Thursday
Feb132014
by 
Bishop Hill
Bishop Hill Greenery is bad for you
Feb 13, 2014 Climate: WG2 Environment Agency The Mail is reporting that the lower reaches of the Thames were not dredged because the Environment Agency saw its first duty as being to protect a rare mollusc.
In a 2010 report, seen by the Mail, they ruled out dredging between Datchet and Staines because the river bed was home to the vulnerable creatures.
And even though a public consultation indicated support for de-silting work, the quango said it would be ‘environmentally unacceptable’ due to the ‘high impact on aquatic species’.
Reader Comments (66)
Has anyone else noticed that no one in government seemed at all concerned until the rich houses beside the Thames starting being flooded?
Feb 13, 2014 at 11:31 AM | MikeHaseler
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The people who live in the Levels, yes.
By the way, has anybody seen or heard any reference to the EU's part in this on the BBC? News/website/radio? I complained to them that they had ignored this, and they wrote to me to note that I was complaining about them not "highlighting" it - a neat but useless sidestep.
So a written complaint has gone in, noting that I was not "highlighting" it, I was complaining about it, and that if they will not report such pertinent details, then people might suspect that this was deliberate and that they might have an agenda. Would they like to disabuse me of this notion.
I'll get the usual pap in return, no doubt.
@john in cheshire
Re "experiments" - beware, there's a great big interweb Twilight Zone lurking out there.
In the "natural cycles good" camp,
- some say the Jet Stream has been shifted by the Solar Minimum/ Space weather.
But in the "man-made bad" camp,
- some say the Jet Stream has been shifted by HAARP (nasty military types using us as guinea pigs)
- some say the Jet Stream has shifted because "they" turned HAARP off (Gov funding cuts).
- and the Met Office say it has been shifted by the warming/cooling drought/excess moisture/ whaterver
And so on.
Mussels and shellfish and voles! Oh, my! How very odd for a country to be ruled by such creatures.
Dredging the Thames would not make any difference to the peak flow capacity. The hydraulic grade line is controlled by a series of weirs constructed to make the Thames navigable using locks. Presumably the weir gates are currently fully open. There is "critical flow" through the weirs and the maximum flow is defined by the weir gate opening and the upstream head.
Prior to construction of the weirs, dredging of the Thames would have been effective. In dry summers though it would have looked pretty ugly with lost of mudflats and no cruise boats. To increase the river flow the weirs would need to have higher capacity by increasing the width. Thus the alarmists are right. Flooding on the Thames has anthropogenic causes.
I know Wiltshire is not like the levels or fens, but we have had and still have flooding, but the council have been out and are making sure grips are dug and ditches clear - and the council has just authorised drainage bye-laws to help enforce landowners, if necessary, to move the water away. Many culverts under roads have got clogged up and are now being cleared out to get that water away, but despite all of this the sheer volume of water is causing flooding in downstream areas and because the groundwater levels are so high many people are experiencing springs bubbling up under their floorboards. I do take my hat off to the local boys who are out and about making sure that things are running as well as possible and they have been doing this for weeks now. The trouble is that all those who are not affected by flooding are belly-aching about potholes and as fast as they get filled the next bout of heavy rain washes it all out again. You can't please everyone!
Much as I might hanker after living by water, I am jolly glad we live high up at the very top end of a river valley under the edge of the chalk escarpment and have been spared the misery that many others have suffered
@Philip Bratby - Yes, I do know who you mean. I will be in touch.
A lot of people have made a lot of noise about dredging rivers and how the neglect of this option has led to the floods. The thing is, having worked on several flood defence project appraisals myself, river dredging is often a flood defence option which enters the project appraisal as one of the options. Flood engineers and hydrologists will assess the likely flood extent and depth of a flood before and after the river dredging using models to estimate the likely extent of damage to nearby property (be it houses, roads, fields etc) and calculate the benefit of dredging by comparing the savings in losses due to dredging against a do nothing option, for various return period floods (i.e. a 1 in 100 year flood (big flood), a 1 in 20 year flood (small floods) etc). You effectively plot a curve (return period versus damages) and the benefit is the difference in area between the two curves (do-nothing curve, dredging curve). This is then compared to the cost of doing the dredging to get a cost benefit ratio. The cost data either comes from the Flood Hazard Manual (a document derived from a huge research effort from the University of Middlesex to assess flood damages, a bit dated now but costs can be adjusted for time) or from the EA itself. I can't remember where the dredging cost comes from but I think it is one quoted from the EA.
The point I'm making is that if rivers aren't being dredged, it's likely because in the cost-benefit analysis, river dredging is not performing as well as alternative flood defence options. That's my view from the experience I had working on such projects.
