Chew Valley Lake
Encyclopedia
Chew Valley Lake
Governing body Bristol Water
Bristol Water
Bristol Water supplies 300 million litres of drinking water to over 1 million customers in a area centred on Bristol, England. It is regulated under the Water Industry Act 1991...

SSSI Ref 1001346
SPA Code UK9010041


Chew Valley Lake is a large reservoir in the Chew Valley
Chew Valley
The Chew Valley is an area in North Somerset, England, named after the River Chew, which rises at Chewton Mendip, and joins the River Avon at Keynsham...

, Somerset
Somerset
The ceremonial and non-metropolitan county of Somerset in South West England borders Bristol and Gloucestershire to the north, Wiltshire to the east, Dorset to the south-east, and Devon to the south-west. It is partly bounded to the north and west by the Bristol Channel and the estuary of the...

, England, and the fifth-largest artificial lake
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...

 in the United Kingdom (the largest in south-west England), with an area of 1,200 acre
Acre
The acre is a unit of area in a number of different systems, including the imperial and U.S. customary systems. The most commonly used acres today are the international acre and, in the United States, the survey acre. The most common use of the acre is to measure tracts of land.The acre is related...

s (4.9 km²). The lake, created in the early 1950s and opened by Queen Elizabeth II
Elizabeth II of the United Kingdom
Elizabeth II is the constitutional monarch of 16 sovereign states known as the Commonwealth realms: the United Kingdom, Canada, Australia, New Zealand, Jamaica, Barbados, the Bahamas, Grenada, Papua New Guinea, the Solomon Islands, Tuvalu, Saint Lucia, Saint Vincent and the Grenadines, Belize,...

 in 1956, provides much of the drinking water
Drinking water
Drinking water or potable water is water pure enough to be consumed or used with low risk of immediate or long term harm. In most developed countries, the water supplied to households, commerce and industry is all of drinking water standard, even though only a very small proportion is actually...

 for the city of Bristol
Bristol
Bristol is a city, unitary authority area and ceremonial county in South West England, with an estimated population of 433,100 for the unitary authority in 2009, and a surrounding Larger Urban Zone with an estimated 1,070,000 residents in 2007...

 and surrounding area, taking its supply from the Mendip Hills
Mendip Hills
The Mendip Hills is a range of limestone hills to the south of Bristol and Bath in Somerset, England. Running east to west between Weston-super-Mare and Frome, the hills overlook the Somerset Levels to the south and the Avon Valley to the north...

. Some of the water from the lake is used to maintain the flow in the River Chew
River Chew
The River Chew is a small river in England. It merges with the River Avon after forming the Chew Valley.The spring from which the Chew rises is just upstream from Chewton Mendip. The river flows North West from Chewton Mendip through Litton, Chew Valley Lake, Chew Stoke, Chew Magna and Stanton Drew...

.

Before the lake was created, archaeological investigations were carried out that showed evidence of occupation since Neolithic
Neolithic
The Neolithic Age, Era, or Period, or New Stone Age, was a period in the development of human technology, beginning about 9500 BC in some parts of the Middle East, and later in other parts of the world. It is traditionally considered as the last part of the Stone Age...

 times and included Roman
Ancient Rome
Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....

 artefacts. The lake is an important site for wildlife and has been dedicated as a Site of Special Scientific Interest
Site of Special Scientific Interest
A Site of Special Scientific Interest is a conservation designation denoting a protected area in the United Kingdom. SSSIs are the basic building block of site-based nature conservation legislation and most other legal nature/geological conservation designations in Great Britain are based upon...

 (SSSI) and a Special Protection Area
Special Protection Area
A Special Protection Area or SPA is a designation under the European Union Directive on the Conservation of Wild Birds.Under the Directive, Member States of the European Union have a duty to safeguard the habitats of migratory birds and certain particularly threatened birds.Together with Special...

 (SPA). It is a national centre for birdwatching
Birdwatching
Birdwatching or birding is the observation of birds as a recreational activity. It can be done with the naked eye, through a visual enhancement device like binoculars and telescopes, or by listening for bird sounds. Birding often involves a significant auditory component, as many bird species are...

, with over 260 species recorded, including some unusual sightings. The lake has indigenous and migrant water birds throughout the year, and two nature trails have been created. The flora and fauna provide habitats
Habitat (ecology)
A habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant or other type of organism...

 for some less common plants and insects.

Some restricted use for recreational activities is permitted by the owner, Bristol Water
Bristol Water
Bristol Water supplies 300 million litres of drinking water to over 1 million customers in a area centred on Bristol, England. It is regulated under the Water Industry Act 1991...

, including dinghy sailing
Dinghy sailing
Dinghy sailing is the activity of sailing small boats by using five essential controls:* the sails* the foils ....

 and fishing
Fishing
Fishing is the activity of trying to catch wild fish. Fish are normally caught in the wild. Techniques for catching fish include hand gathering, spearing, netting, angling and trapping....

, primarily for trout
Trout
Trout is the name for a number of species of freshwater and saltwater fish belonging to the Salmoninae subfamily of the family Salmonidae. Salmon belong to the same family as trout. Most salmon species spend almost all their lives in salt water...

.

Location

Chew Valley Lake in the Chew Valley
Chew Valley
The Chew Valley is an area in North Somerset, England, named after the River Chew, which rises at Chewton Mendip, and joins the River Avon at Keynsham...

 at the northern edge of the Mendip Hills
Mendip Hills
The Mendip Hills is a range of limestone hills to the south of Bristol and Bath in Somerset, England. Running east to west between Weston-super-Mare and Frome, the hills overlook the Somerset Levels to the south and the Avon Valley to the north...

, surrounded by meadows and woods and close to the villages of Chew Stoke
Chew Stoke
Chew Stoke is a small village and civil parish in the Chew Valley, in Somerset, England, about south of Bristol. It is at the northern edge of the Mendip Hills, a region designated by the United Kingdom as an Area of Outstanding Natural Beauty, and is within the Bristol/Bath green belt...

