River Lea

Lea Lee
River Lea at Hertford Basin
Location
Country	United Kingdom
Counties	Bedfordshire, Hertfordshire, Essex, Greater London
Towns	Leagrave, Luton, Harpenden, Hatfield, Hertford, Ware, Hoddesdon, Broxbourne, Waltham Abbey, Enfield Town, Edmonton, Tottenham, Clapton, Stratford, Bow, Canning Town
Physical characteristics
Source
• location	Leagrave, Luton
• coordinates	51°54′37″N 0°27′40″W / 51.910338°N 0.461233°W / 51.910338; -0.461233
• elevation	115 m (377 ft)
Mouth
• location	Bow Creek, River Thames
• coordinates	51°30′26″N 0°00′33″E / 51.5072°N 0.0092°E / 51.5072; 0.0092
• elevation	0 m (0 ft)
Length	68 km (42 mi)
Discharge
• location	Luton Hoo, Luton
• average	1.8 m3/s (64 cu ft/s)
Discharge
• location	Feildes Weir, Hoddesdon
• average	4.3 m3/s (150 cu ft/s)
Basin features
Designation
Ramsar Wetland
Official name	Lea Valley
Designated	9 October 2000
Reference no.	1037[1]

The River Lea (/ˈliː/ 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. 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 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 streams, are a major source of drinking water for London. An artificial waterway known as the New River, opened in 1613, abstracts clean water away from the upper stretch of the river near Hertford for drinking, and lower parts of the river are also abstracted from. The Lea's origin in the Chilterns contributes to the extreme hardness (high mineral content) of London tap water.^[2]