Responding to Emergency: The Role of the U.S. Army Corps of Engineers in Support of the Nation [open pdf - 31KB]
"Although emergency preparedness and response is primarily a state and local responsibility, in instances when the nature of the disaster exceeds the capabilities of state and local interests, the Corps of Engineers stands ready to help save human life, prevent immediate human suffering, and mitigate property damage. The geographically diverse location of Corps of Engineers offices nationwide assures an immediate response to disasters in any area. The Corps is aligned by drainage basins into 8 regional divisions. The divisions are further aligned by smaller drainage basins into 38 districts. During emergencies the division responsible for the affected region coordinates and commands the Corps of Engineers response."
U.S. Army Corps of Engineers San Francisco District: http://www.spn.usace.army.mil/