There are are more than 80,000 dams in the United States,
according to the 2007 update to the National Inventory of Dams.
Approximately one third of these pose a "high" or "significant"
hazard to life and property if failure occurs.
Dam failure or levee breeches can occur with little warning.
Intense storms may produce a flood in a few hours or even
minutes for upstream locations. Flash floods occur within six
hours of the beginning of heavy rainfall, and dam failure may
occur within hours of the first signs of breaching.
Other failures and breeches can take much longer to occur,
from days to weeks, as a result of debris jams or the
accumulation of melting snow.
What to Do Before a Dam
Knowing your risk, making sure an Emergency Action Plan (EAP)
is in place, and evacuating when directed by emergency response
officials are the most important steps you can take to staying
safe from a dam failure. For information on how to prepare for
a flood, visit Before A Flood.
Know your risk. Do you live downstream from a dam? Is the
dam a high-hazard or significant-hazard potential dam? To find
out, contact your state or county emergency management agency
or visit the National Inventory of Dams (NID) or the
Association of State Dam Safety Officials (ASDSO).
Find out who owns the dam and who regulates the dam. This
information also should be available from your state or county
emergency management agency, NID, or ASDSO.
Once you determine that you live downstream from a
high-hazard or significant-hazard potential dam and find out
who owns the dam, see if a current EAP is in place for the dam.
An EAP is a formal document that identifies potential emergency
conditions at a dam and specifies preplanned actions to be
followed to reduce property damage and loss of life. An EAP
specifies actions the dam owner should take to take care of
problems at the dam. It also includes steps to assist the dam
owner in issuing early warning and notification messages to
responsible downstream emergency management authorities of the
If there is a dam failure or an imminent dam failure and you
need to evacuate, know your evacuation route and get out of
harm's way. In general, evacuation planning and implementation
are the responsibility of the state and local officials
responsible for your safety. However, there may be situations
where recreational facilities, campgrounds, or residences are
located below a dam and local authorities will not be able to
issue a timely warning. In this case, the dam owner should
coordinate with local emergency management officials to
determine who will warn you and in what priority.
Flood - If a flood is likely in your area,
- Listen to the radio or television for information.
- Be aware that flash flooding can occur. If there is any
possibility of a flash flood, move immediately to higher
ground. Do not wait for instructions to move.
- Be aware of streams, drainage channels, canyons, and
other areas known to flood suddenly. Flash floods can occur
in these areas with or without such typical warnings as
rain clouds or heavy rain.
If you must prepare to evacuate, you should do the
- Secure your home. If you have time, bring in outdoor
furniture. Move essential items to an upper floor.
- Turn off utilities at the main switches or valves if
instructed to do so. Disconnect electrical appliances. Do
not touch electrical equipment if you are wet or standing
- Do not walk through moving water. Six inches of moving
water can make you fall. If you have to walk in water, walk
where the water is not moving. Use a stick to check the
firmness of the ground in front of you.
- Do not drive into flooded areas. If floodwaters rise
around your car, abandon the car and move to higher ground
if you can do so safely. You and the vehicle can be quickly
After a Flood -
The following are guidelines for
the period following a flood:
- Listen for news
reports to learn whether the community’s water
supply is safe to drink.
- Avoid floodwaters; water may be contaminated by oil,
gasoline, or raw sewage. Water may also be electrically
charged from underground or downed power lines.
- Avoid moving water.
- Be aware of areas where floodwaters have receded. Roads
may have weakened and could collapse under the weight of a
- Stay away from downed power lines, and report them to
the power company.
- Return home only when authorities indicate it is
- Stay out of any building if it is surrounded by
- Use extreme caution when entering buildings; there may
be hidden damage, particularly in foundations.
- Service damaged septic tanks, cesspools, pits, and
leaching systems as soon as possible. Damaged sewage
systems are serious health hazards.
- Clean and disinfect everything that got wet. Mud left
from floodwater can contain sewage and
Much of the info on this page was taken from FEMA's web site
which can be referenced at: