Bewdley Severnside South Flood Alleviation Scheme

Bewdley is a Worcestershire market town, strategically placed as a crossing point on the River Severn. The attractive town core consists of Georgian and earlier buildings in mellow brick and local sandstone. Historically, it evolved during the 15th century as an important inland port on the river, and evidence of the town’s original function is still apparent along Severnside, the historic quay, being an asset in attracting visitors to the town.

The town has historically suffered from fluvial flooding and initial consultations during the 1990’s for a flood defence scheme were discontinued initially on the grounds of a significant negative impact. Flood events in 1999 and extensive flooding of 175 properties in the winter of 2000 acted to focus minds. With the political will to accelerate a scheme, design work for flood defences began by the summer of 2000. Public and stakeholder engagement by the Environment Agency with residents, businesses, local authority and key stakeholders led to the introduction of the design of a new form of demountable flood defence.

The design process was divided into two phases:

  • Phase 1 covered a section upstream of the main Bewdley Bridge crossing; and
  • Phase 2 covered the quayside and car park downstream of the Bridge.

The latter is rich in built cultural heritage, being part of the Bewdley Town Centre Conservation Area, comprising listed buildings and the Bridge, a 300m length of riverbank being retained by a sandstone block listed Grade II quay wall and other amenity assets. Structural investigation showed that the wall structure was weak in places, at risk of collapse if the proposed works were undertaken. Significant strengthening work entailed constructing support beneath and behind the wall, taking down and rebuilding the stone face as work proceeded. The flood defence works required extensive below-ground works, pile drilling, grouting and excavation. Significant archaeological studies and intrusive investigation was required since the working area was thought to contain medieval stonework, timbers and relics from much earlier bridge abutments. Remains of a medieval chapel were discovered, recorded and preserved under the line of the new flood defence.

The Environment Agency and team worked very closely with English Heritage, Worcestershire County Council and Wyre Forest District Council Planning, Conservation and Highways teams, the Bewdley Civic Society and Town Council, in addition to local residents and businesses and the local Flood Forum Group. The level of collaboration was such that a statutory Environmental Statement was produced by the Agency and published by early summer 2000. The project required extensive multi-disciplinary working between Client, Consultant and Contractor.

Importantly, the scheme was seen by the Environment Agency Landscape Architects as a real opportunity for the restoration and enhancement of the town’s quayside amenity as an integral part of the project development and delivery, working in partnership with the organisations listed and with the Regional Development Agency (RDA).

So whilst the key objective was to provide Severnside South with a flood defence for a 1 in 100 year level of protection, discussions progressed and a scheme was developed to remodel the local environment to enhance and restore it within the confines of the historic environment, and within the engineering and environmental constraints of constructing the flood defence. The project scope was developed to assist in the conservation and enhancement of Bewdley’s heritage, to encourage more people to be involved in its heritage, and ensure that they can learn about and enjoy the quayside area. Developing these additional aims was not straightforward, as there were the normal time and financial constraints. This work also did not form part of the core business in developing flood defences. However, it is covered under the Code of Practice on Conservation, Access and Recreation issued under Section 4 of the 1995 Environment Act. The primary Act formed the Environment Agency with powers to protect the natural environment and the Act provides legislation in relation to all facets of the environment.

The design was innovative due to the fact that it was the first flood alleviation project in the UK to utilise demountable defences. In addition it significantly rationalised the entire length of the quayside area, improving access to a refurbished promenade where pedestrians were given increased priority and recognition within a public realm shared with vehicles. The design maintained and enhanced the character and setting of the fine Georgian buildings; introduced a new Civic Space incorporating a two-tier terraced quay with ramped access and extended walkways where access was previously either impossible or unsafe. The consenting process was augmented by the use of a three-dimensional scale model. It assisted local users and decision makers to visualise proposals in terms of scale, surfaces, and changes in level, access and spatial quality. The model is now exhibited at the Town Museum as part of an ongoing exhibition on the history of flooding in the town.

Overview

Location

Location 

Bewdley, Worcestershire

Category

Waterways and wetlands

Landscape Architect

Client

Environment Agency

Brief

To provide defence against flooding, significantly enhancing and remodelling the river frontage and improve access to the historic quay wall.

Awards

Bewdley, Worcestershire

Details

Project Team

Julian Francis, Environment Agency

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Environment Agency, WS Atkins and Volker Stevin

Local planning authority or government body

Worcestershire County Council

Year Completed

Summer 2002 for main engi

Project Size

Technical's

Planting

Planting was largely limited to enhancing the Gardener’s Meadow car park area which was reorganised as an outcome of the project, in particular following its use as the construction site compound. It was also redesigned to accommodate additional vehicles following the imposition of parking restrictions along the quayside as a result of the flood defence project which dually sought to enhance the facades of the terraced properties and to unclutter the riverside corridor. Works included strategically located planter beds together with screening of the return section of new permanent floodwall and comprised a mix of native trees, understorey shrubs and groundcover.

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Implementation and establishment maintenance was undertaken by a directly procured landscape contractor, separate from the main engineering contract, for a period of 5 years following practical completion. Whilst this duration is standard practice for landscape aftercare in the Environment Agency, it also met the landscape conditions imposed by the local planning authority as a result of planning consent and was successfully handed over to the local authority. 

Materials

The above-ground system is based around an innovative completely demountable aluminium barrier system, which minimises the aesthetic impact of the defence during normal river flow conditions. This is used in conjunction with an underground system, comprising a contiguous drilled concrete pile system with a concrete beam to form an integral part of the defence acting as a cut-off to underground flow during floods, and construction of a new pumped surface water sewer system.

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This was either finished at ground level to which a demountable defence system is affixed, or is brought out of ground and is finished with a sandstone block facing and capping which replicated the coursing of the quayside wall. The demountable defences are affixed to a stainless steel plate with threaded stud inserts to receive demountable posts. This in turn is integrally linked to the pile cap for strength.

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In addition to providing defence against flooding, a key objective of the project was to significantly enhance and remodel the river frontage and improve access to the historic quay wall. This has been achieved by the sympathetic use of high quality paving materials and street furniture together with artwork to give a historical context to the quay frontage.

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The greatest challenge was the need to balance the flood defence design and operational requirements with maintaining the character and importance of a historic environment. The site not only encompasses a dozen listed properties but more significantly a Thomas Telford Grade I bridge and a Grade II quay wall. Sections of this historic Quayside wall stonework were repaired and rebuilt, sourcing a sandstone block stone which would weather to form a satisfactory match to existing stone.

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Following lengthy design discussions with the local authority conservation officer and English Heritage, the pedestrian areas of the quayside were treated in a sensitive manner using a mixture of Tegula blocks and granite setts. The new lower quayside access path was constructed in structural concrete with a resin bound surface using locally sourced fine aggregate, with granite sett bands which cleverly obscured the regularly spaced movement joints. Bench seats, litter bins, lighting and signage were chosen and specified in close liaison with the local community as part of a local regeneration project, “Opportunity Bewdley”. Similar specification street furniture was then used in other areas of the town.

Contractors 

Approximate Map Location


Location

Bewdley, Worcestershire

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