The coastal cliffs behind Scarborough Spa were unstable and at serious risk of collapsing into the sea; catastrophic for the immediate locality and economy. More than 400 properties, including the Grade II listed Spa building, were at risk from deepseated landslides or shallow surface slips.
Scarborough Borough Council awarded a two-stage Design & Build contract to Balfour Beatty for the £13.5m project to stabilise the coastal cliffs. This works involved:
i. A pile array comprised of 206 piles, each 25m in length, installed along the rear of the Spa complex into the underlying bedrock. This was complemented with associated cliff drainage and addresses the deep-seated failure mechanism;
ii. Over 4,500 soil nails, each up to 25m in length, installed to ‘pin’ the cliff in position and stabilise shallow and superficial failure surfaces. A layer of geomesh was overlaid, and a soil containment system fixed for placement of topsoil and
grass seeding. This was coupled with low level retaining walls and re-grading of upper slopes and further cliff drainage measures to address shallow-seated instabilities; and
iii. Works to rehabilitate the existing retaining wall along the crest of the cliffs at the Esplanade.
Towards the end of the works, fencing, footpath surfacing, streetlights and landscaping were installed to restore and enhance the historic South Cliff Gardens in a manner that was sympathetic to their Grade II listed garden status. This enabled significant further inward investment from the Heritage Lottery Fund for wider restoration works to these nationally important gardens.
Overall, the scheme greatly benefits society by significantly reducing risks from cliff instability to over 400 properties and business in Scarborough’s South Bay, including the nationally-important Grade II listed Spa building. This significantly reduces the constant stress that people had been living under since the infamous Holbeck Hall cliff landslide along the nearby coast in the 1980s. There had been long-standing fears amongst the community that a similar deep-seated landslide could occur behind the Spa, causing catastrophe and potentially fatalities.
The completed scheme is a significant aspect of Scarborough Borough Council’s coastal risk management portfolio and represents a major civil engineering achievement.