Emergency evacuation zones

Geographical areas delineated in inundation areas downstream from a dam (hazard generator) that define the potential area of impact and allow prioritizing evacuation activities based on proximity of the populations at risk to the hazard in terms of distance and floodwave travel times.

• Emergency Evacuation Zone I - The emergency evacuation zone immediately below a dam and located on both sides of the river or stream. Generally, it is recommended that this zone extend to a distance equivalent to a combination of floodwave travel time of 0-15 minutes and/or a warning time of 0-4 hours, whichever is most conservative. May be labeled as immediate response zone, evacuation zone I, evacuation zone A, or other appropriate name.
• Emergency Evacuation Zone II - The second emergency evacuation zone, beyond emergency evacuation zone I and also located on both sides of the river or stream. Generally, it is recommended that this zone extend to a distance using a combination of floodwave travel times of between 15-90 minutes and/or warning times of between 4-6 hours, whichever is most conservative. May be labeled as protective action zone, evacuation zone II, evacuation zone B, or other appropriate name.
• Emergency Evacuation Zone III - The outermost emergency evacuation zone, extending beyond emergency evacuation zone II and also located on both sides of the river or stream. Its furthest point is that beyond which emergency planning and evacuation for a dam failure inundation would not be required under most conditions; where the floodwave would be attenuated; and beyond which the potential negative impacts on humans would be virtually eliminated. May be labeled as precautionary zone, evacuation zone III, evacuation zone C, or other appropriate name.