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
RATTLESNAKE WASH New Mexico Scour Critical — Countermeasures Installed Fair 1951 4,813
CLIFTY CREEK Indiana Scour Critical — Countermeasures Installed Fair 1983 4,809
HARRISON CREEK Oklahoma Scour Critical — Countermeasures Installed Poor 1940 4,800
DRAIN #73 Michigan Scour Critical — Countermeasures Installed Fair 1930 4,800
WADDELL CREEK California Scour Critical — Countermeasures Installed Fair 1947 4,800
GOOSE RIVER North Dakota Scour Critical — Countermeasures Installed Fair 1966 4,800
CIALITOS RIVER Puerto Rico Scour Critical — Countermeasures Installed Fair 1973 4,800
CHATFIELD HOLLOW BROOK Connecticut Scour Critical — Countermeasures Installed Fair 1935 4,800
GRAYS CREEK South Carolina Scour Critical — Countermeasures Installed Good 1983 4,800
BARRANCAS CREEK Puerto Rico Scour Critical — Countermeasures Installed Fair 1965 4,800
CAYAGUAS RIVER Puerto Rico Scour Critical — Countermeasures Installed Fair 1969 4,800
CREEK Oklahoma Scour Critical — Countermeasures Installed Poor 1984 4,800
Wet Beaver Creek Arizona Scour Critical — Countermeasures Installed Good 1972 4,800
LITTLE RIVER South Carolina Scour Critical — Countermeasures Installed Fair 1964 4,800
SALTO ARRIBA CREEK Puerto Rico Scour Critical — Countermeasures Installed Fair 1925 4,800
VIVI RIVER Puerto Rico Scour Critical — Countermeasures Installed Fair 1925 4,800
BIG CHOCONUT CREEK New York Scour Critical — Countermeasures Installed Fair 1930 4,793
N FORK NINNESCAH RIVER Kansas Scour Critical — Countermeasures Installed Good 1969 4,792
N FORK NINNESCAH RIVER Kansas Scour Critical — Countermeasures Installed Good 1969 4,792
KIIKII STREAM Hawaii Scour Critical — Countermeasures Installed Fair 1950 4,790
BAYOU SAN PATRICIO Louisiana Scour Critical — Countermeasures Installed Good 2006 4,790
BAYOU SAN MIGUEL Louisiana Scour Critical — Countermeasures Installed Fair 1963 4,790
MIDDLE RELIEF Louisiana Scour Critical — Countermeasures Installed Fair 1963 4,790
ABERNATHY CREEK Washington Scour Critical — Countermeasures Installed Fair 1930 4,787
INDIAN RUN Pennsylvania Scour Critical — Countermeasures Installed Fair 1910 4,787
ROCK CREEK Kansas Scour Critical — Countermeasures Installed Fair 1961 4,785
HCFCD DITCH Texas Scour Critical — Countermeasures Installed Fair 1982 4,784
SAN ANTONIO RIVER Texas Scour Critical — Countermeasures Installed Good 2000 4,782
CARY BAYOU Texas Scour Critical — Countermeasures Installed Fair 1967 4,780
E HIND DR/WAILUPE STRM Hawaii Scour Critical — Countermeasures Installed Fair 1949 4,780
TRIB TO CROOKED CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1923 4,777
H W CHANNEL METHOW R Washington Scour Critical — Countermeasures Installed Good 1945 4,775
PERE MARQUETTE RIVER Michigan Scour Critical — Countermeasures Installed Fair 1922 4,771
Laprele Creek Wyoming Scour Critical — Countermeasures Installed Fair 1958 4,769
COBB DITCH Indiana Scour Critical — Countermeasures Installed Fair 1952 4,768
S.COLONEL CREEK Tennessee Scour Critical — Countermeasures Installed Fair 1948 4,763
Little Boxelder Creek Wyoming Scour Critical — Countermeasures Installed Fair 1958 4,762
Little Boxelder Creek Wyoming Scour Critical — Countermeasures Installed Fair 1958 4,762
RICKETTS BRANCH TRIB Texas Scour Critical — Countermeasures Installed Fair 1986 4,762
RICKETTS BRANCH TRIB Texas Scour Critical — Countermeasures Installed Good 1986 4,762
WILDCAT CREEK Oregon Scour Critical — Countermeasures Installed Fair 1961 4,758
WILDCAT CREEK Oregon Scour Critical — Countermeasures Installed Fair 1961 4,758
WILDCAT CREEK Oregon Scour Critical — Countermeasures Installed Fair 1961 4,758
ELM CREEK Texas Scour Critical — Countermeasures Installed Fair 1942 4,757
FENHOLLOWAY RIVER Florida Scour Critical — Countermeasures Installed Fair 1934 4,750
Pinal Creek Arizona Scour Critical — Countermeasures Installed Good 1957 4,750
DRAIN Louisiana Scour Critical — Countermeasures Installed Good 1982 4,748
IRONSTONE CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1907 4,748
SWEETWATER CREEK Louisiana Scour Critical — Countermeasures Installed Fair 1970 4,748
TANGIPAHOA RIVER Louisiana Scour Critical — Countermeasures Installed Fair 1965 4,748

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.