked with managing flood risk from Surface
Water run-off (i.e. rainwater that is on the surface of the ground and has not entered the
watercourse, drainage system, or combined sewer), ground water or flooding from sewers
which are full be capacity due to heavy rainfall. Westminster does not contain or manage
any ordinary water courses. Map 1 shows a 1:100 surface water flood risk map for 1:2 year
rainfall event outside Westminster. Flood Risk Areas can be identified from this mapping
which was undertaken in March 2015.
9.5 The risk of groundwater flooding in Westminster is uncertain and more information is
required to improve understanding of it. Groundwater flooding occurs when the water table
rises to the ground surface and inundates low-lying areas. There are a number of
underground stations and basements that need to pump excess groundwater to prevent
flooding. The risk of groundwater flooding in Westminster is considered to be low, however,
Westminster sits above a chalk aquifer covered with gravels and clay. Chalk shows some of
the largest variations in groundwater levels and in low-lying areas this may be an issue in the
future. Deep basements in the city in some areas require continuous pumping of excess
groundwater. Areas susceptible to groundwater flooding are shown in Map 2 .
9.6 Sewer flooding and manhole surcharge are also possible sources of flooding in the city
which may be caused by excess surface water entering the drainage system after a heavy
downpour. Map 3 shows a map of recorded incidents of sewer flooding in Westminster.
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Map 1 Surface Water flood risk map March 2015
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Map 2 Areas susceptible to elevated groundwater.
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Map 3 Recorded Incidents of Sewer flooding in Westminster.
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Flooding from Canals, Water Bodies and Water Mains
9.6 In Westminster this type of flooding is most likely to result from burst mains from
infrastructure failure in an artificial watercourse or water bodies i.e. canals or other water
features.
9.7 There are a number of canals and water bodies in Westminster , these include
Paddington Branch of Grand Union Canal, including Paddington Basin and Little
Venice,
The Regent’s Canal
Serpentine Hyde Park
Regents Park Lake
St James’s Park Lake
Kensington Gardens Lake and
Five ‘hidden river’s ‘, the Westbourne, Tyburn, Tyburn Brook, Kilbourne and Long
Ditch.
9.8 As extreme rainfall events do not happen regularly but cause serious damage when they
do occur, it is essential to model the effect of such rainfall event on the city. This is
particularly important because climate change is predicted to increase the likelihood of major
rainfall events. However, it would be risky to rely totally on modelling, which is why it is
important that any significant flood events are fully investigated.
10 Westminster Surface Water Flood Risk Assessments
10.1 The surface water flood risk modelling process started with Drain London, the GLA
programme to improve understanding of surface water flood risk in Greater London, Drain
London helped to deliver Preliminary Flood Risk Assessments and Surface Water
Management Plans for each London Council. This process helped to provide a consistent
baseline across London. Subsequently, in 2014, Westminster commissioned WSP to
undertake an Initial Assessment of surface water flood risk in Westminster using a calibrated
Thames Water Sewer model. This study identified those areas most at risk from surface
water flooding and where we will need to focus our resources in the future. These are
Pimlico south,
Pimlico north and Victoria,
Marylebone and Mayfair,
Westbourne Grove,
West Kilburn, and
Maida Vale.
10.2 Identifying where the greatest risk of surface water flooding helps us focus our
approach to flood risk management in the city. Appendix 3
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10.3 This advanced enhanced modelling has provided the evidence base necessary to
secure funding for full Environment Agency Project Appraisal Reports for the whole of the
city.
11 Flood Risk Mitigation and Funding
11.1 Defra provides Grant in Aid for capital schemes through Partnership funding whereby
all flood risk mitigation schemes are offered a fixed subsidy based on the benefits delivered
by scheme. .
11.2 To access funding the Council must apply to the Environment Agency’s Thames
Regional Flood and Coastal Committee with programmes to improve understanding of flood
risk and schemes to reduce flood risk. The Initial Assessment of surface water flood risk
provides the evidence base for future Partnership funding applications to deliver flood risk
capital schemes.
