NOTICE: INFORMATION PROVIDED ON THIS WEBSITE MAY BE INCOMPLETE. PLEASE READ THIS DISCLAIMER.
This information has been provided at the request of the Governor's Office of Emergency Services (OES)
June 17, 1998
The California Office of Emergency Services (CA OES) dam failure inundation mapping and emergency procedure program only applies to dams meeting specific size requirements making them subject to the jurisdiction of the State of California. Dams owned by agencies of the United States government are not under the jurisdiction of this program.
The legislative intent of the original CA OES seismic safety of dams legislation (SB 896, of 1972) was to establish emergency procedures for the evacuation and control of populated areas below dams which could be used to save lives and reduce injury in the event of a dam failure. As a result of this legislation, CA OES established the dam failure inundation mapping and emergency procedure program. This program encompasses inundation mapping, inundation map waivers, and emergency procedures.
Dam owners submit inundation maps to CA OES for review and approval in accordance with guidance issued by CA OES. Inundation maps represent the best estimate of where water would flow if a dam failed completely and suddenly with a full reservoir. However, later downstream changes, such as major land contour alterations, may affect the actual inundation pathway. Copies of the approved inundation maps are sent to the city and county emergency services coordinators of affected local jurisdictions.
Dam owners may be granted two-year waivers from the inundation mapping requirement. Waivers require that the areas, within which death or personal injury would result from the failure of a dam, can be identified and that adequate emergency procedures can be developed without an inundation map. This determination is made based on an on-site inspection by CA OES, in consultation with the local jurisdiction. If a waiver is granted, local jurisdictions are required to report any development in a delineated hazard area to CA OES.
Based upon approved inundation maps, or the delineated areas, cities and counties with territory in the mapped areas are required to adopt emergency procedures for the evacuation and control of populated areas below the dams.
The California Department of Water Resources has a separate Division of Safety of Dams dedicated to addressing the structural and operational safety of dams.
This file last modified on: Monday, November 17, 2003.