, Chew Magna
Chew Magna
Chew Magna is a village and civil parish within the Chew Valley in the Unitary Authority of Bath and North East Somerset, in the Ceremonial county of Somerset, England. The parish has a population of 1,161.To the south of the village is Chew Valley Lake...

 and Bishop Sutton
Bishop Sutton
Bishop Sutton is a small village within the Chew Valley in Somerset. It lies south of Chew Valley Lake and north of the Mendip Hills, approximately ten miles south of Bristol on the A368, Weston-super-Mare to Bath road...

. When it was built in the 1950s, its 1,200 acres (4.9 km²) were flooded with 4,500 million imperial gallons (20,000,000 m³) of water from the Mendip hills, with a catchment area of 14,000 acres (57 km²). It is relatively shallow, with an average depth of only 14 ft (4 m) at top level and a maximum depth of just 37 ft (11 m). It is fed by small rivers, and it flows into the River Chew
River Chew
The River Chew is a small river in England. It merges with the River Avon after forming the Chew Valley.The spring from which the Chew rises is just upstream from Chewton Mendip. The river flows North West from Chewton Mendip through Litton, Chew Valley Lake, Chew Stoke, Chew Magna and Stanton Drew...

 for 17 miles (27 km) before it joins the Avon
River Avon, Bristol
The River Avon is an English river in the south west of the country. To distinguish it from a number of other River Avons in Britain, this river is often also known as the Lower Avon or Bristol Avon...

 to head out to sea. The deepest part is near the dam and the outlet tower, where the steeply sloping shores of Walley Bank and the north shore result in depths of up to 20 ft (6 m). "Denny Island", above the surface throughout the year, is wooded and provides a habitat for wildlife.

The lake is owned and operated by Bristol Water, which created it in 1956 when the demand became too large for nearby Blagdon Lake
Blagdon Lake
Blagdon Lake lies in the Chew Valley at the northern edge of the Mendip Hills, approximately 10 mi south of Bristol, England. The lake was created by Bristol Water , when it dammed the River Yeo, starting construction in 1891 and completing this in 1899...

. Working with the Avon Wildlife Trust
Avon Wildlife Trust
The Avon Wildlife Trust aims to protect and promote wildlife in the area of the former county of Avon — now Bath and North East Somerset, Bristol, North Somerset and South Gloucestershire, in England...

, Somerset Wildlife Trust
Somerset Wildlife Trust
Somerset Wildlife Trust is a wildlife trust covering the county of Somerset, England.The trust, which was established in 1964, aims to safeguard the county's wildlife and wild places for this and future generations and manages almost 80 nature reserves. Examples include Fyne Court, Westhay Moor,...

 and other environmental groups, Bristol Water has encouraged various species of birds and plants, and created a venue for visitors.

It has two large landscaped picnic areas. Facilities include a tea shop, with indoor and outdoor seating areas with a view of the lake, and information centre. There are also a souvenir shop and small art gallery and two nature trails. The Grebe Trail is a hard-surfaced, all-weather path suitable for pedestrians, pushchairs and wheelchairs and covers a circuit 0.75 miles (1.2 km) long, starting and finishing at the wooded picnic area. The Bittern Trail is reached from the Grebe Trail by the footbridge over Hollow Brook. The grassy path is often waterlogged in winter, but there is a boardwalk over a short section. This trail runs along the east shore, visits an open bird hide and returns to the footbridge, making a 1-mile (1.5-kilometre) circuit. Bristol Water imposes conditions on visitors, particularly related to the areas where dogs are allowed.

Access and transportation

Access to the waterside is restricted in places to reduce the disruption to wildlife. Paths around the lake are generally flat and, where paths are surfaced, wheelchair access is possible.

Visitors are officially invited to use public transport, but overwhelmingly arrive by private car, encouraged by the provision of parking spaces. The "Chew Valley Explorer" bus route 672/674 provides access.

In 2002 a 1.9-mile (3-kilometre) safe cycle route, the Chew Lake West Green Route, was opened along the B3114 along the western part of the lake. It forms part of the Padstow
Padstow
Padstow is a town, civil parish and fishing port on the north coast of Cornwall, England, United Kingdom. The town is situated on the west bank of the River Camel estuary approximately five miles northwest of Wadebridge, ten miles northwest of Bodmin and ten miles northeast of Newquay...

 to Bristol
Bristol
Bristol is a city, unitary authority area and ceremonial county in South West England, with an estimated population of 433,100 for the unitary authority in 2009, and a surrounding Larger Urban Zone with an estimated 1,070,000 residents in 2007...

 West Country Way, National Cycle Network
National Cycle Network
The National Cycle Network is a network of cycle routes in the United Kingdom.The National Cycle Network was created by the charity Sustrans , and aided by a £42.5 million National Lottery grant. In 2005 it was used for over 230 million trips.Many routes hope to minimise contact with motor...

 Route 3
NCR 3
-Bristol to Bridgwater:West Harptree | Charterhouse | Wookey Hole | GlastonburyThe route goes south from Bristol into Somerset and around Chew Valley Lake-See also:* The Cornish Way Bude to Bodmin section...

. It has all-weather surfacing, providing a smooth off-road facility for ramblers, mobility-challenged visitors and cyclists of all abilities. It was funded by Bath and North East Somerset
Bath and North East Somerset
Bath and North East Somerset is a unitary authority that was created on 1 April 1996 following the abolition of the County of Avon. It is part of the Ceremonial county of Somerset...

 Council with the support of Sustrans
Sustrans
Sustrans is a British charity to promote sustainable transport. The charity is currently working on a number of practical projects to encourage people to walk, cycle and use public transport, to give people the choice of "travelling in ways that benefit their health and the environment"...

 and the Chew Valley Recreational Trail Association. Minor roads around the lake are also frequently used by cyclists.

