In April 1977, President Carter issued a memorandum directing the review of federal dam safety activities by an ad hoc panel of recognized experts. In June 1979, the ad hoc interagency committee on dam safety (ICODS) issued its report, which contained the first guidelines for federal agency dam owners. The Federal Guidelines for Dam Safety (Guidelines) encourage strict safety standards in the practices and procedures employed by the federal agencies or required of dam owners regulated by the federal agencies. The Guidelines address management practices and procedures but do not attempt to establish technical standards. They provide the most complete and authoritative statement available of the desired management practices for promoting dam safety and the welfare of the public. To supplement the Guidelines, ICODS prepared and approved federal guidelines in the areas of emergency action planning; earthquake analysis and design of dams; selecting and accommodating inflow design floods for dams; and glossary of terms. These publications, based on the most current knowledge and experience available, provided authoritative statements on the state of the art for these important technical areas involving dam safety. In 1994, the ICODS Subcommittee to Review/Update Federal Guidelines began an update to these guidelines to meet the new dam safety challenges and to ensure consistency across agencies and users. In addition, the ICODS Subcommittee on Federal/Non-Federal Coordination developed a new guideline on hazard potential classification systems for dams. With the passage of the National Dam Safety Program Act of 1996, Public Law 104-303, ICODS and its Subcommittees were reorganized to reflect the objectives and requirements of Public Law 104-303. In 1998, the newly convened Guidelines Development Subcommittee completed work on the update of the following guidelines: Federal Guidelines for Dam Safety: Emergency Action Planning for Dam Owners, FEMA 64, October 1998, reprinted April 2004; Federal Guidelines for Dam Safety: Selecting and Accommodating Inflow Design Floods for Dams, FEMA 94, October 1998, reprinted April 2004; Federal Guidelines for Dam Safety: Hazard Potential Classification Systems for Dams, FEMA 333, October 1998, reprinted April 2004. With the amendment of the Act into the National Dam Safety and Security Act of 2002, Public Law 107-310, former ICODS Subcommittees were reorganized under the National Dam Safety Review Board (NDSRB). In 2004, two task groups finalized the ongoing work of the previous Subcommittee on the update of the following guidelines: Federal Guidelines for Dam Safety: Glossary of Terms, FEMA 148, printed April 2004; Federal Guidelines for Dam Safety: Earthquake Analyses and Design of Dams, FEMA 65, printed May 2005. The publication of these guidelines marks the final step in the review and update process. In recognition of the continuing need to enhance dam safety through coordination and information exchange amongst federal and state agencies, the NDSRB will assume responsibility for maintaining these documents and establishing additional guidelines that will help achieve the objectives of the National Dam Safety Program. The NDSRB has established a task group and work is currently underway to prepare an update to the ground motions portion of this document with new research and methodologies.