FLOOD AND COASTAL DEFENCE
I. INTRODUCTION
1. If current projections for climatic change in
the UK and surrounding seas are accurate, in 200 to 300 years
time higher sea levels and increased rainfall may well have wrought
far-reaching, irrevocable change on patterns of flooding and coastal
erosion in England and Wales. In London[1],
the most immediate result will be the greatly increased dimensions
of the Thames, with the river threatening to drown part of Hammersmith
and the Victoria embankment in central London and the Greenwich
peninsula to the east, and to engulf large tracts of the lower
Thames valley. More than 125 km2 of the city will be
at risk of inundation. The Palace of Westminster and the sizeable
Docklands development will not be safe from the threat of catastrophic
flooding. It is almost certain that this increased threat will
have warranted the construction of new defences, and, for pedestrians
in central London, the Thames is likely to be partially obscured
by new embankments and river walls substantially raised above
their present levels. River front developments will have to be
set back almost a third of a kilometre from their existing positions,
fronted by artificial washlands created to contain the Thames
during autumn and winter. If these projections hold true, this
situation will not be confined to London: Cardiff, Swansea, Bristol,
Grimsby, Hull, Manchester and a clutch of other English and Welsh
conurbations will also witness the dramatic consequences of rising
sea and river levels[2],
providing conclusive proof of the unsustainability of imposing
human constraints on the natural cycle of flooding and erosion,
and the ebb and flow of land and sea.
2. For centuries, mankind has intervened with varying
degrees of success in these dynamic processes. That intervention
began with efforts to harness the natural productivity of flood-prone
river valleys and coastal plains, chiefly through drainage and
flood mitigation measures, and through the wholesale reclamation
of land for agriculture from marshes, fresh water habitats, and
the sea[3]. Over time,
these areas of coastal and riverine flood plain were settled,
and their range of land uses diversified considerably; for example,
low-lying land has proved attractive for both urban and industrial
development, and in England and Wales substantial investment has
been made in these areas, especially around estuaries. These new
land uses have demanded new and more sophisticated forms of protection
from fluvial and coastal erosion, and the adoption of so-called
'hard engineered' approaches to flood defence (that is, the use
of defence structures such as concrete return walls, gabions and
rock armour).
3. There have been many occasions over the last two
thousand years when inundation of populated areas at the coast
and further inland has provided salutary lessons of the dangers
of taking such natural processes for granted. In recent years
there have been serious floods at Towyn in North Wales, in 1990,
and inland floods in the English Midlands at Easter 1998. The
1953 east coast floods were the most devastating of such events
this century, and furnished graphic evidence of our inability
to fully understand, let alone control, their occurrence. Triggered
by a storm surge of unprecedented levels, after only nine hours
the entire length of the east coast sea defences of England were
either overtopped or breached[4].
Nationally, 300 lives were lost and the damage to property assets
and infrastructure in real terms is estimated at £5 billion[5].
In the aftermath of this catastrophe, an investigative interdepartmental
Committee, chaired by Viscount Waverley, was established to examine
the causes of the inundation and to propose means of reducing
the possibility of reoccurrence. One of its recommendations, to
raise sea defences to withstand storm surges equal to that of
1953, prompted change in inland and coastal flood protection legislation,
and encouraged a substantial building programme which underpins
the existing network of hard engineered defences on flood plains
and at the coast.
4. However, in spite of the introduction of these
defensive measures, the underlying natural processes of erosion
and deposition have remained fundamentally unaltered, albeit varying
in their location, effects and intensity. The depredations of
coastal erosion are particularly obvious on the vulnerable eastern
English coast, which is mostly composed of softer rocks and clay.
Archival and cartographic evidence indicates that the East Riding
of Yorkshire has suffered continual loss of land to the sea since
records began; a loss which at present amounts on average to 12
hectares of land a year. Similarly, county archives show that
Norfolk has lost 21 coastal towns and villages since the eleventh
century[6]. Indeed the
remorseless action of the tides and the inevitability of flooding
has recently prompted a reappraisal of the hard engineered strategy
towards flood and coastal defence, and the consideration of new
options, including 'managed realignment' of the coast and the
reinstatement in river catchments of 'washlands' - land whose
primary purpose is to store surface waters in the event of flooding.