Bristol International Airport
Bristol International Airport
Bristol Airport , located at Lulsgate Bottom in North Somerset, is the commercial airport serving the city of Bristol, England and the surrounding area. At first it was named Bristol Lulsgate Airport and from March 1997 to March 2010 it was known as Bristol International Airport...

 is approximately 10 miles (15 km) away, and the nearest major road is the A368
A368 road
The A368 is a part primary status A road in North Somerset, England. It runs from Marksbury to Banwell along the northern edge of the Mendip Hills and past the reservoir at Chew Valley Lake....

, which runs along the southern edge of the lake and provides access from Bath and Weston super Mare. The A37
A37 road
The A37 is a major road in southern England. It runs north from the A35 at Dorchester in Dorset into Somerset through Yeovil and Shepton Mallet before terminating at the Three Lamps junction with the A4 in central Bristol...

 and A38
A38 road
The A38, part of which is also known as the Devon Expressway, is a major A-class trunk road in England.The road runs from Bodmin in Cornwall to Mansfield in Nottinghamshire. It is long, making it one of the longest A-roads in England. It was formerly known as the Leeds — Exeter Trunk Road,...

 are slightly further away, providing access from Bristol
Bristol
Bristol is a city, unitary authority area and ceremonial county in South West England, with an estimated population of 433,100 for the unitary authority in 2009, and a surrounding Larger Urban Zone with an estimated 1,070,000 residents in 2007...

. Car parking is available at the visitor centre and Woodford Lodge, for which a charge is made, and a small amount of parking is available at various points around the lake; some of these are restricted to those with fishing permits.

History

The area the lake covers was once rich farmland. Farms and houses had to be removed before the land was flooded, and old roads, hedgerows and tree stumps can reappear when dry summers cause the level of the lake to drop. Prior to the flooding of the reservoir, archaeological
Archaeology
Archaeology, or archeology , is the study of human society, primarily through the recovery and analysis of the material culture and environmental data that they have left behind, which includes artifacts, architecture, biofacts and cultural landscapes...

 excavations were carried out by Philip Rahtz
Philip Rahtz
Philip Arthur Rahtz was a British archaeologist.Rahtz was born in Bristol. After leaving Bristol Grammar School, he became an accountant before serving with the Royal Air Force during the Second World War. During war service, Rahtz became friends with the archaeologist Ernest Greenfield...

 and Ernest Greenfield
Ernest Greenfield
Ernest Greenfield was a British archaeologist. He served with the Royal Air Force during the Second World War. During war service he became friends with Philip Rahtz who persuaded Greenfield to take up professional archaeology. His excavations included the Great Witcombe Roman Villa,...

 employed by the Ministry of Works, from 1953 to 1955. The excavations found evidence of people belonging to the consecutive periods known as Upper Palaeolithic, Mesolithic
Mesolithic
The Mesolithic is an archaeological concept used to refer to certain groups of archaeological cultures defined as falling between the Paleolithic and the Neolithic....

 and Neolithic
Neolithic
The Neolithic Age, Era, or Period, or New Stone Age, was a period in the development of human technology, beginning about 9500 BC in some parts of the Middle East, and later in other parts of the world. It is traditionally considered as the last part of the Stone Age...

 (Old, Middle and New Stone Age
Stone Age
The Stone Age is a broad prehistoric period, lasting about 2.5 million years , during which humans and their predecessor species in the genus Homo, as well as the earlier partly contemporary genera Australopithecus and Paranthropus, widely used exclusively stone as their hard material in the...

), Bronze Age
Bronze Age
The Bronze Age is a period characterized by the use of copper and its alloy bronze as the chief hard materials in the manufacture of some implements and weapons. Chronologically, it stands between the Stone Age and Iron Age...

 and Iron Age
Iron Age
The Iron Age is the archaeological period generally occurring after the Bronze Age, marked by the prevalent use of iron. The early period of the age is characterized by the widespread use of iron or steel. The adoption of such material coincided with other changes in society, including differing...

, including implements such as stone knives, flint
Flint
Flint is a hard, sedimentary cryptocrystalline form of the mineral quartz, categorized as a variety of chert. It occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones. Inside the nodule, flint is usually dark grey, black, green, white, or brown in colour, and...

 blades and the head of a mace, along with buildings and graves. The artefacts
Artifact (archaeology)
An artifact or artefact is "something made or given shape by man, such as a tool or a work of art, esp an object of archaeological interest"...

 from this period are held at Bristol City Museum and Art Gallery
Bristol City Museum and Art Gallery
The Bristol City Museum and Art Gallery is a large museum and art gallery in Bristol, England. It is run by the city council with no entrance fee. It holds designated museum status, granted by the national government to protect outstanding museums...

. Further evidence of Neolithic and Bronze Age occupation is provided by the archaeological survey of the Mendip Hills
Mendip Hills
The Mendip Hills is a range of limestone hills to the south of Bristol and Bath in Somerset, England. Running east to west between Weston-super-Mare and Frome, the hills overlook the Somerset Levels to the south and the Avon Valley to the north...

 Area of Outstanding Natural Beauty.
Excavations have also uncovered Roman remains, indicating agricultural and industrial activity from the second half of the first century to third century AD. These finds included a moderately large villa
Roman villa
A Roman villa is a villa that was built or lived in during the Roman republic and the Roman Empire. A villa was originally a Roman country house built for the upper class...

, at Chew Park where wooden writing tablets (the first in the UK) with ink
Ink
Ink is a liquid or paste that contains pigments and/or dyes and is used to color a surface to produce an image, text, or design. Ink is used for drawing and/or writing with a pen, brush, or quill...

 writing were found. The tablets were sent to the British Museum
British Museum
The British Museum is a museum of human history and culture in London. Its collections, which number more than seven million objects, are amongst the largest and most comprehensive in the world and originate from all continents, illustrating and documenting the story of human culture from its...

, but other Roman material is on display at the Bristol City Museum and Art Gallery with the lake's other historical artefacts.

