Editing River Avon, Bristol (section)

== History ==
[[File:Avon and Severn from Clifton Down 1842.jpg|thumb|left|View down the Avon to the Severn from Clifton Down, 1842]]
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 [[British Iron Age|Iron Age]], prior to the [[Roman conquest of Britain]]. Further east, between Bath and what is now Wiltshire, it may also have formed a border of the territory ruled by the [[Belgae]]. After the Roman occupation the river formed a boundary between the lands of the [[Hwicce]] (which became [[Mercia]]) and the kingdom of [[Wessex]].<ref>{{cite book|last1=Whittock|first1=Hannah|last2=Whittock|first2=Martyn|title=The Anglo-Saxon Avon Valley Frontier|date=2014|publisher=Fonthill|isbn=978-1-78155-282-7}}</ref>

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.<ref>{{Cite web | title=The Kennet and Avon Museum, Devizes | work=Kennet and Avon Canal Trust | url=http://www.katrust.org/museum_heritage_planning_001.htm | access-date=20 August 2006 |archive-url = https://web.archive.org/web/20060425185503/http://www.katrust.org/museum_heritage_planning_001.htm |archive-date = 25 April 2006}}</ref> The [[floodplain]] of the Avon, on which the city centre of [[Bath, Somerset|Bath]] is built, has an altitude of about {{convert|59|ft|0|abbr=on}} above [[sea level]].<ref>{{cite web|url=http://idox.bathnes.gov.uk/WAM/doc/BackGround%20Papers-92552.pdf?extension=.pdf&id=92552&location=VOLUME1&contentType=application/pdf&pageCount=1 |title=Bath Western Riverside Outline Planning Application Design Statement, April 2006, Section 2.0, Site Analysis |date=April 2006 |access-date=2 May 2015 |url-status=live |archive-url=https://web.archive.org/web/20160810063821/http://idox.bathnes.gov.uk/WAM/doc/BackGround%20Papers-92552.pdf?extension=.pdf&id=92552&location=VOLUME1&contentType=application%2Fpdf&pageCount=1 |archive-date=10 August 2016 }}</ref> The river, once an unnavigable series of [[Braided river|braided streams]] broken up by [[swamp]]s and ponds, has been managed by [[weir]]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.<ref>{{cite web|title=Carr's Mill, Lower Bristol Road, Bath Flood Risk Assessment |url=http://idox.bathnes.gov.uk/WAM/doc/BackGround%20Papers-212576.pdf?extension=.pdf&id=212576&location=VOLUME1&contentType=application/pdf&pageCount=1 |publisher=Bath and North East Somerset |access-date=17 September 2010 |url-status=live |archive-url=https://web.archive.org/web/20110722034626/http://idox.bathnes.gov.uk/WAM/doc/BackGround%20Papers-212576.pdf?extension=.pdf&id=212576&location=VOLUME1&contentType=application%2Fpdf&pageCount=1 |archive-date=22 July 2011 }}</ref>

The Bristol Avon Navigation, which runs the {{convert|15|mi}} from the Kennet and Avon Canal at Hanham Lock to the Bristol Channel at Avonmouth, was constructed between 1724 and 1727,<ref>{{cite web|url=https://www.waterways.org.uk/waterways/canals_rivers/bristol_avon/bristol_avon |publisher=Inland Waterways Association |title=Bristol Avon Navigation |access-date=3 March 2013 |url-status=live |archive-url=https://web.archive.org/web/20120806114307/https://www.waterways.org.uk/waterways/canals_rivers/bristol_avon/bristol_avon |archive-date= 6 August 2012 }}</ref> following legislation passed by [[Anne, Queen of Great Britain|Queen Anne]],<ref>{{Cite web | title=Navigation of the river Avon | work=Bristol History.com | url=http://weldgen.tripod.com/bristol-history-com/id2.html | access-date=22 September 2006| archive-url = https://web.archive.org/web/20070110214011/http://weldgen.tripod.com/bristol-history-com/id2.html| archive-date = 10 January 2007}}</ref><ref>{{cite wikisource |plaintitle=Historical Account of the Navigable Rivers, Canals, and Railways, of Great Britain |chapter=Avon River, Gloucestershire |last=Priestley |first=Joseph |year=1831 |publisher=Longman, Rees, Orme, Brown & Green}}</ref> by a company of proprietors and the engineer [[John Hore]] of [[Newbury, Berkshire|Newbury]]. The first cargo of 'Deal boards, Pig-Lead and Meal' arrived in Bath in December 1727.<ref name="allsop" /> It is now administered by the [[Canal & River Trust]].

