Rock imported from Norway
Just under 70,000 tonnes of granite was imported by sea from Norway to construct the defence which includes a 100 metre terminal rock structure at the end of the defences. The rock was delivered by barge directly to the beach.
The majority of the rocks weigh between six and ten tonnes, but some reach as much as fifteen tonnes. This is thought to be amongst the largest used in such defences around the UK.
Rocks of this size are required to withstand the rough seas that this stretch of coastline can experience and will provide protection into the future, should climate change produce the expected worsening of sea conditions. Rock armour's interlocking but porous structure has proven to be effective at withstanding wave action which is the primary cause of the area's rapid coastal erosion.
A key objective of the scheme is to reduce the risk posed to property by coastal erosion for the next 100 years.
Erosion on this section of the Withernsea coastline has historically been at an average of around 4m per year, but in recent years this has increased to approximately 6m per year in places, with last year seeing around 12m of erosion opposite the frontage of the Golden Sands Holiday Park.
Procured through YORcivil2
The work on the coastal defence scheme was managed by principal contractor BAM Nuttall, with KLM Ltd supplying the rock and RJT Excavations Ltd undertaking the earthworks and rock placement. The scheme was designed by Principal Designer JBA.
BAM Nutall needed to overcome several unique challenges to complete the scheme, including developing a novel system of work with subcontractor RJT to manoeuvre the massive rocks into place; working within 5 to 6 hour tidal shifts between which the partially completed works would be submerged at high tide; H&S risks due to deep excavations and unstable partially built defences; ensuring the safety of local residents.
The scheme received £3m of funding from the European Regional Development Fund (ERDF) towards the cost of the project.
South Withernsea Coastal Defence Scheme - Time-Lapse Footage
Footage from East Riding of Yorkshire Council