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 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. Several settlements and hill forts were built on the natural "islands" of slightly raised land, including Brent Knoll and Glastonbury. In the Roman period sea salt was extracted and a string of settlements were set up along the Polden Hills. The 1998 discovery at Shapwick of 9,238 silver Roman coins, known as the Shapwick Hoard, was the second-largest ever found from the time of the Roman Empire. A number of Saxon charters document the incorporation of areas of moor in estates. In 1685, the Battle of Sedgemoor was fought in the Bussex area of Westonzoyland at the conclusion of the Monmouth Rebellion.
As a result of the wetland nature of the Levels, the area contains a rich biodiversity of national and international importance. It supports a vast variety of plant and bird species and is an important feeding ground for birds and includes 32 Sites of Special Scientific Interest, of which 12 are also Special Protection Areas. The area has been extensively studied for its biodiversity and heritage, and has a growing tourism industry.
People have been draining the area since before Domesday Book. In the Middle Ages, the monasteries of Glastonbury, Athelney and Muchelney were responsible for much of the drainage. The artificial Huntspill River was constructed during the Second World War as a reservoir, although it also serves as a drainage channel. The Sowy River between the River Parrett and King's Sedgemoor Drain was completed in 1972; water levels are managed by the Levels internal drainage boards. During 2009 and 2010 proposals to build a series of electricity pylons by one of two routes between Hinkley Point and Avonmouth, to transmit electricity from the proposed Hinkley Point C nuclear power station, attracted local opposition. Discussions have taken place concerning the possibility of obtaining World Heritage Site status for the Somerset Levels as a "cultural landscape". It was suggested that if this bid were successful it could improve flood control, but only if wetland fens were created again; the plans were abandoned in 2010.
Natural character area The Somerset Levels form a natural region that has been designated as a national character area – No. 142 – by Natural England, the public body responsible for England's natural environment. Neighbouring natural regions are: the Vale of Taunton and Quantock Fringes to the west, the Blackdowns to the southwest, the Mid Somerset Hills and Yeovil Scarplands to the southeast, the Mendip Hills to the east and the Bristol, Avon Valleys and Ridges to the northeast.South West National Character Area map at www.naturalengland.org.uk. Accessed on 5 October 2013Somerset Levels and Moors/Mid Somerset Hills at www.naturalengland.org.uk. Accessed on 5 October 2013NCA 142 Somerset Levels and Moors (NE 451) at www.naturalengland.org.uk. Accessed on 5 October 2013
Geography
The Levels are mainly flat areas of inland plains and a coastal sand and clay barrier, east and west of the M5 motorway. There are some slightly raised parts, called "burtles", as well as higher ridges and hills. The Levels are about above mean sea level (O.D.). The general elevation inland is O.D. with peak tides of O.D. recorded at Bridgwater and Burnham-on-Sea. Large areas of peat were laid down in the Brue Valley during the Quaternary period after the ice sheets melted. The area's topography consists of two basins mainly surrounded by hills, the runoff from which forms rivers that originally meandered across the plain but have now been controlled by embanking and clyses (the local name for a sluice). The area is prone to winter floods of fresh water and occasional salt water inundations. The worst in recorded history was the Bristol Channel floods of 1607, which resulted in the drowning of an estimated 2,000 or more people, houses and villages swept away, an estimated of farmland inundated, and livestock killed. Another severe flood occurred in 1872–1873, when over were under water from October to March.
Although underlain by much older Triassic age formations that protrude to form what would once have been islands—such as Athelney, Brent Knoll, Burrow Mump and Glastonbury Tor—the lowland landscape was formed only during the last 10,000 years, following the end of the last ice age. Glastonbury Tor is composed of Upper Lias Sand. The Poldens and the Isle of Wedmore are composed of Blue Lias and Marl, while the Mendips are largely Carboniferous limestone. Although sea level changes since the Pliocene led to changes in sea level and the laying down of vegetation, the peak of the peat formation took place in swamp conditions around 6,000 years ago, although in some areas it continued into medieval times.
It is a mainly agricultural region, typically with open fields of permanent grass surrounded by ditches with willow trees. Access to individual areas, especially for cattle, was provided by means of "droves", i.e. green lanes, leading off the public highways. Some of the old roads, in contrast to the old hollow ways found in other areas of England, are causeways raised above the level of the surrounding land, with a drainage ditch running along each side.
