Seven Times Severn?

The debate about the proposed barrage on the estuary between Devon and Wales is hotting up (http://www.guardian.co.uk/environment/2008/jun/12/conservation.wildlife1)! Many of the environmental groups whose primary focus is on animals appear to think that the impacts are likely to be too great to contemplate (e.g. displacements or reductions of important wader populations of birds and some serious problems for the fish that move up and down the river for spawning). This is not to mention the loss of the famous Severn bore. They also seem to argue that the costs of the barrage could be directed to other 'more efficient' means of 'green' energy savings such as paying for building insulation and/or increasing the use of wind turbines. Environmental bodies that are more concerned with energy production and climate change (http://www.guardian.co.uk/environment/2008/jun/17/renewableenergy.alternativeenergy) appear keener on the project (as do local politicians who see the development in terms of 'jobs', in spite of the requirement for specialist builders who are likely to be imported). The chances of the UK fulfilling its quotas of reductions of 'greenhouse gases' without something substantive happening appear quite slight. It is actually quite difficult to judge the impact of a development like this. It is uncertain whether the river would be 'allowed' to be subject to major cycles of level fluctuation (this would influence the degree to which mud flat feeding sites are exposed for birds). Changes in the water movements could even result in more deposition of sediments in some locations. Turbines would be difficult obstacles for fish movements but some fish species (e.g. eels) are easier to accommodate than others. I suspect we are at the beginning of an increasingly acrimonious debate.