River Avon, Bristol
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The River Avon ( ) is a river in the southwest of England. To distinguish it from a number of other rivers of the same name, it is often called the Bristol Avon. The name 'Avon' is loaned from an ancestor of the Welsh word , meaning 'river'. The Avon rises just north of the village of Acton Turville in South Gloucestershire, before flowing through
Wiltshire Wiltshire (; abbreviated to Wilts) is a ceremonial county in South West England. It borders Gloucestershire to the north, Oxfordshire to the north-east, Berkshire to the east, Hampshire to the south-east, Dorset to the south, and Somerset to ...
into
Somerset Somerset ( , ), Archaism, archaically Somersetshire ( , , ) is a Ceremonial counties of England, ceremonial county in South West England. It is bordered by the Bristol Channel, Gloucestershire, and Bristol to the north, Wiltshire to the east ...
. In its lower reaches from Bath (where it meets the Kennet and Avon Canal) to the Severn Estuary at Avonmouth near
Bristol Bristol () is a City status in the United Kingdom, cathedral city, unitary authority area and ceremonial county in South West England, the most populous city in the region. Built around the River Avon, Bristol, River Avon, it is bordered by t ...
, the river is navigable and is known as the Avon Navigation. The Avon is the 19th longest river in the United Kingdom, at , although there are just as the crow flies between the source and its mouth in the Severn Estuary. The catchment area is .


Etymology

The name "Avon" is loaned from the
Common Brittonic Common Brittonic (; ; ), also known as British, Common Brythonic, or Proto-Brittonic, is a Celtic language historically spoken in Britain and Brittany from which evolved the later and modern Brittonic languages. It is a form of Insular Cel ...
, "river", which survives in the Welsh word ''afon'' . " River Avon", therefore, literally means "river river"; several other English and Scottish rivers share the name. The County of Avon that existed from 1974 to 1996 was named after the river, and covered
Bristol Bristol () is a City status in the United Kingdom, cathedral city, unitary authority area and ceremonial county in South West England, the most populous city in the region. Built around the River Avon, Bristol, River Avon, it is bordered by t ...
, Bath, and the lower Avon valley.


