The Lee Flood Relief Channel (FRC) is located in the

Lea Valley The Lea Valley (also spelt Lee Valley), the valley of the River Lea, has been used as a transport corridor, a source of sand and gravel, an industrial area, a water supply for London, and a recreational area. The London 2012 Summer Olympics wer ...

and flows between

Ware, Hertfordshire Ware is a town and civil parish in the East Hertfordshire district, in the county of Hertfordshire, England. It is close to the county town of Hertford. In the 2021 United Kingdom census, 2021 Census, the parish had a population of 19,622. Hist ...

, and Stratford, east London. Work started on the channel in

1947 It was the first year of the Cold War, which would last until 1991, ending with the dissolution of the Soviet Union. Events January * January–February – Winter of 1946–47 in the United Kingdom: The worst snowfall in the country i ...

following major flooding and it was fully operational by 1976. The channel incorporates existing watercourses, lakes, and new channels. Water from the channel feeds the

Lee Valley Reservoir Chain The Lee Valley Reservoir Chain is located in the Lee Valley, and comprises 13 reservoirs that supply drinking water to London. The Reservoir Chain, together with the flood plain which it occupies, is a major geographic constraint; together with ...

Design

Flood defences are rated according to the probability that a particular level of flood water will be exceeded at least once in a specific period, so a

100-year flood A 100-year flood, also called a 1% flood,Holmes, R.R., Jr., and Dinicola, K. (2010) ''100-Year flood–it's all about chance 'U.S. Geological Survey General Information Product 106/ref> is a flood event at a level that is reached or exceeded onc ...

represents a level that would only be expected to occur once in 100 years. This is often known as 1 per cent protection. The level of flooding in 1947 was estimated to be a 1.4 per cent occurrence, and the flood channel, when it was first designed, was built to cope with this level of flooding. Since it was completed in 1976, there have been no major flood events in the Lea Valley, although there have been three occasions when the river system was full virtually to its capacity: in 1987, 1993 and 2000. Since its completion, the level of protection afforded by the structure has declined, so that in some areas it offers 2 per cent protection, and in some, only 5 per cent protection. 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 ...

published a strategic environmental assessment in 2008, which looked at ways to maintain the flood defences in the Lea Valley.

Course

Hertfordshire and Essex

Marking the start of the FRC at Ware, the channel is incorporated into the

Lee Navigation The Lee Navigation is a canalised river incorporating the River Lea (also called the River Lee along the sections that are navigable). It flows from Hertford Castle Weir to the River Thames at Bow Creek; its first lock is Hertford Lock and i ...

. It flows through Hardmead Lock and Stanstead Lock, which have had automatic

sluice A sluice ( ) is a water channel containing a sluice gate, a type of lock to manage the water flow and water level. There are various types of sluice gates, including flap sluice gates and fan gates. Different depths are calculated when design s ...

gates installed to cope with high water levels. At

Feildes Weir Feildes Weir is a weir on the River Lea located in Hoddesdon, Hertfordshire at the confluence of the River Lea and River Stort. The weir marks the start of the Lower Lee. A channel of the man-made River Lee Flood Relief Channel is incorporate ...

a parallel channel has been constructed. The channel then skirts the Glen Faba Lake and passes under Dobbs Weir Road before entering the North Lagoon of the Nazeing Meads lake complex and leaving at the South Lagoon at Nazeing Weir. Continuing under Nazeing Road ( B194), the channel flows through the

River Lee Country Park The River Lee Country Park is located in the Lee Valley Park and is managed by the Lee Valley Regional Park Authority. Covering on either side of the River Lee Navigation between Waltham Abbey (town), Waltham Abbey and Broxbourne, it is an are ...

at Holyfield Lake and out through Holyfield Weir. Flowing under Stubbins Hall Lane, it merges with the old

River Lea The River Lea ( ) 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 Cr ...

Fishers Green Fishers Green is a settlement in the parish of Waltham Abbey in Essex, England, lying to the north of the main built-up area. It lies on the flood plain of the River Lea. Description In the years following World War II much of the flood plain ...

. After skirting Seventy Acres Lake and then Hooks Marsh Lake, the channel is incorporated into the Horsemill Stream, also known as Waltons Walk. The water forms a natural boundary for the Royal Gunpowder Mills as it passes through the mechanically controlled radial gates of the David Stoker

near

Waltham Abbey Waltham Abbey is a suburban town and civil parish in the Epping Forest District of Essex, within the London metropolitan area, metropolitan and urban area of London, England, East London, north-east of Charing Cross. It lies on the Greenwich ...

. Now flowing parallel with the Lee Navigation, and only yards apart, the channel flows firstly under the A121 road and through Rammey Marsh Sluice - a set of three computer-controlled vertical lift sluice gates and then under the

M25 motorway The M25 or London Orbital Motorway is a major ring road encircling most of Greater London. The motorway is one of the most important roads in the UK and one of the busiest. Margaret Thatcher opened the final section in 1986, making the M25 th ...

to be joined by Cobbins Brook before flowing through Newman's Sluice – a set of four computer-controlled vertical lift sluice gates.

Greater London

The channel crosses

Rammey Marsh Rammey Marsh is located in the Lee Valley Park at Enfield Lock, Enfield, England, and covers approximately . The site is owned and managed by the Lee Valley Regional Park Authority.Royal Small Arms Factory The Royal Small Arms Factory (RSAF), also known by the metonym ''Enfield'', was a UK government-owned rifle factory in Enfield, adjoining the Lee Navigation in the Lea Valley. Some parts were in Waltham Abbey. The factory produced British m ...

