Supplementary Memorandum submitted by
the Ministry of Agriculture, Fisheries and Food (F73)
A NOTE DESCRIBING PROGRESS
MADE IN THE ONGOING NATIONAL AUDIT OF FLOOD AND COASTAL DEFENCE
WORKS, INDICATING THE AREAS WHICH HAVE NOW BEEN AUDITED; THOSE
WHERE COMPLETE DATA SETS ARE NOT YET AVAILABLE, AND THE RESULTS
OF THE AUDIT TO DATE.
It is important that information is available
on the extent, adequacy and state of repair of flood and coastal
defence structures. Responsibility for keeping such information
up-to-date rests with the operating authorities.
As indicated in MAFF's original memorandum to
the Committee, in 1990-91 the Environment Agency's predecessor
organisation, the National Rivers Authority, carried out a Sea
Defence Survey (including tidal defences) which showed that
16 per cent of sea defences in England were in need of moderate
or significant repair, while a further 55 per cent showed some
signs of wear. In 1993 MAFF, on behalf of maritime district councils,
commissioned a Coast Protection Survey which showed that
41 per cent of coast protection works in England were in need
of significant or moderate work, whilst a further 47 per cent
showed some sign of wear. In both cases surveys were based on
visual inspection and assessment of the condition of the separate
elements of defences.
Together these surveys provided a valuable asset
register of the state of coastal defences and have in recent years
been used to guide investment. However such surveys give only
a snapshot in time; hence the results have been reviewed in subsequent
years. As indicated in MAFF's original memorandum, the reviews,
particularly in the case of coast protection frontages, have been
disappointing in that the net change has been one of deterioration.
MAFF has sought a report from local authorities of their plans
for those defences which are in the poorest state, with a view
to ensuring that those with high priority, including those which
protect large urban areas, are identified and provided for in
the capital programme.
Information on the state of river flood defences
is less comprehensive. The Environment Agency has available historical
information as a result of past surveys an flood records. In April
1997 it embarked on a visual survey carried out on a nationally
consistent basis—it is some half completed (completion is
targeted for April 2000). Where assets are in poor condition detailed
structural surveys will be carried out over the succeeding two
years. This information will be used to inform planning decisions,
capital investment, maintenance and flood warning improvements.
The Agency has not published the results of the surveys undertaken
to date.
A NOTE SUMMARISING HOW THE
CONCEPT OF SUSTAINABILITY IS IMPLEMENTED WITHIN MAFF'S FLOOD AND
COASTAL DEFENCE POLICY, IN TERMS OF SETTING OF TARGETS FOR OPERATING
AUTHORITIES
MAFF pays close attention to sustainability
in implementing flood and coastal defence policy. The policy aim
is:
"to reduce the risk to people and the developed
and natural environment from flooding and coastal erosion by encouraging
the provision of technically, environmentally and economically
sound and sustainable defence measures".
Flood and coastal defence works should be sustainable,
and based on an understanding of river and coastal processes.
By working with these processes as far as possible and avoiding
their disruption, except where important man made or natural assets
are at risk, the possibility of committing future generations
to inflexible and expensive options for defence should be minimised.
The requirement that works put forward by operating authorities
for MAFF grant aid should be technically sound, environmentally
acceptable and economically viable also assists in delivering
sustainability. These judgements—encompassing inter alia
the cost of maintaining the defences, the value of assets protected
and the means by which protection is achieved— are made
on a site specific basis. The aggregate outcome of the site specific
decisions is reflected at a programme level in the protection
of life, property and the natural environment, and is currently
measured by the number of houses, commercial properties and area
of land protected, and the aggregated benefit cost ratio (Table
1 of MAFF memorandum refers).
A relevant example of the need to understand
natural processes is the consideration of the impact of sea level
rise on flood and coastal defence decisions. MAFF has, on the
basis of the current best international understanding, specified
allowances for sea level rise for particular stretches of the
coastline. However it is not considered that the response to sea
level rise should be ever higher defences if this commits future
generations to unsustainable levels of investment. MAFF therefore
encourages the strategic consideration of alternative approaches
which take account of sea level rise, including managed realignment
of the coastline.
MAFF has published much relevant guidance to
operating authorities, including the Code of Practice on Environmental
Procedures for Flood Defence Operating Authorities which sets
out in some detail the means to achieve sustainability. MAFF has
also instituted a number of initiatives which assist in the achievement
of sustainability. Shoreline Management Plans provide a basis
for sustainable coastal defence policies within a sediment cell
and define objectives for the future management of the shoreline.
The plans also provide an opportunity for the consideration of
wider environmental objectives in the context of coastal processes
operating over a larger area. They are used to inform subsequent
decisions relating to coastal defence schemes and sectoral coastal
defence strategies, and will also inform the preparation of local
development plans.
Local Environment Agency Plans include a flood
defence strategy for the area concerned which will provide the
framework within which flood and coastal defence works can be
developed, taking account of wider environmental requirements.
They also provide an opportunity for addressing wider strategic
matters in relation to the water environment such as the need
to maintain viable areas and populations of habitats, species
and historic resources.
Water Level Management Plans which are prepared
by operating authorities in accordance with the MAFF/Welsh Office
procedural guide, provide a means by which the water level requirements
for a range of activities in a particular area, including agriculture,
flood defence and conservation, can be balanced and integrated.
They provide opportunities for the adoption of a strategic approach
to the management of flood defence and land drainage within a
hydrological unit and should be the central component of any local
operational plan.
AN ESTIMATE OF THE NUMBER
OF PEOPLE AT RISK FROM FLOODING ON THE EAST COAST OF ENGLAND
Definitive information on the population at
risk of flooding in England is not available, although it is estimated
some five per cent of the population live in the area at risk
of flooding by the sea. In order to refine this estimate of flood
risk, MAFF has carried out a further estimate of the flood risk
from sea flooding, not including estuarial flooding, in the Environment
Agency's Anglian region, based on the Agency's sea defence survey
database. The areas at risk from a one in 200 year tidal event,
on the assumption that no man made defences had been provided,
were examined. Some 36,000 properties and up to 90,000 persons
were shown to be at risk of flooding*[5].
As a result of investment in flood defences
over the years, the actual risk of flooding has been reduced significantly.
For some sites such as Mablethorpe to Skegness, investment has
reduced the risk of flooding in these more densely populated areas
to a standard which exceeds one in 200 years.
21 July 1998.
*
5 NB. The Agency's sea defence
survey database was available for use in the estimation. The assumptions
adopted probably led to an under estimate of the potential for
tidal flooding since data on flooding in areas such as the Wash
were incomplete. Back
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