Saturday, 15 February 2014

A changing urban landscape

Whilst preparing a short article on spring hoverflies for the UK Hoverflies Facebook group it struck me just how much spring has changed in London over the past 40 years. That thought process took me on to other changes in that urban environment that are equally striking.

I grew up in Mitcham (south London) and was extreley fortunate to have Mitcham Common on my doorstep. From a very early age My friends and I built camps (on the ground and up the bigger trees), searched for caterpillars and messed about in the pond. At the time, there were vast acres of open grassland. I now realise this grassland was actually pretty important; it was a last vestige of the grass heaths that once populated many of the Thames terrace gravels that made up the commons of south London. So, although I lived in what might be assumed to be an urban environment, it was in effect quite rural and I was introduced to many interesting facets of natural history.

What I remember best is the ease with which I found the caterpillars of many moths – lots of lime, poplar and elephant hawk moths, and even the occasional puss-moth. The other abiding memory is the sound of a singing skylark over Mill Hill, the kestrels nesting in an old crows nest and the stone chats singing from the top of gorse bushes. Reed buntings bred there too, as did plenty of linnets and goldfinches. During the winter we would occasionally be blessed with the wonderful sight of a short-eared owl hunting over rough grassland, and I remember great excitement when a long-eared owl was discovered (I failed to see this).

Those days are long-past. The skylarks, stone chats and reed buntings are simply ancient records in reports on the ecology of the common. Occasionally, a kestrel hunts on the common, but I cannot recall the last time I saw one. I suspect a list of the losses would actually be considerably longer, as I have made no real attempt to log birds or to make a special effort to look for the unusual visitors such as willow or marsh tits.

The most striking aspect of change is how the traditional birds of the British countryside have disappeared and have been replaced by an assortment of opportunists and recent colonisers. Forty years ago, magpies were pretty scarce and it was a point of interest to find a nest; today I've seen as many as a dozen on the roofs of houses and trees around my mother's house. I well-remember first encountering ring-necked parakeets at Hersham whilst fishing a favoured stretch of the River Mole. That was a huge surprise. Today, there is a very large flock of a couple of thousand parakeets that roost on the common! They have replaced the millions of starlings that once streamed out of London and roosted on the common, but use very different trees. The starlings favoured the hawthorns in dense woodland whereas the parakeets like the tall poplars.

Others in the ascendancy include Canada geese, which now breed in considerable numbers on the pond; much to the detriment of the native mallard that struggle to bring up a spring brood. I think the geese are a definite problem from an ecological perspective. They range quite considerable distances from the pond, grazing the adjacent grassland to a few millimetres high and covering it with droppings. The phorbs in the grassland seem to me to have substantially declined within a radius of 50 metres of the pond – so several hectares of grassland has been affected.

Meanwhile, the fantastic acid grasslands are invaded by scrub and especially a very vigorous bramble that I think can only be a hybrid of a vigorous cultivar. Turkey oak is also springing up all over the place. It is quite a revellation because at one time there was just a single Turkey oak on the common, and it was felled a long while ago – well before the recent seedlings could have been propagated. So, where do the seed sources come from? It suggests that birds (presumably jays) must fly considerable distances before hiding their stash of winter supplies. Interestingly, the grasslands are also invaded by honeysuckle. To my untrained eye it looks like the native Lonicera periclymenium but it has escaped the woodland and is now invading vast patches of grassland.I don't recall seeing this problem anywhere else but perhaps other observers know of similar problems.

This is almost something out of a horror movie as the march of the aliens threatens to overwhelm a fantastic oasis of nature. The other amazing invader is spindle – normally a species associated with Chalk downland, but in recent years clumps have been springing up in the acid grasslands. This too is a potentially troubling addition to the army of invaders. On a more positive note, the majority of the Japanese knotweed has been eradicated!

I've studied the ecology of the common for most of my life and have published several accounts of its invertebrate fauna. It was, and still is (in places) a very special place that I think probably should have been designated as a SSSI. Certainly I think there was a strong case in the context of the ecology of London and the degree to which the site had been documented (as far back as a flora in 1911). Whether that case can be maintained today is a matter of debate. It probably still ranks as one of the most important grasslands in south London but it is under siege from a variety of forces. The Warden and his team battle valiently, but it is a huge job.

So, what is the lesson that can be drawn from this musing? Well, what really strikes me is how the study of the Common has changed. In the 1950s, 60s and 70s there were several local natural historians who regularly recorded the plants and animals of the common. The great, late, J.E. Lousley published an account of the flora in the 1970s; my late father published an account of the birds around the same time; various notes on the entomology of the common were published by the late Len Parmenter; and I know that Alan Stubbs recorded there on several occasions. The common was also a 'constant effort site' monitored by two local ringers (Mike Netherwood and Mick Cook). In the 1980s there was a comprehensive ecological survey (that I led and edited) and in the early 1990s both David Lees and I recorded Diptera, Hymenoptera and Lepidoptera from the common. It has a long history of recording. Who studies the common today? I cannot recall the last time I saw somebody out birding and it is noticeable that there are rarely any posts on iSpot of plants and animals anywhere near Mitcham. It almost seems as though that fantastic wild asset has been abandoned by natural historians.

