Seattle
Wash.
Portland
Mont.
Minn.
N.H.
N.D.
Vt.
Maine
Ore.
Idaho
N.Y.
Wis.
Boston
Minneapolis
S.D.
Mass.
Mich.
R.I.
Wyo.
Detroit
Conn.
Iowa
Chicago
New York
Pa.
Neb.
Ohio
N.J.
San Francisco
Nev.
Ind.
Md.
Del.
Ill.
Denver
Washington, D.C.
Utah
Kansas City
W. Va.
Colo.
Mo.
Va.
Kan.
Las Vegas
Ky.
Calif.
Raleigh
Ariz.
N.C.
Okla.
Los Angeles
Tenn.
Ark.
N.M.
Phoenix
S.C.
Atlanta
Ala.
Ga.
Miss.
Texas
Fla.
Alaska
Houston
La.
Anchorage
Honolulu
Age of Major Dams
Miami
Hawaii
0 yrs
50
100
150
Seattle
Portland
Wash.
N.H.
N.D.
Mont.
Vt.
Maine
Mich.
Idaho
Ore.
Wis.
N.Y.
Boston
S.D.
Minn.
Mass.
R.I.
Wyo.
Detroit
Conn.
Iowa
New York
Chicago
Pa.
Neb.
Ohio
N.J.
Nev.
Ind.
Md.
Del.
Ill.
Denver
Washington, D.C.
Utah
W. Va.
Colo.
Va.
Las Vegas
Kan.
Ky.
Raleigh
Mo.
Calif.
Ariz.
N.C.
Okla.
Tenn.
Los Angeles
Ark.
N.M.
Phoenix
S.C.
Ala.
Ga.
Miss.
Texas
Fla.
Alaska
Houston
La.
Anchorage
Honolulu
Age of Major Dams
Miami
Hawaii
0 yrs
50
100
150
Wash.
N.D.
N.H.
Vt.
Mont.
Mich.
Maine
Idaho
N.Y.
Wis.
Ore.
Mass.
S.D.
Minn.
Wyo.
R.I.
Iowa
Pa.
Conn.
Neb.
N.J.
Ohio
Ind.
Del.
Ill.
Md.
Nev.
Colo.
Utah
W. Va.
Va.
Kan.
Mo.
Ky.
Calif.
Ariz.
N.C.
Okla.
Tenn.
Ark.
N.M.
S.C.
Ala.
Ga.
Miss.
Fla.
Texas
Alaska
La.
Age of Major Dams
Hawaii
0 yrs
50
100
150
Maine
N.D.
Mont.
Vt.
Mich.
Ore.
Idaho
Mass.
N.Y.
S.D.
Minn.
Wyo.
Iowa
Pa.
Neb.
N.J.
Ind.
Nev.
Ill.
Colo.
Utah
Mo.
Kan.
Va.
Ky.
Calif.
Ariz.
N.C.
Okla.
Ark.
N.M.
S.C.
Ala.
Ga.
Miss.
Texas
Fla.
La.
Age of Major Dams
Alaska
Hawaii
0 yrs
50
100
150
Me
Vt
ND
Mt
Id
NY
Mi
Ma
Or
SD
Wy
Ia
Ne
NJ
Nv
Il
Co
Ut
Mo
Ks
Ca
Az
NC
Ar
NM
Ms
Al
Ga
Fl
La
Tx
Ak
HI
Age of Major Dams
0 yrs
50
100
150
Vt
ND
Mt
ID
Mi
NY
Or
SD
Wy
Ia
NE
NJ
Nv
Il
UT
Ks
MO
Ca
NC
Az
NM
Ar
AL
Ga
Ms
Fl
LA
Tx
Ak
HI
Age of Major Dams
0 yrs
50
100
150
After two weeks that saw evacuations near Oroville, Calif., and flooding in Elko County, Nev., America’s dams are showing their age.
Nearly 2,000 state-regulated high-hazard dams in the United States were listed as being in need of repair in 2015, according to the Association of State Dam Safety Officials. A dam is considered “high hazard” based on the potential for the loss of life as a result of failure.
By 2020, 70 percent of the dams in the United States will be more than 50 years old, according to the American Society of Civil Engineers.
“It’s not like an expiration date for your milk, but the components that make up that dam do have a lifespan.” said Mark Ogden, a project manager with the Association of State Dam Safety Officials.
The United States Army Corps of Engineers keeps an inventory of 90,000 dams across the country, and more than 8,000 are classified as major dams by height or storage capacity, according to guidelines established by the United States Geological Survey.
Dam failures can have serious consequences.
Two weeks ago, heavy rains caused the Twentyone Mile Dam in Nevada to burst, resulting in flooding, damaged property and closed roads throughout the region.
The earthen dam, built in the early 1900s and less than 50 feet tall, is one of more than 60,000 “low hazard” dams, according to the Army Corps of Engineers. Typically, failure of a low hazard dam would cause property damage, but it would most likely not kill anyone.
Twentyone Mile Dam
Reno
NEVADA
Las Vegas
Hazard Potential of Dams
Low
Significant
High
Undetermined
Twentyone Mile Dam
Reno
NEVADA
Las Vegas
Hazard Potential of Dams
Low
Significant
High
Undetermined
Last week, 180,000 people downstream from Oroville Dam in California were evacuated after an emergency spillway showed signs of failing.
Built in the 1960s and more than 16 times the height of the Nevada dam, Oroville was listed as a high hazard dam. Had it not been for the speed of the response last week, there could have been severe flooding of the surrounding area.