11.3 The City Council has been allocated a provisional sum of money for capital schemes
should full project appraisal reports conclude they are feasible and economically viable. If
the partnership funding score is 100% no further contributions will be required and work can
commence. If, however, the partnership funding score is less that 100% external funding
from other stakeholders such as landowners, businesses and Thames Water, will need to be
sought.
11.4 Funding may also be sought from Thames Local Levy, which is a fund all local
authorities from the Thames Region pay into.
11.5 The purpose of the partnership funding model is to promote further private investment.
The scheme aims to encourage communities to take more responsibility for managing flood
risk and aims to deliver greater environmental benefit by encouraging total investment to
increase beyond the levels that DEFRA alone can afford.
11.6 Once funding has been secured and the business case has been developed, the City
Council will commission its contractors to undertake schemes.
12 Flood Risk Asset Management.
12.1 This section explains how Westminster will manage its flood risk assets through the
following activities
 Recording and maintaining assets
 Investigating and reporting flood incidents
Recording and maintaining assets
12.3 Flood Risk Assets are all structures or physical features that have an effect on flood risk
in the city, from reservoirs to highway gullies. The recording and maintenance of flood risk
assets is an important element of flood risk management because well maintained assets ,
such as drainage systems , ensure that water flows directly away from buildings and critical
infrastructure.
12.4 Well maintained assets cannot prevent flooding but they can lessen the impacts and
likelihood. Thames Water constructs sewers to a 1:30 flood event, when a rainfall event
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happens which is less probable than this , sewers are likely to overflow causing flooding.
Modelling has indicated that some areas in Westminster could see manhole surcharges for a
1:10 flood event. These are at particular risk of flooding.
Asset register and records
12.5 As the LLFA, Westminster is obliged to establish and maintain a register of structures
or features which are likely to have a significant effect on flood risk in the city. This must be
available to inspection at all reasonable times. Westminster must also produce a record
detailing the ownership and state of repair of each asset, which is not publically accessible.
12.6 The LLFA must determine the criteria for deeming an asset as have a significant effect.
In Westminster assets are deemed to be significant if it is:
 Of such a significant size that its failure could cause drainage problems on its own: or
 Located within an area considered to be at a relatively high probability of flood risk.
12.7 The register stating assets in the city will be published on our website and will be
updated annually with new assets and changes in ownership recorded. The record will be
shared with all the organisations which have contributed data to it.
Maintaining assets
12.8 Asset owners are responsible for maintaining their own assets. City Council flood risk
assets would be managed and maintained by its Infrastructure and Asset Management
Group.
Designation of assets
12.9 The City Council and the Environment Agency are the ‘designating ‘authorities for flood
risk assets. This is, the City Council may ‘designate’ features and structures as flood risk
assets. If an asset is designated, its owner cannot alter or remove it without first consulting
the designating authority. The aim of designating flood risk assets is to safeguard them
against unchecked works which could increase flood risk in the city. It is not possible to
designate assets owned by a risk management authority, such as Thames Water, although
this does not diminish their responsibilities for maintaining them as asset owners.
A process for designating assets will be designed in partnership with neighbouring
authorities to ensure that there is consistency across London.
13 Flood Incident Investigation, response and recovery.
Flood Incident Investigation
13.1 As the LLFA we have a responsibility to produce a flood investigation report for any
significant flood incidents.
The decision as to whether a flood event is significant or not is at the discretion of the LLFA,
current understanding is that the following two criteria should be met
 The incident resulted in internal flooding of a property: and/or
 If there is ambiguity surrounding the source or responsibility for the flood ( e.g. it is
unclear if it is a burst main)
13.2 Investigations will involve consultation with the relevant stakeholders, residents,
landowners and private organisations, all of whom have a duty to co-operate with the City
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Council and provide comments. A flood investigation report will be produced for any incident
and will be published as required by the Flood and Water Management Act 2010.
Reports will seek to provide a clear and thorough understanding of the flooding situation.
