Scour Critical Bridges

23,522 bridges across the US at risk from water erosion around foundations.

Scour Critical Bridges

Scour is the erosion of soil and rock around a bridge's foundation caused by moving water. When foundations are exposed or undermined, a bridge can collapse even if its deck and superstructure are in good condition. Scour is the leading cause of bridge failures in the US. These 23,522 bridges have been identified as vulnerable to scour damage.

Bridge State Scour Status Condition Year Built ADT
DRAINAGE CANAL 039 Florida Scour Critical — Countermeasures Installed Fair 1955 3,000
BUCK CREEK Michigan Scour Critical — Countermeasures Installed Fair 1985 3,000
EDISTO RIVER SWAMP South Carolina Scour Critical — Countermeasures Installed Fair 1949 3,000
EDISTO RIVER SWAMP South Carolina Scour Critical — Countermeasures Installed Fair 1949 3,000
SHEPAUG RIVER Connecticut Scour Critical — Countermeasures Installed Poor 1955 3,000
CREEK Oklahoma Scour Critical — Countermeasures Installed Poor 1950 3,000
LETORT SPRING RUN Pennsylvania Scour Critical — Countermeasures Installed Fair 1978 3,000
Canal 100 Florida Scour Critical — Countermeasures Installed Fair 1949 3,000
Canal 101 Florida Scour Critical — Countermeasures Installed Fair 1949 3,000
PEQUONNOCK RIVER Connecticut Scour Critical — Countermeasures Installed Fair 1965 3,000
CANOVANAS RIVER Puerto Rico Scour Critical — Countermeasures Installed Good 1953 3,000
_ Puerto Rico Scour Critical — Countermeasures Installed Good 2018 3,000
DRAW Colorado Scour Critical — Countermeasures Installed Fair 1935 3,000
WILLIAMS CREEK Michigan Scour Critical — Countermeasures Installed Fair 1927 3,000
SANTA YNEZ RIVER California Scour Critical — Countermeasures Installed Poor 1949 3,000
LITTLE SCHUYLKILL RIVER Pennsylvania Scour Critical — Countermeasures Installed Fair 1893 3,000
CREEK Puerto Rico Scour Critical — Countermeasures Installed Fair 1955 3,000
VIVI RIVER Puerto Rico Scour Critical — Countermeasures Installed Fair 1973 3,000
SWAMP CREEK Pennsylvania Scour Critical — Countermeasures Installed Poor 1939 3,000
MAD DOG CREEK South Carolina Scour Critical — Countermeasures Installed Fair 1973 3,000
MEADOW BROOK Pennsylvania Scour Critical — Countermeasures Installed Fair 1931 3,000
SPRING CREEK Florida Scour Critical — Countermeasures Installed Fair 1953 3,000
TOWN CREEK South Carolina Scour Critical — Countermeasures Installed Fair 1968 3,000
CANOVANAS RIVER Puerto Rico Scour Critical — Countermeasures Installed Poor 1953 3,000
WATER BR MILLERS RIVER Massachusetts Scour Critical — Countermeasures Installed Fair 1988 3,000
Lil Cypress Bayou Louisiana Scour Critical — Countermeasures Installed Poor 1965 3,000
TRIBUTARY TO WEST BRANCH Maryland Scour Critical — Countermeasures Installed Fair 1930 3,000
S B GLENDENING CK New York Scour Critical — Countermeasures Installed Poor 1937 2,998
WEBB CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1962 2,997
NECK RIVER Connecticut Scour Critical — Countermeasures Installed Fair 1983 2,996
DUTCH CREEK Colorado Scour Critical — Countermeasures Installed Fair 1997 2,996
MCNEIL CREEK Oregon Scour Critical — Countermeasures Installed Fair 1955 2,994
FRENCH CREEK Pennsylvania Scour Critical — Countermeasures Installed Poor 1856 2,994
KALAMAZOO RIVER Michigan Scour Critical — Countermeasures Installed Poor 1948 2,991
MUSCOOT RIVER New York Scour Critical — Countermeasures Installed Fair 1960 2,991
BEASON CREEK Tennessee Scour Critical — Countermeasures Installed Fair 1954 2,990
OAK CREEK Oregon Scour Critical — Countermeasures Installed Fair 1958 2,987
JENKINS BRANCH Texas Scour Critical — Countermeasures Installed Good 1979 2,987
PIPE CREEK Indiana Scour Critical — Countermeasures Installed Fair 1965 2,987
STURGEON RIVER Michigan Scour Critical — Countermeasures Installed Fair 1956 2,977
CASTOR CREEK Louisiana Scour Critical — Countermeasures Installed Good 2002 2,974
SHERMAN CREEK Michigan Scour Critical — Countermeasures Installed Fair 1939 2,969
LUBBERS RUN New Jersey Scour Critical — Countermeasures Installed Fair 1986 2,968
DUCKABUSH RIVER Washington Scour Critical — Countermeasures Installed Fair 1934 2,967
WOONASQUATUCKET RIVER Rhode Island Scour Critical — Countermeasures Installed Poor 1949 2,965
WHITE RIVER Indiana Scour Critical — Countermeasures Installed Fair 1990 2,965
SKIPPACK CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1908 2,965
N BR BLACK RIVER Michigan Scour Critical — Countermeasures Installed Fair 1988 2,962
Bear River Wyoming Scour Critical — Countermeasures Installed Poor 1941 2,961
TROUT RIVER New York Scour Critical — Countermeasures Installed Good 1932 2,960

