Experts have recognised the widespread occurrence of slope instability worldwide and it is reasonable to conclude that the costs arising from slope failures (both coastal and inland) are likely to escalate in the future, as a result of both climate change impacts and increasing development pressures, unless active measures are implemented in terms of landslide mitigation and hazard management in the future. The basis for this must be effective land-use planning that has been developed after a thorough assessment of existing and potential hazard.
The relevance of natural and man-made risks to the planning system is already recognised in planning guidance published in a number of countries. It is in the interests of all those involved, ranging from local authorities to insurance companies and other stakeholders, to ensure that guidance is realistic and appropriate in the way that it considers risk.
The Isle of Wight, located approximately 6km off the south coast of England, is famous for the wide range of coastal scenery to be found within a comparatively small area. Measuring 40km from east to west and 25km from north to south, the island coastline incorporates extensive coastal landslides. A wide range of geotechnical studies and investigations have taken place on the Isle of Wight, particularly along its southern coast and this work is on-going with major civil engineering projects are planned between 2001-2004. More specifically:
- The town of Ventnor is situated in the Isle of Wight Undercliff, the largest urban landslide complex in north-western Europe. Here instability is being managed by the Isle of Wight Council engineers, planners, building control, utilities, estate agents, insurers, local residents and businesses;
- Blackgang Chine is a site of rapid and active coastal recession, landsliding and managed retreat of development, including a monitoring and early-warning system protecting a significant tourism asset - Blackgang Chine Theme Park. A rapid renewal of landslide activity occurred at Blackgang in 1994 following exceptional antecedent rainfall.
- Along the open and retreating south-west coast of the Isle of Wight sections of the essential coastal road and footpath are being realigned.
These examples illustrate different options and measures being considered for evaluating and mitigating risks and hazards.