Course

The Avon rises on the southern edge of the Cotswold hills, at Didmarton in Gloucestershire; at Joyce's Pool a plaque marks the source. It flows south-east into Wiltshire to Sherston, where it is joined by the Luckington Brook which drains an area west of Luckington that includes the Badminton House estate. From Sherston the river flows east to Malmesbury, where it is joined by its first major tributary, the Tetbury Avon, which rises just east of Tetbury in Gloucestershire. This is known locally as the Ingleburn, which in
Old English Old English ( or , or ), or Anglo-Saxon, is the earliest recorded form of the English language, spoken in England and southern and eastern Scotland in the Early Middle Ages. It developed from the languages brought to Great Britain by Anglo-S ...
means 'English river'. The two rivers flow north and south of a rocky outcrop, almost creating an island for the ancient hilltop town of Malmesbury to sit on. Upstream of this confluence the river is sometimes referred to as the 'River Avon (Sherston branch)' to distinguish it from the Tetbury branch.Ordnance Survey 1:25,000 scale Explorer map series sheet no 168 ''Stroud, Tetbury & Malmesbury'' After the two rivers merge, the Avon turns southeast away from the Cotswolds and then quickly south into the clay Dauntsey Vale, where it is joined by the River Marden, until it reaches the biggest town so far, Chippenham. The wide vale is now known as the Avon Vale, and the river flows on via Lacock to
Melksham Melksham () is a town and civil parish on the Bristol Avon, River Avon in Wiltshire, England, about northeast of Trowbridge and south of Chippenham. The parish population was 18,113 at the 2021 census. History Early history Excavations in ...
, then turns north-west through
Bradford-on-Avon Bradford-on-Avon (sometimes Bradford on Avon) is a town and civil parishes in England, civil parish in west Wiltshire (district), Wiltshire, England, near the border with Somerset. The town's canal, historic buildings, shops, pubs and restauran ...
, where the centre of the town grew up around a ford, hence the origin of the town's name ("Broad-Ford"). This was supplemented in Norman times by the Grade I listed bridge that still stands today; originally a packhorse bridge, it was widened in the 17th century by rebuilding the downstream side. The Avon Valley between Bradford-on-Avon and Bath is an example of a valley where four forms of ground transport are found: road, rail, river, canal. The river passes under the Avoncliff and Dundas Aqueducts which carry the Kennet and Avon Canal, and at Freshford is joined by the Somerset River Frome. Avoncliff Aqueduct was built by John Rennie and chief engineer John Thomas, between 1797 and 1801. The aqueduct consists of three arches and is long with a central elliptical arch of span with two side arches each semicircular and across, all with V-jointed arch stones. The spandrel and wing walls are built in alternate courses of ashlar masonry, and rock-faced blocks. The central span sagged soon after it was built and has been repaired many times. The Dundas Aqueduct was built by the same team between 1797 and 1801 and completed in 1805. James McIlquham was appointed contractor. The aqueduct is long with three arches built of Bath Stone, with Doric pilasters, and balustrades at each end. The central semicircular arch spans ; the two oval side arches span . It is a Grade I listed structure, and was the first canal structure to be designated as a Scheduled Ancient Monument in 1951. The stretch of river below and above the aqueduct, where it is joined by Midford Brook, has been used by rowing crews from Monkton Combe School since at least the beginning of the 1900s. It then flows past Claverton Pumping Station, which pumped water from the River Avon by Warleigh Weir into the canal, using power from the flow of the river. The pumping station is located in a pump house built of Bath Stone, located at river level. Water is diverted from the river by Warleigh Weir, about upstream. The water flows down a leat to the pumping station, where it powers a
water wheel A water wheel is a machine for converting the kinetic energy of flowing or falling water into useful forms of power, often in a watermill. A water wheel consists of a large wheel (usually constructed from wood or metal), with numerous b ...
, wide and in diameter, with 48 wooden slats. At full power the wheel uses 2  tons (2 