13.3 There is no obligation on any organisation to deliver flood defence or mitigation
schemes to residents or businesses that are at risk of flooding.
New developments need to be designed to be resilient to major flood events and new major
developments will be required to present site drainage management plans when submitting
a planning application. The Site Specific Sustainable Drainage Management plans will
undergo technical review by the LLFA, who will provide comments to the Local Planning
Authority. These comments will be taken into account as a material consideration when the
planning decision is made.
Responding to flood incidents
13.4 Flooding comes from different sources and has differing impacts depending on the
scale of the flood event. Given this, flood incidents are categorised as follows
 Ponding –this occurs after a heavy downpour and is characterised by puddles of
water on roads and footpaths that have neither drained nor evaporated. The water is
neither causing serious disruption nor threatening buildings or critical infrastructure.
 Disruptive flooding- this flooding impacts on peoples movements and ability to
carry out normal tasks by blocking roads or cordoning of flooded area, or is flowing at
such rates as to cause danger to people.
 Damaging or Dangerous flooding – This is flooding that enters buildings or critical
infrastructure causing damage or is flowing at such a rate as to cause serious danger
to people..
13.5 Preparation for responding to ‘damaging or dangerous’ flooding is part of the
emergency response planning and the multiagency flood plan, of which there are two main
elements , response and recovery.
Response to major flooding incident
13.6 The City Council’s Civil Contingency Team will work with local emergency services to
implement the Multiagency Flood Plan which provides a co-ordinated response to major
flood incidents to ensure rapid response and recovery and reduce impacts on people.
13.7 In the event of a major flood incident it is impossible for local emergency services to be
able to help everybody and it will prioritise preservation of life, and seek to help those more
vulnerable.
Recovery from major a flooding incident
13.8 The City Council will seek to begin recovery procedures as soon as possible after a
major flood incident. As flood water recedes, the emergency response may still be going on,
as the recovery phase is initiated. If it is a minor incident, recovery activities such as street
cleaning will for part of normal operations. If it is a severe flood it will require a co-ordinated
effort to determine local strategies in recovery, prioritising needs and allocating resources
appropriately so that the community returns to normality as soon as possible.
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14 Flood Risk Management through planning
14.1 It is vital for good flood risk management that new developments are safe from flood
risk and does not increase flood risk elsewhere. Planning policy is led by the City Council in
its role as the Local Planning Authority. The Lead Local Flood Authority advises the Local
Planning Authority on site specific flood risk assessments and sustainable drainage
management plans for major development sites and sites of > 1 hectare.
National Planning Policy Framework
14.2 The National Planning Policy Framework (NPPF) state that inappropriate development
in areas at risk of flooding should be avoided by directing development away from areas at
highest risk and, where development is necessary, it should be made safe without increasing
flood risk elsewhere.
Westminster City Plan: Strategic Policies 2013
14.3 Westminster City Plan ; Strategic Policy S30 Flood Risk identifies our approach to flood
risk management and seeks to ensure that all sources of flooding are taken into account and
that potential flood risk is reduced through mitigation measures. Relevant London Plan
Policies include Flood Risk (5.12) and Sustainable Urban Drainage (5.13 ”.
14.4 Implementation of Schedule 3 of the Flood and Water Management Act 2010 as of April
6th requires the submission of Sustainable Drainage Management Plans along with any
major planning application submitted to the Local Planning Authority. The Local Planning
Authority is then required to consult the Lead Local Flood Authority for Technical Advice on
the Sustainable Drainage Management Plan, and to take account of LLFA comments as a
material consideration when making a decision on the application.
Basement development policy in Westminster
14.5 Westminster’s adopted Basement Development in Westminster 6.3.6 states that
“ 6.3.1 Cellars and basements can be vulnerable to flooding. Such flooding can come from a
number of different sources, including overflowing drains and nearby watercourses,
groundwater flooding and surface water flooding.
