Download London Councils TEC (Executive)

London Councils’ TEC Executive Sub
Committee
Thames Estuary 2100 – Developing a Item no: 3
Flood Management Plan for London
and the Thames Estuary
Report by:
Michael Ojo
Date:
15 November 2007
Contact Officer:
Michael Ojo
Telephone:
020 7934 9945
Summary
Job title:
Email:
Section Manager, Environment & Public
Realm
[email protected]
The strategic aim of the Thames Estuary 2100 (TE2100) project is to
develop a flood management plan for London and the Thames estuary
that is risk based, takes account of existing and future assets, is
sustainable and inclusive, and addresses the issues in the context of a
changing climate and varying socio-economic scenarios that may develop
over the next 100 years. The need for London to adapt to the impacts of
climate change, and specifically to the increased risk of multisource
flooding means authorities now need the most up to date information and
modelling to make decisions about spatial planning and flood
management investment. The project has recently completed Phase 2 of
a 4-phase programme and the Environment Agency is consulting further,
ahead of the development of the Phase 3 ‘Interim Plan’.
Recommendations
Members are recommended to:

Note the Environment Agency’s ongoing work in developing the
TE2100 project;

Note the key findings of the earlier phases of the project;

Agree to receive further updates on the project as it develops
including a further presentation on the ‘Final Plan’ towards the end
of 2009.
Thames Estuary 2100
TEC Executive Sub Committee - 15 November 2007
Agenda Item 3, Page 1
Background
1.
Thames Estuary 2100 is an Environment Agency initiative, involving the Thames, Southern
and Anglian Regions, to develop a flood risk management plan for the Tidal Thames,
covering the tidal flood plain from Teddington in the West to Sheerness/Shoeburyness in the
East. The project is being delivered within the context of the Government’s strategy for flood
risk management - ‘Making Space for Water’. The final project output, the ‘Final Plan’ will
recommend the actions that need to be taken to manage the increasing flood risk in the
estuary over the next 100 years.
The Need for Action
2.
Flood risk is increasing in the Thames estuary due to a number of factors:



Sea levels are rising due to the oceans warming up;
Climate change is likely to increase the intensity of any storm surges in the North Sea the greatest threat to London and the estuary communities. Climate change is also likely
to raise the levels of freshwater flowing down into the estuary in, increasingly wet, winter
months;
Increasing pressure from development in the defended tidal flood plain will place more
properties in an area of risk.
3.
Although the Thames estuary is currently defended to a very high standard - in any year
protecting against water levels that on average might occur only once in two thousand years
– this standard is gradually diminishing due to rising sea levels and climate change.
4.
Initial understanding of the protection afforded by the tidal defences was that by 2030 the
standard of protection would have dropped to a one in 1000 years annual average chance of
a flood occurring, which is the design standard of the current tidal defence system. Although
the tidal defences, including the Thames Barrier, would continue to provide an excellent
standard of protection beyond that date, TE2100 was commenced in order to have the next
generation of flood risk management measures planned and programmed before the risk
rose further.
The TE2100 Plan
5.
The “TE2100 Plan” takes into consideration the uncertainties that exist about the impacts of
climate change. It will set out what flood risk management measures will have to be
introduced, and when, over the next century. It will be flexible enough to take account of
accelerated climate change beyond current predictions, with an adaptable programme of
measures to manage the resulting risk.
6.
The final TE2100 Plan is proposed to include a fully integrated approach to flood risk
management. It will engage stakeholders in seeking flood management solutions which have
multiple benefits and provide best value for money. It will aim to provide the appropriate
level of flood risk reduction, but also deliver environmental and social benefits. The plan will
look at new ways of managing flood risk that are more sustainable than building forever
higher and higher walls, such as allowing some undeveloped areas to flood or store flood
waters thereby reducing water levels, and flood risk, elsewhere.
7.
TE2100 is considering flood risk not just in terms of reducing the probability of flooding, which
can be managed by flood defences, but also reducing the consequences of flooding in the
event of a flood. The Plan will describe a programme of flood management measures for the
Estuary which will include:
Thames Estuary 2100
TEC Executive Sub Committee - 15 November 2007
Agenda Item 3, Page 2