tonne The tonne ( or ; symbol: t) is a unit of mass equal to 1,000  kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton in the United States to distinguish it from the non-metric units of the s ...
s) of water per second and rotates five times a minute. The water wheel drives gearing which increases the speed to 16  rpm. From here, cranks drive vertical connecting rods which transfer the energy to two long
cast iron Cast iron is a class of iron–carbon alloys with a carbon content of more than 2% and silicon content around 1–3%. Its usefulness derives from its relatively low melting temperature. The alloying elements determine the form in which its car ...
rocking beams. Each rocking beam in turn drives an 18 in (0.5 m) diameter lift pump, which also take their supply from the mill leat. Each pump stroke raises of water to the canal. In 1981, British Waterways installed two electric pumps just upstream from the station. The Avon then flows through Bathford, where it is joined by the Bybrook River, and Bathampton where it passes under the Bathampton Toll Bridge. It is joined by the Lam Brook at Lambridge in Bath and then passes under
Cleveland Cleveland is a city in the U.S. state of Ohio and the county seat of Cuyahoga County. Located along the southern shore of Lake Erie, it is situated across the Canada–U.S. maritime border and approximately west of the Ohio-Pennsylvania st ...
and Pulteney Bridges and over the weir. Cleveland Bridge was built in 1826 by William Hazledine,Inscription on bridge owner of the Coalbrookdale Ironworks, with Henry Goodridge as the architect, on the site of a Roman ferry crossing. Named after the 3rd Duke of Cleveland, it spans the River Avon at Bathwick, and enabled further development of Georgian Bath to take place on the south side of the river. It was designed by architect Henry Goodridge to take the traffic of his day, horse-drawn vehicles and pedestrians, and was constructed using Bath Stone and a
cast iron Cast iron is a class of iron–carbon alloys with a carbon content of more than 2% and silicon content around 1–3%. Its usefulness derives from its relatively low melting temperature. The alloying elements determine the form in which its car ...
arch An arch is a curved vertical structure spanning an open space underneath it. Arches may support the load above them, or they may perform a purely decorative role. As a decorative element, the arch dates back to the 4th millennium BC, but stru ...
ed span. Pulteney Bridge was completed in 1773 and is designated by
English Heritage English Heritage (officially the English Heritage Trust) is a charity that manages over 400 historic monuments, buildings and places. These include prehistoric sites, a battlefield, medieval castles, Roman forts, historic industrial sites, Lis ...
as a Grade I listed structure. The bridge was designed by
Robert Adam Robert Adam (3 July 17283 March 1792) was a British neoclassical architect, interior designer and furniture designer. He was the son of William Adam (architect), William Adam (1689–1748), Scotland's foremost architect of the time, and train ...
, and is one of only four bridges in the world with shops across the full span on both sides. It is named after Frances Pulteney, heiress in 1767 of the Bathwick estate across the river from Bath. Floods in 1799 and 1800 wrecked the north side of the bridge, which had been constructed with inadequate support. It was rebuilt by John Pinch the Elder, surveyor to the Pulteney estate, in a less ambitious version of Adam's design.
Bath and North East Somerset Bath and North East Somerset (B&NES) is a Unitary authorities of England, unitary authority district in Somerset, South West England. Bath and North East Somerset Council was created on 1 April 1996 following the abolition of the county of Avon. ...
council have discussed plans to ban vehicles from the bridge and turn it into a pedestrianised zone, but it remains open to buses and taxis. Some 700 metres below Pulteney weir, the river is joined by the Kennet and Avon Canal which connects through Bath Locks. Together with the Kennet Navigation which joins the
River Thames The River Thames ( ), known alternatively in parts as the The Isis, River Isis, is a river that flows through southern England including London. At , it is the longest river entirely in England and the Longest rivers of the United Kingdom, s ...
at Reading, this provides a through route for canal boats from Bristol to London. From this point downstream the river is known as the Avon Navigation.


