Monday, 10 February 2014
Pause for thought - flooded Levels in perspective
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?