View source for River Lea

{{Short description|River in the south east of England}}
{{for|similarly-named things|Lea River|River Lee (disambiguation)}}
{{Use dmy dates|date=June 2015}}
{{Use British English|date=June 2015}}
{{Infobox river
| name               = Lea
| native_name        =
| native_name_lang   =
| name_other         = Lee
| name_etymology     =
<!---------------------- IMAGE & MAP -->
| image              = HertfordBasin.jpg
| image_size         =
| image_caption      = River Lea at [[Hertford Basin]]
| map                =
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<!---------------------- LOCATION -->
| subdivision_type1  = Country
| subdivision_name1  = [[United Kingdom]]
| subdivision_type2  =
| subdivision_name2  =
| subdivision_type3  = Counties
| subdivision_name3  = [[Bedfordshire]], [[Hertfordshire]], [[Essex]], [[Greater London]]
| subdivision_type4  =
| subdivision_name4  =
| subdivision_type5  = Towns
| subdivision_name5  = [[Leagrave]], [[Luton]], [[Harpenden]], [[Hatfield, Hertfordshire|Hatfield]], [[Hertford]], [[Ware, Hertfordshire|Ware]], [[Hoddesdon]], [[Broxbourne]], [[Waltham Abbey]], [[Enfield Town]], [[Edmonton, London|Edmonton]], [[Tottenham]], [[Clapton, London|Clapton]], [[Stratford, London|Stratford]], [[Bow, London|Bow]], [[Canning Town]]
<!---------------------- PHYSICAL CHARACTERISTICS -->
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| discharge1_location=
| discharge1_min     =
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| discharge2_location= [[Luton Hoo]], [[Luton]]
| discharge2_min     =
| discharge2_avg     = {{convert|1.8|m3/s|cuft/s|abbr=on}}
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| discharge3_location= [[Feildes Weir]], [[Hoddesdon]]
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<!---------------------- BASIN FEATURES -->
| source1            =
| source1_location   = [[Leagrave]], [[Luton]]
| source1_coordinates= {{coord|51.910338|N|0.461233|W|display=inline}}
| source1_elevation  = {{convert|115|m|abbr=on}}
| mouth              =
| mouth_location     = [[Bow Creek (England)|Bow Creek]], [[River Thames]]
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| custom_label       = Designation
| custom_data        = {{Designation list
| embed = yes
| designation1 = Ramsar
| designation1_offname = [[Lea Valley]]
| designation1_date = 9 October 2000
| designation1_number = 1037<ref>{{Cite web|title=Lee Valley|website=[[Ramsar Convention|Ramsar]] Sites Information Service|url=https://rsis.ramsar.org/ris/1037|access-date=25 April 2018}}</ref>}}
| extra              =
}}

The '''River Lea''' ({{IPAc-en|ˈ|l|iː}} {{respell|LEE}}) is in the [[East of England]] and [[Greater London]]. It originates in [[Bedfordshire]], in the [[Chiltern Hills]], and flows southeast through [[Hertfordshire]], along the [[Essex]] border and into [[Greater London]], to meet the [[River Thames]] at [[Bow Creek (England)|Bow Creek]]. It is one of the largest rivers in London and the easternmost major tributary of the Thames.

The river's significance as a major east–west barrier and boundary has tended to obscure its importance as a north–south trade route. Below [[Hertford]] the river has since medieval times had alterations made to make it more navigable for boats between the Thames and eastern Hertfordshire and [[Essex]], known as the [[Lee Navigation]]. This stimulated much industry along its banks. The navigable [[River Stort]], the main tributary, joins it at [[Hoddesdon]].

While the lower Lea remains somewhat polluted, its upper stretch and tributaries, classified as [[chalk stream]]s, are a major source of drinking water for London. An artificial waterway known as the [[New River (London)|New River]], opened in 1613, abstracts clean water away from the upper stretch of the river near Hertford for drinking. The Lea's origin in the Chilterns contributes to the extreme [[hard water|hardness]] (high mineral content) of London tap water.<ref>{{Cite news |title=EC1A 7BE — Water quality in your area |url=http://www.thameswater.co.uk/cps/rde/xchg/corp/hs.xsl/899_5787.htm |work=Thames Water |access-date=2012-03-03 |archive-url=https://web.archive.org/web/20120527211041/http://www.thameswater.co.uk/cps/rde/xchg/corp/hs.xsl/899_5787.htm |archive-date=27 May 2012 |url-status=dead |df=dmy-all }}</ref>

