Theme: Activity 2: Urban Water Retention TechniquesChelmsfordCase study:

Floodcom projectPositive water management in lowland areas facing climate change

Overview Partners used and shared new and modern water retention techniques in this activity. The urban water retention techniques included the challenges of working with historically important landscape features which may impinge on flood defences such as underground World War II piping systems and an ancient pilgrimage route in Chelmsford.

Breda undertook planning designs for its scheme at the Spinolaschans/Spinola entrenchment area and shared knowledge and experience with Chelmsford City Council and the whole partnership.

Context of the schemeNationally, it is a high Government priority to reduce flood risk to homes and businesses. The Environment Agency is the national body responsible for protecting and enhancing the environment in England, including the delivery of flood risk management projects. It is funded from central government via the Department for Environment and Rural Affairs.

At a local level this is translated into Chelmsford City Council’s corporate strategy, which sets out a long term vision for the city area, and its local planning policies. A commitment was made between the Environment Agency and the City Council in 2008 to deliver a flood defence up stream of the city centre and the scheme was incorporated into the Local Plan in 2012.

Description of the areaAlthough the Flood Alleviation Scheme (FAS) is located in Margaretting, the embankment will hold water upstream to protect Chelmsford city centre. Margaretting village itself is not currently, and will not be, at risk from flooding. The amount of water flowing through the gate will dictate when it is closed, and this will be detected by an automatic system. Once the threat of flooding has reduced, the water will be gradually released through the sluice gate.

The main aspects of the FAS include the construction of the embankment including sluice gates across the Wid valley, secondary embankment to protect two houses, Brook Farm and Tyelands, flood wall next to the railway line, highway woks including passing places on access route and embankment including sluice gates across the Wid valley.

Technological innovations of the scheme Chelmsford City Council and the Environment Agency have pioneered a new innovative approach to funding, through adopting a partnership approach. Instead of the Environment Agency providing all the funding for projects the new approach matches their funding with contributions from partnership organisations. In many cases funding is now being topped up by local government, where the local authority has flood protection as one of its priorities.

SummaryChelmsford lies at the junction of three rivers, the Wid, Can and Chelmer. These rivers collect rainwater from north and west Essex; the catchment area for the rivers extends to 650 square kilometres.

ImpactsThere are currently over 1,200 residential and commercial properties at risk of future flooding in Chelmsford. A Flood Alleviation Scheme (FAS) will significantly reduce this figure. The chosen site at Margaretting, on the river Wid valley, has been selected as a suitable solution.

Contact details:Chelmsford City CouncilAndy BestwickE: Andy.Bestwick@chelmsford.gov.ukT: +44 (0) 1245 606 819

www.floodcom.eu

PartnersThe project has five partners:

INSTITUTION INTERDEPARTEMENTALE DES WATERINGUES

IIWATERINGUES

Essex County Council, Lead PartnerCorina HickmanE: corina.hickman@essex.gov.ukT: +44 (0) 333 013 6730

Chelmsford City CouncilAndy BestwickE: andy.bestwick@chelmsford.gov.ukT: +44 (0) 1245 606 819

Waterwegen en Zeekanaal NVDorien VerstraeteE: dorien.verstraete@wenz.beT: +32 (0)3 224 93 68

Institution Interdepartementale Des WateringuesPhilippe ParentE: philippe.parent@institution-wateringues.frT: +33 (0) 321 38 20 56

City of BredaTom RozendalE: t.rozendal@breda.nlT: + 31 (0)76 529 32 36

Such an approach to partnership working and joint funding is relatively new in the UK and the model used for the Chelmsford Flood Alleviation Scheme is now being used for other projects in the country. It has been a challenging, but ultimately a rewarding way of working.

Urban Water Retention schemeThe Margaretting scheme requires extra protection for two houses, minor works for the railway line, and no large scale rail or road disruption.

The earth embankment will be 500m long and 5.5m maximum height, and it tapers at each end to meet the valley sides. The embankment will be created from earth removed from the storage area, which is being slightly lowered to provide the capacity for flood water storage.

A diversion will be made in the natural flow of the river to direct water through a concrete control structure, with automatically operated steel sluice gates. A small control building will be built adjacent to the embankment, with a permanent access track linking it to the public road network.

A secondary earth embankment is needed to give extra protection to two houses at the northern edge of the flood storage area, adjacent to a culvert (Margaretting Brook) that feeds into the River Wid. Margaretting Brook will be diverted with its former course filled in, and new drainage ditches added.

Lessons learntTo fully engage with the local community, and to support the planning application, the Environment Agency developed a Statement of Community Involvement. In essence this set out a series of ways to involve, consult and engage with those affected by the scheme.

The legal processes – The planning application. Funding agreements. Contract documents. There is a long list. Recognise that this is necessary and important, and ensure that it is adequately resourced with people, time, expertise and funding.

It has been necessary to develop new areas of legal expertise, including the employment of external legal teams, to deliver contracts, warranties and development agreements.

Margaretting FAS

Chelmsford Flooded