Seismic Risk of a Co-Located Portfolio of Dams – Effects of Correlation and Uncertainty

This paper looks at issues associated with estimating risk of seismically initiated failure (uncontrolled release of the reservoir) of dams that are co-located with respect to each other and the location of future earthquakes. These may be dams on the same river or dams regionally co-located on different rivers. Failure of one or more dams could lead to serial dam failures on a single river; or produce regional consequences on multiple rivers. With the increased interest in the use of risk-based methods to evaluate the safety of dams, this paper looks at the effect of sources of correlation or dependence on the risk to a portfolio of co-located dam projects. Results of a parametric study that evaluates a number of these factors are described. The consequences of a seismic event are not limited to dam failure and downstream inundation. Since it is far more likely that dams may be damaged (as opposed to failing) during a seismic event, these ‘other’ consequences include loss of function (i.e., hydropower production, water supply, etc.) as reservoirs may need to be lowered following the earthquake.