Today we have seen footage of terrible
flooding along the River Thames; lots of properties under several
feet of water and the saddening sight of a young man now facing
months of repairs to a house he bought just a week ago. This event
brings the Somerset situation rather sharply into perspective and
generates some very real questions for the political establishment.
So far, we have seen a massive outcry
about floods on some of the lowest-lying land in the south-west where
a comparatively small number of people have been affected; and albeit
around 6,500 ha of farmland with livestock displaced. According to a
BBC article posted on 7 February
(http://www.bbc.co.uk/news/uk-england-somerset-26080597), the floods
in Somerset seem to have affected around 150 properties and possibly
involve just 40 properties flooded. The same article reports that in 1919 a
major flood led to there being some 28,000ha submerged!
These statistics put the current
situation into some perspective and make it clear that the real
message of the Somerset situation is that those who howl loudest get
the attention of friends in high places. I expect similar howls in
Windsor and Datchet will evoke a similar response from Ministers.
Meanwhile the poor staff of the Environment Agency have to withstand
ongoing howls about incompetence.
The problem is that there will remain a
huge chasm between what Ministers might like to do, or have committed
to do, and what the public purse can afford. In the end there will
have to be prioritisation. That is exactly what the Environment Agency has
done, using guidance from Defra and the Treasury!
This situation leaves me thinking that
the initial howls and high profile outcry about building bird
sanctuaries at the expense of the Levels actually represents a far
more critical argument. There has always been considerable
resistance to soft engineering in some quarters and, I suspect, the
current situation on the Levels has given detractors just the
platform they need to make the case against managed realignment.
There have been some horrendous sound-bites about spending money on
birds rather than people, but these messages overlook some important
fundamentals.
The concept of 'managed retreat' was
entirely sensible in some locations where sea walls prevented
flooding across a relatively narrow strip of land separating the
tidal environment from rising ground. Why not build two short counter
walls and allow the sea access across to rising ground. The flood
risk management benefits are substantial over the long-term. The
benefits include reduced maintenance costs and the not having to bear
the costs of raising crest heights in response to sea level rise.
They are particularly relevant where cultivation of the land is
subsidised by the public purse. This sensible policy option was shot
down by vocal groups who portrayed the concept as abandonment and
argued that there should be no retreat.
A picture of large-scale flooding
could, and was, conjured up. In reality, the idea that thousands of
hectares would be abandoned was, and remains, untennable. And, the
detractors have a point because the message about how to handle large
areas of vulnerable land was not adequately presented. Consequently,
a new term entered the lexicon: 'managed realignment'.
Managed realignment involves setting
back defence lines to a more defendable location, constructing new,
and better, sea walls in front of land that will subsequently warp up
to form saltmarsh. In some places such warping can be extremely
rapid, as can be seen from the example of Chowderness on the Humber.
Elsewhere it is often much slower, especially where suspended
sediment levels are low. In such places, the realigned site may take
considerably longer to form saltmarsh. Realignment will usually warp up, even where sediment levels are low. There are
exceptions, however, but these involve very unusual conditions where the morphology of
an estuary promotes episodic export of deposited sediment.
This digression is important because
along the tidal stretches of the Parrett the estuarine waters are
heavily sediment-laden. As such, they are absolutely ideally suited to warping up
new saltmarsh, which is a much more resilient flood defence.
That is what will happen at Steart where the small community within
the vicinity of the realignment will benefit from greatly enhanced
flood and wave energy protection once the realignment has warped up.
As the warping progresses, the extent of mudflat suitable for feeding
birds will diminish and natural flood defences will grow. So, whilst
it is fair to say that the Steart project has considerable wildlife
benefits, the ultimate beneficiaries will be the local community.
Those, such as the local MP Ian Liddell-Grainger, who decry the
Steart project are in effect saying that it was not appropriate to
spend money protecting one part of the country and that the money
would have been better spent protecting them! This, I think,
represents philosophical recidivism that translates into an argument
that there are no alternatives to the hard engineering that has
served us well for the past 250 years. In fairness, many opponents of
realignment have always done so. Acknowledgement of this view by the
political establishment, however, would represent an unfortunate
backward step at a time when we ought to be placing adaptation of
extreme events at the front of our socio-economic agenda.
January and February 2014 have
effectively dispelled the arguments for the hard engineering
solution. We have seen how a much lauded engineering masterpiece has
fallen victim to the inevitability of the sea. The massive concrete
structure of the coastal railway at Dawlish could not withstand the
effect of foreshore lowering and beach steepening. The cost of repair
will be massive!
Managed realignment is generally
proposed where mudflats and saltmarshes (first lines for flood
defence) have eroded away, and the sea walls are in many cases just
as threatened as the Dawlish railway line. Simple earthen banks,
perhaps with rip-rap, stand little chance as has been shown in the
1953 storm surge at Canvey Island and the loss of life in eastern
England and The Netherlands, and more recently on estuaries such as
the Blyth in Suffolk.
All of these cases develop a picture in
which it is clear that hard choices have to be made. The hardest
choice is whether a project meets Treasury expenditure guidelines.
Many laudible projects do not meet the guidelines and, as we have
seen in recent days, that was certainly the case for the dredging of
the Parrett and Tone. In other places, where the cost-benefit stacks
up, there will be unhelpful knock-on effects on wildlife sites that
have been accepted in the national interest. These knock-on effects
sometimes make it possible to develop the economic case for
realignment in vulnerable areas where the cost-benefit analysis would
not otherwise stack up. This habitat creation often gets high profile
press for its nature conservation benefits whilst the more important
message is lost: the realignment compensates
for
losses elsewhere and allows the UK to meet its international
commitments to biodiversity conservation. To my mind an even more
important message is lost – the realignment site represents a
considerable strengthening of local flood defences and NOT a
weakening of defences.
So, for those comentators who remain
unconvinced about the value of managed realignment, it is worth
pointing out that one of the alternatives to realignment is 'no
active intervention'. In these situations, the Environment Agency plays no further
part in defending that coastline. If the local landowner wishes to
continue to defend the land, using materials that meet modern higher
standards of material contamination, then they may well be allowed to
do so. But, the costs are firmly placed on their shoulders; as are
the risks! If they choose to defend the land then they may also bear
responsibility if the walls fail and neighbours' land floods?
The outcry over the Somerset Levels
will as likely as not pale into insignificance as the social and
economic costs of the flooding of the Thames at Windsor and maybe the
Severn at Worcester are realised. They may also be overshadowed by
the costs of repairing the Dawlish railway line and the long-term
cost of securing a more sustainable railway connection with
South-West England. Unfortunately, the staff of the Environment
Agency face the unenviable task of clearing up the mess and facing
the public when it becomes clear that ministerial commitments cannot
be fulfilled because the budget is too small and cost-benefit rules
bite. After all, once we move from an auditable system of justifying
measures to one where the biggest howls secure political
intervention, it is only a matter of time before anarchy ensues and
those with the sharpest elbows and most influential friends dominate
budgets provided by the masses. That, surely, cannot be sustained by
many politicians of any colour?
No comments:
Post a Comment