Navigation

The Avon above Bath remains navigable as far as Bathampton where there is the remains of a flash lock. However, the lock past the weir below Pulteney Bridge was demolished when the weir was reconstructed, so passage between the sections is only possible for dinghies and canoes using the roller slipway on the side of the weir. Beyond its junction with the Kennet and Avon Canal, the Avon flows through
Keynsham Keynsham ( ) is a town and civil parish located on the outskirts of the city of Bristol on the A4 that links the cities of Bristol and Bath, Somerset, Bath in Somerset, England. It had a population of 19,603 at the 2021 Census. It was listed i ...
towards
Bristol Bristol () is a City status in the United Kingdom, cathedral city, unitary authority area and ceremonial county in South West England, the most populous city in the region. Built around the River Avon, Bristol, River Avon, it is bordered by t ...
. For much of its course after leaving Wiltshire, it marks the traditional boundary between Somerset and Gloucestershire. For most of this distance the navigation makes use of the natural riverbed, with six locks overcoming a rise of . From Bath to Netham Lock where it divides into the New Cut and the Floating Harbour is . The stretch is made navigable by the use of locks and weirs. In the centre of Bath it passes under various bridges, including the Midland Bridge which was built by the
Midland Railway The Midland Railway (MR) was a railway company in the United Kingdom from 1844 in rail transport, 1844. The Midland was one of the largest railway companies in Britain in the early 20th century, and the largest employer in Derby, where it had ...
Company to allow the Somerset and Dorset Joint Railway access to and from its Green Park terminus station. In November 2011, the navigation between Bath and Bristol was closed because of safety concerns about Victoria Bridge. Weston Lock on the outskirts of Bath is in what now forms the Newbridge area. Weston Cut is a man made channel, opened in 1727, for boats to approach and pass through Weston Lock; the island created between the cut and the river weir became known as Dutch Island after the owner of the brass mill established on the riverside in the early 18th century. Kelston Lock and weir have permanent moorings above and below them. The Riverside Inn and Saltford Marina are also close by. Saltford Lock and weir are overlooked by the remains of the Kelston Brass Mill, which was working until 1925. It is a Grade II
listed building In the United Kingdom, a listed building is a structure of particular architectural or historic interest deserving of special protection. Such buildings are placed on one of the four statutory lists maintained by Historic England in England, Hi ...
. Alongside the lock is a pub, whose garden extends over the lock to the small island between the lock and weir. The lock was opened in 1727 and destroyed in 1738 by rival coal dealers to stop the use of the river for transportation. In its heyday, between 1709 and 1859, Swineford had an active
brass Brass is an alloy of copper and zinc, in proportions which can be varied to achieve different colours and mechanical, electrical, acoustic and chemical properties, but copper typically has the larger proportion, generally copper and zinc. I ...
and copper industry around Swineford Lock, served by the river which also provided water power for the cloth industry, as did the River Boyd, a tributary which flows into the Avon near Bitton. Keynsham Lock opened in 1727. Just above the lock are visitor moorings and a pub, on an island between the lock and the weir. The weir side of the island is also the mouth of the River Chew. The river is joined by the Siston Brook at Londonderry Wharf, terminus of the dramway which brought coal from Coalpit Heath. The final river lock, Hanham Lock, is on the edge of the Bristol built-up area; below here the river is affected by high tides which overtop Netham Weir. Above the weir, in the St Anne's area of Bristol, the river is joined by Brislington Brook. Netham Lock is the point at Netham in Bristol