==Name==
===Etymology===
The name of the River Lea was first recorded in the 9th century, although is believed to be much older. Spellings from the [[Anglo-Saxon]] period include ''Lig(e)an'' in 880 and ''Lygan'' in 895, and in the early medieval period it is usually ''Luye'' or ''Leye''. It seems to be derived from a [[Celtic languages|Celtic]] (brythonic) root ''lug''-meaning 'bright or light' which is also the derivation of a name for a deity, so the meaning may be 'bright river' or 'river dedicated to the god [[Lugus]]'.<ref>{{cite book |title=The Place-Names of Hertfordshire |author=J.E.B. Glover, [[Allen Mawer]], F.M.Stenton |publisher=Cambridge University Press |work=English Place-Name Society, vol. XV |year=1938}}</ref><ref>{{cite book | url=https://books.google.com/books?id=DSIOAQAAMAAJ | title=Oxford Dictionary of London Place Names | author=Anthony David Mills | publisher=[[Oxford University Press]] | year=2001 | page=133 | isbn=0-19-280106-6}}</ref> A simpler derivation may well be the Brythonic word cognate with the modern Welsh "Li" pronounced "Lea" which means a flow or a current.{{Citation needed|date=August 2023|reason=What Welsh word spelt "Li" and "pronounced like 'lea'"?}}

Much of the middle Lea was historically known as 'Mereditch', the first element deriving from the [[Old English]] ‘gemaera’, meaning boundary. This was due to that section of the river’s role as the dividing line between territories, for instance separating Middlesex and Essex. By the 20th century 'Mereditch' had evolved to 'Mare Dyke' and referred to just one channel of the river between [[Chingford]] and [[Enfield, London|Enfield]]. The channel was replaced by parts of the [[Lee Valley Reservoir Chain]] in the mid 20th century.<ref>Place Names of Essex, p9, PH Reany, English Place-Name Society, Volume 12</ref><ref>Place names of Middlesex, p5, Allen Mawer and FM Stenton, English Place-Name Society, Volume 18</ref>

The River Lea is the major component in a number of place-names, including [[Leagrave]], the suburb of [[Luton]] where the source of the river is located, and of [[Luton]] and [[Leyton]]: both mean ''"farmstead on the River Lea"''.<ref>{{cite book |author=Mills, A.D. |title=The Popular Dictionary of English Place-Names |year=1991 |publisher=Phaidon |location=Oxford}}</ref>

===Spelling===
The spelling ''Lea'' predominates west (upstream) of [[Hertford]], but both spellings (''Lea'' and ''Lee'') are used from Hertford to the [[River Thames]]. The [[Lee Navigation]] was established by Acts of Parliament and only that spelling is used in this context. The [[Lee Valley Regional Park Authority]] also uses this spelling for leisure facilities. However, the spelling ''Lea'' is used for road names, locations and other infrastructure in the capital, such as [[Leamouth]], [[Lea Bridge]], the [[Lea Valley Walk]] and the [[Lea Valley lines]] (railway). This spelling is also used in geology, archaeology, etc. to refer to the [[Lea Valley]].

===Other uses===
The term ''River Lea'' is [[Cockney rhyming slang]] for tea.<ref>Brewers Dictionary of London Phrase and Fable, Russ Willey, 2009</ref>

==Natural boundary==
{{maplink|type=line|frame=yes|frame-align=right|stroke-colour=#5E74F3|frame-height=300|frame-width=260|zoom=9|text=Course of the River Lea}}
The line of the Lea, and its major tributary, the Stort, has long been used as a political boundary. In the [[Iron Age]] the Lea and Stort valleys formed a hotly contested frontier zone between the [[Catuvellauni]] to the west and the eastern [[Trinovantes]].<ref>The Trinovantes, by Rosalind Dunnett, Chapter 1, 1975, Gerald Duckworth and Co Ltd</ref> The two rivers are assumed to have been the boundary between the core territory of the [[Kingdom of Essex|Kingdom of the East Saxons]] and its [[Middle Saxons|Middle Saxon Province]].<ref>The boundary is unknown and discussed in "Kingdom, Civitas and County" by Stephen Rippon, Oxford University Press</ref> The whole of the Lea was subsequently used as the boundary between English-ruled territory to the west and the [[Danelaw]], established in the late 9th century, to the east.

From around the ninth or tenth century, and the establishment of [[County#United Kingdom|counties]] in this part of England, the Lea-Stort line has formed the historic boundary between [[Essex]] to the east and [[Hertfordshire]] and [[Middlesex]] to the west. Within London the river is always used as a boundary between London Boroughs - which in turn inherit more ancient county and parish boundaries which also used the Lea as a boundary. Between 1889 and 1965, the lower Lea was the eastern boundary of the [[County of London]] with [[Essex County Council|Essex]].<ref>{{Cite web|title=The Builder map of the county of London - Norman B. Leventhal Map & Education Center|url=https://collections.leventhalmap.org/search/commonwealth:0z7095520|access-date=2021-09-26|website=collections.leventhalmap.org}}</ref>