I feel sure the invertebrate fauna is still interesting. There are numerous interesting plants to see (e.g. petty whin, spiny restharrow and dwarf gorse). There is also plenty of scope for the inquisitive natural historian to start to record what currently exists, so as to provide a baseline for future analysis. We know the botanical interest in 1911, the 1950's to 1970s and 1983-4. Modern digital technology could make it possible to make much more accurate analyses of the flora; and digital photography allows us to compile very accurate pictures of the changing ecology of a site. What seems to be lacking is anybody to pick up the opportunity.

There seems to be no lack of people interested in wildlife, but instead of taking on a local patch, many of them seem to pursue lists of what they have seen purely as an end in itself. If we are going to make a better job of conserving the country's wildlife we need a renaissance of interest in the study and recording of a local patch. Mitcham Common is just one of several south London Commons that would benefit from renewed interest by local natural historians. I expect there are sites across the country just crying out for their own recorder and champion!

also see

Syrphing Time

Relevant papers:

Friday, 14 February 2014

The Dutch are here!

We must assume that everything will be OK now: the Dutch are here pumping out the Somerset Levels, and experts from Royal Haskoning DHV have flown in from Holland to advise on recovery! We can be reassured because Haskoning staff are on the TV providing proper Dutch advice: so, we had all better listen!

It was therefore interesting to hear the Dutch engineer from Haskoning on Channel 4 tonight. Presented as an expert who had been involved in New Orleans, the message was clear – at last we have people who know what they are doing! And so, what were the great words of wisdom? Well, hardly rocket science:

  • The UK and Holland cannot be directly compared because a lot of Holland lies below sea level.
  • The Dutch spend about £600m on flood defence each year.
  • The UK should spend more money.
  • Prioritise what you will protect and what you will let go.

Somewhere I think I have heard something similar, or have I been labouring under false illusions? If I recall correctly, we have Defra and Treasury guidance on cost-benefit analysis. What is this for? Well, it it is not a framework for prioritisation, then I must be sadly mistaken. And, what have we heard from the Environment Agency? I seem to recall Chris Smith saying that the problem was working within the allocated budgets. I also seem to recall that the EA has been forced to cut 1700 jobs this year to save money.

Perhaps what the press should also have said was that many of the flood risk management strategies prepared by the Environment Agency are the work of consultants. They include, to a no small extent, Royal Haskoning DHV! I'd like to get a press and Government 'take' on this and maybe a comment from Eric Pickles on the wisdom of using British-based Dutch consultants.

We must take comfort that there are now proper experts in the UK who will make sure we don't flood again. If there is to be considerably more expenditure on flood defence, money must be found from somewhere. Or, are we going to have to borrow more? The danger is that other environmental management programmes will have to be cut further – maybe water and air quality or perhaps nature conservation?

Fast-forward, The reporting of Channel 4 moved on to the issue of climate change and there were several good sound bites; not least a clear story of extreme weather events in Malaysia and the USA. Unusually high rainfall and associated fatalities in Malaysia were reported, as was extreme drought and very high winter temperatures in California. The message was also clear – basic physics dictates that if the world gets hotter then there will be greater evaporation from the oceans and consequently more rainfall - but not evenly spread around the World.

All of this extreme weather ties in with the predictions. In the case of the UK, the predictions were for more rainfall and increased storminess. Regardless of the cause of climate change, the message is pretty clear: the modelers' predictions are starting to be realised. These, of course, are British modelers, so perhaps the Government had better bring in modelers from a country that knows more about modeling? I'm not sure who might be best placed to do this – maybe Germans, Swiss, Swedish or maybe American? Anybody, as long as they are not fifth columnists from a UK University or institute.

This piece included three interviews with the general public. Two respondents indicated that they had yet to be convinced about climate change, whilst the third came up with the usual point: if there is global warming why is it turning wet and stormy. In other words, global warming equates to nice warm weather. The skeptics must have loved this as the whole message was that somebody had got things wrong here too. I wonder whether there was anybody who said yes they did believe it was climate change? If these three interviewees were representative of the populus as a whole, then a sea-change in action is highly unlikely and we will simply bounce back 50 years to the tried and tested techniques that got us into this mess.

The above might suggest that I am simply having a rant, but actually there is sound logic at the back of what I have said. The point is that the UK has been taking the advice of experts; be they Royal Haskoning's UK arm, or Russell Group universities. On the one hand, we market UK education as amongst the best in the World whilst, on the other, we castigate the products of those universities because they have failed to stop unprecedented floods and storms. Maybe it is time for the policical establishment to wake up to some really hard truths: we have failed to act because out political establishment contains very few scientists. I wonder how many of the current bunch of MPs has an 'O Level' in Physics or Chemistry or, more especially an 'A-Level' in those subjects. I wonder how many have a science-based degree?

If we are to put the 'Great' back into Britain, we need a radical change in direction. Decision-makers need to be equipped with apropriate levels of scientific training. Science needs to be held in the highest esteem and rewarded accordingly. Perhaps the selection committees for prospective parliamentary candidates should have a new set of questions relating to the candidate's ability to understand, assimilate, and act upon sound science? Perhaps the degree in economics or politics and training for government as a 'special advisor' should be replaced by a degree in Physics, Chemistry or Engineering and a spell in the Met Office or an engineering consultancy.

