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'Dredging could make flooding worse' - says report

By tobymeyjes  |  Posted: February 15, 2014


Dredging would make the flooding worse for some communities, says a report

Comments (11)

Widespread dredging could make flooding in some communities worse in the future – not better – according to a new report.

The report, by The Chartered Institution of Water and Environmental Management (CIWEM), suggests solely relying on the method could make some communities more vulnerable to flooding.

Critics have blamed a lack of dredging of the rivers Tone and Parrett for the prolonged flooding on the Somerset Levels.

Deputy Prime Minister Nick Clegg conceded a visit to Langport that the lack of it was a “mistake”.

However, others, such as the RSPB, have questioned its necessity.

The report instead calls for the promotion of sustainable measures of controlling flood crises, rather than what it calls “politically-motivated, knee-jerk reactions”.

Nigel Hendley, CIWEM’s interim chief executive, said flood risk management is an increasingly challenging balance of measures and decisions which require a sound evidence base and expert judgment.

He said: “Dredging can be successfully employed to reduce flood impact under certain conditions, and alongside other measures to protect river ecology, but it can also have serious impacts on downstream flood risk so requires very careful consideration as an option.

“We should seek sustainable alternatives wherever possible and assess these as well as dredging on a site by site basis."

Janina Gray, from the Salmon & Trout Association and chair for the Blueprint for Water coalition, which has endorsed the report, said leadership was essential in tackling the crisis.

She said: “People across the breadth of southern Britain have been swamped by devastating floods.

“These people are looking for solutions and our report shows those encouraging dredging as a simple solution to a complex problem are offering false hope.

“We need the Prime Minister to show leadership not just now but into the future, working with evidence and experts to make the right long-term decisions for people, businesses and wildlife.”

The CIWEM argued that a longer-term, evidence-based policy of land use management is needed to address both flooding and drought at catchment-scale.

Martin Salter, National Campaigns Coordinator at the Angling Trust, said dredging was not a “silver bullet” but that proper catchment management can “make a difference”.

He said: “Rivers establish flood plains for a purpose and we abuse them at our peril. The government also needs to toughen up rather than weaken planning protection for vulnerable floodplains.

“It's worrying hear that there is currently a 30 per cent increase in applications in locations designated as high flood risk by the Environment Agency.”

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  • Moor2River  |  February 17 2014, 2:23PM

    mr-dwarf - I am sorry I didn't post the link, here is the link to the EA document "To Dredge or Not To Dredge?" http://tinyurl.com/cpr2uyd

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  • Moor2River  |  February 17 2014, 2:21PM

    mr-dwarf, you said "The Somerset levels drainage is so flat that erosion is practically impossible" This demonstrates a lack of understanding of basic hydrology. The sheer power of water moving across even a flat channel is enough to cause erosion of the river channel. This is not disputed by any scientist I have ever come aross. You also claim " There is "science" created by the EA that shows dredging reduce flooding - it's actually in their published documents." I would like to see the link to that publication, but you haven't provided it - but I can provide you with a link to an Environment Agency publication that explains succinctly how "Dredging can be effective for improving land drainage but is rarely able to prevent flooding". Please have a good read of it and if you still disagree, then feel free to produce a relevant counter-argument - with references. "

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  • Pink_Diesel  |  February 16 2014, 11:13PM

    If local people on the Levels had what they wanted, indeed they could organise things that there would be absolutely no more flooding. (To be continued).

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  • bullocks400  |  February 16 2014, 8:09PM

    Glad to have ruffled a few feathers. I think that maybe the gist of my view has been confirmed by the response from 'Moor2River'. Calling me or my view stupid is really high level comment, not. I do not deride environmental care, merely those who insist on their supposed superior opinion, knowledge, level of care and apparent right to 'own' the answer. I find in life that there are generally a range of solutions to problems and the current danger is the assendant of the so called expert who often has a narrow perspective, a self important attitude, limited broad experience and an inability to understand the wider practical issues.

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  • Nikgee  |  February 16 2014, 1:25PM

    I wonder what unnatural rubbish they will dredge up if they were to dredge the rivers?