6.3.2 It is important to establish whether there is a significant flood risk before deciding to go
ahead with an application for basement excavation or conversion and you should first
determine whether the application property is located in a flood risk zone or within a surface
water hotspot”. It would also help to consider if the basement is in an area susceptible to
groundwater flooding “ the construction of a basement under a garden may reduce the
infiltration capacity of the ground and could therefore result in additional surface water runoff from the site as well as reduce capacity of the ground to act as a store for rainwater.
Wherever possible, self-contained basement dwellings should be located outside of surface
water hotspots . If building a basement extension in any area prone to surface water flooding
steps should be taken to avoid increasing ( and where possible reduce) surface water flood
risk for the site and beyond. A number of sustainable drainage measures can be used to
reduce the surface water run-off from a site including rainwater tanks, permeable paving and
living roofs. Retrofitting of Sustainable Drainage systems will be encouraged where
appropriate. Applicants should also show they have had regard to the London Plan and
justification provided where this is not practical or appropriate
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6.3.7 In flood risk areas, where permeable surfacing and sustainable urban drainage
measures are recommended in the flood risk assessment or structural statement, the council
may secure their installation and retention by condition.
Sewer and groundwater flooding
6.3.8 Basements may be more susceptible to sewer flooding and this should also be
considered by the structural or civil engineer. As a minimum, it is recommended that all
drainage connections from basements to sewers should be fitted with a one way valve to
prevent drains flooding the basement if they surcharge. During periods where drains are
surcharged, the drainage system may not work. Basement designers should consider
installing pumped sewerage system to protect against this, particularly in areas where there
is an increased sewer food risk
6.3.9 Our technical evidence shows that most basement development is unlikely to impact
on, or be affected by groundwater flooding. However there may be an impact where the
basement floor level extends into or close to existing groundwater. Particular care is needed
in designing basements where:
 Basements extend through the gravels below the perched water table into the
underlying London Clay or which have their lower levels close to the level of Upper
Aquifer (within 300mm of it )
 Basements are in the vicinity of the historic routes of the Westbourne and Tyburn
Rivers and their tributaries.
 New basements proposed to existing houses with basements or lower ground floors,
where the existing perched water level is close to the lowest occupied area of
existing buildings
6.3.10 We will expect these issues to be assessed, monitored and addressed by the
structural engineer undertaking the basement design. However, it is often a combination
of the above types of flooding that leads to increased flood risk and the engineering
design should take account of the specific combinations of geo-hydrological conditions
on the site. This should be considered in the structural statement…”
“Flood Resistance and Resilience
6.3.11 In all basement development, applicants are encouraged to incorporate flood
resistance and resilience measures as part of the design. This includes measures to
prevent water ingress and to reduce flood damage should flooding occur. These may
include, for example, setting all thresholds to basements to be above the flood level and
incorporation of one way valves, incorporation on internal staircases and means of
escape and placement of electrical circuits to minimise potential for damage.”
Strategic Flood Risk Assessment
14.6 As a Local Planning Authority, the City Council is required to produce a Strategic Flood
Risk Assessment (SFRA) as the evidence based for the Local Plan. We produced an SFRA
that was published in 2010 and can be found at
http://www3.westminster.gov.uk/docstores/publications_store/SFRA_Final_Main_Report_Ma
y10.pdf .
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15 Westminster LFRMS Objectives and Actions 2015-2021
15.1 The Local Flood Risk Management Strategy objectives between 2015 and 2021are
To understand and explain the level of flood risk affecting Westminster
To highlight the actions that all partners, businesses and residents will need
to take to manage flood risk
To take a sustainable and holistic approach to flood risk management,
seeking to deliver wider environmental and social benefits
To provide an action plan to address particular areas at risk from surface
water flooding
15.2 The Actions identified to achieve these objectives are
Action LFRMS1 Tackling Flooding through highways management
HIGH 1 Publication of most significant flood risk assets in Westminster
HIGH 2 Designation of significant flood assets to ensure they are maintained
HIGH 3 Manage and Maintain Drainage Assets
Action LFRMS 2 Tackling flood risk through Planning and Development
DEV 1 Provide Technical Advice on SUDs through planning
DEV 2 Develop flood risk policy to manage, mitigate and adapt to flood risk
DEV 3 Review and revise Strategic Flood Risk Assessments, as new data
becomes available or on a 6 yearly cycle, whichever is more appropriate
DEV 4 Review and revise Local flood risk management Strategy and Flood
Risk Management plan on a 6 yearly cycle.