Wednesday, 12 February 2014

The aftermath of the deluge

Pictures of the towns along the Thames valley and the villages on the Somerset Levels paint a grim picture of Britain in 2014 but, thankfully, we have not seen huge loss of life. We have, however, seen a huge verbal backlash against decent people who have always done their level best to do their jobs according to the rules that limit their ability to deliver what people want. The limitations that Environment Agency staff face are largely financial, but one also has to bear in mind that doing a decent job also demands time and consensus-building. They have a very challenging job, and deserve considerable praise rather than the mud-slinging that we have seen from certain parts of the political establishment and elements of the press (who are always keen to stir up a witch-hunt against public servants).

Wave upon wave of new storms have delivered unprecedented rainfall upon already sodden ground; and, further batterings by major storms along the south and west coast. There is likely to be little respite in the foreseeable future, so the criticism of the EA will doubtless increase in volume. There is barely a voice of reason saying 'hang on, this is the most extreme event in 250 years'.

Critics who argue that the situation should have been planned for have little comprehension of what planning for such events might cost, or might involve. If this year's events become the threshold for flood-risk planning then somebody is going to have to find an awful lot of money, and fast!

It is not the EA who are to blame, but society at large. The voters on the Levels and those in Surrey and Berkshire, whose homes are flooded, live in constituencies that returned Conservative MPs. It is these same MPs who have supported draconian cuts to the budgets of the Environment Agency and Natural England and have represented the democratic voices of their constituents. When the weather was good and there was no risk, both organisations were regarded as too fat, and therefore ripe for efficiency gains. Now, the picture looks a little different, at least for the EA.

But the howls are still there - not only calls for Chris Smith's head, but print space given to the view that 'we need the names of those who gave that advice and confirmation that they will never be allowed near a decision of that importance again'. The latter quote is from that well-known voice of reason and common-sense - the Sun no surprises there!

Both views are utterly reprehensible for several very important reasons:
  • If a blame culture develops, public services are paralysed by the need to make sure that nobody makes a decision without seeking sign-off at one or more level above them. This is the 'cover your back' culture that cripples flexibility and initiative.
  • Engineering is hardly the highest-paid profession but it demands considerable skill and many years of training. Chartered membership of the Institution of Civil Engineers (ICE) or the Chartered Institution of Water and Environmental Management (CIWEM) only follows further study and rigorous examination. Why should anybody make the effort when a sword hangs over them saying ' one unfortunate extreme event and your head is on the block'?
  • The Environment Agency is tasked with shedding about 1,700 posts in the next six months. At the moment, I suspect a great many departures will involve voluntary redundancy and I would not be surprised if many of those who have felt the ire of the public and certain Ministers will be minded to apply. I know that I would if in the same position. Morale cannot be high in these circumstances.
  • Precipitating the departure of the oldest and the most experienced, who also tend to be the corporate memory of the organisation, can only lead to mistakes and poor decision-making in future. In other organisations that have taken a similar approach, the result is the reinvention of the square wheel followed by a long process of shaving edges off before somebody is lauded for coming up with the round wheel! Hang on, I think there was something in the text books that we burned at the start of that revolution!
These problems could have been avoided if there was proper respect for technical professionals, and a recognition from an early stage that the events that are unfolding are unprecedented. So, if the blame game has to start anywhere, it must lie with successive Governments who have sought to cap expenditure on flood and erosion risk management. They now face three major challenges:
  1. Managing and supporting a recovery amongst the communities that have been so badly affected by the floods.
  2. Repairing the credibility of the water engineers whose reputations have been mindlessly trashed by irresponsible damnation of advice received based on the sound application of Government guidance.
  3. Crafting a long-term response to these flooding problems without jeopardising the funds available to respond to the dangers that have been identified, but which have yet to happen.
There are numerous lessons to be learned from these various events, but perhaps the most important one is not to dismiss solutions that require:
  • reinforcing planning policy guidance and decision-making where development in the floodplain is proposed;
  • changes in agricultural practices to make sure that water is not flushed from the uplands to the lowlands as fast as possible;
  • changes in agri-environment funding to promote better flood storage at a variety of points within a catchment; and
  • flood-proofing buildings and communities to minimise the impacts of future events.
The reality is that these events are just a harbinger of the future if climate change predictions are to be believed. After this winter, perhaps even some of the skeptics will start to recognise that there is at least a grain of truth about the process and implications of climate change, even if they will not accept that the causes are largely anthropogenic!

The Dutch approach - some more information

Yesterday, I made various comments on the merits, or otherwise, of using Dutch engineers to address flooding issues in England. In that comment I made the point that the level of Dutch investment in flood defences was beyond my knowledge. I subsequently spent a bit of time looking for this information. Doubtless I would find it easily if I spoke Dutch, but I don't! I did, however, find a very interesting presentation by the President of the Dutch Association of Water Authorities.

It is 3.5 years old, but it does provide an indication of the sorts of expenditure made by the Dutch, which as far as I can see are about the 80% of the total expenditure for England. That is by a population of 16.7 million as opposed to 51.5 million in England - roughly £24.00 per head of population as opposed to about £13.00 per head of population.My figures are very 'back of a fag packet so don't take them as absolute! When you bear in mind the extent of the English coastline and river systems as opposed to those of Holland, the differential is clearly much greater.

