Other key achievements of the PVFF

Since its inception in 2013, the PVFF has also:

  • Promoted and established a superb working relationship with communities across the Pang Valley and beyond.
  • Represented the interests of the River Pang and its catchment on the South Chilterns Catchment Partnership and as part of the DRY project with Loughborough University.
  • Held a Flood Fair (2016) for residents across West Berkshire (attended by Flood Re and other Flood risk Product companies) and raised awareness of flooding issues and a Flooding Workshop (March 2019) run in conjunction with the University of Reading, with information stands from Flood Re, Thames Water, the EA, WBC, and Action for the River Kennet and attended by over 100 residents and interested parties, to look at flooding in the Pang Valley in the past, present and future.
  • Gained Grants for Flood Emergency equipment.
  • Gained a grant that helped seed fund bank re-instatement work at BBOWT’s Moor Copse reserve to reduce overbanking and consequential flooding.
  • Given talks to Parish Councils and interested residents, encouraged residents to have their own flood plans and PLP.
  • Helped other Flood Groups set up or improve their ways of working.
  • Attended flood seminars and conferences to stay abreast of new developments.
  • Worked with partner organisations to improve the watercourse and river channel in Compton.
  • Developed our own website, logo etc with, amongst other things, a library of useful documents and live (and historic) river and groundwater graphs.
  • Produced our own "Guide to being a Flood Warden".
  • Documented mill and sluice operating procedures for all key mills and sluices in the valley.
  • Documented all Actions to reduce Flood Risk (Part of the West Berkshire Flood Risk Management Plan) whether completed or open on a live document on the website.
  • Were "Highly Commended" as a Community Group by West Berkshire Council in 2016.
  • Are a key project partner for the Reading University NERC LANDWISE project and have supported academic investigations by various students in to Flood related topics.

 Bourne Natural Flood Management

Completed 2019

Objectives

This natural flood management project has aimed to reduce the peak flows down the Bourne (the largest tributary into the Pang upstream of Tidmarsh) after intense rain events. We have followed the Environment Agency's Natural Flood Management (NFM) strategy to implement natural techniques to slow the flow, to hold back water and to reduce the height of peak flow levels.

Funding and Leadership

The project was funded by a DEFRA NFM Grant (administered by the Environment Agency), specifically allocated for community level groups to use on NFM projects. The project was managed by an experienced volunteer from within the PVFF, and with the support of Englefield Estate, through which the Bourne flows.

Design, Construction, Monitoring

The project has implemented 38 'leaky dams' on the River Bourne. Construction of the dams was carried out by Englefield Forestry with advice from the Environment Agency (with expertise gained in the Stroud Area). Additional works included: bank reinforcement and protection measures to limit runoff and erosion from a forestry track.

A Reading University team conducted flow monitoring.

A post construction River Habitat Survey and Modified Condition Assessment survey is planned for November 2020.

Publicity

The project was featured on BBC South Today.

 Elmwood Natural Flood Management

Completed 2020

Objectives

As with our project on the Bourne, this NFM project has aimed to reduce the peak flows down the Elmwood Stream (the largest tributary into the Pang upstream of Bucklebury Ford) after intense rain events. We have followed the Environment Agency's Natural Flood Management (NFM) strategy to implement natural techniques to slow the flow, to hold back water and to reduce the height of peak flow levels.

Funding and Leadership

The project was funded by a DEFRA NFM Grant (administered by the Environment Agency), specifically allocated for community level groups to use on NFM projects. The project was managed by an experienced volunteer from within the PVFF, and with the support of The Marlston Estate, through which the Elmwood Stream flows.

Design and Construction

The PVFF team chose this catchment following a study of the key inflowing stream catchments that contribute large flows to the Pang from the clay layer on the Bucklebury ridge.

The project has implemented 24 'leaky dams' on the Elmwood Stream. Construction of the dams was carried out by Englefield Forestry having gained experience on the River Bourne project.

Additional measures included log barriers and "dragon's teeth" to prevent 4x4 access to the stream which has caused damage over the years through misuse, doubling up as leaky dams.

 Pang Valley mapping

Completed 2016

Objective

The project aimed to create a shareable map available online that combined map data from the EA, WBC, the British Geological Society and specific map information gathered by the PVFF itself.

Result

Parish representatives through the valley mapped:

  • Key Points that should be monitored
  • Slow/Fast areas where the water should be slowed or sped up.

The PVFF team have used this information as the basis for valley wide maintenance plans and to identify opportunities for 'slow the flow' natural flood management projects.

Mapping

The PVFF team used Google My Maps to create a framework through which parish representatives could record the locations of the Key Points in their own area, and could record "Who maintains", "Who monitors" and "What to do if there is a problem" at each point.

A similar mechanism was used to map the recommended slow and fast areas in the valley and this map layer was enhanced with aerial photos taken during the floods of Feburary 2014.

The resulting PVFF map layers have then been combined with map layers from others sources and are presented through ESRI's ArcGIS online platform.