When reviewing the boundaries of London's parliamentary constituencies, the [[Boundary commissions (United Kingdom)|Boundary Commission]] treats the Thames and Lea as London's major internal barriers. It will not allow a new or altered constituency that spans either river, viewing such a construct as artificial and not reflective of local communities or identities. They have compromised on this further south, on the lower Lea, where the quality and quantity of cross-river links is much greater, and the communities on either side better integrated as a result.<ref>{{Cite web|url=https://boundarycommissionforengland.independent.gov.uk/wp-content/uploads/2018/09/Final-recommendations-report.pdf|title=2018 Boundary Commission Report}}</ref>

==Course==
===Upper Lea===
{{Upper River Lea/Lee}}
[[File:WardownLake.jpg|thumb|right|A pedestrian [[suspension bridge]] spans the boating lake created where the widened river flows through [[Wardown Park]] in Luton.]]
The [[source (river or stream)|source]] of the Lea is usually said to be at Well Head inside [[Waulud's Bank]], a [[Neolithic]] [[henge]] at [[Leagrave|Leagrave Common]] in [[Luton]], [[Bedfordshire]], although just downstream the river is joined by [[Houghton Brook]], a stream that starts {{convert|2|mi|km|0}} further west in [[Houghton Regis]].

After passing through Luton, the young river passes through the [[Luton Hoo]] estate and, six miles from its source, enters [[Hertfordshire]]. The river then flows east-south-east through [[Harpenden]], [[Wheathampstead]] – once capital of the [[Catuvellauni]] tribe – through the narrow green gap between the new towns of [[Hatfield, Hertfordshire|Hatfield]] and [[Welwyn Garden City]], and on to the [[county town]] of [[Hertford]].

===Middle Lea===
[[File:River Lea Amwell.JPG|thumb|right| The River Lea at [[Great Amwell]], home of the [[Amwell Magna Fishery]], was fished by [[Izaak Walton]] – author of ''[[The Compleat Angler]]'']]
At Hertford the shallow river turns briefly north before turning to head due south, and here the river and its surrounding areas change significantly. Around Hertford, the Lea is joined by a number of major tributaries: the [[River Mimram|Mimram]], [[River Beane|Beane]], [[River Rib|Rib]], [[River Ash, Hertfordshire|Ash]], and then the [[River Stort|Stort]].

This extra volume of water has created a broad flood plain with sometimes steep hills on either side. The river passes through this valley in several channels, which are a result of both human intervention and natural causes. The increased flow made the river navigable from Hertford, a situation improved by the creation of the [[Lee Navigation]], a deep canal which begins at [[Hertford Castle Weir]].

The Stort, the most important tributary of the Lea, joins a short distance from Hertford at [[Feildes Weir]], and is itself navigable as far upstream as [[Bishops Stortford]]. The [[Hertford East branch line|Hertford East railway line]] passes along the west side of the Lea's flood plain, from Hertford to Tottenham, improving the accessibility of the area and contributing to the [[ribbon development]] that made the character of the west side of the valley much more developed than the east.

[[File:River Lea and associated channels at Tottenham.jpg|thumb|River Lea, Diversion, and Flood Relief channels at Tottenham]]
Just after Hertford, the river passes the medieval river port of [[Ware, Hertfordshire|Ware]] and the Hertfordshire bank soon becomes entirely developed. On the west bank the river passes [[Hoddesdon]], [[Broxbourne]] and [[Cheshunt]] in Hertfordshire; then [[Enfield, London|Enfield]], [[Edmonton, London|Edmonton]], [[Tottenham]] and [[Tottenham Marshes]] in north London. On the eastern side the river passes [[Waltham Abbey]] on the largely rural Essex bank, and then [[Chingford]] and [[Walthamstow]] in east London.

South of Hertford, the river is lined by lakes; to the north these are primarily flooded former gravel pits but in London they are reservoirs: the 13 reservoirs of the [[Lee Valley Reservoir Chain]], fed by the branches of the river known as the [[River Lee Flood Relief Channel]] and the [[River Lee Diversion]]. These reservoirs come to an end on the boundaries of the London Boroughs of [[Haringey]] and [[London Borough of Hackney|Hackney]] and form part of a broad undeveloped green space, a mile (800&nbsp;m) wide in places, which extends deep into London.

===Lower Lea===
[[File:Clock Mill, Three Mill Studios, Three Mill Lane, London - geograph.org.uk - 1280975.jpg|thumb|The Clock Mill at Three Mills]]
On [[Hackney, London|Hackney's]] northern edge, the Lea shifts to a south-south-easterly direction, the reservoirs end, but the broad green corridor continues as the river passes through [[Walthamstow Marshes]], [[Leyton Marshes]], [[Hackney Marshes]] and the [[Queen Elizabeth Olympic Park]]. In that park, and just to the south of it, the river's course splits, running almost entirely in man-made channels, the [[Bow Back Rivers]]. These channels were once much more numerous and originally created to power water mills including, at the southern end, the restored tidal mill called [[Three Mills]]. The area around the Bow Back Rivers subsequently became a thriving industrial zone. Around [[Bow Creek (London)|Bow Creek]], major industry prevailed, including the [[Thames Ironworks and Shipbuilding Company|Thames Ironworks]], [[Bromley-by-Bow gasholders|Bromley-by-Bow Gasworks]] and [[West Ham Power Station]]. In the 1960s and 1970s, changing economic conditions led to a steep decline and [[Deindustrialization|deindustrialisation]] along this section of the Lea.