An investment programme of strategic flood management options covering short, medium
and long term time horizons to inform the development within government and elsewhere of
the business cases for flood management schemes and for planning strategic flood
management investment;
Practical guidance for decision-makers (at all tiers of government) and those living, working
and investing in the Thames tidal floodplain to enable informed decisions to be made on
managing the consequences of flooding, including the robust application of PPS25,
improved emergency planning and design for flood resilience and flood recovery;
A system of “opportunity banking”, which will enable areas which have good potential for
flood risk management or habitat creation, to be managed to accommodate flood storage
and change to existing management regimes;
A clear explanation of how the Plan is adaptable to the uncertainty of a changing future
environment – including the changing climate and varying socio- economic scenarios that
may develop over the next 100 years.
The Particular Challenges of London and the Thames Estuary
8.
The TE2100 strategy area includes much of Central London, and an estimated 54% of the
proposed Thames Gateway development. This is an area of high flood risk in terms of the
consequences of flooding, being low-lying, densely populated and of critical importance to
the economic well-being of the UK. It also contains areas of international conservation
importance, protected under EU Legislation.
9.
There is the particular challenge of devising and appraising a strategic plan for the Tidal
Thames because London is an economic entity far beyond the value of its property. Reinsurance capacity is now increasingly constrained and there is concern about the
aggregation of flood risk in the Thames Estuary. Also, London historically has flood defence
crest levels enshrined in legislation - which confers responsibilities on adjacent landowners
but potentially also rights in terms of flood risk management. These and other issues are
being considered in the development of the TE2100 Plan.
10.
The floodplains form a corridor which passes through London and eastwards to the sea. In
addition to the large number of people who live and/or work on the floodplains, there are vital
institutional and business centres and heritage sites. Theses include the Houses of
Parliament, central and local Government buildings, the Canary Wharf business district and a
large number of historic buildings and cultural centres. There are also major transport links
and numerous schools, hospitals and other key sites. The assets and people at risk are
summarised in Appendix 1.
Phases 1 and 2
11.
Phase 1 and 2 studies have examined the Thames estuary physical processes, the flood
defence assets, the area at risk of flooding and the pressures imposed on the estuary by the
principal drivers of flood risk including climate change. This comprehensive flood risk
assessment has provided a strategic understanding of current and future flood risk in the
Thames Estuary (primarily from tidal flooding – there is further work to do on tidal/fluvial
interaction and other sources of flooding).
12.
The flood risk management actions recommended by the outputs from these phases are
based on flood risk management policies agreed for management units in the tidal flood risk
area, and will be designed for implementation in partnership with local planning authorities,
landowners, local communities and other groups. The TE2100 Plan will also assist England
in fulfilling obligations under the Directives for EU Habitats & Birds, Strategic Environmental
Assessment and the Water Framework Directive.
Thames Estuary 2100
TEC Executive Sub Committee - 15 November 2007
Agenda Item 3, Page 3
13.
Based on characteristics of the estuary together with understanding of how the estuary works
(i.e. the social, environmental, and physical processes), these phases have defined 38
provisional flood risk Policy Management Units (PMUs) for the whole of the Plan area. Initial
flood management polices for each of these PMUs have been established and High Level
Options (HLOs) have been developed to deliver these policies.
14.
Four high level generic options have been developed using the HLOs as follows:




HLO 1: Improve the existing flood defence system including the Thames Barrier.
HLO 2: Maximise the flood management benefit of the floodplains.
HLO 3: New barrier (a gated structure which is open except when used to prevent
flooding).
HLO 4: New barrage (a partially closed structure which partially or fully closes the river,
changing the tidal characteristics significantly).
Within each of these options there are several sub-options, for example different locations for
new barriers and barrages. In addition, HLO3 is divided into two sub-options (3a and 3b)
depending on whether or not the Thames Barrier is retained.
15.
During Phase 3, the policies will be appraised, shaped and further developed through a
stakeholder consultation process. The options will then be modified accordingly as any
change in policy changes the design criteria for the options.
Next Steps
16.
Building on Phase 2 studies, the Phase 3 programme of consultation and further investigation
and appraisal of options will result in the production of a draft Plan in December 2008, with an
interim output in March 2008.
17.
Final input from climate change and other studies and a further series of stakeholder
consultations during Phase 4 will be completed in 2009 and in January 2010 the Final Plan
will be submitted to government for approval.
18.
Finalisation of the Final Plan during Phase 4 will include agreeing the details on
implementation arrangements for the plan. This may include preparation for public enquiry
and/or primary legislation to allow for staged implementation of the Plan.
Financial Implications for London Councils
19.
There are no financial implications for London Councils or the boroughs from this report.
Implications will be clearer as the project develops and the options for each PMU become
more defined.
Legal Implications for London Councils
20.
There are no legal implications for London Councils or the boroughs arising from this report.
Equalities Implications for London Councils
21.
There are no equalities implications for London Councils or the boroughs from this report.
Appendices
Appendix 1:
Assets and people at risk on the tidal Thames floodplains
Thames Estuary 2100
TEC Executive Sub Committee - 15 November 2007
Agenda Item 3, Page 4
APPENDIX 1 - Assets and people at risk on the tidal Thames floodplains

350 km2 land area

55 km2 designated habitat sites

1.25 million residents (plus commuters, tourists and other visitors)

500,000 homes

40,000 commercial and industrial properties

£160 billion property value

Key Government buildings including the Houses of Parliament

400 schools, 16 hospitals

City Airport

The Olympics site

4 World Heritage sites (Greenwich, Tower of London, Westminster, Kew Gardens)

Heritage and cultural sites including the Tate Modern and Tate Britain art galleries

1,100 km of railway lines, 30 mainline railway stations, 70 underground stations

1,300 km of main roads
Thames Estuary 2100
TEC Executive Sub Committee - 15 November 2007
Agenda Item 3, Page 5