 Bucklebury Flood Alleviation Scheme

Completed 2011

Objective

The project aimed to reduce the risk of flooding in Bucklebury Village following widespread property flooding in 2007, while ensuring that flood risk was not increased in Stanford Dingley downstream.

Result

The scheme was opened in 2011 by the Flood Minister Richard Benyon MP and village project lead Piers Allison. The scheme was designed by Peter Brett Associates to provide a standard of protection to properties of 1 in 154 (0.6%) annual exceedance probability. In February 2014, it proved its worth when the River Pang reached 2007 levels for several weeks and not a house got wet.

Design and Construction

The scheme includes flood embankments, a bypass channel and a new 'dry' ford to divert flood flows around the village. It also includes a further embankment downstream to ensure the flood risk is not increased in Stanford Dingley. Despite the construction phase experiencing a terrible winter, the scheme was delivered incident free in April 2011.

Funding

The project was funded by the Thames Regional Flood Defence Committee with contributions from the villagers and West Berkshire Council. The vilagers formed a Community Interest Company and had a contract with the Environment Agency to manage the delivery of the project.

 Upper Pang Valley groundwater scheme

Started 2016
West Berkshire Groundwater Scheme map

West Berkshire Groundwater Scheme

The West Berkshire Groundwater Scheme shown on the plan is a network of pumps and connecting pipelines designed to abstract groundwater in times of drought in order to augment river flow in tributaries of the River Thames, and so potentially increase the public water supply.

PVFF Proposal

The Pang Valley limb of the West Berkshire Groundwater Scheme is highlighted on the plan. It extends beyond West and East Ilsley to the north and the nine wells discharge into the River Pang downstream of Bucklebury.

Analysis of the effect on groundwater levels during 30 years of abstraction at Compton for public water supply indicated that the overall Scheme could usefully be deployed in winter to drop the groundwater level sufficient to mitigate the worst effects of flooding in the Upper Pang Valley villages.

Progress

Three MSc projects (at Birmingham and Brunel University) have studied the potential for groundwater level reduction, and the downstream consequences of the discharge at Bucklebury into the higher level of river flow experienced in winter.

It has been concluded that the Scheme has the capacity to reduce the groundwater level by ~1m after operating for a few weeks and thus to mitigate the worst effects of groundwater flooding without exposing communities downstream of Bucklebury to a significant increase in flood risk. Pumping would need to continue to the end of the groundwater season.

Remaining Issues and Delivery

Operation of the Scheme becomes more pressing with increasing flooding threat from rising groundwater level. Events as in 2014 can unfold over a period of just a few weeks. Thus, there should be potential for rapid deployment, preferably remotely actuated, however the system is manually operated presently. An appropriate triggering criterion also needs to be developed.

Furthermore, the decision-making process is not straightforward. The Scheme is owned by the Environment Agency within a statutory framework that operates for the benefit of Thames Water. Thames Water, West Berkshire Council and householders incur the main costs arising from high groundwater and flooding, and to mitigate this the operating framework of the Scheme needs to be revised.

Also, running the Scheme for several months incurs costs that need to be set against the savings from flood mitigation to provide economic justification for the proposal.

 Hampstead Norreys bypass channel

Detailed design in 2021, construction in 2022.

Objective

The project will construct a flood bypass channel to divert significant volumes of flood water (that would otherwise overflow within the village), before rejoining the river downstream near the highway culvert on the B4009 Church Street.

The design modes show that the scheme would mitigate the risk of flooding to all existing properties within the beneficial area from a 1 in 20 year flood event, i.e. a flood event similar to the event in February 2014. The proposed maximum flood extent during a 1 in 100 year plus 35% climate change event will also be reduced to a similar extent of the existing 1 in 20 year flood event along Water Street.

Proposed Design

The proposed Flood Alleviation Scheme (FAS) comprises a flood diversion channel, similar to the temporary diversion channel created in 2014, located within the arable fields to the east of the village. This will redirect flows away from the residential area along Water Street where the Pang currently flows.

The proposed FAS will also introduce a small check dam with flow control in the main channel to reduce the flow from entering the channel along Water Street during high flow events.

Detailed Plans


Delivery Partners

 Stanford Dingley bypass channel

Construction in 2023.
Location of Stanford Dingley bypass channel

Objective

The scheme will provide a standard of protection to properties of 1 in 75 (1.33%) annual exceedance probability.

A number of environmental enhancements are proposed as part of the scheme which will be finalised at the detail design stage.

Project Delivery

West Berkshire Council (WBC) will project manage the design and construction of the scheme using their in-house engineering team. WBC will appointed a consultant to carry out the detailed design and a contractor to deliver the scheme on site.

Proposed Design

The design comprises an overflow/bypass channel in combination with a ford upstream of the Mill Bridge. The aim of this proposal is to divert significant volumes of flood water (that would otherwise overflow within the village), before rejoining the river downstream of the bridge.

The scheme includes:

  • Flood relief channel with ford
  • Reprofile South End Road with associated swale
  • Provision of raised kerbs at two locations
  • Regraded existing ditch to fall towards the River Pang.

Detailed Plans


Delivery Partners