Further excavations around the village of Moreton, which has now been totally submerged, found evidence of a thriving community in medieval times and possibly the remains of the Nunnery of Santa Cruz. During the Middle Ages
Middle Ages
The Middle Ages is a periodization of European history from the 5th century to the 15th century. The Middle Ages follows the fall of the Western Roman Empire in 476 and precedes the Early Modern Era. It is the middle period of a three-period division of Western history: Classic, Medieval and Modern...

 farming was the most important activity supported in the area covered by the lake, supported by four flour mills powered by the River Chew. Stratford Mill was demolished and re-erected in the grounds of Blaise Castle
Blaise Castle
Blaise Castle is an 18th century mansion house and estate near Henbury in Bristol , England. Blaise Castle was immortalised by being described as "the finest place in England" in Jane Austen's novel Northanger Abbey....

 Museum, in north-west Bristol. The largest settlement was Moreton, which is listed in the Domesday Book
Domesday Book
Domesday Book , now held at The National Archives, Kew, Richmond upon Thames in South West London, is the record of the great survey of much of England and parts of Wales completed in 1086...

 and survived until the flooding of the lake, when the remains of the Moreton Cross were moved to Chew Stoke
Chew Stoke
Chew Stoke is a small village and civil parish in the Chew Valley, in Somerset, England, about south of Bristol. It is at the northern edge of the Mendip Hills, a region designated by the United Kingdom as an Area of Outstanding Natural Beauty, and is within the Bristol/Bath green belt...

 Parish Church. There is also evidence of lime kilns
Limekiln
A lime kiln is used to produce quicklime through the calcination of limestone . The chemical equation for this reaction is...

, which were used in the production of mortar for the construction of local churches. Farming, both arable
Arable land
In geography and agriculture, arable land is land that can be used for growing crops. It includes all land under temporary crops , temporary meadows for mowing or pasture, land under market and kitchen gardens and land temporarily fallow...

 and dairy
Dairy farming
Dairy farming is a class of agricultural, or an animal husbandry, enterprise, for long-term production of milk, usually from dairy cows but also from goats and sheep, which may be either processed on-site or transported to a dairy factory for processing and eventual retail sale.Most dairy farms...

, continued until the flooding of the lake, with most households also keeping pig
Pig
A pig is any of the animals in the genus Sus, within the Suidae family of even-toed ungulates. Pigs include the domestic pig, its ancestor the wild boar, and several other wild relatives...

s. There were orchard
Orchard
An orchard is an intentional planting of trees or shrubs that is maintained for food production. Orchards comprise fruit or nut-producing trees which are grown for commercial production. Orchards are also sometimes a feature of large gardens, where they serve an aesthetic as well as a productive...

s for fruit production, including apple
Apple
The apple is the pomaceous fruit of the apple tree, species Malus domestica in the rose family . It is one of the most widely cultivated tree fruits, and the most widely known of the many members of genus Malus that are used by humans. Apple grow on small, deciduous trees that blossom in the spring...

s, pear
Pear
The pear is any of several tree species of genus Pyrus and also the name of the pomaceous fruit of these trees. Several species of pear are valued by humans for their edible fruit, but the fruit of other species is small, hard, and astringent....

s and plum
Plum
A plum or gage is a stone fruit tree in the genus Prunus, subgenus Prunus. The subgenus is distinguished from other subgenera in the shoots having a terminal bud and solitary side buds , the flowers in groups of one to five together on short stems, and the fruit having a groove running down one...

s. In recent years there have been sightings of a ghostly young girl who has been seen by local people crossing the B3114 walking towards the lake.

Reservoir

Plans for the building of the reservoir were under discussion before the Second World War
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

, and an Act of Parliament
Act of Parliament
An Act of Parliament is a statute enacted as primary legislation by a national or sub-national parliament. In the Republic of Ireland the term Act of the Oireachtas is used, and in the United States the term Act of Congress is used.In Commonwealth countries, the term is used both in a narrow...

 submitted by the Bristol Waterworks Company was passed in 1939. Following this, farms were bought by the company and farmed by the previous owners as tenancies. Farms and buildings still remaining in private hands were acquired by compulsory purchase. The sanction for construction was given in 1949 and the contract awarded to A.E. Farr & Co., who employed approximately 300 people on the site. The main dam
Dam
A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...

 was initially stabilised by injecting concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...

 into the cracks in the bedrock
Bedrock
In stratigraphy, bedrock is the native consolidated rock underlying the surface of a terrestrial planet, usually the Earth. Above the bedrock is usually an area of broken and weathered unconsolidated rock in the basal subsoil...

. The core of the dam was made of puddled
Puddling (engineering)
Puddle is a watertight material based on clay used in building and maintaining canals or reservoirs. Puddling is the process of lining the channel with puddle....

 clay
Clay
Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...

 mixed with sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...

. This was the first time the gain in strength brought about by the use of sand drains had been quantified. The lake was inaugurated by Queen Elizabeth II
Elizabeth II of the United Kingdom
Elizabeth II is the constitutional monarch of 16 sovereign states known as the Commonwealth realms: the United Kingdom, Canada, Australia, New Zealand, Jamaica, Barbados, the Bahamas, Grenada, Papua New Guinea, the Solomon Islands, Tuvalu, Saint Lucia, Saint Vincent and the Grenadines, Belize,...

, accompanied by Prince Philip
Prince Philip, Duke of Edinburgh
Prince Philip, Duke of Edinburgh is the husband of Elizabeth II. He is the United Kingdom's longest-serving consort and the oldest serving spouse of a reigning British monarch....

, with the unveiling of a commemorative stone and plaque, which can be seen from the dam, on 17 April 1956, although it was not full until 25 February 1958. Flowers were presented to the Queen at the opening of Chew Valley Lake by Judith Blair Brown, daughter of Kennedy Brown, who worked at Bristol Water Works at the time of construction of the lake.

