page_title: Somerset Levels
section_title: Sea defences
hierarchical_section_title: Somerset Levels / Water management / Sea defences
caption_attribution_description: English: The sea wall at Burnham-On-Sea
context_page_description: The Somerset Levels are a coastal plain and wetland area of Somerset, England, running south from the Mendips to the Blackdown Hills.
  The Somerset Levels have an area of about 160,000 acres and are bisected by the Polden Hills; the areas to the south are drained by the River Parrett, and the areas to the north by the rivers Axe and Brue. The Mendip Hills separate the Somerset Levels from the North Somerset Levels. The Somerset Levels consist of marine clay "levels" along the coast and inland peat-based "moors"; agriculturally, about 70 per cent is used as grassland and the rest is arable. Willow and teazel are grown commercially and peat is extracted.
  A Palaeolithic flint tool found in West Sedgemoor is the earliest indication of human presence in the area. The Neolithic people exploited the reed swamps for their natural resources and started to construct wooden trackways, including the world's oldest known timber trackway, the Post Track, dating from about 3800 BC. The Levels were the location of the Glastonbury Lake Village as well as two Lake villages at Meare Lake.
context_section_description: The Levels were frequently flooded by the sea during high tides, a problem that was not resolved until the sea defences were enhanced in the early 20th century. In addition, the problems of high fresh water floods are aggravated by the unrestricted entry of the tide along the Parrett, which is the only river in the Levels and Moors that does not have a clyse on it. Discussions on whether a clyse is needed for the Parrett and whether it should be sited at Bridgwater or nearer the mouth of the river date back to 1939, at the start of World War II, and have not been resolved.
  On 13 December 1981, a large storm hit the North Somerset coast. Meteorological conditions caused a large rising surge in sea level in the Bristol Channel, and wind was measured at 40 knots (74 km/h; 46 mph). Over topping of the sea defences along a 7 miles (11 km) stretch of the Somerset coast at 22 locations from Clevedon to Porlock began after 19:30. Although there was no loss of life, the resultant flooding covered 12,500 acres (5,100 ha) of land, affecting 1,072 houses and commercial properties, with £150,000 worth of livestock killed and £50,000 of feed and grain destroyed. Wessex Water Authority estimated the total cost of the damage caused at £6M. This resulted in a three-year programme of sea defence assessment, repair and improvement. With 400 properties affected in Burnham-on-Sea, after emergency repairs, Wessex Water Authority began planning new sea defences. Construction work started in 1983 on a £7M scheme, creating what was then Britain's biggest wave return wall.
  The Environment Agency's current "Parrett Catchment Flood Management Plan", published in December 2009, divides the Parrett catchment area into eight sub-areas, with the Somerset Levels and Moors falling into sub-area 6 and Bridgwater falling into sub-area 7. As part of the published flood risk assessments for both these sub-areas, it is recognised that: at a future date a tidal clyse may be needed on the Parrett; this causes a funding dilemma; and, geomorphology studies of the Parrett and the Tone are needed to help address many of the uncertainties associated with a tidal exclusion project.
caption: The sea wall and defences at Burnham-on-Sea
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