Potwell Dyke

The need for the scheme

Properties along Church Street, Easthorpe and associated areas are at risk from flooding as evidenced in the flooding event in 2013. Flood modelling has identified an opportunity to significantly reduce that flood risk by creating a feature on the open space south of Church Street. It is calculated that over 70 properties will be removed or benefit from reduced flood risk as a direct result of the scheme.

The proposed scheme

Via is delivering a range of projects on behalf of Nottinghamshire County Council as part of the wider Southwell Flood Alleviation Scheme.  The proposal for this site comprises a reinforced earth bund (bank) with associated flow control and spillway, which will wrap around the edge of the open space to the rear of the properties on Church Street and Harveys’ Field. 

Proposed Layout and Cross Sections

The bund will be seeded with wildflowers and sit within a framework of native planting. Existing access will be maintained, as will the football pitches.

Landscape Proposals

The bund will retain flood water at periods of exceptionally high flow, releasing the water in a controlled manner into the dyke as soon as downstream flow levels subside sufficiently to avoid property flooding. The design of the proposed flood storage area at full capacity is 42,300m3 of water above ground level.

The construction period is anticipated to be a around 16 weeks dependent on weather conditions. Works will be undertaken in a number of stages, as broadly outlined below:

 

 

Stage 1

This will involve limited removal of vegetation and tree felling,

Stage 2

This will involve site set up of construction compound (adjacent to Church St), welfare, access trackway, protective fencing.

Stage 3

This will involve providing construction of the headwall, scour protection and temporary access, temporary footpath closure of public footpaths 14 and 15 and dyke diversion.

Two 1350mm diameter pipes will be placed along the line of the dyke and headwalls and penstock constructed. A temporary access will then be constructed over the new pipes to act as a bridge for the construction works on the eastern side of the Dyke.

Stage 4

This will involve construction of the eastern end of the bund. Public footpath 12 will be temporarily closed or diverted. New steps will be installed over the bund to link public footpaths FP14 and FP15.

Stage 5

This will involve construction of the western end of the Bund. As works progress, the size of the construction compound will be reduced to allow for the bund’s construction. The existing wetland area to the west of the Dyke, south of the bund will be reprofiled, maintaining and extending that area of habitat.

Stage 6

This will involve landscape planting and boundary works. 

Reinstatement and grass seeding will take place across the Higgons Mead. New planting will take place in accordance with the detailed planting proposals. Tree protection measures will be removed. All footpaths will be reopened and reinstated. Estate-type metal railings will be installed to replace sections of existing metal mesh type fencing across the site and the post and rail timber fencing along the Church Street frontage. The construction compound will be removed and any residual areas of the site ‘made good’.

All access for construction vehicles will therefore be taken from Church Street, with the construction compound being on land that formed part of the secondary school which previously occupied part of the site.

HGV lorry movements are likely to be over a period of 11 weeks with up to 10 movements per day (350 loads in total). Approximately 5,200 tonnes of fill material will be imported and a similar volume of material unsuitable for fill will be exported, during the construction phase.

The preferred HGV and construction delivery route is from the A617 (Averham) via Upton Village and Upton Road, Easthorpe on to Church Street (see plan ref. 10762/344 Rev. 0 ‘Proposed Heavy Goods Vehicle Transport Route’).

Discounted options

We explored a number of options when developing this project. Options to create multiple bunds or to retain flow further upstream have been discounted as they were unable to provide the benefits that this location and layout affords.

An option to create a bund crossing the site further South from Church Street was rejected to reduce the impact on the setting of the Minster and views south from Church Street across the open space. The layout was also discounted due to the potential risk to possible buried archaeology in the middle of the open site.

Benefits and impacts

The key benefit is the protection or reduction in flood risk that this scheme will offer to over 70 properties downstream of the site for 75year storm event rising to 166 properties for a 200year event.

Other benefits include the provision of a more diverse habitat within the open space.

The potential impact on buried archaeology has been determined by ongoing survey work and minimised by location within the site and construction methodology.

Access and openness of view across the site has been maintained. Photo montages showing before and after impact on views are available to view online with the planning application documents and include:

Further views are given on the planning website by following the link above

The Environmental Statement uploaded to the planning application website gives a comprehensive assessment of benefit and impact

Next steps

The proposed scheme has now been submitted for planning approval. The submitted documents include a full environmental statement and detailed proposals for the scheme. The application reference ES/4375 is available to view on the County Council Planning website here: Land South of Church St ES/4375

If you wish to comment on the application, there is an on-line form on the planning website or alternatively email development.management@nottscc.gov.uk or write to Nottinghamshire County Council by 11 February 2022.

Via is organising informal information sharing conversations with key stakeholder organisations within the community including the Town Council, sports clubs, Civic Trust, Archaeology and history groups in parallel with the planning consultation period.

If you would like to contact Via regarding this scheme the project e-mail address is southwellfloodalleviation@viaem.co.uk.  

Remember, responses to the Planning Application should be submitted to development.management@nottscc.gov.uk by 11th February.

Subject to planning approval it is hoped that work will start on site in the summer of 2022.

 

Share this page?