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  • mr_dwarf  |  February 16 2014, 1:22PM

    The problem with your argument Moor2River is that you don't have any facts to backup your assertions. Whereas there is 28,000 acres of facts showing exactly the implementation of "reconnecting the flood plain" - the river banks at Crombe were actually reduced. Every living thing dead, from the hibernating field mice, hedgehogs, badger cubs, insects, bees, reptiles, snakes, rare plants, crops, trees and even soil bacteria - all killed. Famine follows flood as all the food resources rot and no food resources can grow in the coming season - becuase everything is dead including the soil which is not biologically active. After the flood comes pestilence where dead animals and plants allow clouds of disease carrying flies to breed. Any fish in the flood die as the water recedes. Any water remaining goes stagnant,stagnant water is a breeding ground for mosquitos - which spread blood diseases for both humans and animals. The rush to bring out comments which support the negligence and incompetence is because those concerned have failed both in their "Duty of Care" and use of "Best of practice". IMHO there is a legal case for all organisations who came up with these policies to be sued for damages. All drainage requires maintenance otherwise it will not work, fail to maintain a waterway and the waterway will begin to fail - this is very, very, very basic. There is no "science" to show that dredging would make matters worse on the Somerset levels. There is "science" created by the EA that shows dredging reduce flooding - it's actually in their published documents. The Somerset levels drainage is so flat that erosion is practically impossible - if the Somerset levels is subject to "erosion" problems then god help Scotland, Wales and the Pennines. Like most engineering solutions erosion can be countered by following the correct procedures such as not being incompetent, following best practice, maintaining the whole of the waterway not some arbitrary location, building relief channels, reservoirs and not having them full all year for wading birds and other obvious engineering solutions. It is clear that the current people in charge of maintaining the waterways don't want to, rather than coming up with solutions they just continue to provide excuses - no engineer is employed to do this. I suggest locals go to the Dutch for their "science" and then closely inspect the "science" being created in the UK for it's validity. Begin bringing the agencies concerned to account. A flood plain shows how a river has eroded AND moved over a valley floor over millenia. Rivers in flood kill everything in their path - it will take almost 2 years for those 28,000 acres to even begin to recover. Some parts of the environment will have been lost forever. Flood mitigation is possible with multiple solutions from creating relief channels, aqueducts, canals, dredging, pumps, pipes, reservoirs, ponds, sediment ponds, drainage, reduction of the water table during summer. Most of them are extremely cheap and dont involve risking peoples lives and destroying the environment.

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  • Barri  |  February 16 2014, 12:38PM

    Silt is caused from top-soil run-off from Farmland. Prevent that and you won't have to dredge watercourses and unblock drains.

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  • greyjaybee  |  February 16 2014, 12:37PM

    Nice to observe a piece talking some sense instead of closing down discussion suggesting dredging will not help the flooding of a flood plain. Bullocks400...common sense is taking into consideration the opinion and advice of those who understand the environment and take the long view instead of that of government ministers seeking to give false hope and keep potential voters on side. It is surely obvious to not allow further building on flood plains and to stop using the word ''environmentalist' in a derogatory way as if the very people who wish to protect our surroundings and everything living therein were boogeymen/women.

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  • GregoryBua  |  February 16 2014, 11:37AM

    Start working from home! Great job for students, stay-at-home moms or anyone needing an extra income... You only need a computer and a reliable internet connection... Make *90 hourly and up to *12000 a month by following link at the bottom and signing up... You can have your first check by the end of this week... WWW.WORKS3.ℂOM

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  • Moor2River  |  February 16 2014, 9:52AM

    The problem with your argument b*llocks400 is the people you witheringly describe as 'environmentalists' actually have a valid, proven, scientific point which people ignore at their peril. Dredging increases erosion so in the short term, it may be a 'quick fix', but in the long term you are storing up problems. What it is about common sense and scientific fact that bothers you so much? How stupid to demand a 'solution' (i.e: dredging,) that actually causes more flooding in the long term?

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