Perhaps the more important aspect of the presentation is the emphasis on adaptation to flooding rather than just building food defences and deepening rivers. What do we see: the use of flood storage areas, adapting buildings and relocating critical infrastructure! I note that flood storage is linked to a 1 in 25 year return period, which is considerably lower than the current floods in England.

What strikes me most about this presentation is that it is being made by a Dutch Water Engineer; not an English Conservationist. The ideas are, curiously, remarkably similar to some aspects of the approach that the Environment Agency has built into its Catchment Management Plans. The emphasis on relocation of key assets and flood-proofing buildings is where I think the differences lie, as we really have yet to start to talk in detail about re-locating key assets and designing new ones that are properly flood-proofed if they lie in a floodplain.


In a radio 4  interview a few minutes after I made this post, there was a piece on a Dutch delegation having come to the UK to determine what they might do to help. In that piece, Dutch expenditure was quoted as double that of the UK. The problem I think in this respect is that there are probably several different sets of figures to go on: EA expenditure on capital defences, EA expenditure on maintenance, expenditure by IDBs on local infrastructure maintenance make up several different components of spending in England. Similarly, the Dutch have national and local expenditure, so the big question is the nature of the figures quoted - it may be comparing apples with pears.

What I thought was more interesting was that the Dutch interviewee talked about the fact that Holland and England were very different and should not be compared. Even more interestingly, he focused on the Dutch learning from us in relation to cost-benefit analysis!

Tuesday, 11 February 2014

Dutch Engineers - do they know best?

On various recent occasions there have been very public comments on the failings of the Environment Agency. Critics have argued that they would invite Dutch engineers to solve the problems of the Levels. The Dutch should be immensely proud of the reputation they have established in England and the esteem with which they are held in parts of English society.

It is certainly true that 17th and 18th Centuries Dutch engineers were in the vanguard of drainage of wetlands. Indeed, we might also reflect that the Dutch have probably played one of the most important roles in eliminating the wetland wildlife of England!

We are now in the 21st Century rather than the 17th Century. The engineering principles the Dutch employed are now very well known and there are plenty of UK engineering companies who have the same skills and expertise. They will happily sell this expertise to UK taxpayers and are already employed in a great many capacities. In some places, one almost gets the impression that they ARE the Environment Agency. So, why pay the Dutch and favour their economy to the detriment of our own exchequer?

Design principles are not particularly difficult. Water conveyance simply depends upon capacity within the channels, the fall of the land,  and whether water can be conveyed into major conduits using flap valves or if there is a need to lift it into rivers and major drains using pumps. The subsequent test is the design dimensions - what sorts of volumes are the systems designed to accommodate?

So, the key question is not where the engineers come from, but how much money you are willing to spend. The greater the planned capacity, the greater the cost. Furthermore, if you design a system of defence against flooding from rivers there is a question of the design of resilience to major events - how big should the flood defences be? The costs of flood defences are directly related to the level of protection that is aspired to: bigger schemes require more engineering clay and there will therefore be greater transportation costs and impacts of lorry movements on the communities along the way.

It is notable that even the Dutch, those masters of drainage and flood management, are talking about soft engineering and even using flood storage! Actually, the Dutch are probably at the cutting edge of such approaches. Many of their major defences are designed to a level of 1:1000 year return period and I have heard of levels of 1: 4000 years defence levels. The flood embankments in many places are like small mountains! The cost must have been astronomical and, of course, it does not stop there because defences have to be maintained and replaced. I have not got a clue what the yearly flood defence budget is, but I would guess it is much more substantial per-capita than in the UK. Small wonder that they are looking for greater cost-effectiveness and are exponents of soft engineering.

The Dutch have a relatively short coastline and invested huge sums in the Delta project to shorten their coastline still further. They also have relatively few rivers, so the river flood defences are relatively less onerous. A great deal of their problems relate to surface water drainage and therefore pumping because a lot of Holland lies at or below sea level. In the winter this challenge is immediately apparent when one flies into Schipol - huge areas of farmland under water or partially inundated. Even the Dutch cannot keep the floodwaters fully at bay in the winter.

Given the demands for vastly increased defences against flooding on the Levels, there is a need to look carefully at the relative costs. How many people and what land area elsewhere could be protected if the current level of defence is maintained on the levels and the proposed maintenance budget is spent on other capital projects? Would the money be well-spent on the Levels or better spent elsewhere? This is a debate that involves all taxpayers.

This is also the challenge that the Environment Agency grapples with on a daily basis across the length and breadth of England, with its huge coastline and numerous rivers and floodplains. They have been doing so in the face of ever-tightening budget constraints that are also compressed by engineering costs that rise at a pace that greatly outstrips inflation.

Maybe it is time to put the critics into the hot seat and let them make the decisions. Once they have made their decisions they would also have to defend them against uproar from the communities they choose not to favour! I doubt the critics would cope well because there innumerable deserving cases.

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 (, 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?

The flooding debate - the soup thickens!