During the storm of 10 July 1968, the lake gained an extra 471 million imperial gallons (2,140,000 m³) and rose 19 inches (480 mm) in under 12 hours. At one point worried Bristol police
Bristol City Police
Bristol City Constabulary, also called Bristol City Police, was a police force responsible for policing the city of Bristol in south-west England until 1974, when it was amalgamated under the Local Government Act 1972 with Somerset and Bath Constabulary and parts of the Gloucestershire Constabulary...

 issued a warning that the dam might not hold, prompting localised evacuation of populated valley areas downstream including Pensford
Pensford
Pensford is a village in the civil parish of Publow and Pensford in Somerset, England. It lies in the Chew Valley south of Bristol and west of Bath...

 and Keynsham
Keynsham
Keynsham is a town and civil parish between Bristol and Bath in Somerset, south-west England. It has a population of 15,533.It was listed in the Domesday Book as Cainesham, which is believed to mean the home of Saint Keyne....

.

Ecology

The lake is designated a Site of Special Scientific Interest
Site of Special Scientific Interest
A Site of Special Scientific Interest is a conservation designation denoting a protected area in the United Kingdom. SSSIs are the basic building block of site-based nature conservation legislation and most other legal nature/geological conservation designations in Great Britain are based upon...

 (SSSI) (Site Ref: 1001346) and a Special Protection Area
Special Protection Area
A Special Protection Area or SPA is a designation under the European Union Directive on the Conservation of Wild Birds.Under the Directive, Member States of the European Union have a duty to safeguard the habitats of migratory birds and certain particularly threatened birds.Together with Special...

 (SPA) (Site Code: UK9010041) largely because of the diversity of species and habitats. Providing further protection, much of the area around the lake also falls within the Mendip Hills
Mendip Hills
The Mendip Hills is a range of limestone hills to the south of Bristol and Bath in Somerset, England. Running east to west between Weston-super-Mare and Frome, the hills overlook the Somerset Levels to the south and the Avon Valley to the north...

 Area of Outstanding Natural Beauty
Area of Outstanding Natural Beauty
An Area of Outstanding Natural Beauty is an area of countryside considered to have significant landscape value in England, Wales or Northern Ireland, that has been specially designated by the Countryside Agency on behalf of the United Kingdom government; the Countryside Council for Wales on...

 (AONB).

The lake appears to have a higher sedimentation rate than would be expected in other similar reservoirs, being in the region of 100–150 t.km−2.yr−1.

Geology

The main geological outcrops around the lake are mudstone
Mudstone
Mudstone is a fine grained sedimentary rock whose original constituents were clays or muds. Grain size is up to 0.0625 mm with individual grains too small to be distinguished without a microscope. With increased pressure over time the platey clay minerals may become aligned, with the...

, largely consisting of red siltstone
Siltstone
Siltstone is a sedimentary rock which has a grain size in the silt range, finer than sandstone and coarser than claystones.- Description :As its name implies, it is primarily composed of silt sized particles, defined as grains 1/16 - 1/256 mm or 4 to 8 on the Krumbein phi scale...

 resulting in the underlying characteristic of the gently rolling valley landscape. There are also bands of sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...

 of the Triassic
Triassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...

 period that contribute to the undulating character of the area. There are also more recent alluvial deposits beside the course of the River Chew.

Birds

Over 260 species of birds have been recorded at Chew, an internationally important site for wintering and migrating wildfowl. From late July to February, up to 4000 duck
Duck
Duck is the common name for a large number of species in the Anatidae family of birds, which also includes swans and geese. The ducks are divided among several subfamilies in the Anatidae family; they do not represent a monophyletic group but a form taxon, since swans and geese are not considered...

s (Anatidae) of twelve different species may be present, including internationally important numbers of Northern Shoveler
Northern Shoveler
The Northern Shoveler , Northern Shoveller in British English, sometimes known simply as the Shoveler, is a common and widespread duck. It breeds in northern areas of Europe and Asia and across most of North America, and is a rare vagrant to Australia...

 (Anas clypeata) and Gadwall
Gadwall
The Gadwall is a common and widespread duck of the family Anatidae.- Description :The Gadwall is 46–56 cm long with a 78–90 cm wingspan. The male is slightly larger than the female, weighing on average 990 g against her 850 g...

 (Anas strepera). Up to 600 Great Crested Grebe
Great Crested Grebe
The Great Crested Grebe is a member of the grebe family of water birds.- Description :The Great Crested Grebe is long with a wingspan. It is an excellent swimmer and diver, and pursues its fish prey underwater. The adults are unmistakable in summer with head and neck decorations...

s (Podiceps cristatus) gather to moult on the lake in autumn. A wide range of data on bird species and their numbers on the lake, dating back to the first "ringing
Bird ringing
Bird ringing or bird banding is a technique used in the study of wild birds, by attaching a small, individually numbered, metal or plastic tag to their legs or wings, so that various aspects of the bird's life can be studied by the ability to re-find the same individual later...

" in 1964, is available from the Chew Valley Ringing Station.

Numerous other birds can be seen, especially during the spring and autumn migration
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...

. Sand Martin
Sand Martin
The Sand Martin is a migratory passerine bird in the swallow family. It has a wide range in summer, embracing practically the whole of Europe and the Mediterranean countries, part of northern Asia and also North America. It winters in eastern and southern Africa, South America and South Asia...

s (Riparia riparia) arrive early and can usually be seen hawking over the water for insects in the second or third week of March. Flocks of tits
Titmouse
The tits, chickadees, and titmice constitute Paridae, a large family of small passerine birds which occur in the northern hemisphere and Africa...

 (Paridae), swallows (Hirundinidae) and terns (Sternidae) can regularly be seen. Waders, such as Lapwings
Northern Lapwing
The Northern Lapwing , also known as the Peewit, Green Plover or just Lapwing, is a bird in the plover family. It is common through temperate Eurasia....

 (Vanellus vanellus), Dunlin
Dunlin
The Dunlin, Calidris alpina, is a small wader, sometimes separated with the other "stints" in Erolia. It is a circumpolar breeder in Arctic or subarctic regions. Birds that breed in northern Europe and Asia are long-distance migrants, wintering south to Africa, southeast Asia and the Middle East...

