Debris flows from the perspective of the Scottish Highlands

This paper presents a review of observations and investigations of the occurrence and setting of recent debris flow events that have affected road links in the North West and Central Highlands of Scotland. In particular, debris flows on the A890 Stromeferry Bypass and the A887 Invermoriston roads are presented as case histories. Additional, less formal observations from other debris flows in Scotland are included for comparison. Common features of the debris flows and their setting are apparent in all cases, as are other localised anthropogenic, geotechnical and geomorphological factors. These features are discussed in the light of causes, indicators of areas potentially susceptible to debris flow activity, and possible remedial and preventative measures. Experiences of debris flow prediction and assessment methods are given along with practical remedial and risk management measures.