5. In managed realignment, which is still largely
an experimental concept, coastal defences are dismantled and the
sea allowed to encroach inland to a predetermined 'set back' line.
This allows both the dissipation of the energy of waves and tides,
and long term adjustments of the shoreline to environmental change,
such as sea level rise. Such an approach might be suitable where
the long term provision of hard defences is economically and/or
environmentally unsustainable. Advocates of managed realignment
draw attention to the way in which this technique is consistent
with the natural cycles of accretion and erosion at the shoreline,
helping to liberate sand and sediment which will strengthen coastal
features, such as beaches, mudflats and sandbanks, further down
the coast, thus enhancing natural coastal defence. By contrast
its critics note that where ever land is lost, the economic well-being
or livelihood of individuals is jeopardised, unless such people
are properly compensated.
6. Irrespective of the means of achieving flood defence
and coast protection, the continued need for effective and efficient
policies was emphasised in written evidence by the Ministry of
Agriculture, Fisheries and Food (MAFF), which has overall responsibility
for this policy area. Five per cent of England's population live
in the 2,200 km2 of land most at risk of flooding from
the sea, while 10,000 km2 is jeopardised by flooding
from rivers[7]. Currently
in England and Wales, 1.3 million properties are classified as
being in flood risk areas[8].
Nationally, if there were no form of defence, the Ministry estimates
that the average annual value of damage from flooding and coastal
erosion in England and Wales would be of the order of £2.1
billion[9].
7. As we have indicated, the physical consequences
of flooding and coastal erosion are likely to become more pronounced
in future, placing these assets in greater danger. Several reasons
account for this increased risk. First, a significant proportion
of existing flood and coastal capital defence works will approach
the end of their operating life over the next decade[10].
Secondly, following the Government's estimate of the need for
4.4 million extra homes by 2016, there is likely to be growing
pressure on local authorities to permit development of flood plain
land for residential purposes; in their evidence to us, the Environment
Agency suggested that this might result in urban development in
England and Wales equal to four times the existing area of the
Birmingham conurbation[11].
Thirdly, the full effects of climatic change have still to be
felt.
8. Over the next 50 years, climatic change is likely
to be responsible for an estimated rise in sea levels in south
east England of approximately 6 millimetres a year. Elsewhere
around the English and Welsh coasts, the estimate for sea level
rise currently varies between 4 millimetres (Northumbria, the
north-west and the south-west) and 5 millimetres (Wales, Wessex
and Yorkshire) per annum[12].
In these regions, this rate of sea level rise may be exacerbated
by the natural downward tilt of land. The higher storm surges
and tidal peaks consequent on rising sea levels and the more unpredictable
meteorological conditions associated with climatic change mean
that even the most prestigious and effective defence measures,
such as London's Thames Barrier, will provide respite from the
potentially devastating effects of flooding only in the medium
term. Eventually, even the highest defensive barriers will be
overtopped. Climatic change will also impact on rainfall regimes.
In their evidence to us, the Meteorological Office noted that
by 2050, winter days with heavy rainfall will become typically
four to five times more common than at present. Coupled with greater
runoff from the continued expansion in urban land area, higher
precipitation levels are likely to increase the risk of inland
flooding in the first century of the next millennium[13].
9. Clearly therefore, the Government is confronted
with very considerable challenges in formulating effective national
policies on flood and coastal defence which begin to address these
long-term strategic needs, whilst also meeting more immediate
financial constraints. We are of the opinion that flood and
coastal defence policy cannot be sustained in the long term if
it continues to be founded on the practice of substantial human
intervention in the natural processes of flooding and erosion.
Indeed, it is of great concern to us that the legacy of flooding
and erosional problems arising from this practice - and the likely
increase in future of climatological and other environmental pressures
on the UK's ageing flood and coastal defence infrastructure -
might combine to present flood and coastal defence authorities
with insuperable difficulties.
