Status of Proposed New Chapters and Proposed Revisions

Existing Chapters

1. General Requirements
2. Selecting and Accommodating Inflow Design Floods for Dams
3. Gravity Dams
4. Embankment Dams
5. Geotechnical Investigations and Studies
6. Emergency Action Plans - Revised November 1998
7. Construction Quality Control Inspection Programs
8. Determination of the Probable Maximum Flood
9. Instrumentation and Monitoring
10. Other Dams
11. Arch Dams
12. [Penstocks and Water Conveyance Facilities - Under development]
13. [Evaluation of Seismic Hazards - Draft Posted on FERC Website]
14. Dam Safety Performance Monitoring Program (DSPMP)

Important Notes, Recent Issuances, and Revisions (2002)

Gravity Dams

• Reduced safety factors against sliding for zero cohesion analyses.
• Detailed methods provided to consider the hydrodynamic forces acting on spillways during flood loading.
• Revised analysis methodology on earthquake loading with new acceptance criteria.
• Final Revised Chapter 3 issued in October 2002.

Emergency Action Plans 

• The new Federal Guideline for EAPs was published in October 1998 and is available from FEMA. FERCs EAP Chapter 6 was revised to be consistent with the new Federal Guidelines and issued in November 1998.
• Revisions were fairly minor formatting changes; however, the importance of having a spillway notification plan for non-emergency releases was emphasized.

Determination of the Probable Maximum Flood (2001)

• A reference document was prepared to provide information on the proper use of hydrologic parameters, equations, and methodologies used in the PMF Chapter.
• Efforts to understand the sensitivity of using the STATSGO data and to adequately assign infiltration rates in computing PMF runoff.
• Revisions to include state-of-the-art hydrology techniques and advancements.
• Better descriptions of the need for calibration and verification of hydrologic models.
• Final revised Chapter 8 issued September 2001

New Chapters Under Preparation

1. Penstocks and Water Conveyance Facilities - Chapter will be developed to focus on operation, maintenance, inspection and potential failure mode analysis. Licensees and Consultants will be requested to join the task group developing the chapter.
2. Evaluation of Seismic Hazards - A draft has been posted to the FERC Website for review. Some sections are under development and it is anticipated that these sections will be added to the draft sometime this summer. Currently we have Dr. I. M. Idriss and Dr. Ralph J. Archuleta participating in the development of the guideline.

Proposed Revisions to Existing Chapters

Embankment Dams

• Incorporate current state-of-the-practice methodologies for both static and dynamic loading evaluations and analyses, particularly when evaluating liquefaction potential.
• Incorporate the operational experience of world-wide dam failures and incidents involving such topics as seepage and piping of embankments and foundation material.
• Those portions of the guideline that pertain to static loading conditions are expected to be drafted by the fall.