Engineering Guidelines for the Evaluation of Hydropower Projects: 4

The Division of Dam Safety and Inspections, Office of Energy Projects, has provided more detail and has included additional practical dam safety information as well as information on dam safety experiences in Chapter IV, Embankment Dams of the Federal Energy Regulatory Commission, Office of Energy Projects, Division of Dam Safety and Inspections Dam Safety Engineering Guidelines.

The draft guideline, though not completed, is available for use and preliminary review. This draft will be further updated to include the state of the practice in analyzing dams subject to liquefaction during the design earthquake. The chapter provides useful information on the historical causes of failures and near-failures of embankment dams that every dam safety engineer should be cognizant of. This knowledge of precedent on what has worked and not worked is an important consideration to use in embankment dam design and inspection.

Included in the chapter is a detailed review of "drained" and "undrained" analyses (formerly referred to as "effective stress" and "total stress" analyses). This discussion will help the engineer to understand the differences between the two types of analyses and the appropriate cases for use of each. The development and selection of appropriate shear strength parameters are thoroughly discussed with regard to loading condition and analysis type. Detailed examples are presented. The rapid drawdown loading condition section has also been expanded. The appendices and text of this chapter will be further developed and posted on the FERC web site as the chapter is completed.

We encourage the preliminary review of the draft guideline and request any comments and suggestions to be sent to James McHenry or Joseph Mueller.

Chapter 4 – Embankment Dams (Revised Draft Version)