Scour Critical Bridges by State

States ranked by number of scour critical bridges.

StateScour CriticalUnaddressedCountermeasuresIneffective
Texas 3,912 75 516 3,321
Pennsylvania 2,233 45 2,187 1
Louisiana 1,302 13 1,288 1
South Carolina 1,263 0 1,217 46
Oregon 1,231 4 1,221 6
Michigan 1,081 14 1,062 5
Nebraska 962 224 732 6
New York 864 9 780 75
Indiana 756 7 749 0
Wisconsin 751 0 748 3
Kansas 638 9 626 3
California 623 27 562 34
Tennessee 581 12 569 0
Washington 516 14 487 15
Puerto Rico 496 9 487 0
Alabama 450 1 423 26
Iowa 392 3 385 4
New Jersey 362 2 360 0
Florida 357 4 339 14
Oklahoma 317 33 283 1
Missouri 312 4 307 1
Mississippi 301 6 286 9
Connecticut 279 0 276 3
Minnesota 257 38 202 17
Vermont 242 0 240 2
Colorado 241 3 238 0
Idaho 215 18 186 11
South Dakota 207 3 203 1
Arkansas 187 3 129 55
Massachusetts 166 15 106 45
Montana 166 13 140 13
Arizona 164 2 160 2
West Virginia 160 2 98 60
Alaska 159 1 146 12
Maine 140 13 126 1
North Carolina 130 9 105 16
New Mexico 127 4 114 9
North Dakota 102 14 87 1
Utah 100 6 82 12
Georgia 99 1 81 17
Illinois 99 3 85 11
Nevada 94 0 85 9
Rhode Island 94 0 93 1
New Hampshire 86 2 78 6
Hawaii 83 0 82 1
Kentucky 56 16 39 1
Maryland 54 1 51 2
Wyoming 51 1 48 2
Delaware 39 0 39 0
Ohio 12 2 4 6
Virginia 8 0 8 0
District of Columbia 5 0 4 1

Scour Critical Rating Codes

Code 2 — UnaddressedBridge is scour critical with no countermeasures installed. The foundation is vulnerable and no protective action has been taken.
Code 3 — Countermeasures InstalledProtective measures (riprap, sheet piling, etc.) have been installed to reduce scour risk, but the bridge remains classified as scour critical.
Code 6 — Countermeasures IneffectiveProtective measures were installed but have been assessed as ineffective. The bridge requires re-evaluation and additional action.

About Scour Critical Bridges

Scour critical bridges have been identified through underwater inspection or analysis as having foundations that are unstable or could become unstable during flood conditions. FHWA requires action plans for all scour critical bridges. Famous scour failures include the 1987 Schoharie Creek Bridge collapse in New York.