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DSPMP/PFMA - Improving FERC's Dam Safety Program

Background

Dam Safety Performance Monitoring Plan Description
The Engineering Guidelines, Draft Chapter 14 titled, "Dam Safety Performance Monitoring Program" provides recommended procedures and criteria to develop a Performance Monitoring Program based upon "potential failure mode thinking" which assists in reviewing and evaluating the safety and performance of water retaining structures regulated by FERC.

The Performance Monitoring Program uses the current Instrumentation and Monitoring Program (see Chapter 9 of the Engineering Guidelines) and updates it as appropriate consistent with potential Failure Modes Analysis.
The procedure includes:

  • A potential Failure Modes Analysis (PFMA); and
  • Development of the Performance Monitoring Program (PMP).

The PFMA and PMP are cutting-edge tools to improve the safety of dams in a cost-effective manner. The concept is to focus on identified, targeted areas of potentially-serious and more-likely dam safety deficiencies so that limited financial resources can be used most effectively in ensuring dam safety and public safety.

A PFMA is an informal identification and examination of "potential" failure modes for an existing dam by a team of persons. It is based on a review of all existing data and information, first hand input from field and operational personnel, site inspection, completed engineering analyses, identification of potential failure modes, failure causes and failure development and an understanding of the consequences of failure.

The PFMA is intended to provide enhanced understanding and insight on the risk exposure associated with the dam. This is accomplished by including and going beyond the traditional means for assessing the safety of a dam by intentionally seeking input from the diverse team of individuals who have information about the performance and operation of the dam.

The PFMA utilizes all of the available data and information as well as standard engineering analyses of an existing dam. It should be viewed as a supplement to the traditional process in which a dam's safety is judged by its ability to pass standards-based criteria for stability and other conditions.

The PFMA is conducted jointly by the licensee, Independent Consultant and FERC staff. This process is guided by a facilitator. For the most part the PFMA is a one-time exercise. Due to its "question asking approach" the potential failure mode examination process:

  • Enhances the dam safety inspection process
  • Enhances and focus the visual surveillance and instrumented monitoring program
  • Identifies shortcomings or oversights in data, information or analyses necessary to evaluate dam safety and a potential failure mode
  • Helps identify the most effective dam safety risk reduction measures.


Based upon the results of the PFMA, the Performance Monitoring Program is developed. The PMP defines the appropriate monitoring for the water retaining structures based upon the PFMA.

An integral part of the PMP is the integration of the licensee's operation, maintenance and inspection programs. In addition, the Part 12D Independent Consultant's inspection and report and the FERC's inspection program will also be focused using the PFMA and the PMP.

The integration of a PFMA with a PMP, results in a very efficient and effective dam safety program. With the knowledge, vision, and understanding gained from a PFMA, the PMP is highly effective. The added value to dam safety includes:

  • Uncovering data and information that corrects, clarifies, or supplements the understanding of potential failure modes and scenarios
  • Identifying the most significant potential failure modes;
  • Identifying risk reduction opportunities;
  • Focusing instrumentation, monitoring and inspection programs so they provide information about the potential failure modes that present the greatest risk to the safety of the dam;
  • Developing operating procedures to assure that there are no weak links that could lead to mis-operation failures.
  • Enables dam owners' financial resources to be applied to dam safety in an appropriately-targeted, cost-effective manner.

The interrelationship of dam safety program elements using a potential Failure Modes Analysis approach is outlined below.

  1. Daily routine inspections / observations - Persons performing the routine inspections or observations should be provided with background information on the potential failure modes identified for the site along with a performance monitoring and visual surveillance plan for each potential failure mode. The licensee is responsible for performing these inspections and for coordinating with the FERC to resolve any issues discovered during the inspections. After a discussion with FERC, a decision will be made whether any action such as monitoring, analysis, or repairs needs to be implemented.

  2. Licensee operation and maintenance inspection and training programs - Those persons performing the routine inspections or observations should be provided with background information on the potential failure modes identified for the site along with a performance monitoring and visual surveillance plan for each potential failure mode. The licensee is responsible for ensuring that its personnel are properly trained and remain current in the knowledge of proper operation and maintenance of the project. Any deficiencies in these matters need to be coordinated with FERC.

  3. FERC operation inspection - FERC will perform this inspection. After the inspection, FERC will discuss with Licensee any concerns found during the inspection. The discussion will also include various items relating to the project, such as the operation and maintenance of the project, any instrumentation and monitoring currently at the project and the emergency action plan that is in place at the plant.

    If during the FERC operation inspection a new potential failure mode is identified, the D2SI-RO will provide this information to the licensee in the Operation Inspection follow-up letter. If the potential failure mode needs to be evaluated prior to the next Part 12D inspection, a schedule will be established to accomplish this. If it is determined that evaluation of the potential failure mode may be delayed until the next Part 12D Inspection, the D2SI-RO will include the request in its one year reminder letter to the licensee.

  4. Part 12D Inspection - The Consultant will be provided the current PFMA (initial plus any updates). The Consultant will perform this inspection with proper coordination with the licensee. Any concerns or issues will be discussed with the licensee and FERC. The PFMA will then be updated accordingly by the consultant.

  5. Joint Part12D and FERC Operation Inspection - Every 5 years a joint inspection will be made by the Consultant and FERC with proper coordination and support of the licensee.

    The first to 1 day will be devoted to a meeting between the necessary licensee representatives and the consultant to review the project history including any past or current deficiencies, completed remediation, special investigations previously completed, instrumentation, etc. The group will discuss the development of performance parameters and potential failure modes.

    The FERC's operation inspection and the consultant's Part 12D inspection, though conducted concurrently, will take place and be done independently. It is intended that the inspections allow opportunities for discussions of any problem areas and other important items that might come up.

    Upon completion of the inspections, the group will meet to discuss any additional thoughts concerning the performance parameters and the potential failure modes to be developed.

    The performance parameters and the potential failure modes will be prepared by the consultant and included as appendices to the Part 12D report.

  6. FERC Construction and Special Inspections - FERC will be responsible for performing and documenting these inspections on as needed bases with proper coordination with the Licensee.

  7. Licensee Initiated and FERC Directed Analyses and Evaluations - If during the operation or inspection of the project a concern or issue is raised that requires additional studies it is the responsibility of the party identifying the concern or issue to initiate a discussion with all parties involved. If policies change as to the design standards, FERC may direct further analyses and evaluation to determine if a deficiency exists.

  8. Recommended Action
    Performance monitoring - If after the PFMA a concern or issue is thought to require monitoring to determine if the dam's performance is at risk, it will be the responsibility of the Licensee to install, monitor, and evaluate monitoring instrumentation with the coordination of the Consultant and FERC.

    Modification - If after the PFMA a modification is required, it will be the responsibility of the Licensee to design and make the necessary modifications, with the coordination of the Consultant and FERC.

DSPMP/PFMA

Improving FERC's Dam Safety Program

 


Updated: June 28, 2010