at which boats from the Avon gain access to Bristol's floating harbour. Construction started in 1804 to build the tidal New Cut, where it is joined by the River Malago, and divert the Avon along the Feeder Canal to the harbour; a system designed and built by William Jessop and later improved by Isambard Kingdom Brunel. A weir carries the river into the New Cut and boats use the adjacent lock. Access to the harbour is only possible during the day, when the lock keeper will open the gates unless the water level in the river between Netham and Hanham is above or below the level of the harbour. Netham Lock and the weir form part of Bristol's flood defence mechanisms. In central Bristol, where the river is tidal, it is diverted from its original course into the New Cut, a channel dug between 1804 and 1809 at a cost of £600,000. The original course is held at a constant level by lock gates (designed by Jessop) and is known as the floating harbour, since it enables ships to stay afloat rather than grounding when the tide ebbs. The harbour is protected by an 1870s replacement for Jessop's locks. This unusual dock has a tentacled plan resulting from its origins as the natural river course of the Avon and its tributary, the River Frome, and is intimately entwined with Bristol's city centre as few docks are. As a result of this, the floating harbour is one of the more successful pieces of dockland regeneration, with much of the dockside now occupied by residential, office and cultural premises, and the water heavily used by leisure craft. Downstream of central Bristol, the river passes through the deep
Avon Gorge The Avon Gorge () is a 1.5-mile (2.5-kilometre) long Canyon, gorge on the River Avon (Bristol), River Avon in Bristol, England. The gorge runs south to north through a limestone ridge west of Bristol city centre, and about 3 miles (5&nbs ...
, spanned by Brunel's Clifton Suspension Bridge: the river is tidal and is navigable by seagoing vessels at high tide but dries to a steep-sided muddy channel at low tide. It was largely the challenge of navigating this section that sealed the fate of the floating harbour as commercial docks, and saw them replaced by docks at Avonmouth where the Avon joins the Severn Estuary. Before reaching its mouth, the Avon is joined by the River Trym at Sea Mills which was the site of ''Portus Abonae'', a Roman port. Shortly after, it passes the village of Pill on the south bank where the Pill Hobblers were based in order to tow ships up the river to Bristol and where yachts and other boats still have moorings in Chapel Pill and Crockerne Pill. It then passes under the Avonmouth Bridge which carries the M5 motorway. The main span is long, and the bridge is long, with an air draught above mean high water level of . The river then serves two major dock areas. The Royal Portbury Dock is on the southern side of the mouth of the river. The deepwater dock was constructed between 1972 and 1977, and is now a major port for the import of
motor vehicle A motor vehicle, also known as a motorized vehicle, automotive vehicle, automobile, or road vehicle, is a self-propelled land vehicle, commonly wheeled, that does not operate on railway track, rails (such as trains or trams), does not fly (such ...
s. The Royal Portbury Dock has the largest entrance lock into any UK port, accommodating vessels up to beam, length and draft. The Avonmouth Docks are on the north side of the river and are one of the UK's major ports for chilled foods, especially fruit and vegetables. The first dock at Avonmouth, Avonmouth Old Dock, was opened in 1877 and acquired by Bristol Corporation in 1884. In 1907, a much larger dock, the Royal Edward Dock, was opened. The docks form part of the Port of Bristol and were operated by the Port of Bristol Authority, part of Bristol City Council, until 1991 when the council granted a 150-year lease to the Bristol Port Company. Pilotage is provided by Bristol Pilots LLP who supply authorised pilots for the River Avon and Bristol City docks, as well as the Severn estuary and the Bristol channel; they are based at Avonmouth Docks.


