Silt laden Severn water - all this fine silt will be deposited if the flow is forcibly reduced

Same old barrage of misinformation

10.21.08

I must congratulate Jonathan Porritt for a beautiful and expensive presentation on BBC Wales “Week in / Week Out”. My fear is that one of the previous leaders in the environmental debate is being misled by the very commercial pressures that he wished to harness. Jonathan is presenting with great conviction and passion, the outmoded half-truths developers have been spouting for years to get a great construction project underway and feed the profits of their shareholders. This deception and manipulation deeply saddens me.

One has to ask, who is financing this slick presentation and how were they able to convince the BBC to present such a one sided and self-interested presentation on a national issue? This amounts simply to propaganda. I take my hat off to the consortium of construction companies who are straining at the leash to start pouring concrete into the river with their “get rich quick scheme”.

Clearly misleading

The barrage proposals were spoken of as “proven technology”. This is unfortunately simply untrue. There are no schemes like this any where in the world. Jonathan has fallen for one of the simple deceptions being pushed by industry that the tidal power plant in La Rance is comparable with plans for the Severn. Firstly the Rance River is tiny. The structure there is more like a bridge. And fundamentally, the water is crystal clear and not bit like the magnificent brown Severn. The important thing here and something the pro-barrage scientists continually gloss over is silt. Silt on a massive scale, silt that could render a barrage a dead lump of giant concrete in a stinking life-less river in a matter of decades. If anything has been proven about barrages, it is that they don’t work in silty estuaries. Scientists with years of experience on the Severn and similar estuaries worldwide are trying to warn us, but their voices are being brushed aside by the developers and Jonathan is blinkering himself and believing what he is told about the evidence.

In the program, much is made of Roger Falconer’s research in Cardiff University. I have no doubt that he is a well read and canny man. But his models have glaringly obvious flaws. The extensive plastic models are shown with steep sides and pumping clear water. This further promotes the myth that the Severn is like La Rance. So why is such a clever man, pushing these misleading models? What is his agenda? Could the fact that his research is sponsored by a Halcrow, a construction company be skewing his perspective? Is this the manipulative hand of industry influencing science for its own ends?

Old beliefs

Things have moved on since these old plans were first brought to the table. Jonathan, with his alarmist view of looming catastrophe, would do well to take his head out of the sand and look at the advances in technology. Devices now exist that would allow us to generate tidal power from the Severn forever, true renewable energy.

The pointless and emotive sacrifice of a fully functioning river system to the gods of climate change is a misguided indulgent “green” luxury. Jonathan’s “mega green” project is simply not what he is claiming. I fear his well-earned reputation as the “high priest” of environmentalism is being tarnished by a diet of manipulative misinformation.

Is a barrage a renewable energy source?

10.07.08

The Sustainable Development Commission states that, because of siltation, a Severn barrage could lose half its capacity within just 10 years. The Government defines renewable energy as being inexhaustible. Can a barrage across the Severn be described as producing “renewable” energy if it “uses up” the resource, which is the funnel shaped estuary?

Government studies show that silty estuaries are not suitable for tidal range storage schemes like barrages and lagoons. In Canada, where similar schemes have been tried, whole estuaries have been become blocked with vast expanses of mud. How long could the Severn estuary produce power in this state?

If the Severn flowed with crystal clear water like La Rance in France, then a barrage might work. But La Rance’s geology is totally different with tidal power produced in an estuary with steep granite sides. Even so, silting problems here have meant this pilot scheme has not been rolled out.

Learning from a costly Canadian mistake

Prof Simon Haslett from Newport University has studied the Severn for over ten years, he said:

“The Canadians have been experimenting with tidal power generation in the Bay of Fundy for many years, building a barrage across one of its tributaries as long ago as 1984.

The consequences have convinced them that building a barrage is inefficient, has many undesirable environmental impacts and is unsightly.

For the Canadians the idea of a barrage is now history and doesn’t even get raised as an option during tidal power debates.”

It’s mud and it sticks

Dr Graham Daborn, a world-leading expert on estuaries, points out that estuarine silt can’t be modelled in the same way as sand - a non-sticky grain. As a living thing containing mini molluscs, bacteria and worms, silt deposits are stickier than sand and do not simply wash away. In fact, silt accumulations could be around 80 times stronger than traditional modelling predicts. He states that, “such accumulations would quickly fill up an estuary”.

The harnessing of truly renewable energy is possible in the Severn using tidal stream turbines. These are devices placed in the tidal current a little like underwater windmills. Canada is already embracing this leading edge technology in the Bay of Fundy - with turbines produced right here in the UK! The latest tidal stream devices are perfect for the shallow Severn.

To continue down the blinkered path of barrages and tidal storage solutions is fruitless. Not only is it exorbitantly expensive for the UK taxpayer, it is unlikely to work for long, it will destroy an irreplaceable resource and leave an indelible scar on our landscape. We need to help our Government embrace more effective, lower impact and truly renewable technologies.

Stuart Ballard
Save Our Severn

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