There is wonder in technology and human ingenuity, but the most wonderful technology is one that leaves nature intact and thriving, while deriving benefits for human society. Invisible, replaceable, upgradeable, removable, sustainable and modular. Elegant not brutal, clever but not macho, evolving, not monolithic.

Morgan Parry
Head of WWF Cymru

Prof Simon Haslett, Head of Geography at Bath Spa University has been talking to the Gloucester Citizen and has this to say:

Canadian scientists are urging the British Government not to go ahead with the Severn Barrage. They have warned it could cause major environmental damage and waste millions of pounds of taxpayers’ money.

Concerns about the planned Severn Barrage came to light at a major environmental summit in Canada.

Bath Spa University scientist Prof Simon Haslett, who spoke at the conference, says Canadian scientists are alarmed about the scheme from their own experience of harnessing tidal power.

The head of geography in Bath Spa’s School of Science and the Environment is warning that Britain should not make the same mistakes.

Prof Haslett gave a briefing on the Government’s proposal to build a barrage across the Severn Estuary at the annual conference of the Atlantic Geoscience Society in Halifax, Nova Scotia.

His presentation was part of a special session on Canada’s own experiment with tidal power in the Bay of Fundy.

This has the highest tidal range in the world, even higher than the Severn Estuary.

But Canadian experts at the conference told him the Bay of Fundy scheme had caused serious environmental damage and they were shocked that a Severn Barrage was even being considered.

Prof Haslett 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.

“The UK needs to learn from their experience and not make the same mistakes.

“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 so old that they are amazed the UK is even considering it.

“The Canadians now only use turbines that are placed in the tidal stream, so that electricity is generated both on the falling and rising tide.

“Some turbines are submerged on the seabed, so you can’t even see them - a bit like undersea wind farms.”

Prof Haslett has researched and written extensively on the Severn Estuary over the past 10 years.

“If the Canadians are right, we shouldn’t even waste any time and millions of pounds of taxpayers’ money considering a barrage,” he said.

The Petitcodiac River in the Bay of Fundy has extensive experience of dams and barrages. These photos show graphically the alarming rate at which mud is deposited when the flow is slowed by and obstruction - in this case a causeway with a sluice gate. They experienced deposition rates of 1m per year!

The Petitcodiac River in 1954

The Petitcodiac River in 1996

What went wrong? Mud breeds mud. - more photos and details of the Petitcodiac experience.

The good news is that lessons have been learned. Due to the extent of the unforeseen silting problems and subsequent pressure of flooding, the causeway in now being removed and replaced with a bridge. It is hoped this will restore the river to a healthy and navigable state.

I have been following the developments of these proposals for the last five years and this story is full of misconceptions, so many in fact that it looks like it is designed to deliberately mislead. I have attended conferences by the Institute of Civil Engineers in Cardiff and the Severn Estuary Partnership in Clevedon and feel well qualified to comment.First of all I would like to let you know what’s in the estuary all ready. We have Salmon fishing and it is Europe’s biggest inland fishery because of the elver fishing. Porpoise and dolphins have been seen as far north as Gloucester and seals bask on the sand bars of Newnham. It is alive with wildfowl and has the astonishing spectacle of the Bore. People come from all over the world to see our natural wonder. It is the oldest documented wave in the world as the Romans wrote about it.

INCREASED FLOODING

The most blatant piece of misinformation is the claim that a barrage would have a role in flood defence. None of the barrage proposals have flood defence in mind. They would in fact aggravate flooding both downstream and upstream. The incoming tide would be constricted, resulting in the seaward side rising by up to a metre, threatening low-lying coastal areas. The catastrophic floods suffered by Worcestershire and Gloucestershire this year were caused by rain. This caused huge amounts of freshwater to flow down the Severn. If a barrage had been blocking its escape out of the estuary the floods could have been worse and lasted longer. I have been told in person by the engineers involved in the barrage design that flood mitigation has not been part of their brief.

DOWN ON POWER

The claims for power output are exaggerated. The actual projected figure is nearer 5% and while this sounds a lot, by the time losses in transport across the national grid are taken into account it will be nearer 3%. Importantly this power will only be produced twice a day, not all the time. It would provide 3% of power supply just twice a day only on the outgoing tide. This would not only overload the national grid with surges of power, it would also come too late to hit the morning or evening power demand spikes. This is because the power can only be generated on ebb tides with low tide on the Severn always after the morning and evening peak. This surge of overproduction twice a day would also require a strengthening of the national grid to cope with it. This would of course be an additional expense.