My last comment on Facebook elicited various uncomplimentary comments about Eric Pickles that are best not repeated. It is perhaps worth reflecting, however, that Mr Pickles seems to have very little respect for strategic planning - the dismembering of planning guidance is illustrative. The approach taken yesterday also reinforces a growing impression that some politicians have a contemptuous approach to sound science.  Thus, I suspect in a few years time we will be looking at major Government expenditure to provide flood defences to ill-placed developments that have been fast-tracked to avoid any serious environmental and social scrutiny!

Moving on, I note that excerpts of the 2008 Parrett Catchment Flood Management Plan are being selectively quoted. I have not managed to access this document but I have found the 2012 version. In this version there is discussion of a 1% annual probability flood (in other words a 1:100 year event) and the use of parts of the Levels as flood storage. So, it is clear that there was already an acceptance (within the EA and by implication Ministers) that cost-effective flood risk management would be delivered by flood storage. I have a feeling that these sorts of events have happened at several points over the past 20 years. This year is different and as yet I have not found any indication of the return period estimate for the current flooding. We can be pretty sure it exceeds the 1: 100 year level, and in all probability exceeds a 1:200year event – which is generally the maximum that is socio-economically viable for capital expenditure. So the points made by EA Chairman Chris Smith are certainly consistent with the general principles of Project Assurance Guidance issued by Defra.

So, I think the general evidence points towards the reality that we are in an exceptional event and the playing of the blame game is utterly disingenuous by all sides. In the local context, it is wholly understandable that people will adhere to a view propagated by certain interested parties. At a political level it is always nice to be able to blame somebody else, especially where Government guidance is a factor behind decision-making. In this case, some politicians seem to be far more willing to shoot from the hip and pretty wildly in the direction of a supposed enemy. The tragedy is that their target is the science of flood risk prediction and management. We could avoid the current problems, but I doubt that even in the current situation the political masters would sanction diversion of long-term resources from the defence of London, York or Worcester – or perhaps even Windsor and Eton which seem to be at risk at the moment.

My biggest gripe lies with the press who seem to be doing their level best to stir up emotions and to propagate the blame game. Only this morning there was a resident of Windsor on Radio 4 responding to inquiries about the local situation. They reported that flooding normally occurs on the opposite bank but this time the problem was more extensive. When asked 'who do you blame' they immediately responded that it was the Environment Agency's fault and that they should have been dredging the Thames!

I fear rational discussion will not occur until some of the vested interests, and people with an axe to grind, are isolated by sound science and measured reflection. The big issue now is whether there is scope for a sensible discussion about future-proofing the main villages on the Levels and about the degree to which the public is going to commit extra funds on a continuous basis to allow the status-quo to be maintained. This is not going to be a one-off event, so maybe it is time for a shift in political approach and a wake-up call to all about the implications of climate change (anthropogenic or otherwise) – it is going to involve a combination of too much or too little water at increasingly frequent intervals! We are stuck with existing climate change and can only guess at the long-term situation because models are generally pretty poor at providing accurate estimations of future change - their accuracy drops off very rapidly regardless of how well trained and validated they are!

This winter's floods have the potential to pit the Somerset Levels against the Severn Valley and the Upper Thames in a mad rush for new Government funding and re-allocation of existing funds. That may not bode well for those coastal communities hoping for upgrades of coastal flood defences!

Mr Pickles kicks the Environment Agency

 9 February 2014

The more I hear Ministers talking about how they should have ignored Environment Agency advice, the more I get irate. I thought that it would be worth talking a look at what is available on the extent of flooding and where the pinch points are along both the Tone and the Parrett. Interestingly, the Tone goes straight through the most flooded areas on the only map I could find, and joins the Parrett at Stanmore Bridge. So, dredging the Tone means that at low tide rather more water will enter the Parrett, which for many kilometres downstream is effectively a tidal canal. Dredging the Parrett upstream of the confluence will only lead to faster egress of water onto the flatlands of the Levels; all of which are upstream of Bridgwater. A sizeable part of each of these sections below Ham Bridge (ST285251) on the Tone, and Oath Lock (ST383278) on the Parrett is tidal. Thus in both cases even if dredged, there will be limited extra capacity at high tide and especially on spring tides. Thus, in as extreme a situation as this one, the likelihood is that flooding would still have occurred.

Now, moving on a step. The Parrett remains narrow and tidal as far downstream as Bridgwater where there are several apparent pinch points (according to maps). These pinchpoints are bridges and tightly constrained urbanised sections of river, so it is highly likely that over a single tidal cycle coincident with a major fluvial event such as this one, it might be expected that there would either be structural damage to bridges or, as likely as not, over-topping of defences and flooding of Bridgwater. Looking at Black & Veatch's assessment of tidal flood defences it appears as though Bridgwater is protected against a 1:200 return period tidal event (not once every 200 years). The defences appear to be primarily designed to deal with a tidal event rather than a fluvial event in which the upstream defences have been designed to ensure that the levels remain unflooded.

So, all this talk that dredging would have saved the day is as likely as not completely unsubstantiated and the advice the EA gave to Ministers is correct. In this sort of situation, with or without dredging, flooding would have ensued.

This leaves me hugely uneasy because it is highly likely that severe events of the sort we have just seen are pretty likely to return in a not too distant time-frame. If so, it seems to me that there is a pretty strong risk that dredging the Tone and Parrett may actually mean that in modest events farmland may not flood, but that in a major event Bridgwater would be inundated and then farmland would follow as water is held back by key urban pinchpoints.

