Bridgwater Bay is on the Bristol Channel, 5 kilometres (3.1 mi) north of Bridgwater in Somerset, England at the mouth of the River Parrett and the end of the River Parrett Trail. It stretches from Minehead at the southwestern end of the bay to Brean Down in the north. The area consists of large areas of mudflats, saltmarsh, sandflats and shingle ridges, some of which are vegetated. It has been designated as a Site of Special Scientific Interest (SSSI) covering an area of 3,574.1 hectares (35.741 km2; 13.800 sq mi)[1] since 1989,[2] and is designated as a wetland of international importance under the Ramsar Convention.[3] The risks to wildlife are highlighted in the local Oil Spill Contingency Plan.[4]
Several rivers, including the Parrett, Brue and Washford, drain into the bay. Man-made drainage ditches from the Somerset Levels, including the River Huntspill, also run into the bay. The mud flats provide a habitat for a wide range of flora and fauna. These include some nationally rare plants, beetles and snails. It is particularly important for overwintering waders and wildfowl, with approximately 190 species recorded including Eurasian whimbrel (Numenius phaeopus), black-tailed godwit (Limosa limosa), dunlin (Calidris alpina) and wigeon (Anas penelope). Fishing has taken place using shallow boats, known as flatners, and fixed wooden structures for hundreds of years. It was also the last site in England used for 'mudhorse fishing'. There are several small harbours along the coast.
Mud danger signs on Bridgwater Bay near the mouth of the River Parrett are necessary because fast, high-amplitude tides here have led to drownings on the extensive mud flats.
At low tide large parts of the bay become mud flats 4 kilometres (2.5 mi) wide, due to the tidal range of 15 metres (49 ft),[13] second only to the Bay of Fundy in Eastern Canada.[14][15] The intertidal mud flats are, as a result, potentially dangerous and it is not uncommon for the emergency services to mount rescue operations on them. Following the death of Lelaina Hall off Berrow in 2002, a local fund raising campaign succeeded in purchasing a Swedish-built BBV6 rescue hovercraft.[16][17][18] The hovercraft is operated by Burnham Area Rescue Boat (BARB) in Burnham-on-Sea.[19] Much of the coastline within the western part of the reserve is accessible via a waymarked public footpath,[20] and the South West Coast Path begins at Minehead at the western end of the bay. The tidal range holds potential for energy generation and plans for a tidal barrage in the bay have been considered.[21]
Man-made sea defenses include a sea wall at Burnham-on-Sea and a 3 kilometres (1.9 mi) section south from Brean Down. There are also sand dune belts which are managed for their protective function and as a wildlife habitat.[23] There are some concerns that the proposed Severn Barrage could leave some sites high and dry, and others permanently under water.[24] The Steart Peninsula has flooded many times during the last millennium. The most severe recent floods occurred in 1981. By 1997, a combination of coastal erosion, sea level rise and wave action had made some of the defences distinctly fragile and at risk from failure. As a result, in 2002 The Environment Agency produced the Stolford to Combwich Coastal Defence Strategy Study to examine options for the future.[25]
The foreshore at Watchet, which lies at the mouth of the Washford River, and on the edge of Exmoor National Park, is rocky, but has a small harbour. The cliffs between Watchet and Blue Anchor show a distinct pale, greenish blue colour, resulting from the coloured alabaster found there. The name "Watchet" or "Watchet Blue" was used in the 16th century to denote this colour.[26][27]
East Quantoxhead used to have a small harbour which brought in limestone for local limekilns and exported alabaster. It is thought that it was also used for smuggling.[28]