“The larger dams are being watched very carefully. The smaller dams don’t enjoy that level of scrutiny,” Mr. Ogden said.
The U.S. would need to spend billions to repair public and private dams.
Seattle
Wash.
Portland
Mont.
N.H.
N.D.
Vt.
Minn.
Maine
Ore.
Minneapolis
Idaho
N.Y.
Boston
Wis.
S.D.
Mass.
Mich.
R.I.
Wyo.
Conn.
Detroit
Iowa
Chicago
New York
Pa.
Neb.
N.J.
Ind.
Columbus
San Francisco
Ill.
Md.
Del.
Utah
Nev.
Ohio
W. Va.
Denver
Washington, D.C.
Kansas City
Colo.
Va.
Kan.
Las Vegas
Mo.
Ky.
Raleigh
Calif.
Ariz.
N.C.
Okla.
Tenn.
Los Angeles
N.M.
Phoenix
Atlanta
S.C.
Ark.
Miss.
Ala.
Ga.
La.
Texas
Fla.
Alaska
Houston
Anchorage
Honolulu
Ownership of Major Dams
Miami
Hawaii
Private
Public
Unknown
Seattle
Wash.
Portland
N.H.
N.D.
Mont.
Vt.
Minn.
Maine
Ore.
Wis.
Idaho
N.Y.
Boston
S.D.
Mass.
R.I.
Mich.
Wyo.
Detroit
Conn.
Iowa
Chicago
New York
Pa.
Neb.
Ohio
N.J.
Ind.
Ill.
Md.
Del.
Nev.
W. Va.
Denver
Washington, D.C.
Utah
Colo.
Va.
Las Vegas
Kan.
Ky.
Raleigh
Mo.
Calif.
Ariz.
N.C.
Okla.
Tenn.
Los Angeles
Ark.
Phoenix
N.M.
Atlanta
S.C.
Miss.
Ala.
Ga.
Texas
Fla.
Alaska
Houston
La.
Anchorage
Honolulu
Ownership of Major Dams
Miami
Hawaii
Private
Public
Unknown
Wash.
N.H.
N.D.
Mont.
Vt.
Maine
Ore.
Idaho
N.Y.
Mass.
S.D.
Minn.
Wis.
Wyo.
Mich.
R.I.
Conn.
Iowa
Pa.
Neb.
N.J.
Ohio
Ill.
Ind.
Del.
W. Va.
Md.
Nev.
Utah
Colo.
Kan.
Va.
Mo.
Ky.
Calif.
Ariz.
N.C.
Okla.
Tenn.
Ark.
N.M.
S.C.
Ala.
Ga.
La.
Miss.
Texas
Fla.
Alaska
Ownership of Major Dams
Hawaii
Private
Public
Unknown
Wash.
N.H.
N.D.
Vt.
Mont.
Maine
Ore.
N.Y.
Idaho
Mass.
S.D.
Minn.
Wyo.
Wis.
Mich.
R.I.
Iowa
Conn.
Pa.
Neb.
N.J.
Ind.
Ill.
Ohio
Del.
Utah
W. Va.
Colo.
Md.
Nev.
Mo.
Kan.
Va.
Ky.
Calif.
Ariz.
N.C.
Okla.
Tenn.
N.M.
S.C.
Ark.
Miss.
Ala.
Ga.
La.
Texas
Fla.
Ownership of Major Dams
Alaska
Hawaii
Private
Public
Unknown
WA
Vt
ND
Mt
Id
Or
NY
Wi
Ma
Mn
SD
Wy
Mi
Ia
Ne
NJ
In
Il
Co
Ut
Nv
Mo
Va
Ks
KY
Ca
Az
NC
Tn
Ar
NM
SC
Ms
Al
Ga
Tx
La
Ak
Fl
HI
Ownership of Major Dams
Private
Public
Unknown
ME
ND
Mt
MN
Or
NY
SD
Wy
Mi
Ia
PA
NJ
OH
Il
Nv
MO
VA
Ks
Ca
NC
Az
NM
Ms
Ga
Tx
Fl
Ak
HI
Ownership of Major Dams
Private
Public
Unknown
In 2016, the Association of State Dam Safety Officials estimated that it would cost $60 billion to rehabilitate all the dams that needed to be brought up to safe condition, with nearly $20 billion of that sum going toward repair of dams with a high potential for hazard.
In 2015, Representative Sean Patrick Maloney, Democrat of New York, introduced the Dam Rehabilitation and Repair Act to provide grant assistance to rehabilitate publicly owned dams that fail to meet minimum safety standards. A version of the legislation that covered private dams — which account for more than half of the dams in the United States — was incorporated into a larger water infrastructure bill and signed into law by President Barack Obama in December.
Oroville Dam is owned by the state of California, but the Twentyone Mile Dam is owned by Winecup Gamble Ranch, a cattle operation in northeastern Nevada.
While most legislation involves inspection and rehabilitation, hazardous dams that have outlived their usefulness can also be removed.
“The very fact that you are blocking a river and allowing a reservoir to fill up with millions of gallons of water presents a risk,” said Bob Irvin, the president of American Rivers, an environmental conservation and advocacy organization. The group has partnered with the State of Maryland to remove the Bloede Dam, built in 1907, where several people have drowned over the years.
Nationwide, 1,384 dams had been removed from 1912 through 2016, according to the nonprofit American Rivers. A majority of those dams were removed within the last two decades, with 72 removed in 2016.