USACE Publishes Policy Update for Inundation Maps and the National Inventory of Dams

Headquarters, USACE
Published Jan. 25, 2021

The U.S. Army Corps of Engineers published Engineer Circular 1110-2-6075, “Inundation Maps and Emergency Action Plans and Incident Management for Dams and Levee Systems,” in October. This update allows for the use and public dissemination of inundation maps in emergency action plans (EAP) and the National Inventory of Dams (NID), It also provides the dam safety community access to critical information about residual flood risks from USACE dams and levees.

“USACE-generated inundation maps assist with modeling, exercise scenarios, emergency planning, and community preparedness. USACE also supports our partners through programs such as Floodplain Management Services, Silver Jackets, and Planning Assistance to States to develop inundation maps for non-USACE infrastructure to support flood preparedness activities,” said Lt. Gen. Scott A. Spellmon, USACE Commanding General and U.S. Army Chief of Engineers.

Access to USACE-generated inundation maps was previously restricted to emergency management authorities and other federal agencies only after signing a non-disclosure agreement.  This policy update will increase transparency by effectively characterizing flood risk to stakeholders and the public, establish an agency-wide standard for the application of inundation maps in EAPs, while maintaining safeguards for sensitive information.

Sharing inundation maps through the National Inventory of Dams and public engagement will provide the best information available for the public and communities to understand potential flood risk from USACE dams and empower them to make more-informed decisions during flooding events.

“Engineer Circular 1110-2-6075 provides consistency for USACE EAP and EAP inundation map products to promote common understanding and ease of use for these resources. For example, the guidance promotes a consistent approach for organizing and implementing EAPs; communicating, creating and labeling inundation maps; conducting exercises; addressing security provisions; reviewing and approving plans and resources; reporting incidents; and authorities and responsibilities,” said Spellmon.

An EAP is required for all USACE-operated and maintained dams and levees. In the event of a breach or non-breach flooding, the EAP is a comprehensive planning tool that shapes advanced coordination and evacuation plans and facilitates timely emergency response activities.

National Inventory of Dams

USACE maintains and publishes the publicly accessible online NID database,, in cooperation with the Association of State Dam Safety Officials (ASDSO), the states and territories, and federal dam-regulating agencies. The NID is the central component in sharing information on approximately 90,580 federal and non-federal dams nationwide, including approximately USACE’s 740 dams. Information in the NID includes location, size, type, inspection, regulatory facts and other technical data for each dam that meets the criteria to be included in the NID.

The addition of inundation map data to the NID ensures a common operating picture and helps communities both upstream and downstream manage risk. Access to inundation maps on the NID webpage is scheduled for late 2021. Individuals requiring access to USACE dam project EAP inundation maps prior to this should contact their local USACE district office.

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Adoratia Purdy

Release no. 21-007