10. Nonetheless, despite the demanding policy context,
we believe that the inherent challenges posed also provide very
considerable opportunities for securing the distinctive defensive
needs of the different regions of England and Wales into the next
century and beyond, and for enhancing and enriching the often
impoverished environmental condition of flood plains and intertidal
zones, while ensuring local and regional accountability is respected.
In this report, we recommend a package of planning, administrative
and financial measures which, we believe, will enable these goals
to be realised. A number of general principles have informed our
recommendation of these measures, as follows. The first of these
is our desire to overcome the widespread public culture which
is intolerant of the acceptance of naturally occurring and unavoidable
risk associated with flooding; even if forms of defence were introduced
which were far more sophisticated than those currently in operation,
there will inevitably continue to be some residual possibility
of flooding. The second is our belief that while strategic policy
on these issues is best taken at the national level, the implementation
of policy is best done at the regional level, rather than locally
or nationally; and the third is our conviction that the national
planning system must be reformed to accord greater importance
to flood and coastal defence priorities.
11. We have not attempted to specify the precise
form that administrative and institutional structures should take
in future, in order to achieve optimal delivery of national flood
and coastal defence policies. We believe such an aim would be
misguided anyway, as much of the precise institutional and organisational
detail is best determined through consultation among relevant
groups. Instead, we have drawn attention to what we believe to
be the inherent strengths, as well as the weaknesses and contradictions,
within the existing system.
12. In our press notice of 6 March 1998 setting out
the terms of reference for this inquiry, we asked for information
from interested parties on:
- the effectiveness of MAFF's current expenditure
and policy on flood and coastal defence in England, focusing upon
the efficiency of implementation of these policies through the
activities of organisations involved in the maintenance and operation
of existing flood and coastal defence strategies, including the
Environment Agency, maritime local authorities, internal drainage
boards and coastal groups; and
- the other social, economic and environmental
implications of existing flood and coastal defence policy, and
the sustainability of policy in social, economic and environmental
terms[14].
13. In the event, we received over 70 memoranda from
a variety of organisations and individuals, and held five oral
evidence sessions at Westminster. In addition, visits were made
to the north Norfolk and Lincolnshire coasts and Humberside to
assess the nature and extent of coastal protection and sea defence
schemes in operation there; to the Environment Agency's offices
in Peterborough, to examine the procedures in place for flood
mitigation and flood warning dissemination in inland areas of
eastern England; and to the Thames Barrier. We are most grateful
to all those who assisted us during the course of the inquiry.
We also thank Professor John Pethick of Newcastle University who
acted as our specialist adviser and whose considerable expertise
proved of great value to us.
14. In Section II of this Report, we outline the
current administrative and financial framework for flood and coastal
defence in England and Wales. Section III specifies the current
obstacles and barriers to the effectiveness of current flood and
coastal defence policies. Our conclusions and recommendations
are presented in Section IV.
1 These possible consequences of climatic change for
the hydrological regime of the River Thames were outlined to the
Committee by Mr David Wilkes, Thames Tidal Defence Manager, Environment
Agency Back
2
Willis Faber & Dumas Limited, 1996 Research Report. UK
west coast flood risk; Willis Faber & Dumas Limited, 1998
Research Report. UK east coast flood risk Back
3
In evidence to the Committee, the Wildlife Trusts and WWF-UK
estimated that in the UK over the last thousand years, 100,000
hectares of land have been reclaimed from the sea alone; Q314 Back
4
Willis Faber & Dumas Limited, 1996 Research Report. UK
west coast flood risk Back
5
Ev p 194 Back
6
Grimsby Evening Telegraph, January 30 1993 Back
7
Ev p 194 Back
8
Ev p 5 Back
9
Ev p 194; the Environment Agency's "conservative..."
estimate is £2 billion, see Ev p 5 Back
10
Ev p 202 Back
11
Ev p 11 Back
12
Parry M and Duncan R (eds), 1995 The Economic Implications
of Climate Change in Britain Back
13
Appendix 42 Back
14
Agriculture Committee Press Notice no.19, 6 March 1998 Back
|