The river was historically tidal as far north as [[Hackney Wick]], but now the tide is held back by the [[Bow Locks]] between Bromley-by-Bow and West Ham. Although watercraft can follow the Lea down to the Thames, it is generally more practical to follow the [[Limehouse Cut]] (which meets the Lea at Bow Locks) down to [[Limehouse Basin]], and use the [[Limehouse Basin Lock]] to join the Thames.

The communities on the west side of the lower Lea include [[Hackney, London|Hackney]], [[Bow, London|Bow]] and [[Bromley-by-Bow]]. On the east side, they include southern parts of [[Walthamstow]], then [[Leyton]], [[Stratford, London|Stratford]] and [[West Ham]]. The last few miles of the river are known as [[Bow Creek (England)|Bow Creek]] and the river meets the Thames between [[Blackwall, London|Blackwall]] (on the west side) and [[Canning Town]] (on the east).

[[File:Experimental Lighthouse, Trinity Buoy Wharf - geograph.org.uk - 2096393.jpg|thumb|Lighthouse at [[Trinity Buoy Wharf]], [[Blackwall, London|Blackwall]]; at the confluence of the Lea and Thames]]

==River history==
[[File:Boats on river lea.jpg|right|thumb|Rowing boat on the River Lea]]
[[File:Bow Locks3.jpg|right|thumb|[[Bow Creek (England)|Bow Creek]] (tidal) meets the [[Limehouse Cut]] (canal) with a view of London's [[London Docklands|Docklands]]]]

===Crossings===
In the [[Roman era]], [[Old Ford#Location of the ford|Old Ford]], as the name suggests, was the most downstream crossing point of the River Lea. This was part of a pre-Roman route that followed the modern [[Oxford Street]], [[Old Street]], through [[Bethnal Green]] to [[Old Ford]] and then across a causeway through the marshes known as [[Wanstead|Wanstead Slip]] (now in Leyton). The route then continued through Essex to [[Colchester]]. At this time, the Lea was a wider river, and the tidal estuary stretched as far as [[Hackney Wick]].<ref>{{cite journal |url=http://www.british-history.ac.uk/report.asp?compid=22742 |title=Bethnal Green: Communications |journal=A History of the County of Middlesex |volume=11 |last=Stepney |first=Bethnal Green |year=1998 |pages=88–90 |access-date=15 November 2006}}</ref> Evidence has been found of a late [[Roman Britain|Roman]] settlement at Old Ford, dating from the 4th and 5th centuries.

In 1110, [[Edith of Scotland|Matilda]], wife of [[Henry I of England|Henry I]], reputedly took a tumble at the ford, on her way to [[Barking Abbey]] and ordered a [[Bow Bridge (London)|distinctively bow-shaped, three-arched, bridge]] to be built over the River Lea (''The like of which had not been seen before''), at Bow, the first bridge over the lower Lea. The lower Lea was at that time a wide, tidal and unchannelled river, so the construction of the bridge allowed a far greater degree of social and economic integration between Essex on one side and Middlesex (including the City of London) on the other than had been possible before.

[[Lea Bridge]], the second bridge over the lower Lea was built after 1757, to replace the pre-existing ferry.<ref>{{cite book |chapter=Leyton: Introduction |title=A History of the County of Essex: Volume 6 |editor=W R Powell |location=London |year=1973 |pages=174–184 |via=British History Online |chapter-url=https://www.british-history.ac.uk/vch/essex/vol6/pp174-184 |access-date=27 July 2021}}</ref> It connected [[Clapton, London|Clapton]] to the west, and [[Leyton]] and [[Walthamstow]] to the east. The Iron Bridge carrying the Barking Road over the river to [[Canning Town]] was built in 1810. There are significantly more crossings over the more central ''Lower Lea'', than there are over the ''Middle Lea''.<ref>{{Cite book|chapter-url=https://www.british-history.ac.uk/vch/essex/vol6/pp57-61|chapter=West Ham: Rivers, bridges, wharfs and docks |via=British History Online|title= in A History of the County of Essex: Volume 6 |editor=W R Powell |location=London |year=1973| pages=57–61}}</ref>

===Trade and industry===
During the [[Middle Ages]], [[Temple Mills]], [[Abbey Mills Pumping Stations|Abbey Mills]], Old Ford and Bow were the sites of water mills (mainly in ecclesiastic ownership) that supplied flour to the bakers of Stratforde-atte-Bow, and hence bread to the City. It was the channels created for these mills that caused the Bow Back Rivers to be cut through the former Roman stone causeway at Stratford (from which the name is derived).

