"Tidal reef" proposed for River Severn instead of barrage

Severn Barrage should be scrapped in favour of tidal reef - RSPB
Conservationists are calling for a "tidal reef" to be built across the River Severn to generate electricity rather than a barrage.

Louise Gray, The Telegraph 25 Nov 08;

The tidal power at the mouth of the River Severn has the potential to generate up to 5 per cent of the UK's electricity needs.

At the moment the Government is currently looking at 10 different proposals on how to harness the power, including a tidal reef and a barrage.

A barrage from Cardiff in Wales to Weston-super-Mare in Somerset on the other side of the river, is the most well known option. However it is unpopular with conservationists who say that the 10 mile dam will be unsightly and cause major ecological damage by preventing the migration of fish and destroying bird habitats.

The Royal Society for the Protection of Birds, Europe's largest conservation organisation, insists a tidal reef is a better idea than a barrage.

Unlike a barrage, the 12 mile reef from Minehead in Somerset to Aberthaw, in south Wales, will be lower in the water and further down stream. It will also be better for the environment because the slower moving turbines are less dangerous to migrating fish.

However the technology is untested.

Now the RSPB has commissioned a study by Europe's largest firm of consulting engineers to look into the feasibility of a reef.

It concluded that the 12 mile structure of a reef would generate more electricity than a barrage because there will be more turbines working over a longer period of time. The reef would also cost less to build and last longer, according to the report.

Professor Rod Rainey, of engineering consultants Atkins, who authored the report, said: "We believe this scheme could be more powerful but less costly than other plans being put forward, particularly the Cardiff to Weston barrage."

The RSPB also claims a tidal reef would keep intact most of the estuary's saltmarshes and mudflats on which at least 68,000 birds feed in winter.

Dr Mark Avery, director of conservation at the RSPB, said harnessing the Severn's tidal power must not harm wildlife.

"A tidal reef could reign in that damage, cost the taxpayer much less and be built more quickly. Ministers should look seriously at the enormous pitfalls of a conventional barrage and the potential for using the Severn's tidal energy in a much better way," he said.

Ministers are to shortlist some of the 10 proposals for the Severn next month, including the Cardiff-Weston barrage and the tidal reef, stretching from Minehead in Somerset to Aberthaw, in the Vale of Glamorgan.

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