Poole Bay Beach Management Scheme

2015-2032

A 17-year Beach Management Scheme to protect our coastal frontages, making them more climate resilient.

Hengistbury Head Long Groyne works

From Monday 22 November, ground investigation works will begin at Hengistbury Head long groyne. This work will help inform the design of the planned upgrade and repair of this long groyne, which plays a critical role in helping control coastal erosion in Poole and Christchurch Bays read more

Timber Groyne renewal programme

Work is currently underway to renew timber groynes between the Middle Chine & West Cliff zig-zag. This winter three groynes will be deconstructed and replaced with four more evenly spaced groynes … read more

Background to the Poole Bay Beach Management Scheme

Poole Bay stretches from Sandbanks in the west to Hengistbury Head in the east. Over the last 100 years coastal defence works have included the building of seawalls, construction of a groyne field and the creation and maintenance of an artificially widened beach along this length of coast. In 2011, the Poole and Christchurch Bays Shoreline Management Plan (SMP) set policies to manage the risk of coastal erosion along Poole Bay, through a mostly ‘Hold the Line’ approach over the next 100 years, meaning coastal defences should be maintained and upgraded or replaced in their current position where funding permits.

The ‘Hold the Line’ approach is achieved using a combination of beach replenishment and groynes.

Why beach replenishment?

In Poole Bay the physical protection of the coastline with a sea wall and promenade limits the natural erosion of cliffs which would otherwise top-up beach levels. Cyclic beach replenishment schemes are therefore required to maintain a frontline defence and this requires the use of non-native material. Studies have shown approximately 70,000m³ of sand is lost from the Poole Bay frontage each year.

The beach material is transported by wave action and generally moves eastwards towards Hengistbury Head by a process called longshore (or littoral) drift. Eventually sediment may be transported and deposited further offshore in Poole Bay or into Christchurch Bay.

Why groynes?

As part of the coast protection measures in Poole Bay, groynes are strategically placed to retain the beach material moved by longshore drift. Beaches at Poole and Bournemouth include a variety of groyne types including rock, timber and hybrid structures (constructed from timber with rock on the outer ends) – the former of which have a longer life-span. The combination of groynes with periodic beach replenishment allows the sea walls and cliffs to be better protected.

The current Beach Management Scheme is replacing the life-expired timber groynes along the Bournemouth section of Poole Bay which have a life-span of approximately 25 years.

Sediment Transport (longshore drift) in Poole & Christchurch Bays

Source: SCOPAC Sediment Transport Study 2012, Poole Harbour Entrance to Hengistbury Head. Available at www.scopac.org.uk/sts/poole-bay.html

Source: SCOPAC Sediment Transport Study 2012, Hengistbury Head to Hurst Spit. Available at www.scopac.org.uk/sts/christchurch-bay.html

Project Overview

Beach Management in Poole Bay is designed to provide protection to a significant number of residential and commercial properties. Without it, properties, highways and supporting infrastructure would be lost to coastal erosion.

The Poole Bay Beach Management Scheme will take place over a 17-year period between 2015-2032, and will be carried out in three distinct phases. It is estimated the entire scheme will cost in the region of £50 million, with the majority funded by the Environment Agency.

Overall the aims are to: 

  • replace Bournemouth’s existing 53 timber groynes, in multiple short phases (based on the life-expiry dates of the structures);
  • construct an additional three new timber groynes;
  • repair and upgrade Hengistbury Head Long Groyne;
  • complete three beach renourishments, approximately once every five years.

Project Progress

Phase 1 (2015 – 2020)

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2015-2017

Assessing the performance of timber groynes at Bournemouth Beach

As part of the timber groyne renewal programme at Bournemouth beach, a study was made into the performance of five ‘experimental’ groynes that had been built between 1985-1987 in order to evaluate the performance of different timber types in the field. Assessments were also made on the feasibility of re-using timber from the deconstructed groynes in the forthcoming renewal programme

Full details and reports available at www.southerncoastalgroup-scopac.org.uk/scopac-research/timber-groynes-performance

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Winter 2015/16

Bournemouth Beach Groyne replacement

The first 10 timber groynes replaced from the east of Boscombe Pier by Honeycomb Chine to Fisherman’s Walk, near the zig-zag path

Project details

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Spring 2016

Bournemouth Beach Replenishment

355,500m³ of dredged material was distributed on the beach between Bournemouth Pier and Solent Beach, Southbourne

Project details

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Winter 2016/17

Bournemouth Beach Groyne Replacement

Replaced 8 timber groynes eastwards from Fisherman’s Walk to Gordon’s Corner

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Winter 2017-2019

Bournemouth Beach Groyne Replacement / Construction

Replaced 12 timber groynes at Southbourne, from St Catherine’s Path to the eastern end of the promenade. Delivered over a two year period; six groynes in each year

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2019

Hengistbury Head Long Groyne, exploratory work

A intrusive condition survey was carried out from May 2019. A number of voids in the underlying foundations have been found and there is a risk of localised failure

For safety reasons the groyne was closed to the public in August 2019, pending repairs scheduled for Phases 2/3

Phases 2 & 3 (2020 – 2032)

In May 2020 the Environment Agency awarded BCP Council £33 million of combined government Flood Defence Grant in Aid (FDGiA) and Local Levy. A capital contribution of £3.3 million by BCP Council was approved in October 2019.

Phases 2 and 3 will:

  • Replace the remaining 26 timber groynes located along the seafront from Southbourne to Alum Chine;
  • Provide two beach renourishments; 
  • Repair and upgrade Hengistbury Head Long Groyne to ensure the continuation of coast protection for Poole Bay and Christchurch Harbour.
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Winter 2020/21

Beach Renourishment

 A £7.5 million programme to renourish seven depleted beach areas with approx 350,000m³ of beach material

Beach areas included Solent Path to St Catherine’s Path, Gordon’s zig-zag to Fisherman’s Walk, Boscombe Pier, East Cliff, West Cliff to Middle Chine and either side of Shore Road in Poole; completed March 2021

Project details

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Winter 2020/21

Timber Groyne Renewal

Five groynes between the Poole/Bournemouth boundary and Middle Chine were deconstructed and replaced with 4 more evenly spaced groynes

Project details

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Winter 2021/22

Timber Groyne Renewal

Three groynes will be deconstructed and replaced with 4 more evenly spaced groynes; work commenced October 2021

Project details

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Winter 2021/22

Hengistbury Head Long Groyne works

Ground investigation works start 22 November, the results of which will help inform the design of the planned upgrade and repair of the long groyne. Work is expected to last a few weeks, with progress reliant on tides and weather conditions.

  • The long groyne was constructed from 1937–1939 and plays a critical role in the control of coastal erosion in Poole Bay and Christchurch Harbour
  • Exploratory work carried out in 2019 found a number of voids in the underlying foundations of the 82 year old structure, with an associated risk of localised failure. For safety reasons groyne access has been closed to the public since August 2019

Project details