- Severn Estuary
The Severn Estuary ( _cy. Môr Hafren) is the
estuaryof the River Severn, the longest riverin Great Britain. Its high tidal rangemeans it has been at the centre of discussions in the UKregarding renewable energy.
In navigational and cartographical terms, the river becomes the Severn Estuary after the
Second Severn Crossingnear Severn Beach, South Gloucestershireand stretches to a line from Lavernock Point(south of Cardiff) to Sand Point near Weston-super-Mare. The estuary is about convert|2|mi|km wide at Aust, and about convert|9|mi|km|0 wide between Cardiff and Weston-super-Mare.
The estuary forms the boundary between Wales and
Englandin this stretch. On the northern side of the estuary are the Caldicot and Wentloog Levels, on either side of the city of Newport; and, to the west, the city of Cardiff together with the resort of Penarth. On the southern, English, side, are Avonmouth, Portishead, Clevedon, and Weston-super-Mare. Denny Islandis a small rocky island of convert|0.24|ha|acre|1|abbr=off, with scrub vegetation, approximately three miles north of Portishead. Its rocky southern foreshore marks the boundary between Englandand Wales, but the island itself is reckoned administratively to Monmouthshire, Wales.
The estuary has one of the highest tidal ranges in the world — about convert|15|m|ft|0. [cite web | url= http://www.environment-agency.gov.uk/commondata/acrobat/severnpositionmay2006_1508223.pd | format= PDF | work= UK Environment Agency | title= Severn Estuary Barrage | date=
31 May 2006| accessdate= 2007-09-03 ] [cite web | url= http://www.bbc.co.uk/bristol/content/articles/2005/07/04/bristolchannel_feature.shtml | title= Coast: Bristol Channel | work= BBC | accessdate= 2007-08-27 ] During the highest tides, the rising water is funnelled up the estuary into the Severn bore, a self-reinforcing solitary wave that travels rapidly upstream against the river current. [cite web | url= http://www.environment-agency.gov.uk/regions/midlands/434823/ | publisher= Environment Agency| title= Severn Bore and Trent Aegir | accessdate= 2008-01-13] . The estuary's funnel shape, its tidal range, and the underlying geology of rock, gravel and sand, produce strong tidal streams and high turbidity, giving the water a notably brown coloration.
The tidal range also results in the estuary having one of the most extensive intertidal wildlife habitats in the UK, comprising mudflats, sandflats, rocky platforms and islands. These form a basis for plant and animal communities typical of extreme physical conditions of liquid mud and tide-swept sand and rock. The estuary is recognised as a wetland area of international importance and is designated as a
Ramsar site. [ [http://www.jncc.gov.uk/pdf/RIS/UK11081.pdf Information on Severn Estuary Ramsar site designation] ]
West of the line between Lavernock Point and Sand Point is the
Bristol Channel, which in turn discharges into the Celtic Seaand the wider Atlantic Ocean. The islands of Steep Holmand Flat Holmare located close to that line, in the middle of the estuary.
Sometimes the term Severn Estuary is used to refer to a geographically wider area stretching from Gloucester to west Wales and Devon, although the upstream stretch between Gloucester and Aust is more correctly called the River Severn, and the maritime stretch between Wales and the coast of Somerset and Devon is more correctly called the Bristol Channel.
The Severn Estuary has the potential to generate more renewable electricity than all other UK estuaries. If harnessed, it could create up to 5% of the UK’s electricity, contributing significantly to the UK’s climate change goals as well as the European Union's renewable energy targets. [cite web | url= http://new.wales.gov.uk/topics/environmentcountryside/energy/severntidal/?lang=en | publisher=
Welsh Assembly Government| title= Severn Tidal Power| accessdate= 2008-09-01] . A Severn tidal power feasibility studyis, in 2008, currently being undertaken by the UK Government to assess all tidal range technologies (including barrages, lagoons and others). The study will look at the costs, benefits and impacts of a Severn tidal power scheme and will help Government decide whether it could or could not support such a scheme.
evern Estuary Partnership
The Severn Estuary Partnership (SEP) was set up in 1995 as an independent initiative to focus the activities of local government, statutory authorities and interested parties such as farmers and fisherman. Its stated aim is "To bring together all those involved in the development, management and use of the Estuary within a framework which encourages the integration of their interests and responsibilities to achieve common objectives".cite web | url= http://www.severnestuary.net/sep/pdfs/sesengli.pdf | format= PDF | title= Strategy for the Severn Estuary (English language summary) | work= The Severn Estuary Partnership | accessdate= 2007-12-24] In 2001 SEP published the "Strategy for the Severn Estuary", which sets out a plan for the management of the estuary.
SEP uses a geographically extended definition of the Severn Estuary, beginning at the tidal limit of the River Severn in
Gloucesterand ending at a line drawn between Hurlestone Point near Mineheadand Nash Pointin the Vale of Glamorgan.
Severn Tidal Power Feasibility Study
* [http://www.severnestuary.net The Severn Estuary Partnership]
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