Policy paper

Salmons Brook flood risk management scheme

Updated 17 October 2018

In 2016 the Environment Agency completed a £15.3 million flood alleviation scheme to reduce the risk of flooding from Salmons Brook in north London. The scheme was formally opened in March 2016 by Amanda Nobbs, then Chair of the Thames Regional Flood and Coastal Committee.

Parts of Edmonton and Enfield have historically had a high risk of flooding from the Salmons Brook and Saddlers Mill Stream. In October 2000, 192 properties in the Montagu Road area of Edmonton flooded.

This multi-site scheme has lowered the flood risk to 1,393 properties (2,587 homes, as some of the properties are flats). Of these, 727 homes will see their flood risk reduce to a 1.3% (1-in-75) chance of flooding in any one year. The homes most at risk before the scheme had a 5% (1-in-20) chance of flooding in any year.

The Environment Agency received planning permission from the London Borough of Enfield Council to build the scheme in November 2012, and construction began in May 2013.

A combination of central government grant-in-aid and a contribution from the Thames Regional Flood and Coastal Committee levy funded construction of scheme.

The scheme

Salmons Walk, between Montagu Road and Plevna Road, Lower Edmonton

The Environment Agency has built a new flood defence wall alongside the cemeteries to prevent flooding from the river. The flood defence wall beside the Tottenham Park Cemetery has been brick clad to match the surrounding area. In front of the new flood wall by the Federation Cemetery the bank has been rebuilt and planted so that in time it will benefit wildlife. Climbers have been planted in front of the wall as a screen.

A new brick-clad flood wall has been built beside the allotments and Barrowfield Close. The river bank in front of the flood defence has been rebuilt, including a new shared foot and cycle path.

Montagu Recreation Ground, Lower Edmonton

The Environment Agency has installed an extension to the railway culvert at the edge of the recreation ground, and built the low bund (earth bank) across it to contain and temporarily store floodwater during times of high river flow. This also has a new path on it. A new headwall at the start of the culvert has been brick faced in a similar way to the railway arch that is now hidden.

A new culvert around the pavilion takes flood water from the existing culvert under Montagu Road on a simpler route to join the river in the recreation ground.

The Environment Agency has worked with the London Borough of Enfield to improve wildlife habitat and public access within the Montagu Road recreation ground.

Enfield Golf Course, World’s End and Cheyne Walk open space, Grange Park

The Environment Agency has constructed an embankment to temporarily hold back flood water in times of high river flows. The embankment has been covered with grass to match the nearby Cheyne Walk open space and Enfield Golf Course. Other landscaping to plant trees and reinstate the areas used during construction has been completed.

Sandhurst Road and Falcon Fields, Ponders End

Modifications have been made to an existing structure to divert more flood water down the Boundary Ditch beside Sandhurst Road, reducing the risk of flooding around Montagu Road, Lower Edmonton.

To avoid this causing additional flooding in Ponders End, the banks of the Boundary Ditch have been raised by up to 0.5 metre opposite the Redburn trading estate, Woodcote Close and around some parts of the Falcon Fields allotments.

You can look at photos of the Salmons Brook scheme on Flickr.

Scheme maintenance

Although construction has been completed, the Environment Agency will continue to be involved in looking after the flood alleviation scheme. The Environment Agency has a planning obligation to ensure that the reinstated landscaping establishes and is maintained for the next 5 years, until March 2021. In the longer term the Environment Agency will have responsibility for the new embankments and river structures, and the landowner, Enfield Council, will be responsible for management of the rest of the public open space sites at Cheyne Walk Open Space, Montagu Recreation Ground and the path along Salmons Walk. As the embankments are reservoir structures, although dry nearly all of the time, the Environment Agency is regularly inspecting and maintaining them.

Community engagement

The Environment Agency held regular drop-in sessions for residents during the construction work.

Regular newsletters were sent to all residents near the construction sites with updates on progress and events.

During construction of the scheme the Environment Agency worked with residents, local schools and community groups, and several schools visited the site. At Montagu Road, Lower Edmonton, First Rung, a local group improving young people’s skills to increase employment opportunities, ran a project to produce street art on the site hoardings.

Grange Park residents and the then MP for Enfield Southgate joined the Environment Agency at an event in January 2015 to mark the handing back of the Greenway foot and cycle path at Cheyne Walk Open Space.

In March 2016 an event was held at Montagu Recreation Ground with local residents, the then MP for Edmonton, Enfield Council and the Environment Agency’s project team to mark the opening of the whole scheme.

Flood insurance

Once operational, the Salmons Brook flood alleviation scheme has reduced the likelihood of flooding in Edmonton and Enfield. The Environment Agency has re-modelled the flood risk for the Salmons Brook with the new scheme in place and has updated the flood map and the National Flood Risk Assessment (NaFRA). This might have a beneficial impact on your home insurance when it comes up for renewal.

Contact

For more information on the project, please email HNLenquiries@environment-agency.gov.uk.