Settlements
Most of the settlements on the Levels are small villages. In the south, Aller, which has a population of 374, includes the hamlet of Beer (sometimes Bere) and the deserted medieval village of Oath on the opposite bank of the River Parrett. The area known as the Isle of Athelney was once a very low isolated island linked by a causeway to East Lyng, each end of which was protected by a semi-circular stockade and ditch. The ditch on the island is now known to date from the Iron Age, and was used by Alfred the Great as a fort before the Battle of Ethandun in May 878; in gratitude for his victory Alfred founded a monastery, Athelney Abbey, on the Isle in 888, which survived until the Dissolution of the Monasteries under Henry VIII in 1539. Bawdrip is a small village which has a population of 498. Brent Knoll is a large village at the foot of Brent Knoll Camp that dominates the surrounding landscape; the name means Beacon Hill in Old English. Brent Knoll has been inhabited since at least the Bronze Age. Before the Somerset Levels were drained, Brent Knoll was an island known as the Isle (or Mount) of Frogs.
Glastonbury (population 8,784) and Street (11,066) lie on opposite sides of the River Brue, and provide a central point for trade and commerce. Larger centres are generally on slightly higher ground around the edges of the Levels. Bridgwater is a market town, the administrative centre of the Sedgemoor district, and a major industrial centre. With a population of 33,698, it straddles the major communication routes through South West England. Situated on the edge of the Somerset Levels, along both banks of the River Parrett and from its mouth, it was at one time a major port and trading centre. The hamlet of Dunball forms part of the port on the river. Burrowbridge lies on the River Parrett further inland. The name probably comes from the Old English (fortified hill) and (bridge). In the village is Burrow Mump, an ancient earthwork now owned by the National Trust. Burrow Mump is also known as St Michael's Borough or Tutteyate. It is a natural hill of Triassic sandstone capped by Keuper marl. Excavations showed evidence of a medieval masonry building on the top of the hill.
Along the coast, settlements such as Berrow are built on the line of sand dunes separating the low-lying marshes from the Bristol Channel. At the northern end Bleadon lies on the River Axe; and there was for many years a small harbour, sometimes known as Lympsham Wharf. The arrival of the Bristol and Exeter Railway in 1841, which crossed the Axe on a bridge, obstructed river traffic beyond the wharf, making it the limit of navigation for coastal vessels. An act of Parliament of 1915 authorised the drainage of the river and installation of a flood gate at Bleadon, although attempts to control the water had occurred on Bleadon Level since medieval times, including an early windmill, in 1613, to pump water into the sea from behind a sea wall. Burnham-on-Sea (population 18,401) is at the mouth of the River Parrett where it enters Bridgwater Bay. The position of the town on the edge of the Somerset Levels has resulted in a history dominated by land reclamation and sea defences since Roman times. Burnham was seriously affected by the Bristol Channel floods of 1607, and various flood defences have been installed since then. A concrete sea wall was built in 1911, and after the Second World War further additions to the defences were made, using the remains of a Mulberry harbour; the present curved concrete wall was completed in 1988. Highbridge, which neighbours Burnham, is near the mouth of the River Brue and the villages of East and West Huntspill.
Climate Along with the rest of South West England the Somerset Levels have a temperate climate, which is generally wetter and milder than the rest of the country. Note: the information cited can be found on the tabs within the page. The annual mean temperature is approximately . Seasonal temperature variation is less extreme than most of the United Kingdom because of the adjacent sea. The summer months of July and August are the warmest, with mean daily maxima of approximately . In winter, mean minimum temperatures of are common. The Azores high pressure area influences the southwest of England's summer weather, but convective cloud sometimes forms inland, reducing the number of hours of sunshine. Annual sunshine rates are slightly less than the regional average of 1,600 hours. Most rainfall in the southwest is caused by convection or Atlantic depressions, which are most active in autumn and winter, when they are the chief cause of rain. In summer, a large proportion of the rainfall is caused by the Sun heating the land, leading to convection and to showers and thunderstorms. Average rainfall is around , and about 8–15 days of snowfall is typical. November to March have the highest mean wind speeds, and June to August have the lightest winds. The predominant wind direction is from the southwest. It was devastated by the UK storms of January–February 2014.
Water management
The Moors and Levels, formed from a submerged and reclaimed landscape, consist of a coastal clay belt only slightly above mean sea level, with an inland peat belt at a lower level behind it.
Early attempts to control the water levels were possibly made by the Romans (although records only date from the 13th century), but were not widespread.