Department of Emergency Management and Security

CONTACT INFORMATION: Open during regular business hours 8 a.m. - 4:30p.m., Monday - Friday
4890 Alliance Drive, Suite 2200, Fairfax, VA 22030
Seamus Mooney

Dam Failure

What It Is

Dam failures or levee breaches can occur with little warning, sometimes within hours - or less - of the first signs of structural concerns. Dams can fail for one or a combination of the following reasons:

-Overtopping caused by floods that exceed the capacity of the dam
-Structural failure of materials used in construction
-Movement and/or failure of the foundation
-Settlement and cracking of concrete or embankment
-Piping and internal erosion of soil in embankment dams
-Inadequate maintenance and upkeep
-Deliberate acts of sabotage

Dam Hazard Annex


Dam Failure Hazard Annex

Click on the appropriate link below to download a PDF copy of the Dam Failure Hazard Annex page from the Community Emergency Response Guide.

English (PDF) | Spanish (PDF) | Korean (PDF) | Arabic (PDF) | Mandarin (PDF) | Vietnamese (PDF)

Key Terms

  • A Flood Watch means there is a possibility of flooding or a flash flood watch.
  • A Flash Flood Watch means flash flooding is possible.  Be prepared to move to higher ground.  A flash flood can occur without any warning.
  • A Flood Warning means a flood is occurring or will likely occur soon. If you are advised to evacuate, do so immediately.
  • An Excluded Area (Zone X) on a FEMA flood map is an area that is protected by a dam or levee that would otherwise be in the Special Flood Hazard Area, or "100-year floodplain"; properties in excluded zones are not required to carry flood insurance to get a mortgage, but owners should strongly consider it regardless.
  • An Emergency Action Plan (EAP) is a formal document that identifies potential emergency conditions at a dam and specifies actions to be followed to minimize loss of life and property damage. 

What To Do

  • Sign up for Fairfax Alerts and have a battery or crank powered NOAA weather radio available.
  • Decide early whether you will evacuate, and where you will go if ordered to leave.
  • Disconnect electrical appliances.
  • Know if your residence or business is in a floodplain or an "excluded area" that is protected by a dam or levee but would otherwise be within the Special Flood Hazard Area.
  • Apply for flood insurance, even if you may be in an "excluded area" or otherwise not be required to do so.
  • Learn First Aid.
  • Refer to Power Outage/Blackout and Medical Emergency Annexes.

  • If you encounter rising water, move to higher ground immediately.
  • Always stay clear from floodwaters.
  • Do not drive through flooded roads - "turn around, don't drown."
  • Stay away from downed power lines to avoid the risk of shock or electrocution.
  • Do not touch electrical equipment if you are wet or standing in water.

  • Return home when local officials say it is safe.
  • Avoid walking or driving through floodwaters.
  • Do not eat any food that may have come in contact with flood water. If in doubt, throw it out.
  • Remove all porous items that have been wet for more than 48 hours and that cannot be cleaned and dried. These items can remain a source of mold growth and should be removed from the home.
  • Check in with family and friends by texting or using social media.
Fairfax Virtual Assistant