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Chew Valley Lake

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   Chew Valley Lake
   Latitude       51° 20′ 4.92″ N
   Longitude      2° 37′ 4.92″ W
   Location       Somerset, UK
   Area           1,200 acres (4.9 km²)
   Volume         20,000,000 m³
   Governing body Bristol Water
   SSSI Ref       1001346
   SPA Code       UK9010041

   Chew Valley Lake ( grid reference ST5659) is a large reservoir in the
   Chew Valley, Somerset, England, and the fifth-largest artificial lake
   in the United Kingdom (the largest in south-west England), with an area
   of 1,200  acres (4.9 km²). The lake, created in the early 1950s and
   opened by Elizabeth II of the United Kingdom|Queen Elizabeth II in
   1956, provides much of the drinking water for the city of Bristol and
   surrounding area, taking its supply from the Mendip Hills. Some of the
   water from the lake is used to maintain the flow in the River Chew.

   Before the lake was created, archaeological investigations were carried
   out that showed evidence of occupation since Neolithic times and
   included Roman artifacts. The lake is an important site for wildlife
   and has been dedicated as a Site of Special Scientific Interest (SSSI)
   and a Special Protection Area (SPA). It is a national centre for
   birdwatching, 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 (plants)
   and fauna provide a variety of habitats and include some less common
   plants and insects.

   Some restricted use for recreational activities is permitted by the
   owner, Bristol Water, including dinghy sailing and fishing, primarily
   for trout.

Location

   Map of the lake
   Enlarge
   Map of the lake

   Chew Valley Lake in the Chew Valley at the northern edge of the Mendip
   Hills, surrounded by meadows and woods and close to the villages of
   Chew Stoke, Chew Magna and Bishop Sutton. 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 several small rivers,
   and it flows into the River Chew for 17 miles (27 km) before it joins
   the 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. Working
   with the Avon Wildlife Trust, Somerset Wildlife Trust 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. It is not a surfaced path.
   This trail runs along the east shore, visits an open bird hide and
   returns to the footbridge, making a 1-mile (1.5 km) circuit. Bristol
   Water impose conditions on visitors, particularly related to the areas
   where dogs are allowed.

Access and transportation

   Access to the waterside is restricted at several points 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 km) safe cycle route, the Chew Lake West Green
   Route, was opened around the western part of the lake. It forms part of
   the Padstow to Bristol West Country Way, National Cycle Network Route
   3. 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 Council with
   the support of Sustrans and the Chew Valley Recreational Trail
   Association. Minor roads around the lake are also frequently used by
   cyclists.

   Bristol International Airport is approximately 10 miles (15 km) away,
   and the nearest major road is the A368, which runs along the southern
   edge of the lake and provides access from Bath and Weston super Mare.
   The A37 and A38 are slightly further away, providing access from
   Bristol. 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

   Plaque unveiled by Queen Elizabeth II in 1956
   Enlarge
   Plaque unveiled by Queen Elizabeth II in 1956

   The area the lake covers was once rich farmland. Several 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 excavations were carried out by Philip Rahtz and Ernest
   Greenfield 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 and Neolithic (Old,
   Middle and New Stone Age), Bronze Age and Iron Age, including
   implements such as stone knives, flint blades and the head of a mace,
   along with buildings and graves. The artifacts from this period are
   held at Bristol City Museum and Art Gallery. Further evidence of
   neolithic and bronze age occupation is provided by the archaeological
   survey of the Mendip Hills 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, at
   Chew Park where wooden writing tablets (the first in the UK) with ink
   writing were found. The tablets were sent to the British Museum, but
   other Roman material is on display at the Bristol City Museum and Art
   Gallery with the lake's other historical artifacts.

   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 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 Museum. The largest settlement was Moreton, which is
   listed in the Domesday Book and survived until the flooding of the
   lake, when the remains of the Moreton Cross were moved to Chew Stoke
   Parish Church. There is also evidence of lime kilns, which were used in
   the production of mortar for the construction of local churches.
   Farming, both arable and dairy, continued until the flooding of the
   lake, with most households also keeping pigs. There were also a variety
   of orchards for fruit production, including apples, pears and plums.

The reservoir

   Plans for the building of the reservoir were under discussion prior to
   the Second World War, and an Act of Parliament submitted by the Bristol
   Waterworks Company was passed in 1939. Following this several 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 was initially
   stabilised by injecting concrete into the cracks in the bedrock. The
   core of the dam was made of puddled clay mixed with sand. 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,
   accompanied by Prince Philip, with the unveiling of a commemoration
   stone and plaque, which can be seen from the dam, on 17 April 1956,
   although it was not full until 25 February 1958.

   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 issued a warning
   that the dam might not hold, prompting localised evacuation of
   populated valley areas downstream including Pensford and Keynsham.

Ecology

   View of Chew Valley Lake showing Herriot's Bridge
   Enlarge
   View of Chew Valley Lake showing Herriot's Bridge

   The lake is designated a Site of Special Scientific Interest (SSSI)
   (Site Ref: 1001346) and a Special Protection Area (SPA) (Site Code:
   UK9010041) largely because of the variety of species and habitats.
   Providing further protection, much of the area around the lake also
   falls within the Mendip Hills Area of Outstanding Natural Beauty
   (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, largely
   consisting of red siltstone resulting in the underlying characteristic
   of the gently rolling valley landscape. There are also bands of
   sandstone of the Triassic 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, the third most
   important site in Britain for wintering wildfowl. From late July to
   February, up to 4000 ducks (Anatidae) of twelve different species may
   be present, including internationally important numbers of shoveler
   (Anas clypeata) and gadwall (Anas strepera). Some 400 great crested
   grebes (Podiceps cristatus) gather 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" in 1964, is available from the Chew Valley Ringing
   Station.

   Numerous other birds can be seen, especially during the spring and
   autumn migrations. Sand martins (Riparia riparia) arrive early and can
   usually be seen hawking over the water for insects in the second or
   third week of March. Mixed flocks of tits (Paridae), swallows
   (Hirundinidae), terns (Sternidae) and little gulls (Larus minutus) can
   regularly be seen. A variety of waders, such as lapwings (Vanellus
   vanellus), dunlin (Calidris alpina) and common snipe (Gallinago
   gallinago), are attracted to the muddy shores as the water level drops
   in autumn. By midwinter up to 40,000 gulls, mostly black-headed (Larus
   ridibundus) and common (L. canus), may be roosting. Good numbers of
   reed (Acrocephalus scirpaceus) and sedge warblers (A. schoenobaenus)
   nest in the fringing reeds, along with grebes (Podicipedidae) and coots
   (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 (Aythya
   fuligula) , pochard (Aythya ferina), shelduck (Tadorna tadorna) and
   gadwall raise broods most years. Recent breeding successes also include
   water rail (Rallus aquaticus) and Cetti's warbler (Cettia cetti).

   A new wetland reserve has been created at Herons Green on the opposite
   side of the causeway to the lake. A large shallow pool fringed with
   sedges (Cyperaceae), rushes (Juncaceae) and reedgrasses (Calamagrostis)
   and surrounded by lightly grazed, rough grassland may also prove
   attractive to snipe and Lapwings.

Fish

   In late summer large shoals of roach (Rutilus rutilus) and perch
   (Osteichthyes) fry can congregate around the margins and weed beds,
   which are predated by the brown trout (Salmo trutta morpha fario) and
   rainbow trout (Oncorhynchus mykiss).

Insects

   Aquatic midges (Chironomidae) provide the highest proportion of the fly
   life of the Lake. The trout (Salmonidae) will feed at the surface on
   these and water boatmen (Corixidae), and below the surface on the
   caddisfly (Trichoptera) larvae and pupae; they will also take the adult
   Caddisflies when they emerge. Many other aquatic fauna including
   daphnia and snails are also found in the lake. Near Herriot's Pool
   large populations of dragonflies including ruddy darters (Sympetrum
   sanguineum) and migrant hawker (Aeshna mixta) hunt over the water. Two
   scarce species of wainscot moth make their home in the reed beds.

Vegetation

   Chew Valley Lake from Burledge Hill, showing Denny Island
   Enlarge
   Chew Valley Lake from Burledge Hill, showing Denny Island

   The lake is surrounded with some fringing reedbeds, carr woodland and
   grassland, which are managed by Bristol Water. The water conditions are
   eutrophic with some run off from local fields and streams. Open-water
   plant communities are rather sparse, largely comprising fennel pondweed
   (Potamogeton pectinatus), lesser pondweed (Potamogeton pusillus),
   opposite-leaved pondweed (Groenlandia densa) and water-crowfoot
   (Ranunculus spp.). On neutral soils around the reservoir,
   pepper-saxifrage (Silaum silaus), burnet-saxifrage (Pimpinella
   saxifraga) and devil's-bit scabious (Succisa pratensis) occur, and on
   calcareous soils fairy flax (Linum catharticum), dwarf thistle (Cirsium
   acaule) and salad burnet (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. Hedgerows support
   the nationally rare bithynian vetch (Vicia bithynica). Mature oak
   (Quercus) and ash (Fraxinus excelsior) trees are characteristic of the
   area with occasional groups of scots pine (Pinus sylvestris) and
   Chestnuts (Castanea sativa). Many elm (Ulmus) trees have been lost in
   this area, and dead/dying elms are also evident in the surrounding
   landscape.

Leisure use

   The lake is used for a wide variety of leisure pursuits.

Birdwatching

   Birds on Chew Valley Lake taken from Herriot's Bridge
   Enlarge
   Birds on Chew Valley Lake taken from Herriot's Bridge

   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 road,
   path and bird hides are available 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.

   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 easily cater for fleets of over one hundred boats and it
   hosts many large national events. Normal club racing has fleet starts
   for the following dinghy classes: Flying Fifteen (keelboat), Laser
   (dinghy), Solo (dinghy) and Topper (dinghy) as well as a handicap fleet
   run under the Portsmouth yardstick 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.

   The club is open for sailing to members on Wednesday and every weekend
   with racing held on Wednesday evenings and Sundays. Various Royal
   Yachting Association 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. A selection of dinghies is also available for members to try.

   The club is a private sailing club and so visitors should contact the
   Club prior to visiting.

Fishing

   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 dams or stone embankments, the sailing club, in front
   of Stratford bird hide, in front of the picnic areas and in the nature
   reserve, and various other regulations are in force. There is a fleet
   of 32 motor boats for hire to fish.
   Retrieved from " http://en.wikipedia.org/wiki/Chew_Valley_Lake"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
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