1989 proposal, Salient points

Comprising 15.9km in length and generating 8,640MW from some 216 turbines, the proposed barrage would have produced an average annual output of 17TWh, or 7% of the UK’s power demand for circa 120 years 2 and taken 14 years to construct 2, including preliminary studies.

With capital costs of £8.28bn (1989 prices), the scheme would have provided a significant boost to the regions economies – employing towards 35,000 individuals at peak construction periods and at least 10,000 post construction 2.

The proposed scheme involved fixing pre-fabricated concrete caissons onto a prepared estuary bed. 2 large and 2 smaller locks would have provided shipping access to docks landward of the barrage at a cost of over £600 million (1989 prices) 12. A dual carriageway (in both directions) for the general public would enhance regional transportation links between South Wales and Somerset, boosting post construction economies 2.

Particularly in the early years, engineering projects of this scale tend to attract significant tourist volumes. Indeed, the report estimates that tourism would increase by as much as 5-20%; attracted both by the engineering and the vast water sport potential, creating towards 2400 full-time jobs. Significantly more work opportunities would be gained from housing and marina developments, with property prices predicted to raise strongly 13.

Difficulties with the scheme

Amongst other NGO’s, the Gloucestershire Wildlife Trust opposed these plans due to their detrimental effect on the tidal regime and migratory bird and marine life (appendix A). Studies 14 have shown that 19% of European and North African wintering ringed plover rely on the Severn estuary during summer months and 7% of Bewicks Swans depend on the estuary (table 1 – full table in appendix B). Remarkably, the significance of the estuary to both of these species is ignored in the 1989 proposal. Analysis is only mentioned for “over-wintering speciesin the context of breeding populations” 15. This method reduces the proportion of Ringed Plover that rely on the estuary from 19% to 0.6% and eliminates Bewicks Swan entirely 15. These deflated figures are achieved despite basing the percentages on NW European populations and not Europe & North Africa (a larger area and therefore theoretically greater numbers are needed to achieve the 1% threshold of an internationally important site) as required by international standards 12.