Hydrology and water quality

At Great Somerford the Avon has a mean flow rate of , and a typical river level range between and with a highest level of . At Melksham the Avon has a mean flow rate of . December 2013 was the highest level recorded at Bradford on Avon when the level reached with a normal range at the monitoring station being to . At Bathford the highest river level was also in December 2013 when it reached while the normal range is and , with a flow rate of . In Bath at St James, which is upstream of Pultney Weir the mean flow is , with a similar flow () downstream of the weir. At the Destructor Bridge in Bath the typical height range is to with a high of also in December 2013. At Saltford, the range is to , with a highest recording of on 24 December 2013. At Keynsham, the typical range is between and ; the highest was on 25 December 2013 when it reached . At Netham Weir, where the New Cut carries the flow away from Bristol Harbour, the typical range for the depth of the river is to , with the highest ever recorded being . For the purpose of water quality monitoring and improvement, the river is divided into several catchment management areas; South of Malmesbury, Bristol Avon Rural and Bristol Avon Urban. In the rural area, 22 water bodies are classified as good, 46 as moderate and 8 as poor. The main reasons for not achieving good scores are pollution from waste water, agriculture and rural land management. In the urban area, one water body is rated good, while 12 are rated moderate and one is poor. The pollution from upstream is added to by the effects of industry, manufacturing and other businesses and is significantly affected by physical modifications to the water course. Within the catchment area there are 137 river water bodies and 6 lakes; of these 22 per cent of rivers are rated as good ecological status, 40 per cent good for chemical status and 31 per cent good for biological status.


Conservation areas

The river is important for its dragonfly communities, with a strong population of scarce chaser (found in only six other areas in England), together with a strong population of white-legged damselfly. red-eyed damselfly is also found. The river is also important for aquatic plants, including Loddon pondweed. The Kellaways – West Tytherton
Site of Special Scientific Interest A Site of Special Scientific Interest (SSSI) in Great Britain, or an Area of Special Scientific Interest (ASSI) in the Isle of Man and Northern Ireland, is a conservation designation denoting a protected area in the United Kingdom and Isle ...
, north east of Chippenham, is of geological interest as the river bank exposes Callovian highly-fossiliferous sandstone which contains well-preserved bivalves,
gastropods Gastropods (), commonly known as slugs and snails, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and from the land. Ther ...
,
brachiopod Brachiopods (), phylum (biology), phylum Brachiopoda, are a phylum of animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear e ...
s, belemnites and ammonites. Further downstream at Newton St Loe the Newton St Loe SSSI is another Geological Conservation Review SSSI. It represents the only remaining known exposure of fossiliferous
Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...
gravels along the River Avon. In conjunction with other sites within the wider area, it has aided the development of a scientific understanding of the history of early
glaciation A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate be ...
within
South West England South West England, or the South West of England, is one of the nine official regions of England, regions of England in the United Kingdom. Additionally, it is one of four regions that altogether make up Southern England. South West England con ...
. The bodies of
mammoth A mammoth is any species of the extinct elephantid genus ''Mammuthus.'' They lived from the late Miocene epoch (from around 6.2 million years ago) into the Holocene until about 4,000 years ago, with mammoth species at various times inhabi ...
s (''Mammuthus'') and horses (''Equus'') have been found at the site. The
Avon Gorge The Avon Gorge () is a 1.5-mile (2.5-kilometre) long Canyon, gorge on the River Avon (Bristol), River Avon in Bristol, England. The gorge runs south to north through a limestone ridge west of Bristol city centre, and about 3 miles (5&nbs ...
has been designated as a Site of Special Scientific Interest because it supports some rare fauna and flora, including species unique to the gorge. There are a total of 24 rare plant species and two unique trees: the
Bristol Bristol () is a City status in the United Kingdom, cathedral city, unitary authority area and ceremonial county in South West England, the most populous city in the region. Built around the River Avon, Bristol, River Avon, it is bordered by t ...
and Wilmotts's whitebeams.BBC Bristol,
The Avon Gorge – Bristol's Great Glacier?
." Retrieved 5 May 2006.
Other notable plants include Bristol rock-cress, Bristol onion, spiked speedwell, autumn squill and honewort. Other areas along the river which have this designation include Bickley Wood, Cleeve Wood, Hanham for its large population of Bath asparagus ('' Ornithogalum pyrenaicum''). Stidham Farm near
Keynsham Keynsham ( ) is a town and civil parish located on the outskirts of the city of Bristol on the A4 that links the cities of Bristol and Bath, Somerset, Bath in Somerset, England. It had a population of 19,603 at the 2021 Census. It was listed i ...
contains at least At least of
Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...
terrace-gravels, consisting of
limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...
clasts mainly, but also with Millstone Grit, Pennant Sandstone, flint and chert clasts. The site is of considerable importance for studies relating to the possible glaciation of the area, and of the terrace
stratigraphy Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithost ...
, particularly as it is one of only two accessible terrace deposits in this part of the Avon valley. Newton St Loe SSSI is also listed for geological reasons as it represents the only remaining known exposure of fossiliferous Pleistocene gravels along the River Avon. In conjunction with other sites within the wider area, they have aided the development of a scientific understanding of the history of early glaciation within
South West England South West England, or the South West of England, is one of the nine official regions of England, regions of England in the United Kingdom. Additionally, it is one of four regions that altogether make up Southern England. South West England con ...
. At Horseshoe Bend, Shirehampton the wooded cliff and a narrow
salt marsh A salt marsh, saltmarsh or salting, also known as a coastal salt marsh or a tidal marsh, is a coastal ecosystem in the upper coastal intertidal zone between land and open saltwater or brackish water that is regularly flooded by the tides. I ...
are supported by rocks of Devonian age Old Red Sandstone and Carboniferous Limestone, overlain by with
Triassic The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is t ...
dolomitic conglomerate. The site's principal interest and the reason for its designation as an SSSI is the presence of a population of the true service-tree (''Sorbus domestica'') growing on the cliffs. This tree is nationally rare in Britain, and this site hosts the largest known population in England. Other notable species of '' Sorbus'' here are the whitebeams '' Sorbus eminens'' and '' Sorbus anglica'', both of which are also nationally rare in Britain. The nationally scarce large-leaved lime (''Tilia platyphyllos'') also occurs, and herbs include field garlic (''Allium oleraceum'') and pale St. John's-wort (''Hypericum montanum''). The saltmarsh vegetation, which lies at the base of the cliff, is predominantly made up of sea aster (''Aster tripolium'') and English scurvygrass (''Cochlearia anglica''). There are however two nationally scarce vascular plant species here as well – slender hare's-ear (''Bupleurum tenuissimum'') and long-stalked orache (''Atriplex longipes''). The tidal reaches of the River Avon provide habitat for waterbirds, with 64 species having been recorded up to 2004, including 21 species of shorebird, and 13 species of gull.


