OPEN BOARD PAPER
ITEM No. 8
PAPER REF: EA (07) 64
MEETING DATE: 21 NOVEMBER 2007
PAPER BY: THE DIRECTOR OF WATER MANAGEMENT
SUBJECT: URBAN FLOOD MANAGEMENT AND WARNING: A STRATEGIC
1.1 This paper sets out a mechanism through
which strategic overview of urban flooding and quality assurance
of key processes supporting management of all inland flood risks
could be achieved.
1.2 Defra's Making Space for Water programme
promotes the Environment Agency as the sole body capable of taking
on the strategic overview of all inland flooding. This paper deals
with the elements of that role involving management of flooding
within the built environment.
1.3 We agree that there is a need for one
organisation to take a strategic overview, provided appropriate
powers and resources come with the new responsibilities, and that
Local Authority and utility company responsibilities are made
clear. We believe that the Environment Agency should be that organisation.
Defra, prior to the summer floods had gone out to consultation
on the Environment Agency taking such a strategic overview role.
1.4 Two key issues need to be addressed
in order to deliver effectively a strategic overview of urban
flooding. Firstly, there must be an assessment of risk posed by
all forms of flooding that is shared by all key operators. This
is critical to identify where risks are greatest and intervention
most urgent. Secondly, a common action-planning process that can
coordinate responses and investments across the broad range of
organisations involved, but which has sanctions to ensure compliance
and standards of output, needs to be agreed.
1.5 We do not seek a significant delivery
role, and see Local Authorities being best placed to co-ordinate
local planning and delivery. This is because:
they operate the planning systema
major lever in the management of the urban environment;
they are a key stakeholder;
the scale of response will be at
the local level; and
they represent the communities and
2.0 A SHARED
2.1 Under Planning Policy Statement PPS25
(and TAN15 in Wales), Strategic Flood Risk Assessments (SFRAs)
are required for all areas. They are currently variable in quality,
often not providing a good assessment of the risk from surface
water, sewer and other forms of flooding. This is principally
due to use of inappropriate methodology and lack of suitable data
and information on some forms of floodingeither because
it does not exist or it has not been provided by others, such
as water utility companies.
2.2 We propose that the Environment Agency
takes responsibility for developing an industry standard toolkit
of methods for preparing a SFRA that includes data and models
provided by water utility companies. The Environment Agency position
should be to object to Local Development Frameworks (LDFs) that
are not accompanied by a SFRA that is fit for purpose. We understand
that this approach is broadly supported by Communities and Local
Government (CLG) and Defra officials and representatives of Water
2.3 Water utility companies may need to
be compelled to share their data and models required to make a
proper assessment of the overall flood risk. We are exploring
how this might be achieved with Defra, CLG, Ofwat and Water UK.
3.1 The technical and practical challenges
of mapping where flooding from surface water, sewers, drains and
run-off may happen are much greater than for flooding from rivers
and the sea. To achieve an accurate result will rely substantially
on data, information and models being provided by water utility
companies, the Environment Agency, Local Authorities and others.
However, even with this data available, local conditions as seemingly
trivial as street furniture location, kerb height or new buildings
can have significant impact on local flow, depth and longevity
of urban flooding.
3.2 However a rapid, GIS-based national
topographic screening technique has been developed and tested
in four locations over the last two months by the Environment
Agency in partnership with the Met Office. It demonstrates that
it is possible to identify the most susceptible locations where
there is potential for surface water to collect and cause flooding
3.3 We are currently assessing the feasibility
and potential costs of applying this approach more widely to give
a rudimentary national picture of susceptibility to flooding from
extreme rainfall. But to be fully effective, such an approach
would need also to incorporate information about the drainage
infrastructure, overland flood routes and other routes water could
take. We see the Surface Water Management Plan (SWMP) as the driving
force to ensure these data are incorporated in locations where
the risk is greatest. The need for such plans would be identified
by Environment Agency Catchment Flood Management Plans (CFMPs)
which by 2009 will cover all of England. CFMPs in turn inform
SFRAs, which will trigger Surface Water Management Plans (SWMPs)
and local area action.