 (Calidris alpina) and Common Snipe
Common Snipe
The Common Snipe is a small, stocky wader native to the Old World. The breeding habitat is marshes, bogs, tundra and wet meadows throughout northern Europe and northern Asia...

 (Gallinago gallinago), are attracted to the muddy shores if the water level drops in autumn. By midwinter up to 55,000 gull
Gull
Gulls are birds in the family Laridae. They are most closely related to the terns and only distantly related to auks, skimmers, and more distantly to the waders...

s, mostly Black-headed Gull
Black-headed Gull
The Black-headed Gull is a small gull which breeds in much of Europe and Asia, and also in coastal eastern Canada. Most of the population is migratory, wintering further south, but some birds in the milder westernmost areas of Europe are resident...

 (Chroicocephalus ridibundus) and Common Gull
Common Gull
The Common Gull or Mew Gull Larus canus is a medium-sized gull which breeds in northern Asia, northern Europe and northwestern North America. It migrates further south in winter...

 (Larus canus), may be roosting. Good numbers of Reed Warbler
Reed Warbler
The Eurasian Reed Warbler, or just Reed Warbler, Acrocephalus scirpaceus, is an Old World warbler in the genus Acrocephalus. It breeds across Europe into temperate western Asia. It is migratory, wintering in sub-Saharan Africa....

 (Acrocephalus scirpaceus) and Sedge Warbler
Sedge Warbler
The Sedge Warbler is an Old World warbler in the genus Acrocephalus. It is a medium-sized warbler with a brown, streaked back and wings and a distinct pale supercilium. Sedge Warblers are migratory, crossing the Sahara to get from their European and Asian breeding grounds to spend winter in Africa...

s (A. schoenobaenus) nest in the fringing reeds, along with grebes (Podicipedidae) and Eurasian Coot
Eurasian Coot
The Eurasian Coot, Fulica atra, also known as Coot, is a member of the rail and crake bird family, the Rallidae. The Australian subspecies is known as the Australian Coot.-Distribution:...

 (Fulica atra).

Much of the management work carried out in the nature reserve is aimed at encouraging ducks to breed, and small numbers of Tufted Duck
Tufted Duck
The Tufted Duck, Aythya fuligula, is a medium-sized diving duck with a population of close to one million birds.- Description :The adult male is all black except for white flanks and a blue-grey bill. It has an obvious head tuft that gives the species its name.The adult female is brown with paler...

 (Aythya fuligula), Common Pochard (Aythya ferina), Common Shelduck
Common Shelduck
The Common Shelduck is a waterfowl species shelduck genus Tadorna. It is widespread and common in Eurasia, mainly breeding in temperate and wintering in subtropical regions; in winter, it can also be found in the Maghreb...

 (Tadorna tadorna) and Gadwall
Gadwall
The Gadwall is a common and widespread duck of the family Anatidae.- Description :The Gadwall is 46–56 cm long with a 78–90 cm wingspan. The male is slightly larger than the female, weighing on average 990 g against her 850 g...

 raise broods most years. Recent breeding successes also include Water Rail
Water Rail
The Water Rail is a bird of the rail family which breeds in well-vegetated wetlands across Europe, Asia and North Africa. Northern and eastern populations are migratory, but this species is a permanent resident in the warmer parts of its breeding range...

 (Rallus aquaticus) and Cetti's Warbler
Cetti's Warbler
Cetti's Warbler , Cettia cetti, is an Old World warbler which breeds in Europe, northwest Africa and east southern temperate Asia as far as Afghanistan and NW Pakistan. It is the only bush warbler to occur outside Asia...

 (Cettia cetti).

A new wetland reserve has been created at Heron's Green Pool on the opposite side of the causeway to the lake. A large shallow pool fringed with sedges
Cyperaceae
Cyperaceae are a family of monocotyledonous graminoid flowering plants known as sedges, which superficially resemble grasses or rushes. The family is large, with some 5,500 species described in about 109 genera. These species are widely distributed, with the centers of diversity for the group...

 (Cyperaceae), rushes
Juncaceae
Juncaceae, the rush family, are a monocotyledonous family of flowering plants. There are eight genera and about 400 species. Members of the Juncaceae are slow-growing, rhizomatous, herbaceous plants, and they may superficially resemble grasses. They often grow on infertile soils in a wide range...

 (Juncaceae) and reedgrasses
Calamagrostis
Calamagrostis, or Small-reed or Reedgrass, is a genus in the Grass family Poaceae with about 260 species that occur mainly in temperate regions of the Northern Hemisphere and the southern hemisphere. Towards equatorial latitudes, species of Calamagrostis generally occur at higher elevations in...

 (Calamagrostis) and surrounded by lightly grazed, rough grassland
Grassland
Grasslands are areas where the vegetation is dominated by grasses and other herbaceous plants . However, sedge and rush families can also be found. Grasslands occur naturally on all continents except Antarctica...

 may also prove attractive to Snipe and Lapwings.

Fish

In late summer large shoals of roach (Rutilus rutilus) and perch
Perch
Perch is a common name for fish of the genus Perca, freshwater gamefish belonging to the family Percidae. The perch, of which there are three species in different geographical areas, lend their name to a large order of vertebrates: the Perciformes, from the Greek perke meaning spotted, and the...

 (Perca fluviatilis) fry congregate around the margins and weed beds, which are predated by the brown trout
Brown trout
The brown trout and the sea trout are fish of the same species....

 (Salmo trutta morpha fario) and rainbow trout
Rainbow trout
The rainbow trout is a species of salmonid native to tributaries of the Pacific Ocean in Asia and North America. The steelhead is a sea run rainbow trout usually returning to freshwater to spawn after 2 to 3 years at sea. In other words, rainbow trout and steelhead trout are the same species....

 (Oncorhynchus mykiss). Chew Valley also holds a large population of pike
Northern Pike
The northern pike , is a species of carnivorous fish of the genus Esox...

 (Esox lucius), and fishing for these is permitted at certain times of the year.

