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Living with Dams: Know Your Risk | April 2012
Many people who live in
dam failure inundation
zones are completely
unaware of the potential
hazard lurking upstream.
The “inundation zone” is the area that
would be impacted downstream of
the dam in the event of a failure or
uncontrolled release of water generally
much larger than the normal river or
stream flood event.
The “dam failure inundation zone” is
broader than the FEMA “100-year flood”
insurance mapped zone.
How do I find out if I live in a dam
failure inundation zone:
Contact your local emergency
management agency (a simple
internet search will most likely
locate the appropriate office).
Contact the state dam safety
program (see the U.S. map at
).
Before Buying: Do Some Research,
Know the Facts
Before buying a home or business,
determine whether it is in a dam failure
inundation zone. This determination is
the buyer’s responsibility. Prospective
buyers should know if there is an
upstream existing dam or the potential
for an upstream dam to be built. This is
sometimes very difficult to determine
while standing on the property since the
upstream dam may not be in sight. In
some cases, the dam site may be several
miles upstream of the property and the
view may be obscured. Listed below
are some resources that will assist your
research:
7.5 minute U.S. Geological Survey
Google Earth
The state dam safety agency office,
the local emergency management
office or the local soil and water
district office.
KEY:
RED
= > 1,000 dams
YELLOW
= Between 500 and 1,000
dams
BLUE
= Between 100 and 500 dams
GREEN
= 100 dams or less
Number of high- and significant-hazard potential dams;
those that have the potential to cause loss of life (high) or
extreme property damage (significant) should they fail.
NOTE:
Since Alabama is the only state that does not
have a state regulatory program the data on numbers of
dams may be low.