Investigation works on long groyne at Hengistbury Head

With a jack-up-barge in position, ground investigation surveys will take place into September to help prepare for the upgrade and repair of the entire long groyne structure at Hengistbury Head.

The structure is described as “critical” in stabilising and controlling coastal erosion in Poole Bay and Christchurch Bay.

A detailed inspection of the groyne in 2019 revealed it to be in a very poor condition. Several voids were discovered in the foundations below the waterline, with an associated risk of localised collapse.

Land-based surveys are complete and the sea-based jack-up-barge will work 24 hours a day to take borehole samples from five seabed locations around the groyne.

• Read more: Jack-up barge arrives in sea off Hengistbury Head

All the borehole samples (on land and sea) are up to 20 metres in depth and will enable BCP Council to assess what the ground is made up of so the design of the new groyne can suit the ground conditions.

During this time, the area will remain closed for public safety.

Jack-up-barge in place for Hengistbury Head long groyne works. Picture: BCP Council

Councillor Mark Anderson, portfolio holder for environment and place said: “The 83-year-old structure has been critical in stabilising and controlling coastal erosion in both Poole Bay and Christchurch Bay.

“Along with the beach and other shoreline structures, the long groyne helps protect local communities and infrastructure so it is vital we upgrade it so it can continue to perform effectively, particularly with the additional threat of sea level rise and an increasing number of storm events.

“Without the long groyne, beach material would rapidly wash away, and the cliffs could start to erode again.

“This would eventually lead to the sea breaching Christchurch Harbour at Double Dykes and Mudeford Sandbank and the impacts could extend to the Purbecks and New Forest.”