Insects

Aquatic midges
Chironomidae
Chironomidae are a family of nematoceran flies with a global distribution. They are closely related to the Ceratopogonidae, Simuliidae, and Thaumaleidae...

 (Chironomidae) provide the highest proportion of the fly life of the Lake. The trout
Trout
Trout is the name for a number of species of freshwater and saltwater fish belonging to the Salmoninae subfamily of the family Salmonidae. Salmon belong to the same family as trout. Most salmon species spend almost all their lives in salt water...

 (Salmonidae) will feed at the surface on these and water boatmen (Corixidae), and below the surface on the caddisfly (Trichoptera) larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...

e and pupa
Pupa
A pupa is the life stage of some insects undergoing transformation. The pupal stage is found only in holometabolous insects, those that undergo a complete metamorphosis, going through four life stages; embryo, larva, pupa and imago...

e; they will also take the adult Caddisflies when they emerge. Other aquatic fauna including daphnia
Daphnia
Daphnia are small, planktonic crustaceans, between 0.2 and 5 mm in length. Daphnia are members of the order Cladocera, and are one of the several small aquatic crustaceans commonly called water fleas because of their saltatory swimming style...

and snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...

s are also found in the lake. Large populations of dragonflies, including Migrant Hawker
Migrant Hawker
The Migrant Hawker is one of the smaller species of hawker dragonflies. It can be found away from water but for breeding it prefers still or slow-flowing water and can tolerate brackish sites. The flight period is from July to the end of October. A. mixta occurs in North Africa, southern and...

 (Aeshna mixta) and significant numbers of Ruddy Darter
Ruddy Darter
The Ruddy Darter is a European species of dragonfly of the family Libellulidae.-Description:The Ruddy Darter attains a wingspan of up to 6 cm. The head, thorax and abdomen of the male are vivid red, while the female is slightly smaller, and is a golden-yellow colour with black markings...

 (Sympetrum sanguineum) occur. Eleven species of wainscot moth
Moth
A moth is an insect closely related to the butterfly, both being of the order Lepidoptera. Moths form the majority of this order; there are thought to be 150,000 to 250,000 different species of moth , with thousands of species yet to be described...

 make their home in the reed beds, including the nationally local Brown-veined Wainscot (Archanara dissoluta) Twin-spotted Wainscot (Archanara geminipuncta) and Silky Wainscot (Chilodes maritimus).

Vegetation

The lake is surrounded with fringing reedbeds, carr woodland and grassland
Grassland
Grasslands are areas where the vegetation is dominated by grasses and other herbaceous plants . However, sedge and rush families can also be found. Grasslands occur naturally on all continents except Antarctica...

, which are managed by Bristol Water
Bristol Water
Bristol Water supplies 300 million litres of drinking water to over 1 million customers in a area centred on Bristol, England. It is regulated under the Water Industry Act 1991...

. The water conditions are eutrophic with run off from local fields and streams. Open-water plant communities are rather sparse, largely comprising fennel pondweed
Potamogeton
Potamogeton is a genus of aquatic, mostly freshwater, plants of the family Potamogetonaceae. Most are known by the common name pondweed, although many unrelated plants may be called pondweed, such as Canadian pondweed...

 (Potamogeton pectinatus), lesser pondweed
Potamogeton
Potamogeton is a genus of aquatic, mostly freshwater, plants of the family Potamogetonaceae. Most are known by the common name pondweed, although many unrelated plants may be called pondweed, such as Canadian pondweed...

 (Potamogeton pusillus), opposite-leaved pondweed
Groenlandia
Groenlandia is a genus of aquatic plants of the family Potamogetonaceae....

 (Groenlandia densa) and water-crowfoot
Ranunculus
Ranunculus is a large genus of about 600 species of plants in the Ranunculaceae. Members of the genus include the buttercups, spearworts, water crowfoots and the lesser celandine....

 (Ranunculus spp.). On neutral soils around the reservoir, pepper-saxifrage
Saxifrage
Saxifraga is the largest genus in the family Saxifragaceae, containing about 440 species of Holarctic perennial plants, known as saxifrages. The Latin word saxifraga means literally "stone-breaker", from Latin + ...

 (Silaum silaus), burnet-saxifrage
Saxifrage
Saxifraga is the largest genus in the family Saxifragaceae, containing about 440 species of Holarctic perennial plants, known as saxifrages. The Latin word saxifraga means literally "stone-breaker", from Latin + ...

 (Pimpinella saxifraga) and devil's-bit scabious (Succisa pratensis) occur, and on calcareous soils fairy flax
Flax
Flax is a member of the genus Linum in the family Linaceae. It is native to the region extending from the eastern Mediterranean to India and was probably first domesticated in the Fertile Crescent...

 (Linum catharticum), dwarf thistle
Cirsium
Cirsium is a genus of perennial and biennial flowering plants in the Asteraceae, one of several genera known commonly as thistles. They are more accurately known as Plume thistles. These differ from other thistle genera in having feathered hairs to their achenes...

 (Cirsium acaule) and salad burnet
Salad Burnet
Sanguisorba minor is a plant in the family Rosaceae that is native to western, central and southern Europe; northwest Africa and southwest Western Asia; and which has naturalized in most of North America...

 (Sanguisorba minor subspecies minor) are found.

The small and medium-sized fields around the lake are generally bounded by hedges and occasionally by tree belts and woodland, some of which date back to the most evident period of enclosure of earlier open fields which took place in the late medieval period. Mature oak
Oak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...

 (Quercus) and ash
Ash tree
Fraxinus is a genus flowering plants in the olive and lilac family, Oleaceae. It contains 45-65 species of usually medium to large trees, mostly deciduous though a few subtropical species are evergreen. The tree's common English name, ash, goes back to the Old English æsc, while the generic name...