3.4 Early warning systems can help reduce
the impact of flooding, provided they trigger an effective response,
either by people or in key emergency response organisations, but
we are currently unable to provide meaningful warnings for imminent
surface water or sewer flooding.
3.5 It is difficult to predict accurately
where the heavy rainfall that would cause severe surface water
flooding will actually fall. While the current Meteorological
Office severe weather warnings are helpful in raising awareness,
the majority of areas issued with heavy rainfall warnings by the
Met Office in June and July 2007 did not experience the rainfall
3.6 We support early conclusions from the
summer floods that a form of warning service for surface water
flooding caused by very heavy rainfall should be available to
the public and our professional partners. However the difficulty
of achieving a high degree of accuracy of rainfall quantity, location,
timing and impact cannot be over estimated.
3.7 A joint Defra/Environment Agency study
considering the technical feasibility for such a system was completed
shortly after the summer 2007 floods. It concluded that a form
of warning service was technically feasible for flooding from
groundwater and very heavy rainfall, but it raised a number of
questions which are currently under further investigation, regarding
forecasting, surface water flooding, run-off in different rainfall
levels, and drainage infrastructure conditions.
3.8 Early proposals include a rudimentary
service that could provide an early warning of problem rainfall.
To be effective, such a system would rely on triggering different
stages in previously agreed emergency plans. The need for such
plans would be identified in the SWMP process and delivered as
part of Area Action Plans or our own flood warning plans. This
approach could offer a more effective response by professional
partners in highest risk areas, butin the short and medium
term at leastwould be subject to a much greater degree
of uncertainty than the current system for river and coastal flooding
3.9 It must be appreciated however, that
in order to provide warnings that give people at household, street
or community level the time required to take appropriate action,
much finer spatial scale weather forecasts will be required from
the Met Office. The case still has to be made that more precise
forecasts that could come with more computer power would provide
the level of resolution required, and translate into better warnings
of surface water flooding and result in effective action by people
and authorities. It is therefore unlikely that a household-level
warning system for flooding caused by run-off from heavy rainfall
will be practical in the near future.
3.10 To be effective, warnings would need
to be received by a more informed and aware public who are prepared
to take action, but who tolerate a high false alarm rate. The
challenges of effectively delivering such a system should not
be underestimated. For example despite substantial investment
over several years to promote it, only 41% of people are signed
up to our Flood Warning Direct service, and only around 75% of
those receiving a warning take appropriate action. In order to
be effective, significant effort to promote such schemes and the
expected response will be required.
4.1 PPS25 technical guidance allows for
the preparation of SWMPs in areas where urban drainage is a critical
problem. They are considered by CLG to be an important new planning
document that would become part of the Local Development Framework.
4.2 SWMPs are the mechanism by which stakeholders
should agree responsibility for different elements of urban flooding,
and the actions to tackle it. It is expected that they would inform
Local Government's Area Action Plans (an integral part of the
land use planning process), as well as the investment strategies
of the stakeholders involved. They represent the opportunity to
put in place the broad range of implementation tools which we
believe the summer floods identify as policy or operational gaps.
4.3 We propose that SWMPs are prepared by
Local Authorities. Locations where they are required would be
identified by the improved SFRA process, and through our own CFMPs
which are developed in discussions with Local Authorities and
other key stakeholders.
4.4 The Environment Agency's sanction would
be through objection to a Local Authority's Local Development
Framework if it were not accompanied by an appropriate SWMP.
5.1 It will need to be broadly accepted
that SFRAs should cover all forms of flooding and that water utilities
companies (and others) will be required to share data and models
to ensure they are fit for purpose. This could be achieved through
PPS25 technical guidance. A requirement for water companies to
share data and models could be delivered through Ofwat guidance
and PR09, the water price round.
5.2 For any sanction of objecting to a local
development framework to be effective, we will need support of
the planning inspectorate and the Secretary of State. It will
also need to be made clear that SFRAs and SWMPs must cover existing
as well as new development and that the intentions of PPS25 in
restricting new flood plain development are fulfilled.