At Kilve are the remains of a red brick retort, built in 1924, when it was discovered that the shale found in the cliffs was rich in oil. The beach is part of the Blue Anchor to Lilstock Coast SSSI (Site of Special Scientific Interest). Along this coast the cliffs are layered with compressed strata of oil-bearing shale and blue, yellow and brown lias embedded with fossils. In 1924 Forbes-Leslie founded the Shaline Company to exploit them. This retort house is thought to be the first structure erected here for the conversion of shale to oil but the company was unable to raise sufficient capital and this is now all that remains of the anticipated Somerset oil boom.[29]
The intertidal mud flats of the bay have a long history of use for fishing, with structures on Stert Flats being dated by dendrochronological analysis to between 932 and 966.[6] It is the last site in England used for 'mudhorse fishing' in which a wooden sledge is propelled across the mudflats to collect fish from nets.[24] Catches include: Thinlip mullet,[30]plaice, dogfish, cuttlefish, skate, shrimp, prawns, sea bass, and sole.[31]Watchet Boat Museum displays the unusual local flatner boats which were used for fishing in the bay, along with associated artefacts.[32]
At low tide extensive areas of mudflats (the Steart and the Berrow Flats) are exposed, providing important feeding and overwintering grounds for waders (shorebirds). Invertebrate fauna including six nationally rare species and eighteen nationally scarce species can be found in the ditches and ponds around the shores.[2] Consequently, Bridgwater Bay is a national nature reserve, and is managed by Natural England.[33] Some of the potential risks to wildlife are highlighted in the local Oil Spill Contingency Plan.[4]
Common cord-grass (Spartina anglica) was planted in the area in the 1990s. It can now be found on surrounding marshes where it has invaded the fronting mudflats.[35] The Spartina is generally shorter in the bay than at other sites due to the high tides and the turbidity of the water, reaching around 30 centimetres (11.8 in) as opposed to 150 centimetres (59.1 in) elsewhere.[36] On higher ground common saltmarsh-grass (Puccinellia maritima) can be found along with sea aster (Aster tripolium). Where the land is ungrazed, common reed (Phragmites australis) often forms a zone above the sea aster. Where the upper marsh is grazed by cattle red fescue (Festuca rubra) and creeping bent (Agrostis stolonifera) are found. The area of marsh furthest from the sea supports Sea couch (Agropyron pungens) and sea club-rush (Scirpus maritimus).[2]
The ditches are populated with aquatic and bankside plant species. These include the nationally restricted rootless duckweed (Wolffia arrhiza). Other uncommon species such as frogbit (Hydrocharis morsus-ranae) and water fern (Azolla filiculoides) can also be found. The nationally restricted brackish water-crowfoot (Ranunculus baudotii) and sea clubrush (Scirpus maritimus) indicate the slightly brackish nature of the water.[2]
White rock-rose (Helianthemum apenninum) on the south cliff of Brean Down
Over 190 species of birds have been identified near the bay, some of which use it as a feeding ground during their migrations. Waders and wildfowl often over-winter on the reserve.[3] The populations of Eurasian whimbrel (Numenius phaeopus) and black-tailed godwit (Limosa limosa) are internationally important. Significant populations of dunlin (Calidris alpina) and wigeon (Anas penelope) also frequent the bay.[39][40][2][3][41] In early winter the wigeon select Puccinellia maritima in preference to Agrostis stolonifera and Festuca rubra.[42][43]Avocets have become regular autumn and winter visitors to the area in recent years, favouring the lower reaches of the River Parrett,[44][39] and, for the first time in over 50 years, bred on the reserve in 2012.[3]
^ abcdefghi"SSSI citation sheet"(PDF). Sites of Special Scientific Interest. English Nature. Archived from the original(PDF) on 10 September 2008. Retrieved 12 November 2008.
^Morley, J.V. (July 1973). "Tidal Immersion of Spartina Marsh at Bridgwater Bay, Somerset". The Journal of Ecology. 61 (2): 383–386. doi:10.2307/2259033. JSTOR2259033.
^Twist, Colin, Rare Plants in Great Britain - a site guide
^ abcGreen, Ian, Peter Green and Geraldine Crouch The Atlas Flora of Somerset