2013 nwha conference ferc’s risk-informed decision making doug johnson – regional engineer -...

2013 NWHA CONFERENCE

FERC’S RISK-INFORMED FERC’S RISK-INFORMED DECISION MAKINGDECISION MAKING

Doug Johnson – Regional Engineer - PortlandDoug Johnson – Regional Engineer - Portland

From PFMA to Risk From PFMA to Risk AssessmentAssessment

834 High Hazard Potential

234 Significant Hazard Potential

In the Beginning… for FERCIn the Beginning… for FERC

Risk Assessments begin with a Risk Assessments begin with a Potential Failure Mode Analysis (PFMA) Potential Failure Mode Analysis (PFMA)

The FERC first began using risk in a The FERC first began using risk in a dam safety context in 2003 when it dam safety context in 2003 when it documented the PFMA process into its documented the PFMA process into its dam safety guidelines (Chapter 14).dam safety guidelines (Chapter 14).

PFMAPFMA

A PFMA is an exercise to • identify all potential failure modes under static

loading, normal operating water level, flood, and earthquake conditions including all external loading conditions for water retaining structure

• assess those potential failure modes of enough significance to warrant continued awareness and attention to visual observation, monitoring and remediation as appropriate.

PFMA (cont.)PFMA (cont.)

PFMs are developed by the core teamPFMs are developed by the core team Likely and unlikely factors affecting Likely and unlikely factors affecting

the chances of occurrence are the chances of occurrence are documented.documented.

PFMs are categorized by level of PFMs are categorized by level of seriousness.seriousness.

PFMA ProgressPFMA Progress

Since the program was initiated all Since the program was initiated all high hazard potential dams have high hazard potential dams have been analyzed.been analyzed.

Significant and Low hazard potential Significant and Low hazard potential dams are still in progress.dams are still in progress.

What is Risk-Informed Decision What is Risk-Informed Decision Making (RIDM)Making (RIDM)

Decision-making, which has as an Decision-making, which has as an inputinput the the results of a risk assessment. results of a risk assessment.

Risk information will play a Risk information will play a key rolekey role in decisions in decisions related to dam safety but will not be the only related to dam safety but will not be the only information to influence the final decisions.information to influence the final decisions.

RIDM involves a RIDM involves a balancingbalancing of social and other of social and other benefits and the residual risks.benefits and the residual risks.

Extension of PFMA processExtension of PFMA process

PFMAs detail how a dam might failPFMAs detail how a dam might fail PFMAs do not directly consider the PFMAs do not directly consider the

scope of potential consequencesscope of potential consequences PFMAs do not estimate the likelihood PFMAs do not estimate the likelihood

of an adverse eventof an adverse event RIDM will consider these items RIDM will consider these items

Why Risk?Why Risk?

Tolerable RiskTolerable Risk

Risk society is willing to live with in order Risk society is willing to live with in order to secure certain benefits,to secure certain benefits,

Risk society does not regard as negligible Risk society does not regard as negligible or something it might ignore,or something it might ignore,

Risk that society is confident that are Risk that society is confident that are being properly managed by the owner, being properly managed by the owner, andand

Risk the owner keeps under review and Risk the owner keeps under review and reduces still further as practicable.reduces still further as practicable.

Joint Federal Risk GroupJoint Federal Risk Group

Includes Reclamation, Army Corps, Includes Reclamation, Army Corps, TVA, FEMATVA, FEMA

A common federal approach to RiskA common federal approach to Risk Standards for risk reduction: Standards for risk reduction:

Governance vs. ToleranceGovernance vs. Tolerance

RIDM Engineering GuidelinesRIDM Engineering Guidelines

1.1. Concrete DamsConcrete Dams2.2. Embankment DamsEmbankment Dams3.3. Internal Erosion and PipingInternal Erosion and Piping4.4. Spillway Gates and Outlet WorksSpillway Gates and Outlet Works5.5. Operational Issues, SCADAOperational Issues, SCADA6.6. Hydrologic Hazard AnalysisHydrologic Hazard Analysis7.7. Probable Seismic Hazard AnalysisProbable Seismic Hazard Analysis8.8. ConsequencesConsequences9.9. Risk AnalysisRisk Analysis10.10. Risk AssessmentRisk Assessment

Benefits to Owners and FERC Benefits to Owners and FERC

Provides a process to better understand Provides a process to better understand and quantify potential failure modes;and quantify potential failure modes;

Identifies previously unidentified failure Identifies previously unidentified failure modes with high risk, in particular, non-modes with high risk, in particular, non-traditional failure modes;traditional failure modes;

Builds on the work completed in PFMAsBuilds on the work completed in PFMAs Provides a means to compare the safety of Provides a means to compare the safety of

different dams using a common basis - different dams using a common basis - risk;risk;

Benefits to Owners and FERCBenefits to Owners and FERC Improves understanding of the uncertainty Improves understanding of the uncertainty

and variability in traditional analyses;and variability in traditional analyses; Provides a way to understand the risk Provides a way to understand the risk

associated with a single dam or an entire associated with a single dam or an entire inventory of dams;inventory of dams;

Allows evaluation of risk reduction Allows evaluation of risk reduction alternatives and effectively reduces the risk alternatives and effectively reduces the risk regulated dams pose to the public in regulated dams pose to the public in quantifiable and defensible terms; quantifiable and defensible terms;

Focuses resources on those structures that Focuses resources on those structures that pose the greatest risk. (FERC Strategic Plan)pose the greatest risk. (FERC Strategic Plan)

Final ThoughtsFinal Thoughts

FERC RIDM program will proceed in FERC RIDM program will proceed in parallel with deterministic methods parallel with deterministic methods for the near future.for the near future.

Phased approach to implementation.Phased approach to implementation. Dams requiring full quantitative risk Dams requiring full quantitative risk

will be few.will be few. In longer run, PFMA process may be In longer run, PFMA process may be

expanded to include Qualitative Risk expanded to include Qualitative Risk AssessmentAssessment