Planning Panel9th July 2012Highlands School, Grange Park, Enfield

SALMON’S BROOK FLOOD ALLEVIATION SCHEME

Presentation team

Graham Cowell (Environment Agency)Steve Whipp (Environment Agency)Mike Gara (Environment Agency)Roland Grzybek (Halcrow)Windsor Young (Volker StevinMike Ferens (MMA)

Flooding in Enfield• Enfield has a history of flooding• Most recently in October 2000• 192 properties flooded• Approximately 2000 properties at

risk • 5% chance of flooding in any year Flooding, October 2000

Flooding in Granville Road, October 2000

Flood Alleviation Scheme Objectives

Reduce the risk of flooding to 1393 properties (2587 households), of which 727 properties will be protected from a 1.3% (1 in 75) AEP flood. Reduce the risk of flooding from Saddlers Mill stream coming up through the manholes in Montagu Road.Provide environmental and amenity enhancements to the area as part of the works.Benefit – cost ratio of 6.2 for a 1.3% standard of protection.Aim to start construction in 2012/13

Flood Alleviation Scheme Elements

Flood Storage at Enfield Golf CourseRaised defences along Salmons WalkNew culvert route under Montagu RoadFlood Storage at Montagu Road Recreation Ground & environmental improvementsLocalised Measures to address Saddlers Mill stream

Enfield Golf Course & Cheyne Walk Open Space

Saddlers Mill Stream

Boundary Ditch

Sandhurst Road & Falcon Fields

Salmons Walk

Montagu Road Recreation Ground

Salmons Brook

Montagu Road

Flood Maps Pre & Post Scheme –Edmonton 1 in 75

Flood Maps Pre & Post Scheme –Saddlers Mill stream area 1 in 75

Flood Maps Pre & Post Scheme –Montagu Road Area 1 in 75

Enfield Golf Course

Store flood water temporarilyProvide an environmentally sensitive design Mitigate any impacts on the Golf CourseProvide a structure that is safe to operate with minimal maintenance Conform to the Statutory Reservoirs Act 1975No increase in flood risk to those properties upstream of the structure

Enfield Golf Club

Cheyne Walk Open Space

Flood embankment

Access tracks Allotments

Enfield Golf Course

What the proposed flood embankment will look like at Cheyne Walk Open Space

What the proposed flood embankment will look like at Enfield Golf Course

Montagu Road Area

Salmons Walk, raised defences along walk

Montagu Road, new culvert route

Montagu Road Recreation Ground, environmental improvements amenity creation & new flood storage

Salmons Walk

Require raised defences along Salmons Walk -approx 1m x 550m both banksProvide the appropriate environmental enhancementsEnhance the path to a combined footpath and cycleway standard.

An artist’s impression of Salmons Walk after the scheme – looking towards

Montagu Road

Montagu Road Recreation Ground

Store flood water temporarilyProvide environmental enhancements to the watercourse and surrounding area in a restored river settingMeet the current needs of users of the open space Conform to the Statutory Reservoirs Act 1975

Football Pitch

Existing flood storage

Pavilion

New open channel

New trees

New paths

Concrete removed

New fixed structures to control water

Raised ground and new shrubs

New embankments

Shaped river banks

Montagu Road Recreation Ground

Looking south from near the pavilion >>

An artist’s impressions of Montagu Road Recreation Ground after the scheme

<< Looking towards Zambezi Drive from near the pavilion

Construction Access – Enfield Golf Course – proposed routeConstraints

Open space access via Uplands wayCheyne walk would require car parking restrictions along its whole lengthPinch points –vehicles unable to exit safely at LandraGardens due to traffic restrictions (bollards etc)School hours

Construction Access – Salmons Walk – proposed routeConstraints

Linear site –access required at both ends. Only entrances to Salmons Walk. Limited access from PlevenaRoadMain access Montagu road

Construction Access – Bury Street West – proposed route

Access during construction – Enfield Golf Course & Cheyne Walk Open Space

Golf course will remain open with all holes playable -slightly shortened 9th hole (although localised improvements within the golf course currently being considered with EGC may cause more temporary disruption).Cheyne Walk

• Pedestrian access at all times to allotments and open space.

• Vehicular access available at evenings and weekends. Vehicular by arrangement with contractor in special circumstances during working hours. Deliveries ok by arrangement

Barnabas Court – pedestrian access and vehicular access all times.

Access during construction –Salmons Walk

Due to our legal health and safety obligations for a working construction site to protect members of the public we cannot allow access during the works. We will sign an alternative route. e.g. Cemetery Walk and local roads.Post scheme – Salmons Walk will be provided with a new combined cycleway and footpath.

Access during construction –Montagu Road

Access to current play areas, community centre and sports field will be maintained during the works. The minimum space possible will be occupied on the recreation ground to allow access to the open space during construction. Temporary traffic lights will be required while the culvert is constructed on the edge of Montagu RoadTo deliver materials to Salmons Walk there will be some construction traffic across Montagu Road.

Access during construction – Bury Street West

Site currently closed to general public – no change in accessNo impact on Enfield Council depot for day to day operationsWorks are very small-scale localised in-channel works. Construction duration estimated at a few weeks.

Planned Extent and duration of the works

Enfield Golf Course and Cheyne Walk

Site set up and utilities diversions – 5 monthsFlume structure – 5 monthsDelivery clay – 3.5 monthsEmbankment construction – 3.5 monthsLandscaping & finishing – 3.5 monthsGrass seeing – 1 month

Planned Extent and duration of the works

Salmons Walk

Site set up and surveys – 1 monthFlood defence wall right bank d/s – 11 months Flood defence wall left bank d/s – 11 monthsSheet piling – 3 months

Planned Extent and duration of the works

Montagu Road

Montagu Road culvert – 7 monthsEarth embankment – 6 months Landscaping – 1 month

Construction noise and disturbanceGeneral

Works will use construction best practice for which we have won numerous construction awards. We will operate under the Considerate Contractors Scheme – audited by an independent body. We will operate in standard working hours.We have planned our deliveries outside the rush hour and school run.We will operate within the requirements for noise levels. Plant and design has been chosen to minimise disturbance as much as possible. We will use modern anti-noise anti vibration construction machinery with appropriate silencing mechanisms.Condition surveys will be undertaken where required. We do notenvisage that the works and associated site traffic will cause any structural damage to the properties along the proposed route.

These activities from previous projects have not caused damage to properties

Stakeholder consultation to date:

Stakeholder consultation to date includes:Public exhibitions, 2004, 2008, 2012.Public newsletters 2004, 2005, 2008, 2011 (council & MP), 2012Area Forums 2010, 2012Presentation MeetingsCemeteriesEnfield Golf ClubEnfield Council

Communication during construction

Dedicated community liaison officerLocal residents forumLocal schools engagement24 hour hot lineRegular progress update

Flood Alleviation Scheme Benefits

Best opportunity to reduce flood risk in the Lower Lee valley. Included by defra in their funding announcement for flood alleviation schemes for the last 2 years. Reduce the risk of flooding to 1393 properties (2587 households), of which 727 properties will be protected from a 1.3% (1 in 75) AEP flood. Reduce the risk of flood water from Saddlers Mill Stream coming up through the manholes in Montagu Road and in to properties.Provide bio-diversity, habitat creation and amenity enhancements to the area as part of the works.Prevent £156.2 million of damage in the 1.3% chance flood event.

Questions?

Steve Whipp, Environment Agency, Senior User – Clien t

Mike Gara, Environment Agency, Project Manager

salmonsfas@environment-agency.gov.uk .