ABC,
The accusation is that dredging by the EA in the levels wasn't abandoned as too costly a part of a flood defence plan. It was abandoned because priority was given to other things such as creating wetland habitat. In other words as part of a greater scheme to abandon flood defence itself and let the Levels revert to nature.
Someone needs to send the EA a copy of "Conference at Cold Comfort Farm". It covers academia, mystical notions of nature, water voles and engineering very thouroughly. For instance
Have you seen Ticklepenny’s Well lately? You always took such an interest in it, I remember.’
‘Nay, I niver goes theer. It fair curdles my belly ter see ut. Th’ well! wheer I used ter spit down into th’ dark secret waters!’
‘Yes, it must be very upsetting for you. There is no water there now, you know.’
‘Th’ water knows. An’ th’ water flows’ crooned Urk, gazing off through the darkness towards Ticklepenny’s Field, ‘Ay, it’s gone away after th’ water-voles, th’ water has.’
‘It would be a good thing to get the well working again, with constant cold water and a bucket. Don’t you agree?’ After a longish pause Urk made the helpful remark that there was now a curse on the well, so that neither water nor water-voles could return to it. ‘Surely it is simply a question of removing the bricks which block the hole where the stream enters?’ said Flora.
‘Nay. Ye dunna know. ’Tes a curse.’
‘It’s bricks,’ muttered Flora, but did not argue the point, for his interest was aroused and she did not want to annoy him.
ABC
The costs of dredging were highlighted over at Eureferendum
"An example was given by my Drainage Board source. To dredge a 1.2-mile section of the Parrett, they got a quote of £7,500. For five miles dredging of the same river, the Environment Agency claims it will cost £4 million. By then assessing the economic cost of flooding agricultural land as zero, it is then very easy to show that flood prevention is not "cost effective".
Another interesting political question is are the politicians due to break this weekend for a week?
lapogus wrote:
"Incidentally, I read a comment last night that the EA staff and contractors have been very busy in East Anglia clearing ditches and drains, which is maybe a sign that they have learnt some lessons from Somerset."
When Hull flooded two or three years back, it was discovered the reason most houses got flooded was that the council hadn't cleaned the drains since before Noah's flood. Red faces, 'lessons to be learned' etc. So for the next year they carefully cleaned the drains and put up big yellow notices saying 'we've cleaned the drains'. Back to normal now.
It is the cost of disposing of dredged silt which is part of the problem. EU regulations has turned dredged silt into a controlled waste which is expensive to deal with. If the silt could be placed next to the river cost would be greatly reduced.
Anyone who has worked with the UK Environment Agency should not be surprised that they put the interests of nature above humans. I had the experience of a senior EA official quite seriously tell me that we should abandon one of our major city centres in the North of England and relocate it somewhere else. The Agency is infested with 'green zealots', rather than people whose primary duty is to serve the needs of the population who pays their wages.
8:41 PM Charlie
AIUI the disposal of dredged silt "hazard" is based largely on worst case stagnant pond scenario where it might have been sat there happily will 'o the wisp fermenting away for years (several of the river dredge spoil reports I've looked at witter on about Phosphorus and then disappointedly declare that they didn't find any...) It seems largely a makework for clipboard wielders and dredging conglomerates to milk - the Dutch & Belgians are very good (world class) at this.
A large part of the problem is the obstructiveness of the officials which is of such an order that obtaining a waiver for riverside spoil placement might take years and tens of thousand of pounds to move benign mud a couple of hundred metres - which can't be right.
Dredging is not a panacea - but where it's actually appropriate to hamstring it's implementation in the way they have - is madness.
@ChrisY
The demands placed on some farmers and ground workers working on water courses are simply so bizarre as to have those folk simply speechless. "I want you to rescue every worm in the field before you plough it"
It seems pretty clear which molluscs' interests were being served here, and they weren't the ones that live underwater.
Being a danged furriner, I don't know anything about the pros and cons of dredging the Thames. But the arguments that were used against it are familiar, I suspect, to anyone who lives in a Western country that has been overrun by greenies.
All and any proposals to change the surface of Gaia are evaluated in terms which ensure that either the proposal is knocked back (because it inevitably upsets some critter or plant), or just made so expensive and onerous that many proposals are killed by attrition. The default position is that nothing must change. As we find, again and again, doing nothing often means that things do change - dramatically and for the worse. Devastating bushfires that destroy everything in their path because clearing and preventive burnoffs are banned is a stark example here in Australia.
Both the mindset and the regulatory instruments that support it need either a big bushfire or a river diversion (as with the Augean stables) put through them asap.
Has anybody else noticed how all this rain and wind has been cooling the surface of the North Atlantic?
http://www.ospo.noaa.gov/data/sst/anomaly/2014/anomnight.2.10.2014.gif