It will be interesting to watch the coming years - one must hope for the sake of the residents of Bridgwater that there are no further major events! Clearly the big question then arises as to whether there is a case for a tidal surge barrier similar to that used at Barking or at Hull. That would certainly provide some relief against tidal impacts, but I wonder how it would perform in the face of the sort of fluvial events we have witnessed? I therefore cannot see how any strategic solution can proceed without some use of realignment or spillways to make use of parts of the Levels as containment space for major fluvial events. If such measures are not used, it is pretty inevitable that extra money will have to be used to raise banks considerably higher than they are today in order to accommodate extreme events of the sort we have recently seen.

Some common sense at last!

09 February 2014

At last some common sense from an MP. I have just heard Richard Benyon speaking on Radio 4 about the prioritisation of resource allocation for flood risk management. Wonderful stuff - and most importantly supportive of the EA's staff.

How on earth anybody can put their back into a job when they are being kicked from all sides and blamed for a calamity that could not be predicted. I'm glad I no longer work in a Government Agency.

It was also greatly heartening to hear Richard Benyon prepared to criticise a fellow Tory MP too. Maybe there are a few MPs who might be encouraged to lead a call for some commonsense and a better understanding of the fact that this is possibly the worst rainfall event in recorded history (i.e. about 250 years!).

Somerset levels - yet more!

8 February 2014

I listened to an interview with Ian Liddell-Grainger this morning concerning the flooding and response to flooding. I was amazed to hear him say that dredging would help to resolve the problem because it would allow pumping at high tide.

Who on earth provides this advice? Dredging is highly unlikely to lead to a significant reduction in high tide levels and is most likely to lead to increased tidal propagation (as per my previous post). The trouble is that once high-profile people make these sorts of comments it becomes accepted fact and the message of incompetence on the part of river managers gets even more embedded.

I begin to feel that it is time to give up a technical profession as we are seeing an increasing failure amongst politicians to make sure that they genuinely understand technical issues.

There is a need to look very carefully at the ways in which key landscape management issues are presented. For many years I have held the view (and even said as much - see links below) that the biggest problem with sensible adaptation measures is that they are promoted by nature conservationists who arguably present this as a wildlife gain. I think there is a need to re-think this approach and to develop a way of promoting certain types of management from more of an engineering and socio-economic angle. That means re-education in various places.

Thus, in the case of water management, I would highlight the following as critical areas:

  • Blanket bog regeneration 
  • Upland re-wildling using native species
  • Managed realignment
  • Creation of washlands
  • Sediment husbandry

In this respect, there is also an urgent need to look at the cost-benefit of such measures in a much longer time-frame. At the moment headline costs of a managed realignment can be presented as wasting XX million pounds for a 'bird sanctuary' but in fact the real engineering benefits may be felt over decades and may even have a bearing on resilience well beyond the lifetime of current generations.

Hopefully this period of extreme weather will get somebody thinking sensibly. The danger is that all the sensible adaptation measures will be thrown out as the ideas of intellectuals and that the real answer is to dredge deeper and build increasingly larger defences. The problems at Dawlish seem to me to be an exemplar - if the final decision is to invest on the existing route then future generations will be inheriting the results of our folly compounding the arrogance of the engineers who first placed the railway on an eroding coastline!

Useful links

Dredging the River Parrett

 4. February 2014

The recent flooding of the Somerset levels has led to many calls for renewed dredging of the River Parrett and for reversion of wildlife conservation measures within the Somerset Levels. Calls to dredge are borne out of historic practices, but it is perhaps worth reflecting that the current problems may be far more complicated than can be resolved simply by dredging and draining.

Dredging within tidal rivers can have significant unforeseen consequences. One factor that needs to be carefully considered in this instance is the way in which deepening and widening may lead to elevated high tide levels. This is a feature of several of Europe's largest rivers that have been deepened to improve navigability. Some quite extreme examples can be seen in the Elbe, the Ems and Seine. But, there have been impacts closer to home: deepening of the Thames also led to increases in tide heights in London. In the case of the Thames, this was a long while ago and effectively beyond living memory. Modern flood-risk management counters that effect, but it is worth bearing in mind that, without deepening, the tidal flood risks to London would be lower. Quite how much lower the risks might have been are probably un-quantified, but it would be an interesting exercise to translate this into the additional cost of flood defences!

Moving on to the Parrett, it is worth reflecting that cessation of dredging will have led to siltation and narrowing and shallowing of the tidal channel. This in turn would have led to a reduction in tidal propagation and thus there would have been flood risk management benefits where tidal flooding was concerned. Why might this be?

