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Living with Dams: Know Your Risk | April 2012
Dam Safety, Flood Risk and
Emergency Management
Responsibilities
The Public
Understand that you are at risk and
that there are steps you can take now
to protect yourself from floods should
a dam fail or release flood waters.
Know your evacuation routes.
Dam owners and operators
Maintain and operate the dam to
assure that the dam does not fail.
Work with state and local officials to
mitigate the consequences of dam
incidents.
Maintain an Emergency Action Plan.
Inform local officials of risks associated
with the dam.
Work with the Federal or state
regulator to comply with safety
standards.
State and Local Governments
State governments are responsible for
public safety regulation for more than
80% of the nation’s dams (non-Federal
dams).
State and local governments are
responsible for determining how land
is used in floodplains and for enforcing
floodplain management regulations.
Local governments are responsible for
emergency response and evacuation
in a flooding situation.
Federal Dam Safety,
Floodplain and Emergency
Management Programs
Several Federal agencies have built
or own dams including the U.S. Army
Corps of Engineers, the Department
of the Interior, the Tennessee Valley
Authority and the Department of
Agriculture. Collectively, the Federal
government owns 3,225 (2010 data)
dams. Additionally, the Department
of Agriculture’s Natural Resources
Conservation Service assisted in
building over 11,000 dams now
owned by local watershed districts.
Some Federal agencies including
the Federal Energy Regulatory
Commission (FERC) and the Mine
Safety and Health Administration
(MSHA) regulate privately owned
dams. According to the National
Inventory of Dams, FERC and MSHA
collectively regulate more than 2,200
dams (2010 data).
FEMA provides Federal, state and local
governments with valuable data for
assessing and reducing the risk of
floods to people and their homes and
businesses.
FEMA analyzes and identifies the
flood hazards near levees and
dam inundation areas and helps
communities identify the risks
associated with levees and dams.
FEMA does not own, operate,
maintain, or certify dams or levees for
safety.
How Can Public Advocacy
Improve Dams Near You or
Lessen Your Risk?
Urge your state policymakers to
incorporate a dam-break inundation
clause on the state’s uniform Sellers
Disclosure of Property Condition
statement.
Urge local zoning restrictions near
dams. (California is the only state that
currently requires sellers to disclose
whether any portion of their property
is located in a dam-break inundation
zone [Cal. Gov’t § 8589.4]).
Likewise, urge policymakers to require
disclosure of dam-related issues
to potential owners of dams and
property bordering impoundments,
as well as property within dam break
inundation zones
While it is impossible to guarantee
that a dam will never fail, it is possible
to minimize the chances of dam
failure through a well-organized
and funded dam safety program.
Legislation is vitally important because
it defines responsibility and authority
for dam safety and provides funding
for state dam safety programs.
Many state dam safety programs
are underfunded and do not have
sufficient authorities to effectively
regulate dam safety. States have
identified many dams as deficient, but
without strong enforcement authority,
they have few options for ensuring
their safety.
WHAT IS THE 100-YEAR FLOOD?
The 100-year flood (the flood that has a
1 percent-annual-chance of being
equaled or exceeded) mapped on
FEMA’s Flood Insurance Rate Maps is
intended for insurance, floodplain man-
agement, and planning efforts and is not
intended to be a safety standard.
With a 100-year flood, you have a 26
percent chance of experiencing a flood
of that magnitude or greater during the
life of a 30-year mortgage. You have a
4 percent chance of experiencing a fire
during the same period of time.
Dam failure flood inundation areas may
far exceed the 1 percent flood zones
(100-year flood) mapped by FEMA.
Floods greater then a 100-year flood can
and do happen, as seen in the Midwest,
which received two 500-year floods in a
15-year period (1993 and 2008).
Dam failure floods are almost always
more violent than the normal stream,
river or coastal flood.