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
CULEBRINAS RIVER Puerto Rico Scour Critical — Countermeasures Installed Poor 1955 9,000
ARENAS CREEK Puerto Rico Scour Critical — Countermeasures Installed Fair 1939 9,000
TANGIPAHOA RIVER Mississippi Scour Critical — Countermeasures Installed Fair 1960 9,000
PUGET SOUND @ EAGLE HRBR Washington Scour Critical — Countermeasures Installed Fair 1972 9,000
TANGIPAHOA RIVER Mississippi Scour Critical — Countermeasures Installed Fair 1960 9,000
SAN ANTONIO RIVER Texas Scour Critical — Countermeasures Installed Fair 1954 8,973
QUASSAIC CREEK New York Scour Critical — Countermeasures Installed Poor 1975 8,970
SWARTZ CREEK Michigan Scour Critical — Countermeasures Installed Fair 1981 8,961
LITTLE EAGLE CREEK Indiana Scour Critical — Countermeasures Installed Fair 1977 8,956
AU SABLE RIVER Michigan Scour Critical — Countermeasures Installed Fair 1984 8,950
W FK Dairy Creek Oregon Scour Critical — Countermeasures Installed Good 1941 8,934
BLUFF CREEK Texas Scour Critical — Countermeasures Installed Fair 1947 8,932
THOMAS CREEK New York Scour Critical — Countermeasures Installed Fair 1968 8,932
LEY CREEK New York Scour Critical — Countermeasures Installed Fair 1950 8,922
MIDDLE CREEK Indiana Scour Critical — Countermeasures Installed Fair 1940 8,918
Detrital Wash Arizona Scour Critical — Countermeasures Installed Fair 1982 8,908
BEACON HILL BROOK Connecticut Scour Critical — Countermeasures Installed Fair 1966 8,900
CROOKED OAK CREEK Oklahoma Scour Critical — Countermeasures Installed Poor 1972 8,900
UNIBON RIVER Puerto Rico Scour Critical — Countermeasures Installed Fair 1921 8,900
AIBONITO RIVER Puerto Rico Scour Critical — Countermeasures Installed Poor 1970 8,900
COOPER RIVER New Jersey Scour Critical — Countermeasures Installed Poor 1924 8,890
Detrital Wash Arizona Scour Critical — Countermeasures Installed Fair 1982 8,855
LOWER LOOKINGGLASS CRK Oregon Scour Critical — Countermeasures Installed Fair 1949 8,853
CK South Dakota Scour Critical — Countermeasures Installed Fair 1961 8,815
CK South Dakota Scour Critical — Countermeasures Installed Fair 1961 8,815
PHILLIPSE BROOK New York Scour Critical — Countermeasures Installed Fair 1929 8,815
OSWEGO CREEK Oregon Scour Critical — Countermeasures Installed Fair 1930 8,805
TANK FARM DITCH California Scour Critical — Countermeasures Installed Good 1988 8,803
MILL RIVER Connecticut Scour Critical — Countermeasures Installed Fair 1955 8,800
SUGAR CREEK North Carolina Scour Critical — Countermeasures Installed Fair 1980 8,800
AGUACATE CREEK Puerto Rico Scour Critical — Countermeasures Installed Poor 1920 8,800
COROZAL RIVER Puerto Rico Scour Critical — Countermeasures Installed Fair 1966 8,800
THOMPSON CREEK South Carolina Scour Critical — Countermeasures Installed Fair 1931 8,800
BRANCH RANCOCAS CREEK New Jersey Scour Critical — Countermeasures Installed Fair 1949 8,793
CLEAR CREEK Indiana Scour Critical — Countermeasures Installed Fair 1972 8,790
CLEARFIELD CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1937 8,758
SHIAWASSEE RIVER Michigan Scour Critical — Countermeasures Installed Fair 1983 8,752
MILL CREEK Kansas Scour Critical — Countermeasures Installed Good 1966 8,750
TRUCKEE RVR Nevada Scour Critical — Countermeasures Installed Fair 1971 8,750
ROGUE RIVER Oregon Scour Critical — Countermeasures Installed Fair 2006 8,744
Trask River Oregon Scour Critical — Countermeasures Installed Fair 1949 8,740
TUALATIN RIVER Oregon Scour Critical — Countermeasures Installed Fair 1924 8,728
SYCAMORE CREEK Michigan Scour Critical — Countermeasures Installed Fair 1962 8,725
FLINT RIVER Michigan Scour Critical — Countermeasures Installed Fair 1928 8,725
CLEAR CREEK Indiana Scour Critical — Countermeasures Installed Fair 1972 8,720
WALKER CREEK Kansas Scour Critical — Countermeasures Installed Good 1965 8,718
WALKER CREEK Kansas Scour Critical — Countermeasures Installed Good 1965 8,718
CHIMACUM CREEK Washington Scour Critical — Countermeasures Installed Fair 1916 8,718
GUADALUPE RIVER Texas Scour Critical — Countermeasures Installed Fair 1962 8,716
SADDLE RIVER New Jersey Scour Critical — Countermeasures Installed Fair 1940 8,710

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.