The River Lea flows through the old brewing and [[malting]] centre of [[Ware, Hertfordshire|Ware]], and consequently transport by water was for many years a significant industry based there. Barley was transported into Ware, and malt out via the river, in particular to London. Bargemen born in Ware were given the "freedom of the River Thames" — avoiding the requirement of paying lock dues — as a result of their transport of fresh water and food to London during [[the great plague|The Great Plague]] of 1665–66. A local legend says that dead bodies were brought out of London at that time via the river for burying in Ware, but there is no evidence for this.<ref>{{cite web|url=http://www.wareonline.co.uk/history/history3.asp|title=Ware – The Story so Far – 3 of 3|publisher=Ware Online|access-date=2 March 2010|url-status=dead|archive-url=https://web.archive.org/web/20090225080351/http://wareonline.co.uk/history/history3.asp|archive-date=25 February 2009|df=dmy-all}}</ref>

The extensive level of waterborne trade led the historian [[John Stow]], writing in 1603, to describe the Lea as "this pleasant and useful river".<ref>{{Cite web|url=https://www.dhi.ac.uk/strype/TransformServlet?page=book1_047|title=John Strype's Survey of London Online|website=www.dhi.ac.uk}}</ref>

The riverside has hosted a number of major armaments manufacturers, such as the [[Waltham Abbey Royal Gunpowder Mills]], the [[Royal Small Arms Factory]] at [[Enfield Lock]] (which is now a housing development known as [[Enfield Island Village]]) and the [[Congreve Rocket|Congreve Rocket Factory]] on the site of [[Stratford Langthorne Abbey]].

The river Lea formed an important part of the development of one of the UK's historically most important aircraft manufacturers, [[AVRO]]. The railway arch where A.V. Roe in 1909 built and achieved the first all-British powered flight still stands next to the river Lea on the [[Walthamstow Marshes]].

===Management of the river===
Improvements were made to the river from 1424, with tolls being levied to compensate the landowners, and in 1571, there were riots after the extension of the River was promoted in a private bill presented to the [[British House of Commons|House of Commons]]. By 1577, the first lock was established at Waltham Abbey and the river began to be actively managed for navigation.<ref>{{Cite web|url=http://spenserians.cath.vt.edu/TextRecord.php?action=GET&textsid=103|title=William Vallans: A Tale of Two Swannes.|website=spenserians.cath.vt.edu|access-date=2016-07-17}}</ref>

[[File:New Gauge.jpg|right|thumb|The New Gauge House, where water leaves the River Lea at the start of the [[New River (London)|New River]]]]
The [[New River (London)|New River]] was constructed in 1613 to take clean water to London, from the Lea and its catchment areas in Hertfordshire and bypass the polluting industries that had developed in the Lea's downstream reaches.<ref name=Enfield>{{Cite web|url=http://www.enfield.gov.uk/448/River%20Lee%20and%20Stort%20Navigation%20A%20History.htm|title=River Lee History|publisher=Enfield.gov.uk|access-date=31 May 2007|archive-date=8 November 2007|archive-url=https://web.archive.org/web/20071108024838/http://www.enfield.gov.uk/448/River%20Lee%20and%20Stort%20Navigation%20A%20History.htm|url-status=dead}}</ref> The artificial channel further reduced the flow to the natural river and by 1767 locks were installed below Hertford Castle Weir on the [[canal]]ised part of the Lea, now the Lee Navigation with further locks and canalisation taking place during the succeeding centuries. In 1766, work also began on the [[Limehouse Cut]] to connect the river, at [[Bromley-by-Bow]], with the Thames at [[Limehouse Basin]].<ref name=Enfield/>

The [[Waterworks River]], a part of the tidal [[Bow Back Rivers]], has been widened by {{convert|8|m|ft|0}} and canalised to assist with construction of the [[Olympic Park, London|Olympic Park]] for the [[2012 Summer Olympics]]. In 2009, [[Three Mills Lock]] was installed on the [[Prescott Channel]] to maintain water levels on the Lea, within the park at a depth of {{convert|2|m|ft|0}}. This allowed access to the site by 350–tonne barges with the aim that at least half of the material required for construction could be delivered or removed by water.<ref>[http://www.london2012.com/documents/oda-publications/demolish-dig-design-update.pdf ''Milestone 5''] {{webarchive|url=https://web.archive.org/web/20080512144306/http://www.london2012.com/documents/oda-publications/demolish-dig-design-update.pdf |date=12 May 2008 }} ''demolish, dig, design'' January 2008 (The Olympic Delivery Authority) accessed 25 April 2008</ref>

In January 2024, the River Lea burst its banks as Hackney Wick residents tell of 'knee-high' flood water.<ref>{{Cite web |last=Mata |first=William |date=2024-01-05 |title=Hackney Wick residents tell of 'knee-high' flood water as scale of damage emerges |url=https://www.standard.co.uk/news/london/hackney-wick-flood-flooding-canal-river-lee-dace-road-wick-lane-smeed-road-b1130527.html |access-date=2024-01-29 |website=Evening Standard |language=en}}</ref>