DEV 5 Use LFRMS to inform development of Local and Neighbourhood
Development Plans, Drainage management and Maintenance Plans and
programming; contingency plans and asset management plans.
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Action LFRMS 3 Tackling flood risk through improved understanding and raising
awareness
AWARE 1 Modelling Surface Water Flood Risk
AWARE 2 Prepare Flood Risk Awareness Communications Plan
AWARE 3 Investigate and publish significant flood incident reports
AWARE 4 Publish significant flood risk asset register.
Action LFRMS 4 Tackling flood risk through partnership working.
PART 1 Work in partnership with flood risk management authorities,
stakeholders and relevant departments to address flood when it happens, and to
ensure contingency plans are appropriate.
PART 2 Work with Thames Water and other key stakeholders to mitigate and
manage flood risk from surface water and manhole surcharge in Westminster,
PART 3 Organise, attend and participate in flood risk management meetings
such as Drain London/LoDeg, London Central North Flood Risk Group, internal
Flood Risk Management Group,
Action LFRMS 5 Flood Risk Management and Maintenance
RISK 1 Seek opportunities for Sustainable Drainage Systems across the city.
RISK 2 Implementation of Local Flood Risk Strategy and Action Plan
RISK 3 Identify prioritised programme of flood risk management projects and
funding for 2015-2020 and provide multiple benefits in terms of biodiversity,
amenity, health and wellbeing.
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16 Funding Strategy
16.1 The main source of flood risk in Westminster is from surface water flooding and
possible interaction with sewer flooding leading to manhole surcharges in certain areas.
Therefore, any actions will focus on understanding, mitigating and managing the risk, and
increasing resilience and resistance to flood risk in the city.
16.2 Flood risk management funding is available both nationally and locally.
16.3 Nationally Defra provide a direct grant to Lead Local Flood Authorities.
16.4 Funding for technical advice on surface water drainage proposals has also been
allocated to Lead Local Flood Authorities to carry out their duties as a consultee on major
planning applications from April 16 2015.
16.5 Local flood risk funding is also allocated via the Thames Regional Flood and Coastal
Committee through Levy Funding and/ or through Environment Agency’s Flood Defence
Grant in Aid (FDGiA). These funds may be accessed by a bidding process in which the the
need for the project and a Cost Benefit Analysis of the project must demonstrate how it will
reduce the number of properties and people at risk of flooding.
16.6 Funding may also be allocated by Highways Authorities, Local Planning Authorities
Community Infrastructure Levy for public realm and flood risk projects benefiting more than
one sites, and section 106 funding for individual development sites if the need and the
relationship with developments is proven.
16.7 Opportunities will also be sought to find alternative sources of funding. Beneficiaries of
flood risk management schemes will be encouraged to invest in those schemes.
17 Monitoring and Review
17.1 Implementation of the strategy and action plan will be monitored reviewed. The results
will be reported in the Annual Monitoring Report produced by Westminster City Council.
18 Sustainability and links with other strategies and Frameworks
18.1 This document is consistent with the National Flood Risk Strategy’s overall aims and
objectives of






A community focus and partnership working
A catchment based approach
Sustainability
Proportionate, risk based ( actions prioritised for areas at highest risk)
Multiple economic, environmental and social benefits; and
Beneficiaries should be allowed and encouraged to invest in local flood risk
management.
18.2 The strategy also takes account of the Water Framework Directive, the Thames River
Basin Management Plan and the Local Flood Risk Strategy Strategic Environmental
Assessment (Appendix 2).
