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Friday, May 12, 2006

More on the Severn barrage

Interesting letter in the Western Mail this morning from Dr W Roscoe Howells, the former Director of Scientific Services, at the Welsh Water Authority. On the proposed Severn Barrage he writes:

In the early 1980s, I participated in discussions on the likely effects on the environment of a tidal barrage in the Severn estuary. The group concerned comprised representatives of various statutory bodies, including a representative of the then Welsh Office.

We identified a number of problems which could arise.

They included significant changes in water quality and sediments up and down stream of the barrage as well as major effects on birds and other animals living and feeding in and around the estuary.

Another concern was the effects on fish living in the estuary and passing through it. Some of the rivers flowing into the estuary have very important and valuable salmon fisheries and the impact of a barrage could be disastrous.

Only a very few tidal barrages have ever been constructed and significant environmental problems have been experienced at all of them. The construction of a barrage in the Severn would change that estuary for ever.

The "re-emergence" of this scheme has been generally welcomed in the press and in other quarters. In view of the facts, this enthusiasm must be tempered by realism and great caution.

I believe that the Labour Assembly Government must take these concerns seriously and ensure that they are taken into account in any proposals. This is particularly so in the light of the rather curious stance taken by the Minister for Enterprise, Innovation and Networks in the short debate on this subject on Wednesday.

On the Severn Barrage he made some very valid points:

Why does the Assembly Government propose that the Severn barrage should be considered? There is an overwhelming need to reduce our carbon emissions while increasing the amount of electricity produced, so we would consider it extremely foolish to ignore the potential of such a development as the Severn barrage to produce 17 TWh per year. As Rosemary Butler said, it would be equivalent to two large nuclear power plants operating for at least 120 years, and that without the problems of treatment, long-term storage, and disposal of nuclear waste from spent fuel and reactor decommissioning.

He then went on though to comment on the idea of tidal lagoons as an alternative:

Members raised the issue of tidal lagoons in the Severn estuary and elsewhere, and they have been put forward by some as an alternative to a barrage. We would welcome such lagoons if they can be shown to be effective, robust, financially viable, socially acceptable, and environmentally benign.

Surely, these conditions must apply to a barrage as well. The Minister cannot have it both ways, he must maintain an open mind on lagoons. It was pleasing though that he then went on to say:

Concerns have been raised in the chamber and outside about environmentally designated sites, and one cannot, and must not, underestimate the importance of environmental issues when considering the feasibility of such a barrage. Any study of the pros and cons of a barrage will have to consider its potential impact on the Severn estuary special protection area, the proposed special area of conservation in the Severn and on the special areas of conservation relating to the Wye and Usk rivers. We will need to know whether, and to what extent, important species of fish and birds would be affected. It would be appropriate for the study also to consider what impact changes resulting from global warming will have on these species. We need to consider both sides of the issue.

We believe that a new study would need to consider the environmental impacts, the effect on shipping to upstream ports—although I note that the city of Bristol supports our position on a Severn tidal barrage—flood defence issues, as Rosemary Butler has said, the impact on fishing and water recreation, and the knock-on economic consequences for both sides of the Severn.

This is a very important debate, but it is one in which we must not lose sight of the wider environmental impact of any proposal as happened with Cardiff Bay.
Any ideas what would happen to the Severn Bore if a barrage were to be built?
No, but I suspect it would be affected by any structures put in the Severn Estuary.
If there is a barrage the bore is gone.

I was brought up on the bankis of the Severn. Tidal lagoons yes - barrage no!
it is unclear whwther the bore would be gone, it seems that the tidal 'wave' may well propogate through the sluices that let water in to the impounded area and produce a surfable wave, check out the paper submitted to the ICE by Kirby and Shaw in 2002 on environmental impacts of the barrage(even if they are a bit millitant!). as a surfer i would be gutted by the loss of such a freak wave... but if sea level rises because we do sweet f a about global warming many of our best waves will be lost underwater.. that would suck ass, dude. and the birds will be screwed as well... (sob)tidal stream may be the best answer (see www.marineturbines.com) keep talking and thinking, but dont speak from the heart, but from the brain...
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