Risk Reduction Alternatives Analysis – An Essential Phase of Risk-Informed Decision Making
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In a risk‐informed dam safety framework, risk is characterized and risk‐informed decisions are made. Risk reduction activities are then implemented.

At the heart of this framework is risk‐informed decision making (RIDM). RIDM largely involves two principal questions:

Question 1: Should action be taken to reduce risk?
Question 2: If yes, what actions should be taken to reduce risk?

RIDM practice associated with question 1 has advanced significantly within the industry and become more widespread. RIDM practice associated with question 2 is still evolving, and practice is inconsistent across the industry. The risk‐informed decision-making process, not the traditional engineering decision-making process, should be applied to the question of what actions should be taken. Selecting appropriate risk reduction actions involves further risk characterization and RIDM, which often conflicts with the apparent traditional engineering path forward. Further, because dam facilities are usually complex systems with multiple interdependent potential failure modes (PFMs), it can be inappropriate to select risk reduction measures on evaluation of individual and isolated PFMs (PFM-by-PFM basis).

Rather, to answer question 2 in RIDM (what actions should be taken?), a risk reduction alternatives analysis (RRAA) should be performed. This paper offers a scalable method that formulates alternatives based on RIDM criteria and sets up a risk-informed decision for selecting risk reduction modifications. This RRAA involves:

(1) Identifying the RIDM criteria to be used to inform selection of an alternative;
(2) Developing alternatives that might be implemented at the facility, with each alternative defined as a proposal for an entire set of modifications for implementation at a facility;
(3) Evaluating how effective each alternative would be in addressing the collection of PFMs/risks at the facility (i.e., degree of risk reduction) and evaluating the implementation burden of each alternative (e.g., cost, service disruption); and
(4) Making a risk‐informed decision to select an alternative.

Publication Summary

  • Geosyntec Authors: Derek Morley, Brian Martinez, Joe Goldstein
  • All Authors: Derek Morley, Brian Martinez, Joe Goldstein
  • Title: United States Society on Dams (USSD) 2022 Annual Conference
  • Event or Publication: Event
  • Practice Areas: Dams; Dam Safety
  • Citation: United States Society on Dams (USSD) 2022 Annual Conference and Exhibition at the Town and Country Resort in San Diego, California on April 11 through 14, 2022.
  • Date: Wednesday, April 13 at 4:05 p.m. PDT
  • Location: San Diego, California
  • Publication Type: Platform Presentation