, which is now a housing development called

Enfield Island Village Enfield Island Village is a modern property development in Enfield Lock, in the London Borough of Enfield, north London. Before April 1994, Enfield Island Village formed part of the Epping Forest district of Essex, but it was transferred to the b ...

. Further downstream, the channel merges with the

to become the man-made, concrete-banked River Lee Diversion as it skirts the eastern perimeter of the

King George V Reservoir The King George V Reservoir, also known as King George's Reservoir, is located in the London Borough of Enfield and is part of the Lee Valley Reservoir Chain that supplies London with drinking water. The storage reservoir is bordered by Sewardst ...

, the first of the

, and then the

William Girling Reservoir The William Girling Reservoir is located in the London Borough of Enfield and is part of the Lee Valley Reservoir Chain that supplies London with drinking water. It is named after William Girling OBE, a chairman of the Metropolitan Water Board ( ...

. The river forms the boundary of the

London Borough of Enfield The London Borough of Enfield () is a London boroughs, London borough in Greater London, England. The main communities in the borough are Edmonton, London, Edmonton, Enfield, London, Enfield, Southgate, London, Southgate and Palmers Green. Enfi ...

and

Waltham Forest The London Borough of Waltham Forest () is an outer London borough formed in 1965 from the merger of the municipal boroughs of Leyton, Walthamstow and Chingford. The borough's administrative headquarters are at Waltham Forest Town Hall, wh ...

and the historical boundary between

Middlesex Middlesex (; abbreviation: Middx) is a Historic counties of England, former county in South East England, now mainly within Greater London. Its boundaries largely followed three rivers: the River Thames, Thames in the south, the River Lea, Le ...

and

Essex Essex ( ) is a Ceremonial counties of England, ceremonial county in the East of England, and one of the home counties. It is bordered by Cambridgeshire and Suffolk to the north, the North Sea to the east, Kent across the Thames Estuary to the ...

. Flowing under the

North Circular Road The North Circular Road (officially the A406 and sometimes known as simply the North Circular) is a ring road around Central London. It runs from Chiswick in the west to North Woolwich in the east via suburban north London, connecting var ...

and close to Banbury Reservoir, it splits from the River Lee Diversion to cross

Tottenham Marshes The Tottenham Marshes are located at Tottenham in the London Borough of Haringey. The marshes cover over and became part of the Lee Valley Park in 1972. The marsh is made up of three main areas: Clendish Marsh, Wild Marsh West and Wild Marsh ...

, and passes close to the

Lockwood Reservoir Lockwood Reservoir is located in Walthamstow in the London Borough of Waltham Forest. It is one of the ten Walthamstow Reservoirs, which are part of the Lee Valley Reservoir Chain. The reservoirs supply drinking water to London and are owned ...

High Maynard Reservoir High Maynard Reservoir is located in Walthamstow in the London Borough of Waltham Forest. The storage reservoir is one of the Lee Valley Reservoir Chain and supplies drinking water to London. History In 1852, the East London Waterworks Company w ...

and Low Maynard Reservoir. Flowing firstly under Forest Road ( A503 road) and then the Gospel Oak to Barking line, it skirts the

Walthamstow Reservoirs Walthamstow Wetlands is a nature reserve in Walthamstow, East London, east London, adjacent to the River Lea in the London Borough of Waltham Forest. It is focused on the Walthamstow Reservoirs, built by the East London Waterworks Company betwe ...

close to Walthamstow Marshes. It passes under Coppermill Lane before flowing under the Lea Valley Line as the channel approaches

Lea Bridge Road Lea Bridge Road is a major through route in east London, across the Lea Valley from Clapton to Whipps Cross in Leyton. It forms part of the A104 road. Places served on the road are the Lea Valley Park, Lea Bridge railway station and the ...

, part of the A104 road. It crosses

Hackney Marshes Hackney Marshes is an area of open space in London's Lower Lea Valley, lying on the western bank of the River Lea. It takes its name from its position on the eastern boundary of Hackney, the principal part of the London Borough of Hackney, an ...

and passes through a culvert before joining the Old River Lea close to the

New Spitalfields Market New Spitalfields Market is a fruit and vegetable market on a site in Leyton, London Borough of Waltham Forest in East London. The market is owned and administered by the City of London Corporation. The market is Europe's leading horticultural ma ...

. Passing under the Eastway road and then flowing under the A115 (Carpenter's Road) to meet the

Waterworks River Waterworks River is a river, at one time a tidal river, in the London Borough of Newham, one of the Bow Back Rivers that flow into the Bow Creek part of the River Lea, which in turn flows into the River Thames. The river is an artificial channel ...

below Carpenter's Road Lock in Stratford, the channel continues through the

Prescott Channel The Prescott Channel was built in 1930–35 as part of a flood relief scheme for the River Lee Navigation in the County Borough of West Ham, England, and was named after Sir William Prescott, the then chairman of the Lee Conservancy Board ...

and Bow Creek to reach the Thames at

Leamouth Leamouth is a locality in the Blackwall area of Poplar, in the London Borough of Tower Hamlets. The area takes its name from the former ''Leamouth Wharf'' and lies on the west side of the confluence of the Bow Creek stretch of the Lea, at it ...

References

External links

Glen Faba lakes

Nazeing Meads lakes

Seventy Acres lake-Conservation Project

Waltons Walk fishery
{{DEFAULTSORT:Lee Flood Relief Channel Rivers of Essex Rivers of Hertfordshire Rivers of London Water supply and sanitation in London Thames Water

Flood Relief Channel Flood control channels are large and empty basins where surface water can flow through but is not retained (except during flooding), or dry channels that run below the street levels of some larger cities, so that if a flash flood occurs the excess ...