The speed at which the incoming tide enters a river is governed by the dimensions of the river in cross-section. Conversely, the dimensions of the cross-section at any point are a function of the volumes of water passing on flood and ebb tides, and the speeds at which they travel. The cross-section reaches a dynamic equilibrium provided sufficient sediment is available to infill any void where flow rates fall below the threshold at which deposited sediment is re-mobilised. Dredging creates an un-natural void and deeper water. There are three important consequences of such a morphological change:

  • Incoming flood tides will travel upstream at a faster rate than they did previously, shortening the duration of the flood tide and reducing the scouring effect of the ebb tide which will recede more slowly.
  • More sediment will be drawn into the river and will be deposited onto the green foreshore and in the dredged channel. Consequently, dredging is not a 'one-off' and will have to be repeated regularly.
  • Depending upon the gains in tidal elevation, it may be necessary to raise the height of the flood banks to provide the same level of protection under the un-dredged regime.
In general, the carrying capacity of the Parrett has been adequate to meet needs in 'normal' conditions of rainfall (not perfect but at levels commensurate with cost-benefit analyses). Rainfall in January 2014 has reportedly been around twice normal levels for this time of year and appear to be higher than previous records. This is therefore an extreme event on a scale that could not have been predicted. It falls outside the cost-benefit calculations that would have supported the maintenance of the sorts of measures that are being called for.

Thus, it seems to me that it would be wise to reflect and evaluate the relative merits of increasing the risk of elevated tidal propagation against the likely costs and risks of a future extreme event. One possible way of reducing the flood risk from tidal propagation is to realign the banks and create much larger tidal washlands. Such measures may appear to be 'environmental' and seemingly lack any obvious human benefit but in fact they have the potential to be a highly cost-effective way of countering exceptional tidal events, as well as providing some of the very necessary accommodation space for excess fluvial discharges that might otherwise threaten Bridgwater.

I would therefore argue that current measures to manage fluvial and marine flooding events should not simply rely on a knee-jerk return to dredge and drain on the levels. There is a real need to determine precisely where, when and why the rivers over-topped their defences and to consider whether there might not be a place for win-win for people and for wildlife. My instincts say that the measures that had been in practice sought such a solution but were overwhelmed by an extreme event that would probably have caused similar devastation even if the Parrett had been dredged. After all, increased tidal propagation and an elevated high tide could coincide with a similar rainfall event and there would be the same result! Once the land is flooded the key issue is the capacity of the pumps and not the capacity of the Parrett on an ebb tide.

One possible solution is to consider a more pragmatic approach to former wetlands. Perhaps it is time to return to the use of summer pastures along similar lines to those one sees on many northern European rivers. In these cases, a small outer flood defence prevents normal tidal flooding but is over-topped by extreme events. Secondary defence lines some distance inland then provide a barrier between people and the river and accommodation space to counter major tidal or fluvial events.

This is arguably a solution that will not please the purists who seek more inter-tidal wildlife habitat but, equally, it will have detractors amongst the agricultural community! The sad reality is that we must expect more of these events if model predictions for our changing climate are to be believed. Importantly, this debate must consider predicted changes to weather patterns. We must learn to adapt in the face of rising sea levels, increased storminess and the potential for more frequent extreme events regardless of arguing about the causes which have probably got a long while to run and will not be brought under control in the foreseeable future.

Biodiversity offsets

8 January 2014

Recent announcements about the coalition Government's proposals for biodiversity offsetting raise some very serious questions about the degree to which policy is based on sound science. In 2005 a team of English Nature specialists investigated the issue of offsetting from the perspective of how long it might take replacement habitat to reach a condition commensurate with established semi-natural habitats. The evidence was disturbing because it highlighted a series of fundamental problems:
  • Established habitats are very largely the product of management that existed prior to deep ploughing and modern herbicides, pesticides and fertilisers. These modern practices mean that it is not possible to look at arable reversion from the same perspective as times when agriculture was less intensive.
  • All of the evidence pointed to very long time-frames for the creation of habitat that is any way analogous to existing semi-natural habitats. Apart from some wetlands, the timescales run into many decades or hundreds of years, and ancient habitats look to be extremely unlikely to be replicated. For example the plants and animals inhabiting a secondary woodland younger than 400 years are rarely, if ever, as rich as those in ancient woodlands.
  • The most critical factors involve a combination of soil chemistry, mycology, lithology and hydrology, and we know precious little about the role of bacteria in determining conditions. Soils that have been recently ploughed and fertilised with petrochemical-based fertilisers bear little resemblance to the chemical and biological conditions that existed prior to WW2, let alone those of the 17th Century, which marks the point at which woodlands start to be considered to be 'ancient'.
A paper published by this team in 2006 provides the foundation for the scientific debate about the likely efficacy of biodiversity offsets. Yet this, and associated evidence, seems to have been ignored, if pronouncements concerning ancient woodlands are genuinely the Government position. Suggestions that the replacement of an ancient woodland with 100 trees for each ancient tree lost is environmentally sound need to be tested scientifically. Is the Government thinking of the environment in a visual or an ecological sense? I think it must be assumed that this is a landscape rather than an ecological judgement because I cannot see how the Government's conservation advisers could conclude that there would be anything other than biodiversity loss from the destruction of ancient woodlands.

I have spent a substantial amount of time studying the insects of the British Isles and have visited a great many sites, from Shetland to Cornwall and Kent, both ancient and modern. In many cases one barely gets past the entrance before it is apparent that the site is going to be of interest or is going to be pretty mundane. One gets the feeling from the ground flora, the canopy structure (in woodlands) and the overall layout of the site. The insects are pretty telling too. Long-established sites invariably prove to be more interesting and there are good reasons for this.

