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Living with Dams: Know Your Risk | April 2012
“Fact or Fiction” – Common Beliefs about Dams
FACT
State dam safety programs have oversight of most dams in the U.S.
State agencies regulate more than 80% of the nation’s dams.
Most dams are privately owned. Dam owners are responsible for
maintenance and upgrades.
Private dam owners are responsible for more than 65% of the nation’s
dams. Many lack the financial resources necessary for adequate dam
maintenance.
There are more than 85,000 dams in the U.S. Most states are home
to hundreds – or thousands – of dams of regulatory criteria.
Texas has the most dams – more than 7,000 – followed by Kansas
(6,087), Missouri (5,099), Oklahoma (4,755), and Georgia (4,606).
[2010 data]
Mississippi, North Carolina, and Iowa each have more than 3,000
dams.
Five states – Alabama, Montana, Nebraska, South Carolina, and
South Dakota – each have more than 2,000 dams.
More than 1,000 dams are in each of 15 additional states.
Of all states, Delaware has the fewest number of dams, with 86.
Advancing age can make dams more susceptible to failure.
The average age of dams in the U.S. is more than 53 years old.
As dams get older, deterioration increases and repair costs rise. Some
common problems of older dams are:
Deteriorating metal pipes and structural components—after 50
years, metal rusts and fails.
Sediment-filled reservoirs. Some sediment may have contaminants
from chemicals in runoff from upstream areas.
Subdivisions and businesses built upstream—roofs and concrete
streets and sidewalks increase the volume of runoff to the
reservoir.
FICTION
“The Army Corps of Engineers is
responsible for most of the dams
in the U.S.”
“Dams are like roads and bridges.
The government takes care of them.”
“There are only a few dams in my
state.”
“That dam has been here for years –
it’s not going anywhere.”