===War and conflict===
Millfields Park on the Lea at [[Hackney, London#Anglo-Saxon|Hackney, is the reputed site of a victory]] of [[Aescwine of Essex|Aescwine]] of [[Kingdom of Essex|Essex]] over [[Octa of Kent]] in 527, which allowed Aescwine to become the first [[List of kings of Essex|King of Essex]].<ref>{{Cite book|last=Sexby|first=John James|title=The municipal parks, gardens, and open spaces of London : their history and associations|date=2014|publisher=E. Stock|isbn=978-1-107-70676-7|location=London|pages=349–350|oclc=905859382}}</ref> However, the historicity of these events and the very existence of Aescwine are disputed.

Somewhere between 878 and 890, the [[Treaty of Alfred and Guthrum]] was drawn up that amongst other things used the course of the Lea to define the border between the Danes and the English. In 894, a force of [[Danes (Germanic tribe)|Danes]] sailed up the river to Hertford,<ref>{{cite book | last = Hadfield | first = Charles | author-link = Charles Hadfield (historian) | title = The Canal Age | publisher = Latimer Trend & Company | year = 1968 | location = Plymouth | pages = 15, 19 | isbn = 0-7153-8079-6 }}</ref> and in about 895 they built a fortified camp, in the higher reaches of the Lea, about {{convert|20|mi|km|1}} north of London. [[Alfred the Great]] saw an opportunity to defeat the Danes and dug a new channel to lower the level of the river, leaving the Danes stranded.<ref>{{Cite web|url=https://king-alfred.com/wp/2019/10/16/river-lea/|title=The River Lea - King Alfred and the Vikings.|date=16 October 2019|website=The King Alfred Blog}}</ref>

In 1216, during the [[First Barons' War]], the future [[Louis VIII of France]] besieged [[Hertford Castle]] for a month, leading to its surrender. He only held the castle for a relatively short time as he lost the war soon after.<ref>{{Cite web|url=https://www.british-history.ac.uk/vch/herts/vol3/pp501-511|title=The borough of Hertford: Castle, honour, manors, church and charities &#124; British History Online|website=www.british-history.ac.uk}}</ref>

In 1648 during the [[English Civil War#Second English Civil War (1648–1649)|second English Civil War]] a Royalist force crossed the Thames from Greenwich and hoped to cross Bow Bridge, over the Lea and into Essex. After inconclusive clashes with the [[Tower division#Military function|Tower Hamlets Militia]] and other Parliamentarian forces, an engagement known as the [[Bow Bridge (London)#Battle of Bow Bridge|Battle of Bow Bridge]], the Royalists headed for [[Siege of Colchester|Colchester and were besieged there]].<ref>Covered briefly in The English Civil War, A Peoples History. Diane Purkiss. p534-6</ref>

During WWI, parts of London on either side of the Lea were badly hit by German Army and Navy airship raids. It is believed the crews mistook the extensive reservoir chain for the Thames and released their bombs on what they took to be central London.<ref>London 1914-17 The Zeppelin Menace, Ian Castle. Osprey Publishing 2008</ref>

==Environmental issues==
The ecological, landscape and recreational importance of the river and its surrounding land has been recognised through inclusion in a number of parks and by several planning policy designations.

===Management and designations===
Much of the river lies within the [[Lee Valley Park]]. Some of the land surrounding the river has been designated as [[Metropolitan Green Belt]] or [[Metropolitan Open Land]] in order to prevent further urbanisation.

===Wildlife===
The river contains fish and other wildlife such as the occasional [[Pinniped|seal]].<ref>{{Cite web|url=https://www.standard.co.uk/news/london/seal-seen-frolicking-in-the-river-lea-in-what-experts-say-is-a-sign-of-cleaner-water-a4112631.html|title=Moment playful seal is spotted catching fish in London's River Lea|date=2019-04-09|website=Evening Standard|language=en|access-date=2019-08-29}}</ref>

Some boat trippers reported observing on 5 August 2005 a [[Canada goose]] being pulled underwater very quickly. The [[London Wildlife Trust]] suggested that this was most likely caused by a [[Pike (fish)|pike]].<ref>{{cite news |url=http://news.bbc.co.uk/1/hi/england/london/4748335.stm |title=Boat trip fuels 'river croc' tale |publisher=BBC |access-date=2011-12-27 |date=5 August 2005}}</ref>