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18.3 It is clear when assessed against the LFRMS SEA objectives, that implementation of
the strategy will help achieve water quality as well as flood risk management objectives.
Given that the strategy will not impact on any designated European Designated Sites it was
concluded that a Habitat assessment was not required.
19 Timetable and how to comment
19.1 Comments are invited on this draft Local Flood Risk Strategy and its Environmental
Report by June 5th 2015.
Comments may be sent to D James, Westminster City Council.


Email – djames1@westminster.gov.uk
Post – D James , Infrastructure Asset Management Group
o 11th floor
o City Hall
o 64 Victoria Street
o SW1E 6QP
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Appendix 1
Stakeholder roles and responsibilities
Risk Management Authorities
The following organisations are recognised as Risk Management Authorities under the
FWMA 2010.
Lead Local Flood Authorities
The Environment Agency
Water Companies
Highways Authorities
Internal Drainage Boards (not applicable in Westminster)
District and County Councils ( not applicable in Westminster).
The key RMAs in Westminster are
City of Westminster
Environment Agency,
Thames Water and
Transport for London.
All RMA’s have the following duties and powers.
1) Duty to subject to scrutiny from lead local flood authorities’ democratic processes.
They can be called to account for their actions by the Culture and Environment
Scrutiny Committee
2) Duty to co-operate with other RMAs in the exercise of their flood and coastal
erosions risk management functions, including sharing flood risk management data;
3) Power to take on flood risk functions from another risk management authority when
agreed by both sides.
1 City of Westminster
The City of Westminster under the FWMA 2010 was designated as a Lead Local Flood
Authority for its administrative area.Thus Westminster has a strategic role in overseeing the
management of surface water and groundwater flood risk along with the following new
powers:



To do works to manage flood risk from surface water or groundwater:
To designate structures and features that affect flooding;
To request information from any person in connections with the authority’s flood and
coastal erosions risk management functions.
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It also gives LLFAs the following responsibilities
Strategic Leadership – bringing together stakeholders and leading on developing a
strategy to manage flood risk in the city.
Meeting flood risk regulations
Producing flood investigation reports
Maintaining register and records of assets
Designating assets
Recording flood incidents
Implementing SUDs through planning.
As well as these new roles, the City of Westminster has other longstanding responsibilities
which play and important role in flood risk management. These include:
Responsibilities as a planning authority
Responsibilities as a highways authority
Responsibilities for civil contingency planning
Responsibilities for parks and open spaces
Responsibilities for social housing.
2 Thames Water
Thames Water is responsible for supply and drainage of water in Westminster and has the
following flood risk management responsibilities to
Provide, maintain and operate systems of public sewers and works for the purpose of
effectively draining an area, including maintenance of all drains which serve more than one
property or which extend beyond the curtilage of the property.
Respond to flood incidents involving their assets.
Undertake capacity improvements to alleviate sewer flooding problems with priority being
given to frequent internal flooding problems.
Adopt all new lateral drains and sewers that are to connect to the public sewer from April
2013
Statutory consultee to LPA for Sustainable Drainage Management Plans for major
developments.
Maintain its reservoirs according to the standards of the reservoir act.
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Thames Water does not have responsibility for highways or land drainage until the surface
water enters the combined sewer network in Westminster, nor does it have responsibility for
drainage within a property or serving one property.
3 Environment Agency (EA)
The EA has a strategic role in flood risk management for England with responsibilities to
Publish a National Flood Risk Management Plan which provides a clear national
framework for all forms of flood risk management
Managing regional flood and coastal committees (RFCC) and support their decisions
in allocation funding for flood defence and flood resilience schemes
Review and supporting LLFAs
Providing data and information and tools to inform government policy and aid RMAs
in delivering their responsibilities.
Reporting and monitoring flood and coastal erosions risk management .
Operationally the EA focuses on flooding from main rivers and the sea, which includes the
Tidal Thames in Westminster. It also is a statutory consultees for all planning applications in
flood zone 3 and the enforcement authority for reservoirs greater than 10,000 m3
It also maintains and publishes a register of reservoirs.