At one time the countryside was far less regimented and there were uses for virtually everything. Coppiced trees provided small timber for tools, fencing or other utensils, and for firewood. Standard trees provided structural timber and planking, whilst certain trees were deliberately pollarded to provide timbers of particular shapes for construction or shipbuilding. Grassland might have been rotated to lie fallow to improve soil productivity; elsewhere it would have provided grazing or hay. The vocabulary of the countryside reflects this diversity of use with terms such as coppice (copse), meadow and pasture forming place names. This mixed environment in which habitat was closely juxtaposed allowed plants and animals to disperse relatively readily. Today, such habitat is isolated in little pockets that we call nature reserves or protected sites.

Site protection has arisen because a part of society actually values wild places. This is particularly so for ancient woodlands, which form a central part of the countryside, for their landscape, cultural and wildlife value. The landscape attributes are obvious, but the wildlife is rarely recognised. Much of the important wildlife (in terms of rarity and specialness) is small and relatively inconspicuous. Few visitors to the countryside other than the most ardent specialists would delight in the sight of a Duke of Burgundy Fritillary Butterfly or perhaps a Musk Beetle. It therefore follows that relatively few would miss their passing. But, many older people lament the loss of fields full of orchids or comment that butterflies seem to be much scarcer these days. In the case of my passion, numerous associates comment on the decline in insect activity at hogweed. Only today one of these friends commented that the hogweed fauna of Shropshire seemed to have declined substantially in recent years. One wonders why?

Once the basic landscape matrix has been lost, wildlife cannot move as freely. If a special site is destroyed, the special plants and animals don't just move - they die! Once they are gone, the overall numbers available to set seed, disperse spores or lay eggs to create a new generation also decline. This is why there has been an ongoing effort to arrest biodiversity loss. The first target date was 2000. That date was ambitious and the target was not achieved. A new target was set for 2010 and it too was missed. The current target is 2020 and yet in the midst of this decline, the Government determines that further ancient sites should be destroyed and replaced with pastiche. After all, nobody will notice providing the countryside has trees to create visual spectacles! If one waits for 100 years for the site to attain the characteristics needed by the plants and animals displaced when the ancient woodland was cleared, where will the colonists come from? They disappeared when the wood was bulldozed!

This saddens me greatly because we must brace ourselves for a further round of accelerated wildlife loss. There are already many parts of the country that are to all intents and purposes ecological deserts. The fens of south Lincolnshire immediately spring to mind, but there are others such as the Vale of York, the southern uplands of Scotland, much of Radnorshire and many parts of the uplands of northern England where the landscape may be spectacular but is dominated by sheepwalks! And then there are the urban habitats where the gardens are turned into concrete and wooden shrines to the motor car or the barbecue!

9 January 2014

Looking at the pronouncements on possible ratios of replacement trees to original trees, I wonder if the Government has seriously considered the areas of land required to offset loss of ancient woodland? Using some basic calculations, it seems to me that they are going to have to require some major areas of the countryside to be allocated to tree planting if they are serious about a 100:1 replacement ratio.

I have just done some 'back of a fag packet calculations (thankfully I gave up 10 years ago, so I have to use scrap paper but I doubt that makes much difference to the science!) and the following figures come up:

1. In traditional coppice with standards, tree density is likely to be anywhere between 30 and 100 crowns per hectare. That, I suspect refers solely to the 'standards' and thus the question must be whether additional provision needs to be made for the coppice stools?

2. Working on a density of 65 crowns per hectare as a median, that suggests that the Government is proposing a compensation ratio of 6.5 ha for every 1 lost to development. This figure is based on a planting density of 1,000 trees per hectare in the replacement woodland, giving a ratio that far exceeds any so far for displacing migratory waterfowl.

3. If the pastiche is to replicate ancient woodland, then there also needs to be management to create the mix of coppice stools and standards. What needs to be borne in mind from an ecological perspective is that the coppice stools form a substantial part of the ecological value. This is largely underground and comprises the decaying timber that supports many fungi and the animals whose larvae feed on the fungi and bacterial soup that results.

4. It follows that the offset will require intensive management, unless of course we are simply looking at replacing an ancient woodland with a poor quality plantation. If so, there is even more to go on in terms of ecological loss because the relative importance of plantations and semi-natural habitats ought to be relatively easily demonstrated.

There is plenty of sound ecology to challenge the proposals, but perhaps the more important issue is economics? Is it really worth trashing an ancient woodland if the developer has the cost of buying anything between 3 and 10 ha to replace each hectare lost, and then has to pay for intensive management for sufficient time to create anything approaching pastiche? Someone better than me can do the economics, but it seems to me that the likely cost of creating the offset will at least mirror the cost of the ancient woodland and may indeed greatly outstrip it because woodland is relatively cheap and even low grade arable is phenomenally expensive, without adding on the cost of long-term silviculture.

Why this blog?

Until now, I have used my Facebook page as away of expressing thoughts on a variety of land-management issues; that is until after a recent post a friend suggested that I should run a blog. So, the obvious thought was 'why not'?

My intention is to use this blog on an intermittent basis where i can offer a measured and rational view on topical issues relating to land management and, in particular, nature conservation issues.

January 2014 has been an exceptionally busy time, with the Government's environmental credentials exposed to scrutiny on a number of fronts; most notably on Biodiversity Offsets and Flood Risk Management. So my opening posts will concentrate on these issues.