 (Fraxinus excelsior) trees are characteristic of the area with occasional groups of scots pine
Scots Pine
Pinus sylvestris, commonly known as the Scots Pine, is a species of pine native to Europe and Asia, ranging from Scotland, Ireland and Portugal in the west, east to eastern Siberia, south to the Caucasus Mountains, and as far north as well inside the Arctic Circle in Scandinavia...

 (Pinus sylvestris) and Chestnut
Chestnut
Chestnut , some species called chinkapin or chinquapin, is a genus of eight or nine species of deciduous trees and shrubs in the beech family Fagaceae, native to temperate regions of the Northern Hemisphere. The name also refers to the edible nuts they produce.-Species:The chestnut belongs to the...

s (Castanea sativa). Many elm
Elm
Elms are deciduous and semi-deciduous trees comprising the genus Ulmus in the plant family Ulmaceae. The dozens of species are found in temperate and tropical-montane regions of North America and Eurasia, ranging southward into Indonesia. Elms are components of many kinds of natural forests...

 (Ulmus) trees have been lost in this area, and dead/dying elms are also evident in the surrounding landscape.

Four areas of woodland containing 157 trees has been planted by The Life for a Life Charity around the lake on the Restaurant side, for the cremated remains of loved ones to be placed beneath them. These forests contain Scots Pine
Scots Pine
Pinus sylvestris, commonly known as the Scots Pine, is a species of pine native to Europe and Asia, ranging from Scotland, Ireland and Portugal in the west, east to eastern Siberia, south to the Caucasus Mountains, and as far north as well inside the Arctic Circle in Scandinavia...

 (Pinus sylvestris), English Oak (Quercus robur), Rowan
Rowan
The rowans or mountain-ashes are shrubs or small trees in genus Sorbus of family Rosaceae. They are native throughout the cool temperate regions of the Northern Hemisphere, with the highest species diversity in the mountains of western China and the Himalaya, where numerous apomictic microspecies...

 (Sorbus aucuparia) and the Silver Birch
Silver Birch
Betula pendula is a widespread European birch, though in southern Europe it is only found at higher altitudes. Its range extends into southwest Asia in the mountains of northern Turkey and the Caucasus...

 (Betula pendula).

Birdwatching

During 2005–2006 Bristol Water started restoring two artificial islands. These are intended to provide safe nesting and roosting sites for a range of wildfowl. Permits to enter the reservoir enclosure and to use the access roads, paths and bird hides are available (for a fee) only to members of ornithological and naturalist societies recognised by Bristol Water. They can be obtained from Woodford Lodge and include conditions of use imposed by the owners.

Sailing

Chew Valley Lake Sailing Club has a large sailing area, approximately 1.9 miles (3 km) long, for dinghy sailing
Dinghy sailing
Dinghy sailing is the activity of sailing small boats by using five essential controls:* the sails* the foils ....

. The lake is divided into two areas: a restricted summer area which is available during the fishing season (mid-March to mid-October), and the full area which can be used throughout the winter and on Sunday afternoons. The sailing area is marked out by lines of small white buoys. Racing marks are red buoys with flags, although large inflatable marks are used of open events.
The club can cater for fleets of over one hundred boats and it hosts large national events. Normal club racing has fleet starts for the following dinghy classes: Flying Fifteen (keelboat)
Flying Fifteen (keelboat)
The Flying Fifteen is a 20-foot two person keelboat.Designed by the legendary Uffa Fox in 1947, the 6m Flying Fifteen has maintained its reputation as an exciting and competitive two-man racing craft...

, Laser (dinghy)
Laser (dinghy)
The International Laser Class sailboat, also called Laser Standard and the Laser One is a popular one-design class of small sailing dinghy. According the Laser Class Rules the boat may be sailed by either one or two people, though it is rarely sailed by two. The design, by Bruce Kirby, emphasizes...

, Solo (dinghy)
Solo (dinghy)
The National Solo class is a racing dinghy designed by Jack Holt in 1956. The Solo is sailed in the United Kingdom, Holland and Australia.Originally designed in wood, competitive boats are now widely available in Fibre Reinforced Plastic or composite construction as well as wood.2006 was the 50th...

 and Topper (dinghy)
Topper (dinghy)
The Topper is an 11 foot sailing dinghy designed by Ian Proctor. The Topper is a one-design boat sailed mostly in the British Isles. It was recognised as an International class by the International Sailing Federation...

 as well as a handicap fleet run under the Portsmouth yardstick
Portsmouth yardstick
The Portsmouth Yardstick or Portsmouth handicap scheme is a system of handicapping used primarily in small-boat yacht racing.The handicap is applied to the time taken to sail any course, and the corrected time can be used to compare widely different sailboats on even terms. Portsmouth Numbers are...

 scheme. Five separate slipways enable easy launching. Off the water, the clubhouse facilities include large changing rooms, hot showers, hot food at the weekends, a bar and terrace overlooking the lake. The club also caters for disabled people with facilities on both floors and a lift. Various Royal Yachting Association
Royal Yachting Association
The Royal Yachting Association is the national governing body for certain watersports in the United Kingdom. Activities it covers include:* Sailing* Windsurfing* Motor cruising* Sportsboats* Personal watercraft* Powerboat racing...

 sailing courses are held at the club for members including race training, youth training, powerboat training, race officer training as well as more informal training run within each fleet.

Fishing

Seasonal day and afternoon bank fishing permits are available at Woodford Lodge. The restrictions imposed by Bristol Water mean that no fishing is allowed from the dam
Dam
A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...

s or stone embankments, the sailing club, in front of Stratford bird hide, in front of the picnic
Picnic
In contemporary usage, a picnic can be defined simply as a pleasure excursion at which a meal is eaten outdoors , ideally taking place in a beautiful landscape such as a park, beside a lake or with an interesting view and possibly at a public event such as before an open air theatre performance,...

 areas and in the nature reserve
Nature reserve
A nature reserve is a protected area of importance for wildlife, flora, fauna or features of geological or other special interest, which is reserved and managed for conservation and to provide special opportunities for study or research...

, and various other regulations are in force. There is a fleet of 32 motor boats for hire to fish.

External links

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