In 2011, Mike Wells claimed that he saw a "goose go vertically down" in the river. Again a pike or [[mink]] was suggested as most likely.<ref>{{cite news |url=https://www.bbc.co.uk/news/uk-england-london-16158610 |title=Goose-killer lurks in River Lea |publisher=BBC |access-date=2011-12-27 |date=13 December 2011}}</ref> [[Vice Magazine]] suggested that Wells' story may have been invented to publicise authorities' attempts to evict houseboats from the area that year, ahead of the [[2012 Olympic Games]].<ref>{{cite news |last1=Haddow |first1=Joshua |title=Hunting for the Olympics River Monster |url=https://www.vice.com/en/article/river-lea-monster-olympics-2012-marsh-land-conspiracy/ |access-date=9 September 2019 |work=Vice |date=29 May 2012}}</ref>

===Pollution===
The river is threatened by pollution, with sewage frequently discharged into the river as well as less common events causing major damage, such as an oil leak in 2018,<ref>{{cite web|url=https://www.hackneygazette.co.uk/news/river-lea-oil-spill-boats-grounded-between-tottenham-and-hackney-3583448|title=River Lea oil spill: Boats stopped between Tottenham and Hackney Wick to contain pollution outbreak one week on|last=Alwakeel|first=Ramzy|website=Hackney Gazette|date=20 February 2018|access-date=2022-08-25}}</ref> or the toxic [[urban runoff|runoff]] from a warehouse fire in 2019.<ref>{{Cite web|url=https://www.hackneygazette.co.uk/news/environment/environment-agency-investigating-after-hundreds-of-dead-fish-spotted-in-river-lea-by-clapton-1-6074248|title=Investigation launched after 'hundreds' of dead fish spotted in River Lea by Clapton boaters|last=Gelder|first=Sam|website=Hackney Gazette|date=28 May 2019|language=en|access-date=2019-08-29}}</ref> The sewage pollution, as well as that of fertiliser washed in from agricultural fields causes [[eutrophication]], an excess of nutrients, which not only unbalances the [[ecosystem]], but also leads to de-oxygenation of the water.

Dumping, litter and [[microplastics]] are a major problem on the Lea with much of this waste arriving in the river in sewage.<ref>{{cite web| url = https://www.hackneygazette.co.uk/news/plastic-pollution-on-river-lea-at-hackney-marshes-7836460| title = River Lea at Hackney Marshes filled with plastic rubbish {{!}} Hackney Gazette| date = 19 March 2021}}</ref> In April 2021, [[Hackney London Borough Council|Hackney Council]] wrote to the [[Environment Agency]] calling for action to address sewage discharge and pollution in the river.<ref>{{Cite web|date=2021-04-12|title=Town Hall 'demands action' from Environment Agency to clean up River Lea|url=https://www.hackneycitizen.co.uk/2021/04/12/town-hall-demands-action-environment-agency-polluted-river-lea/|access-date=2021-11-27|website=Hackney Citizen|language=en-GB}}</ref> In November 2021, local volunteers stated they were removing 100&nbsp;kg of [[plastic pollution]] from the Lower Lea every month.<ref>{{Cite web|date=2021-11-05|title=Campaigners call for action on 'jaw-dropping' amount of pollution in River Lea|url=https://www.hackneycitizen.co.uk/2021/11/05/campaigners-action-jaw-dropping-pollution-river-lea/|access-date=2021-11-27|website=Hackney Citizen|language=en-GB}}</ref>

Water extraction, for drinking water, farming and industry, has led to a reduction in river flow impacting wildlife and concentrating the pollutants present in the remaining river water.

Projects such as that led by [[Thames21]] installing [[reedbed]]s help to remove pollutants whilst oxygenating the water, as well as creating habitat for the likes of [[European water vole|water voles]] and improving the aesthetics of the man-made concrete sections of the canalised river.<ref>{{cite web | url=https://www.thames21.org.uk/project-reedbed-2/ | title=Project Reedbeds | date=8 September 2023 }}</ref>

==Sport==
In their early days, [[Tottenham Hotspur F.C.|Tottenham Hotspur]] played their games at [[Tottenham Marshes]] on the Middle Lea while [[Leyton Orient]] have had a number of home grounds in the [[Lower Lea Valley]], with both having their current grounds within a mile of the river. [[West Ham United F.C.|West Ham United]] was established as the works team of the [[Thames Ironworks and Shipbuilding Company|Thames Ironworks]], a shipyard which straddled either side of the Lea at its confluence with the Thames.

The 2012 Olympics was focused in the [[Queen Elizabeth Olympic Park]] on the banks of the Lea, and its main Stadium, on an island between two branches of the river, is now home to West Ham United. The [[Lee Valley White Water Centre]] in Hertfordshire is another sporting legacy of the games.

