Water and Energy International
Year : 2022, Volume : 65r, Issue : 2
First page : ( 6) Last page : ( 11)
Print ISSN : 0974-4207. Online ISSN : 0974-4711.

Impact of Climate Change and Time dependent Hazards on dam Safety

Wieland Martin¹

¹Chairman, ICOLD Committee on Seismic Aspects of Dam Design, c/o AFRY Switzerland Ltd., Zurich, Switzerland

Online Published on 21 June, 2022.

Abstract

This paper is concerned with the impact of climate change and other hazards on the safety of large dams. It is typical for most hazards from the natural environment, man-made environment and site-specific and project-specific hazards that they depend on time. Similarly, the safety criteria are also changing with time. Therefore, dam engineers have always been concerned with such changes and climate change is no exception. Because of these changes, which cannot be predicted at the time a dam is being built, safety evaluations have to be carried out periodically. Well-designed, well-constructed and well-maintained storage dams that satisfy current safety criteria have a long lifespan and therefore safety assessments must be carried out repeatedly. The reservoir may have a similar lifespan as the dam, but the use of the stored water will change with time and the useable reservoir volume may decrease due to sedimentation, whereas the basic function of the dam remains unchanged. The main hazards due to climate change that are addressed in this paper are floods, floating debris, mass movements and debris flows into the reservoir, which may endanger the safety of a dam. To account for all these time-dependent changes a resilient dam should be the solution, i.e., the dam should have certain reserves beyond the safety flood or safety evaluation earthquake. Mass movements are among the main climate change hazards for dams, but strong earthquakes can trigger many more landslides and rockfalls than the worst meteorological events. This means that certain hazards are more critical than climate change. Due to changes in safety standards in design codes, the design loads have been increased continuously for weather-affected loads and actions when climate change was not an issue.

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