5.3 Other quality control and monitoring
options could be considered through the extended role of the National
Audit Office given its ability to investigate Local Authority
activity, although we have not investigated this option fully
5.4 We believe that there is a clear and
logical extension to the existing system of flood management and
warning developed and operated by the Environment Agency. Flood
mapping, modelling and data analysis, coupled with risk assessments,
should be carried out or facilitated by the Environment Agency
where currently most expertise lies. Strategic plans, such as
CFMPs, inform the planning process and associated plans developed
by tiers of Local Authorities and would trigger planning and management
actions. The roles of other operators and their responsibilities
have to be made clear.
5.5 Flood warning in urban areas prone to
localised flooding remains difficult and further work is required
to establish whether technological advances both in rainfall forecasting
and in on-the-ground flow modelling pioneered by the Environment
Agency may make this possible.
6.1 The multi-agency approach to emergency
planning and management, established under the Civil Contingencies
Act, stood us in good stead during the flood emergency. We believe
these need little further development to focus on particular flood
6.2 The data, information and emergency
planning scenarios that operate through this framework will need
to change to reflect the risks posed by surface water and other
forms of flooding. An effective programme of surface water management
planning, supported by more comprehensive strategic flood risk
assessments should highlight areas where these risks need to be
managed, in part through more robust emergency planning and response.
Examples would be locations where extreme rainfall would result
in overland flood flows, the filling up of natural depressions
with rainwater, or the likely failure of drainage infrastructure.
6.3 Whist we expect the Environment Agency
would continue to provide authoritative information on flood risk
from all sources in the planning and emergency management phases,
we expect there to be a need for greater involvement by othersparticularly
water utility companies in providing core data, models and information
to support the Environment Agency's flood forecasting.
6.4 We do have concerns that the readiness
and responsiveness of key responders to warnings of potential
flooding could be improved. We would expect this to be tackled
through the current Cabinet Office/Defra Flood Emergencies Capability
Programme. This should be reinforced by a greater involvement
of the Environment Agency in helping ensure emergency plans are
fit for purpose. Joint exercises may help promote better understanding
of each responders' roles.
7.0 FUNDING AND
7.1 To be successful, the SWMP will require
effective influence over the investment and operational plans
of a range of organisations. Whilst the specifics will differ
between areas with different problems to be tackled, we expect
that the key organisations would include Local Authorities, water
utility companies (including sewerage undertakers), the Environment
Agency, the Highways Agency, Regional Development Agencies, developers
and major landowners (for example key non-governmental organisations,
the National Health Service, and the Ministry of Defence).
7.2 It will be important that the key players
in a particular location are involved in the planning process
from an early stage, and that the recommendations in the SWMP
can be delivered through changes to their respective activities.
In extreme cases this could include re-design and replacement
of sewer systems to higher standards, or changed management of
public green spaces to protect them as overland flood routes.
7.3 Funding and resource requirements to
deliver this approach will be a hurdle. The approach outlined
in this paper requires Local Authorities to take on a body of
work which has to date been given little attention, even though
the mechanisms for strategic plan production are in place. It
is estimated that each SWMP could cost between £50 and £150k.
The practical action then required on the ground could also give
rise to significant costs but these could be spread across the
Environment Agency, Local Authorities, developers, Regional Development
Agencies, water companies, the Highways Agency and others, depending
on location and response. Local Authorities would be expected
to coordinate these, given that other operators would need to
be made compliant through legislation or existing planning or
7.4 Costs could also be significant for
the Environment Agency. Developing and maintaining a toolkit of
flood risk assessment methods, and providing advice on their use
would require technical staff and investment in science and technology
to support it. We are carrying out work now to estimate the level
of resource such a duty would require.
8.1 The approach proposed would allow more
strategic management of inland flood risk, led by the Environment
Agency but in partnership with Local Authorities, water utility
companies and others. It locates operation in the hands of Local
Authorities and others, whilst giving the Environment Agency sanction
over quality and output through the land use planning system and
8.2 To be successful, the approach would
require Local Authorities to take flood risk management seriously,
and for it to be supported by Government as a fundamental part
of the planning system and its examination. It requires other
operators such as the utilities to share data, and take responsibility
for action. This in turn will require the support of regulators
and Government. It would also require significant investment in
better forecasting, more detailed urban flood mapping and a new
approach to flood warning. The Environment Agency is the lead
organisation in this area and would welcome the opportunity to
help Local Authorities and others develop this new approach.