Authorities

A catchment board for the Avon was created by the Land Drainage Act 1930 and became the Bristol Avon River Board under the River Boards Act 1948; the board was in turn replaced by the Bristol Avon River Authority under the Water Resources Act 1963. Twenty-five minor watercourses were added to the Authority's jurisdiction in 1973. Reorganisation in 1974, under the Water Act 1973 brought the Avon catchment into a new regional body, the Wessex Water Authority. Privatisation saw responsibility for the catchment pass to the National Rivers Authority on its formation on 1 September 1989. In 1996 the authority became part of the
Environment Agency The Environment Agency (EA) is a non-departmental public body, established in 1996 and sponsored by the United Kingdom government's Department for Environment, Food and Rural Affairs, with responsibilities relating to the protection and enha ...
. Navigation conservancy in the lower river from Avonmouth to the lock at Hotwells is the responsibility of The Bristol Port Company as both statutory and competent harbour authority. Navigation within Bristol's floating harbour is retained by Bristol City Council as statutory and competent harbour authority. On 2 July 2012, responsibility for maintenance of the river navigation above Bristol passed from British Waterways to the Canal & River Trust.


History

The distribution of archaeological finds suggests that the western end of the river between Bath and Avonmouth formed a border between the Dobunni and Durotriges during the late
Iron Age The Iron Age () is the final epoch of the three historical Metal Ages, after the Chalcolithic and Bronze Age. It has also been considered as the final age of the three-age division starting with prehistory (before recorded history) and progre ...
, prior to the
Roman conquest of Britain The Roman conquest of Britain was the Roman Empire's conquest of most of the island of Great Britain, Britain, which was inhabited by the Celtic Britons. It began in earnest in AD 43 under Emperor Claudius, and was largely completed in the ...
. Further east, between Bath and what is now Wiltshire, it may also have formed a border of the territory ruled by the
Belgae The Belgae ( , ) were a large confederation of tribes living in northern Gaul, between the English Channel, the west bank of the Rhine, and the northern bank of the river Seine, from at least the third century BC. They were discussed in depth b ...
. After the Roman occupation the river formed a boundary between the lands of the Hwicce (which became
Mercia Mercia (, was one of the principal kingdoms founded at the end of Sub-Roman Britain; the area was settled by Anglo-Saxons in an era called the Heptarchy. It was centred on the River Trent and its tributaries, in a region now known as the Midlan ...
) and the kingdom of Wessex. The river Avon had been navigable from Bristol to Bath during the early years of the 13th century but construction of mills on the river forced its closure. The
floodplain A floodplain or flood plain or bottomlands is an area of land adjacent to a river. Floodplains stretch from the banks of a river channel to the base of the enclosing valley, and experience flooding during periods of high Discharge (hydrolog ...
of the Avon, on which the city centre of Bath is built, has an altitude of about above
sea level Mean sea level (MSL, often shortened to sea level) is an mean, average surface level of one or more among Earth's coastal Body of water, bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical ...
. The river, once an unnavigable series of braided streams broken up by
swamp A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...
s and ponds, has been managed by
weir A weir or low-head dam is a barrier across the width of a river that alters the flow characteristics of water and usually results in a change in the height of the water level. Weirs are also used to control the flow of water for outlets of l ...
s into a single channel. Periodic flooding, which shortened the life of many buildings in the lowest part of the city, was normal until major flood control works were completed in the 1970s. The Bristol Avon Navigation, which runs the from the Kennet and Avon Canal at Hanham Lock to the Bristol Channel at Avonmouth, was constructed between 1724 and 1727, following legislation passed by Queen Anne, by a company of proprietors and the engineer John Hore of Newbury. The first cargo of 'Deal boards, Pig-Lead and Meal' arrived in Bath in December 1727. It is now administered by the Canal & River Trust. Throughout Bristol's history the
Avon Gorge The Avon Gorge () is a 1.5-mile (2.5-kilometre) long Canyon, gorge on the River Avon (Bristol), River Avon in Bristol, England. The gorge runs south to north through a limestone ridge west of Bristol city centre, and about 3 miles (5&nbs ...
has been an important transport route, carrying the River Avon, major roads and two railways. The Bristol Channel has a very high tidal range of , second only to
Bay of Fundy The Bay of Fundy () is a bay between the Canadian provinces of New Brunswick and Nova Scotia, with a small portion touching the U.S. state of Maine. It is an arm of the Gulf of Maine. Its tidal range is the highest in the world. The bay was ...
in Eastern Canada; and the gorge is relatively narrow and meandering, making it notoriously difficult to navigate. Several vessels have grounded in the gorge including the ''SS Demerara'' soon after her launch in 1851, the schooner ''Gipsy'' in 1878, the steam tug ''Black Eagle'' in 1861 and the ''Llandaff City''. In 1877, Halfpenny Bridge, a pedestrian toll bridge crossing the river from
Bath Spa railway station Bath Spa railway station is the principal station serving the city of Bath, Somerset, Bath in Somerset, England. It is on the Great Western Main Line, down the line from the zero point at between to the east and to the west. It is the busies ...
to Widcombe, collapsed with the loss of about 10 lives amongst a large crowd going to the Bath and West Agricultural show. The Avon has flooded several times in its recorded history. These floods include the one in 1799/1800 damaging Pulteney Bridge. Various points along the river including the valley around Freshford are at risk of fluvial flooding, as a result of sediment entering the river and narrowing the channel. To help cope with this some areas on the banks of the river are designated as a functional floodplain to cope with increased flow volumes. The potential changes to weather patterns as a result of climate change suggest that further measures are likely to be needed to protect the population from flooding risk. A tidal surge, combined with high water levels from the flooding of the surrounding area caused flooding in the city of Bristol.


Route and points of interest


See also

* Other Rivers Avon * Photograph of the Clifton Suspension Bridge from Brunel Way * Photograph of the estuary at Avonmouth * Rivers of the United Kingdom * Wife of Bath


References


External links


Bristol Avon Rivers Trust
{{DEFAULTSORT:Avon, Bristol Bath and North East Somerset Kennet and Avon Canal Tributaries of the River Severn Rivers of Gloucestershire Rivers of Somerset Rivers of Wiltshire River navigations in the United Kingdom Rivers of Bristol Bristol Avon catchment