Severn Estuary Tidal Power: Supplemental Information May 2010 Together with the Severn Estuary Tidal Power research paper, this report provides briefing on the current Severn tidal power situation and includes detailed analysis of the short listed proposals. The National Assembly for Wales is the democratically elected body that represents the interests of Wales and its people, makes laws for Wales and holds the Welsh Government to account. The Members’ Research Service is part of the National Assembly for Wales. We provide confidential and impartial research support to the Assembly’s scrutiny and legislation committees, and to all 60 individual Assembly Members and their staff. Members’ Research Service briefings are compiled for the benefit of Assembly Members and their support staff. Authors are available to discuss the contents of these papers with Members and their staff but cannot advise members of the general public. 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Enquiry no: 10 / 1008 Severn Estuary Tidal Power: Supplementary Information May 2010 Chris Peters Paper Number: 10 / 011 - SI Members’ Research Service gratefully acknowledges the parliamentary fellowship provided to Mr Peters by the Natural Environment Research Council, which enabled this research paper to be completed. Contents 1. Middle barrage (Cardiff – Weston) ............................................................................................1 1.1. Construction ..........................................................................................1 1.2. Timeline.................................................................................................1 1.3. Projected cost ........................................................................................2 1.4. Socio-economic impacts.........................................................................2 1.4.1. Transport and logistics ..........................................................................3 1.4.2. Tourism .................................................................................................4 1.5. Fisheries ................................................................................................5 1.6. Environmental impacts...........................................................................6 1.6.1. Terrestrial and freshwater ecology.........................................................6 1.6.2. Ornithology ...........................................................................................8 1.6.3. Bird watching.......................................................................................10 1.6.4. Marine ecology ....................................................................................10 1.7. Geomorphology ...................................................................................11 1.8. Flood risk.............................................................................................12 1.9. Historic environment ...........................................................................14 1.10. Navigation ...........................................................................................15 1.11. Marine aggregates ...............................................................................16 1.12. Marine waste disposal..........................................................................16 2. Small barrages (Shoots barrage and Beachley barrage) ............................................. 18 2.1. Construction ........................................................................................18 2.2. Socio-economic impacts.......................................................................18 2.2.1. Transport and logistics ........................................................................19 2.2.2. Tourism ...............................................................................................20 2.3. Fisheries ..............................................................................................20 2.4. Environmental impact ..........................................................................21 2.4.1. Terrestrial and freshwater ecology.......................................................21 2.4.2. Ornithology .........................................................................................21 2.4.3. Marine ecology ....................................................................................22 2.5. Geomorphology ...................................................................................23 2.6. Flood risk.............................................................................................24 2.7. Historic environment ...........................................................................24 2.8. Navigation ...........................................................................................25 2.9. Other sea uses.....................................................................................26 3. Tidal lagoons (Fleming and Bridgewater Bay lagoons) ............................................... 28 3.1. Construction ........................................................................................28 3.2. Socio-economic impacts.......................................................................28 3.2.1. Transport and logistics ........................................................................29 3.2.2. Tourism ...............................................................................................29 3.3. Fisheries ..............................................................................................30 3.4. Environmental impact ..........................................................................30 3.4.1. Terrestrial and freshwater ecology.......................................................31 3.4.2. Ornithology .........................................................................................31 3.4.3. Marine ecology ....................................................................................32 3.5. Geomorphology ...................................................................................32 3.6. Flood risk.............................................................................................33 3.7. Historic environment ...........................................................................33 3.8. Navigation ...........................................................................................34 3.9. Other sea uses.....................................................................................34 4. Comparison with La Rance and Eastern Schelde............................................................ 36 4.1. La Rance ..............................................................................................36 4.2. Eastern Schelde....................................................................................37 Annex ............................................................................................................................................................. 39 A. Glossary of terms...........................................................................................................................39 Energy terms ....................................................................................................................................39 B. Abbreviations...................................................................................................................................40 1. Middle barrage (Cardiff – Weston) 1.1. Construction Construction of caissons1 and turbines and the employment of general construction labour are the three greatest components that will impact socially and economically on local areas.2 There is great uncertainty regarding the displacement, or ‘leakage’ of construction related economic benefits from local to national or even international areas. The sheer number of turbines required in a large (Cardiff – Weston) barrage may result in the turbines being constructed in the region.3 A smaller barrage for example may see an increased leakage of turbine construction out of the immediate area as technology is sourced from elsewhere. The issue of leakage affects all areas of construction. Turbines have been used as an example as they represent a substantial element of the overall project cost.4 1.2. Timeline The Severn Tidal Power Group (STPG) consider that the Cardiff – Weston barrage could be built in approximately seven years, depending on the number of work yards made available for the construction of caissons, and on the sizes of ship locks5 required. The ship locks are a key element of a barrage construction and must be completed before the installation of turbine caissons starts to obstruct shipping lanes.6 Lord Hunt, Minister of State, Department of Energy and Climate