Page - 36 - in Book of Full Papers - Symposium Hydro Engineering

Table 2 Evacuation Travel Times TRAVEL TIME (HOURS) % of EVACUEES < ½ hour 14% ½ hour – 1 hour 33% 1-2 hours 10% 2-3 hours 19% 3-4 hours 2% 4-5 hours 6% 5-10 hours 3% > 10 hours 13% 4. LESSONS LEARNED The Oroville emergency evacuations provided some new lessons, and reinforced many existing lessons, for emergency managers. The list below is not meant to be exhaustive, but highlights some of the more important ones in the view of the authors. Many of the lessons reinforced by this event are describe by the authors in previous work [1]. 4.1. LACK OF INUNDATION MAPS Perhaps the most important lesson learned, or in this case reinforced, was the value of having inundation maps for a wide range of potential scenarios available for emergency managers at a moment’s notice. As described above, the situation on February 12 was relatively calm leading up to the emergency, and nobody was concerned about a potential breach of the Emergency Spillway. Within a couple hours of recognizing erosion that could impact the stability of the Emergency Spillway, local emergency managers were sending out evacuation notices with little understanding of the area at risk. Their only available information was for a complete failure of the main dam embankment, which would have led to flows that would be orders of magnitude higher than were expected from breach of the Emergency Spillway. This short amount of time does not allow even the most experienced hydraulic engineers to model properly the scenario in question. Therefore, it is important to have inundation maps available covering a wide range of potential breach and non-breach scenarios as part of the EAP. DWR was already aware of the need for additional maps for Oroville and other dams in their portfolio. They were already in the process of creating a library of inundation maps to cover a wider range of breach and non-breach scenarios. If 36