Accounting for natural disasters in dam design and dam safety

Abstract

Large earthquakes (M8) have occurred in Nepal at least once a century since the first recorded event in 1200 AD. In April and May of 2015, Nepal was devastated by the Gorkha and Dolakha earthquakes. Thousands were impacted and about 20% of the hydroelectric capacity in the country lost. At the time of this event, there were no formal and accepted methods for selecting the standards that a dam must satisfy to be “safe” either nationally or provincially that, potentially, could have reduced these impacts.

This paper describes the preparation of national dam safety guidelines that were specifically tailored to recognize the natural hazards that are unique to mountainous countries such as Nepal. Given the importance of these hazards, a unique new guideline was developed to account for mass movement hazards (GLOFs, LDOFs, debris flows, landslides) that was linked to the Hazard Classification System developed for Nepal. A discussion on the Natural Hazards that impact dam safety in Nepal and the new guideline designed to help mitigate the impact of these hazards is presented.