THE PEOPLE PAY

The projected costs have been under reported. The budget projected for the proposed Weston-Cardiff scheme is £17 billion. Most people expect this to double to see a completed project - a possible cost of £34 billion - all of this would have to be met by us through our taxes.

The fact is, £17 billion is a colossal amount of public money. Spending this amount on microgeneration would be much more efficient - for example, by paying for or subsidising efficient small-scale wind turbine and photovoltaic cell installation in both new build and existing homes. The payback here would be much bigger and the environmental impact tiny by comparison.

It is reported that a publicly financed scheme would produce cheaper electricity. This is only if it is subsidised further by the Government again using our taxes. A ‘green’ subsidy would have to be found again out of the public purse.

IRREPLACEABLE

Under UK and European law, any lost habitat would have to be compensated for with the same sort of habitat. In the case of the Severn this would be impossible as there is no other ‘harsh estuarine habitat’ in the UK, that is why it is so protected. It would have to be recreated and this too would be impossible.

BLOCKED BY MUD

One of the biggest problems any barrage would face is that of silting. The water in the estuary contains a colossal amount of silt. The problem would not be with the turbines as technology exists to keep them clear, the problem would be with the estuary itself. The silt is kept in suspension by the speed of the tides. If the water was slowed down, as it would be if the tide was held in by a barrage, the silt would fall out of the water and could block up the estuary. This would render the proposed scheme useless as the water would have nowhere to go. This also has the potential to create more flooding problems. I was lucky enough to talk to a representative from the Bay of Fundy in Canada that has a higher tidal range than our river. They had rejected the idea of barrages as they projected they would be rendered inoperable in only two years. (I wonder if this is why private money is not funding the proposal).

‘GREEN WASH’

Mr Hain in the article, insists that this proposal is ‘green energy’. It simply is not. The effects on the estuary of building a barrage would be devastating. It would decrease the UK’s overall biodiversity by destroying a unique harsh habitat - one that could not be recreated anywhere. The wider affects of changing the sea levels on surrounding areas have the potential to be devastating. The amount of raw material needed to build the Weston-Cardiff proposal would have to be found and transported from somewhere.

The smaller proposal of the Shoots Barrage below the 2nd Severn Crossing would still have the same devastating effect on the estuary and the problems of silting are much worse this far up the river and the return on electricity generated is much less.

Mr Hain goes on to talk of the scale of construction and the potential for development in the area and the enlarging of Cardiff airport. These plans rub off his thin ‘green’ paint. These aims are not in line with environmental targets and are would lead to an increased use of fossil fuels and demands on resources. I also think that his ambitions are misleading, as any development around the river and estuary would still be restricted by the existing protection afforded by planning designations.

THE EXPERIMENT

The small barrage at La Rance in France is often held up as an example of what can be achieved. There is a flaw in this comparison as La Rance is a steep sided sandy estuary with negligible fresh water out flow, were as the Severn is flat, shallow and muddy. Even so, La Rance still suffers problems with silting, showing what a huge problem it could be in the Severn. It is interesting to note that La Rance was built as prototype for a much bigger scheme across the Mont Saint Michel Bay, which has never been built.

OUR BRIGHT GREEN FUTURE

The Severn is a spectacular place, let’s not ruin it for generations to come by choking it with one of these outmoded schemes. Let’s not leave them with the problem of clearing it up when it has fallen into disrepair. The cost of de-commissioning a barrage would also have to be factored in, just as it is for conventional and nuclear power stations.

If we truly have an ambition for a ‘green’ sustainable future then micro generation offers much more scope. A modest and sustainable amount of power can be harnessed from the Severn using underwater windmills called Tidal Stream Turbines. These are being developed and produced by a company in Bristol. They have already been trialed in the Bristol Channel off Ilfracombe and, unlike the old technology of barrages, they are being constantly developed. The latest model is now being installed in Strangford Lough in Northern Ireland. The future is bright and we shouldn’t be tempted or worried into shortsighted ‘green elephant’ projects - we can be much smarter than that.

Stuart Ballard. BA(hons)