Anthony Gibson, former south regional director of the NFU: A case for dredging

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Written by:   | Posted 17-January-2014 8:53

I don’t really need to make the case for dredging the rivers on the Somerset Levels.

The Environment Agency’s computer modelling, carried out in the wake of last year’s floods, has done it for me.

This demonstrated that, if the carrying capacity of the Parrett and Tone was restored from its existing 60 per cent of potential to around 90 per cent, the severity of flood events would be, in their words, “significantly reduced”.

What does that mean? Well, last winter, the worst affected area, Curry Moor, would have been under water for three weeks, rather than three months, the village of Moorland might not have flooded, the A361 would have remained open for all but a few days and the bills for the eventual pumping out and the flooding-related damage would have been vastly smaller.

There are those (and they include a former EA chairman in Baroness Barbara Young) who argue that the only truly ‘sustainable’ solution would be to close the pumping stations, breach the flood banks and allow the waters to spill out over the flood plain whenever rainfall and tides dictate.

This, they claim, would allow the flood plain to do the job it is supposed to do, spreading the floodwaters over a wider area and creating in the process a paradise for wetland birds and plants.

If the Levels and Moors were a typical flood plain, this might make sense. But it is not. It is one of the most artificial landscapes and ecosystems in Europe. It is as it is – with all of its conservation designations – because of the way the water has been controlled and managed over the centuries.

The flood banks which have been built alongside the Parrett and the Tone mean that the level of the water in the rivers is anything up to ten feet above the level of the land.

This makes them, in the language of the drainage engineers, “high level carriers”.

And the problem with a high level carrier is that, after it has flooded, water will only run back into it when the level in the river is lower than that on the land.

If you take the current flood, it could be months before river levels have fallen far enough for gravity drainage to clear the last of the flooding, months in which the residual floodwater will have become so stagnant, de-oxygenated and polluted that you daren’t allow it to drain back into the rivers, for fear of killing all the fish.

From being a drained marsh, the moors would become a foetid swamp. This is not a theoretical scenario. It is precisely what happened in the summer of 2012 when the floodwater did indeed become so polluted that the EA could not pump it back into the rivers without treating it first with what seemed like the UK’s entire supply of hydrogen peroxide.

Wildlife sites on which millions of pounds of taxpayers’ money had been spent were reduced to a slimy, stinking mess. That will be the future for the Levels if the ‘let nature take its course’ fundamentalists have their way.

I have been much involved in recent months in the Levels and Moors Task Force, which includes all the key interest groups, to put together a “vision” for how the area might look in 2030 and, from that, will move on to finding ways and means of making it a reality.

The consensus is that we want the Levels to remain the green gridiron of rhynes, willows and droves which it is now, with extensive grassland farming and a rich mixture of wetland wildlife combining for their mutual benefit.

But such a vision isn’t worth the paper it is written on if we do not regain control of the water. Managed, it is a blessing; uncontrolled, a curse. Yes, we can make greater use of the gravity floodplain, and action to reduce the speed and volume of run-off from the upper catchment is essential, but de-silting the rivers and keeping them clear is the key.

This would not mean an end to flooding. Areas like Currymoor will still flood after heavy winter rainfall. That doesn’t just save Taunton and Bridgwater from flooding, it also means that people, business, farming and roads on the slightly higher ground within the Levels are protected.

But that all depends on the rivers being restored to something like their full capacity, so that from Long Load in the east to Westonzoyland in the west, land will be slower to flood, volumes will be lower and the pumps can be run earlier and not for as long.

The sort of flooding which has made the lives of the people of Moorland, Muchelney, Thorney and Westonzoyland such a misery for the past two winters, and which has wrought such havoc with farming and the local economy, really would then become a once in 100 year nightmare, not one that happens every year.

Former south regional director of the National Farmers Union and the organisation’s ex-media director Anthony Gibson has been representing farming interests on the Somerset Levels.

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