[[File:S.S. Dunbrody stranded in Avon (21589500680).jpg|thumb|S.S. Dunbrody stranded in the 1890s owing to the high tidal range]]
Throughout Bristol's history the [[Avon Gorge]] 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 {{convert|15|m|ft}},<ref>{{cite web | url= http://www.environment-agency.gov.uk/commondata/acrobat/severnpositionmay2006_1508223.pd | format= PDF | work= UK Environment Agency | title= Severn Estuary Barrage | date= 31 May 2006 | access-date= 3 September 2007 |archive-url = https://web.archive.org/web/20070930155720/http://www.environment-agency.gov.uk/commondata/acrobat/severnpositionmay2006_1508223.pd |archive-date = 30 September 2007}}</ref> second only to [[Bay of Fundy]] in [[Eastern Canada]];<ref>{{cite book | title= Extreme Depositional Environments: Mega End Members in Geologic Time
| first1= Marjorie A.| last1= Chan | last2= Archer|first2= Allen William | location= [[Boulder, Colorado]] | isbn= 0-8137-2370-1 | publisher= [[Geological Society of America]] | year= 2003 | url=https://books.google.com/books?id=b3_1Ry0gDqEC&q=bristol+channel&pg=PA152 | page= 151 }}</ref><ref>{{cite web|url=https://www.bbc.co.uk/bristol/content/articles/2005/07/04/bristolchannel_feature.shtml |title=Coast: Bristol Channel |work=BBC |access-date=27 August 2007 |url-status=live |archive-url=https://web.archive.org/web/20060525130200/http://www.bbc.co.uk/bristol/content/articles/2005/07/04/bristolchannel_feature.shtml |archive-date=25 May 2006 }}</ref> 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''.<ref>{{cite web|title=Wrecks On The River Avon |date=2 December 2012 |url=http://www.brh.org.uk/site/articles/wrecks-on-the-river-avon/ |publisher=Bristol Radical History Group |access-date=3 March 2013 |url-status=live |archive-url=https://web.archive.org/web/20130222070603/http://www.brh.org.uk/site/articles/wrecks-on-the-river-avon/ |archive-date=22 February 2013 }}</ref>

In 1877, Halfpenny Bridge, a pedestrian toll bridge crossing the river from [[Bath Spa railway station]] to [[Widcombe, Bath|Widcombe]], collapsed with the loss of about 10 lives amongst a large crowd going to the [[Royal Bath and West Show|Bath and West Agricultural show]].<ref name="bbc-20121112">{{cite news|url=https://www.bbc.co.uk/news/uk-england-somerset-20294135 |title=Kennet and Avon canal's history made into audio story |publisher=BBC |date=12 November 2012 |access-date=24 February 2015 |url-status=live |archive-url=https://web.archive.org/web/20150926010854/http://www.bbc.co.uk/news/uk-england-somerset-20294135 |archive-date=26 September 2015 }}</ref><ref>{{cite web|url=http://anengineersaspect.blogspot.co.uk/2010/05/fall-of-widcombe-bridge-over-avon-june.html |title=The Fall of the Widcombe Bridge over the Avon -- June 6, 1877 |author=Nanette South Clark |publisher=An Engineer's Aspect |date=17 May 2010 |access-date=24 February 2015 |url-status=live |archive-url=https://web.archive.org/web/20150224172948/http://anengineersaspect.blogspot.co.uk/2010/05/fall-of-widcombe-bridge-over-avon-june.html |archive-date=24 February 2015 }}</ref>

The Avon has flooded several times in its recorded history. These floods include the one in 1799/1800 damaging [[Pulteney Bridge]].<ref name="transportheritage">{{cite web|title=Pulteney Bridge, Bath|url=http://transportheritage.com/find-heritage-locations.html?sobi2Task=sobi2Details&sobi2Id=304|url-status=live|archive-url=https://web.archive.org/web/20140310202531/http://transportheritage.com/find-heritage-locations.html?sobi2Task=sobi2Details&sobi2Id=304|archive-date=10 March 2014|access-date=3 March 2013|publisher=Transport Heritage}}</ref> Various points along the river including the valley around [[Freshford, Somerset|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.<ref>{{cite web|title=Streams, rivers, waterways, and ponds |url=http://flewg.weebly.com/streams-rivers-waterways-and-ponds.html |publisher=Freshford and Limply Stoke Environment Working Group |access-date=1 July 2015 |url-status=live |archive-url=https://web.archive.org/web/20150702063811/http://flewg.weebly.com/streams-rivers-waterways-and-ponds.html |archive-date= 2 July 2015 }}</ref><ref>{{cite web|title=Strategic Flood Risk Assessment |url=http://www.wiltshire.gov.uk/west_wiltshire_sfra_level_1_august_2008_main_report.pdf |publisher=West Wiltshire District Council |access-date=1 July 2015 |url-status=live |archive-url=https://web.archive.org/web/20160304093424/http://www.wiltshire.gov.uk/west_wiltshire_sfra_level_1_august_2008_main_report.pdf |archive-date= 4 March 2016 }}</ref> 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.<ref>{{cite web|title=Bristol Avon Catchment Flood Management Plan |url=https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/294182/Bristol_Avon_Catchment_Flood_Management_Plan.pdf |publisher=Environment Agency |access-date=1 July 2015 |url-status=live |archive-url=https://web.archive.org/web/20150702125514/https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/294182/Bristol_Avon_Catchment_Flood_Management_Plan.pdf |archive-date= 2 July 2015 }}</ref> A tidal surge, combined with high water levels from the [[Winter flooding of 2013–14 on the Somerset Levels|flooding of the surrounding area]] caused flooding in the city of Bristol.<ref>{{cite news|title=Tidal surge on River Avon floods Bristol streets |work=BBC News |url=https://www.bbc.co.uk/news/uk-england-bristol-25598155 |access-date=1 July 2015 |url-status=live |archive-url=https://web.archive.org/web/20150925224146/http://www.bbc.co.uk/news/uk-england-bristol-25598155 |archive-date=25 September 2015 }}</ref>