4 Transport for London (TfL)
Transport for London is responsible for the Strategic Road Network in Westminster. It is
responsible for London Underground and gullies and culverts and for ensuring that these
assets do not cause flood risk. TfL are a RMA.
Other key stakeholders
5 Residents and businesses
It is the responsibility of residents and businesses to look after their homes and properties,
including protecting them from flooding. Which in some circumstances other organisations or
property owners may be liable due to neglect of their own responsibilities, although there will
be occasions where flooding happens despite all parties carrying out all of their duties and
responsibilities.
It is therefore suggested that residents and businesses at ground or basement level may
wish to consider
Flood insurance
Flood resistance and resilience measures
Prioritising what would be important to save at times of flooding
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Identify who can help them and who they can help in the event of a flood, or any
emergency; and
To make a flood plan (www.environment-agency.gov.uk) and prepare a flood kit.
Some areas have a higher risk of flooding than others and it is important that we help
businesses and residents understand that risk and consider protection measures, resistance
and resilience measures in preparation for a possible flood event.
Westminster will seek to deliver capital schemes to mitigate flood risk in areas identified with
the greatest risk.
6 Greater London Authority (GLA)
The GLA is not a LLFA and has no statutory role in flood risk management. However it
developed Drain London to improve knowledge of flood risk in London and helped
Westminster prepare its Preliminary Flood Risk Assessment and draft Surface Water
Management Plan as required by the Flood Risk Regulations.
The Drain London project provides quarterly meetings with London Councils and key
stakeholders to consider flood risk issues, plans and projects across the capital and to seek
to find ways for them to work together to minimise and mitigate flood risk.
7
Canal and River Trust
The Canal and River Trust, own the canals in Westminster and it is the responsibility of the
Canals and River Trust to ensure that no flooding occurs from canal networks.
8
Network Rail
Network Rail is responsible for the mainline stations in Westminster (Charing Cross, Victoria,
Paddington ???) . They manage the entire track including, cuttings, culverts, and tunnels
which can be essential to manage flood risk. They are not a RMA but have a responsibility
for ensuring that their assets are maintained and do not increase flood risk.
9
Neighbouring Councils
All of Westminster’s neighbouring boroughs are LLFAs. It is essential that we work in
partnership with our neighbours to ensure a catchment based approach to manage flood
risk. Westminster works with the North Central London Flood Risk group to ensure a
catchment approach.
Summary of Responsibilities
Responsibility
Increase
understanding of
flood risk
Fund and deliver
flood mitigation
schemes
Stakeholder
WCC
WCC/EA
WCC/TRFCC
Action
Flood investigation reports
Publish flood risk
management plan
Seek funding to prepare
Environment Agency Project
Appraisal Report for schemes
submitted for inclusion in the
Timeline
2015-2021
June 2015
Sept 2015
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Asset Register
All asset
owners
Report and
Respond to flood
incidents
All
stakeholders
Police, fire
bridgade,
ambulance
services, EA,
WCC, NHS,
Thames
Water ,
Canals and
River Trust
WCC
Take account of
flood risk through
planning
WCC/develo
pers
Thames Regional Flood and
Coastal Committee Medium
Term Plan for RFCC and
Grant in Aid Capital Funding.
Engage with businesses and
residents on potential flood
risk management schemes
Contribute to and seek
partnership funding for flood
mitigation schemes.
Register and publish flood
risk asset list.
Inspect, maintain and repair
own assets.
Maintain and improve flood
asset register
Flood incident reporting,
investigating and recording,
2015-2021
2015-2021
2015-2021
Attend Silver and Gold
meetings
Prepare, and implement a
Multiagency flood plan
Develop Planning policy to
manage flood risk in
Westminster.
Refresh Strategic Flood Risk
Assessment to inform flood
risk assessments.
Ensure all new Major
Applications have a
sustainable drainage
management plan agreed by
the Lead Local Flood
Authority and take account of
this as a material
consideration in making
planning decisions.
29