We have cleared and re-profiled the area which was affected by the slip in 2012, in addition to clearing trees, and maintaining highway drains. We have concentrated our efforts on monitoring the highway, associated drainage systems and retaining walls. We have also recently installed monitoring equipment within existing and new boreholes on council land and by agreement with owners on some privately owned land to measure ground water and ground movements and are currently undertaking Lidar surveys- new work has been carried out in the wake of each report that we have commissioned.
In 1987 and 1989 reports into the Pantteg and Godre’r Graig landslips commissioned by the former Lliw Valley Borough Council produced a Hazard and Risk Assessment Plan.
In 1997, following local government reorganisation, Neath Port Talbot Council carried out its own review into the landslip areas resulting in a revised Hazard Risk Zone Map.
Following a landslip in December 2012, Neath Port Talbot Council commissioned Jacobs Engineering UK to review and update the existing risk assessment of the landslip areas. This report was published in January 2014 including an updated Hazard Risk Map.
The report made a number of recommendations for risk reduction measures, the majority of which were implemented. The report also recommended a further quantitative assessment including the implementation of systems to record and assesses rates of ground movement.
In 2015 Neath Port Talbot Council commissioned Earth Science Partnership to undertake a geotechnical assessment and advise the council on quantitative assessment methods and a suitable monitoring and management regime for the landslip area.
The report (2016) recommended the development of a formal management strategy based on long term monitoring and assessment of quantitative data such as ground water levels and topographical data from LiDAR surveys (a technique using laser light to monitor ground and surface movements.
The recommendations to develop a formal management strategy of the landslip area are being implemented; for example boreholes are in place within which data-loggers are collecting critical information and the first LiDAR survey has been completed.