Nov 21, 2014
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
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
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.
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