Development of A Risk-Informed Approach To The Seismic Evaluation of Hydropower Projects - Methodology

摘要

Approximately ten years ago Bakun, et al. presented new information about the magnitude and location of the 1872 Chelan earthquake. This work prompted the Federal Energy Regulatory Commission (FERC) to re-evaluate the earthquake ground motions that could be expected at hydropower projects in the Mid-Columbia region. At the same time, the FERC was laying the groundwork to move toward adopting a risk-informed regulatory approach to dam safety. For these reasons, they recommended the Mid-Columbia public utility districts (PUD), Chelan, Grant and Douglas counties, work together to conduct a probabilistic seismic hazard analysis (PSHA) for the region. Now that the FERC has formally committed to incorporating risk-informed decision making into its dam safety program, this paper addresses two fundamental questions: 1. How can the results of a PSHA be used in the seismic safety evaluation of hydropower projects? and 2. How can risk-informed seismic evaluations of hydropower projects be carried out in the context of the FERC's commitment to incorporate risk-informed decision-making in its regulatory processes? Working with the FERC, Chelan and Grant County PUD's initiated a project to develop a risk-informed seismic evaluation process to address these questions. As part of this effort they are currently evaluating several project sub-systems with the ultimate intent of implementing the methodology for their entire projects. This paper summarizes the risk-informed seismic project and some of the lessons and insights that have been learned.