The Pednormead End project

The Pednormead End Flood Resilience Project is a flood management scheme for the community of Pednormead End in Chesham.

We are committed to managing flood risk and this project is one of the various key projects aimed at managing flood risk across the county.

Update - 24 June 2022

We've postponed the planned culvert replacement construction work on Pednormead End Chesham, which was due to start on 27 June 2022. It will now start in summer 2023.

This is due to technical issues found during our pre-construction surveys.

The other part of the flood scheme, Property Flood Resilience measures, (offered to houses impacted by internal flooding) is now close to being completed and this will help to mitigate against floods which may occur in the future for those properties at risk.

We apologise for the inconvenience caused and thank you for your patience.

If you have any queries, contact us at [email protected] or call us on 01296 382416.

The background

Following an investigation in 2015, it was found that over 100 homes are susceptible to flooding in the future in Pednormead End, an area of Chesham located in South-East Buckinghamshire.

The cause of flooding in the past, and potential flooding in the future is caused by:

  • excessive surface water
  • water rising over the top of the banks on River Chess (caused by heavy downpours)
  • rising groundwater

Historical flooding at Pednormead End extends over 100 years, with the most extensive occurring in 1918. More recent flood events occurred in 2001, 2006, and September 2014.

In 2015, Atkins, a consultancy group, was asked to investigate a range of flood management options for Pednormead End. This resulted in the development of the flood management project.

The project

The project is a £3.3m flood management project to limit future damage caused by flooding, including:

  • building a bigger culvert under Church Street
  • offering property flood resilience packages to every affected home

Benefits

There are multiple benefits of the proposed project, including:

  • improved flood resilience for properties against flooding
  • property owners will be increasingly self-sufficient and resilient during a flood event
  • improved safety and structural integrity of the culvert under Church Street
  • improved drainage of surrounding roads leading to less standing water, reducing the instance of pot holes, and therefore fewer maintenance costs, improved safety and reduced disruption
  • enhanced peace of mind, reduced stress and improved quality of life for property owners concerned with flood risk
  • businesses able to operate and trade during and after a flood event

Property Flood Resilience (PFR) packages

The Property Flood Resilience (PFR) packages provide property owners with practical and cost-effective measures which reduce the amount of water entering buildings.

PFR help to reduce flood risk by identifying:

  • products which are appropriate for the type of flooding experienced
  • requirements and constraints of the property itself
  • the needs of home and business owners

There is a range of measures which can be used to limit water entry including:

  • barriers on windows and doors
  • use of non-return vales to prevent backing-up of floodwaters
  • automatically closing airbricks and pump systems

We carried out a number of webinars in 2021. You can view our virtual event question and answer session summary.

Project progress

By the end of June 2022, installation will have been completed for the most part at all properties within the scheme.

This involved receiving listed building consent for 13 properties and Highways Departure from Standards (DfS) consents for flood barriers facing public footpath.

Next steps

The PFR scheme is in its final stages, with the following activities still ongoing:

  • snagging (final minor works at properties)
  • post installation surveys by the independent surveyors RAB Consultants
  • issuing of post installation flood risk reports (PIFRR) to homeowners

Pednormead End Culvert Replacement

Background of the culvert replacement

To help reduce flooding during the more frequent flood events, the existing piped culvert that carries a tributary of the River Chess under the Missenden Road is to be replaced with a precast concrete box culvert.

In addition to this work, a section of the Bury Pond culvert that runs under Church Street near the Queens Head Pub, will be also repaired. To help mitigate high ground water levels in the area, filter drains will also be installed on either side of the new box culvert.

Design

The design has been careful to ensure the size of the new culvert is suitable to fit into the restricted space available and ensuring that its capacity does not push more flood water downstream.

Project stages

The first stage of the project was undertaken between June 2020 to December 2020 and began by focusing on lowering and diverting utility services ahead of the culvert replacement.

Unfortunately, due to the complexity of the utility diversions and high ground water levels, the project was put on hold with the intention of resuming work in summer 2021.

Once again high groundwater levels in 2021 meant it was not safe to resume underground high voltage electricity diversion works at this time and the project was put on hold once again.

A map showing the replacement and scheme overview for Pednormead End

The replacement and scheme overview for Pednormead End

Planned work in 2022

The work planned in 2022 has been postponed to 2023, due to technical difficulties.

The planned work will take 12 weeks to complete and will be carried out in 3 phases:

Phase 1

Diversion of an underground high voltage electricity cable and repair of a damaged section of the Bury Pond culvert that runs under Church Street near the Queens Head Pub.

Phase 2

Replace the existing River Chess culvert from its outlet adjacent to the Queens Head Pub to the Missenden Road/Wey Lane junction and reinstate.

Phase 3

Replace the existing River Chess culvert from the Missenden Road/Wey Lane junction to its inlet adjacent to house number 5 Missenden Road and reinstate.

Resurface carriageway and replace road markings.

Measures

During construction the following measures are planned:

  • a 24 hour road closure at the junction of Missenden Road, Church Street, Pednormead End and Wey Lane
  • we'll maintain pedestrian access around the works area and make sure footway diversion routes are clearly signed
  • we may have to undertake some work out of our usual hours of 8am to 6pm, Monday to Friday (affected residents and businesses will be notified ahead of this)
  • all reasonable measures will be taken to ensure access to all properties within the works area (where this is not possible we will speak to local residents and businesses directly)
  • water pumps will be in operation throughout the duration of works to mitigate the impact of high-water table on the planned works
  • a silt buster will be in use to ensure pumped water is filtered before returning to the River Chess (this process is done within the requirements of the Environment Agency and will be  monitored)
  • we'll minimise noise and dust levels

Coronavirus safety measures

The project team are regularly reviewing Public Health England and government advice to guide the delivery of the project.

Robust risk assessments are being completed to ensure our delivery staff and residents are safe.

These will be kept under regular review to reflect the current circumstances.

If you are concerned how COVID-19 will be managed through the delivery of the project, get in touch using the contact details below.

Contact

If you have any questions about the Pednormead End Culvert replacement, or would like to enquire about how to participate in the Property Flood Resilience (PFR) packages, contact us.

Telephone: 01296 674 846

Email: [email protected]