==Narrative accounts==
===London Bridge Is Falling Down===
Various versions of the nursery rhyme [[London Bridge Is Falling Down]] make reference to Bow Bridge. The oldest known version could be that recalled by a correspondent to the ''[[Gentleman's Magazine]]'' in 1823, in which he claimed to have heard from a woman who was a child in the reign of [[Charles II of England|Charles&nbsp;II]] (r.&nbsp;1660–1685) and had the lyrics:

{{blockquote|<poem>London Bridge is broken down,
:Dance over the Lady Lea;
London Bridge is broken down,
:With a gay lay-dee.</poem>}}

There are a [[London Bridge is Falling Down#"Fair lady" identity|number of theories]] about the identity of the ''Fair Lady'', including the idea that it may refer to [[Matilda of Scotland|Matilda]],<ref>John Clark [https://archaeologydataservice.ac.uk/archiveDS/archiveDownload?t=arch-457-1/dissemination/pdf/vol09/vol09_12/09_12_338_340.pdf London Bridge and the archaeology 4 of a nurserv rhvme]</ref> the builder of Bow Bridge and its neighbours, or that it may apply to the River Lea itself.<ref>Peter and Iona Opie, (1985). The Singing Game. Oxford, UK: Oxford University Press. pp. 61–72. ISBN 0192840193.</ref>

===Other===
The poem ''A Tale of Two Swannes'' is set along the River Lea. It was written by [[William Vallans]] and published in 1590.<ref>English Poetry 1579–1830, [http://spenserians.cath.vt.edu/TextRecord.php?&action=GET&textsid=103 William Vallans:A Tale of Two Swannes].</ref>

The old course of the river is the one featured in the early chapters of the classic fishing book ''[[The Compleat Angler]]'' by [[Izaak Walton]]. The author begins at Tottenham and proceeds upriver from there.

A guide to walking along the river valley was written by Leigh Hatts,<ref>L. Hatts, ''The Lea Valley Walk'', Cicerone Press, 2nd edition, 2007, {{ISBN|978-1-85284-522-3}}.</ref> and an account of a walk along the complete length of the river in 2009 was published as a blog by "Diamond Geezer".<ref>Diamond Geezer, [https://lndn.blogspot.com/2009_08_01_lndn_archive.html Walking the Lea Valley], with [https://www.flickr.com/photos/dgeezer/sets/72157621790088657 more photos on flickr].</ref>

In 2014, German writer [[Esther Kinsky]] published a novel, ''Am Fluß'', now available in English as ''River'', translated by Iain Galbraith,<ref>''River'', translated by Iain Galbraith and published by Fitzcarraldo Editions. {{ISBN|978-1-91069-529-6}}</ref> based around her walks along the lower Lea from the marina at Horseshoe Point to its confluence with the Thames.

In 2015, singer-songwriter [[Adele]] dedicated [[River Lea (song)|a track]] to the river on her third studio album, ''[[25 (Adele album)|25]]''.{{citation needed|date=October 2021}}

==Notable fisheries==
* [[Amwell Magna Fishery]]
* [[Carthagena Weir]]
* [[Dobbs Weir]]
* [[Fishers Green]]
* [[Kings Weir]]

==Tributaries==
* For a full list of tributaries, please expand the box entitled 'River Lea / Lee, England' at the bottom of this page.

==See also==
{{Portal|United Kingdom|Transport}}
* [[List of dams and reservoirs in the United Kingdom]]
* [[List of rivers of England]]
* [[Tributaries of the River Thames]]
* [[Walthamstow Pumphouse Museum]]

==References==
{{Reflist|30em}}

==External links==
{{Commons category|River Lea}}
* Peter Marshall, [http://river-lea.co.uk/ The Lea Valley], photographs from 1980 to 2008
* UK Urban Exploration Forums, [http://www.28dayslater.co.uk/river-lea-through-luton-march-2009.t38588 River Lea through Luton] {{Webarchive|url=https://web.archive.org/web/20160407154837/http://www.28dayslater.co.uk/river-lea-through-luton-march-2009.t38588 |date=7 April 2016 }}, photos of the underground culvert in March 2009
* [https://www.tate.org.uk/art/artworks/pollard-trolling-for-pike-in-the-river-lee-t03437 ''Trolling for Pike in the River Lee''], 1831, by [[James Pollard]] at [[Tate Britain]]
* [https://www.tate.org.uk/art/artworks/pollard-fly-fishing-in-the-river-lee-near-the-ferry-boat-inn-t03436 ''Fly Fishing in the River Lee near the Ferry Boat Inn''], 1831, by [[James Pollard]] at [[Tate Britain]]
* [https://www.thames21.org.uk/project/lovethelea/ Love the Lea project]
*[https://web.archive.org/web/20110728182425/http://wikipaddle.org/wiki/River_Lea_(Hertford_Loop) Wikipaddle: River Lea (Hertford Loop)] article from a kayaking and canoeing perspective
{{River item box
|type=confluence
|river=[[River Thames]]
|upstream=[[River Ravensbourne]] (south)
|downstream=[[River Roding]] (north)}}
{{Locks and Weirs on River Lea}}
{{River Lea}}

{{authority control}}

{{DEFAULTSORT:Lea, River}}
[[Category:River Lea| ]]
[[Category:Lea catchment| ]]
[[Category:Luton]]
[[Category:Ramsar sites in England]]
[[Category:Tributaries of the River Thames|Lea]]