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
ABERNETHY CREEK Oregon Scour Critical — Countermeasures Installed Poor 1933 9,700
MATTABESSET RIVER Connecticut Scour Critical — Countermeasures Installed Fair 1942 9,700
ARROYATA CREEK Puerto Rico Scour Critical — Countermeasures Installed Fair 1950 9,700
SONOMA CREEK California Scour Critical — Countermeasures Installed Good 1949 9,700
BACK SWAMP South Carolina Scour Critical — Countermeasures Installed Fair 1931 9,700
BACK SWAMP South Carolina Scour Critical — Countermeasures Installed Fair 1974 9,700
S BR TOBACCO RIVER Michigan Scour Critical — Countermeasures Installed Fair 1962 9,699
S BR TOBACCO RIVER Michigan Scour Critical — Countermeasures Installed Fair 1962 9,699
WATER FIRST LEVEL CANAL Massachusetts Scour Critical — Countermeasures Installed Poor 1919 9,698
KOLB CREEK Indiana Scour Critical — Countermeasures Installed Fair 1950 9,690
TROWBRIDGE CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1961 9,678
PAPAKATING CREEK New Jersey Scour Critical — Countermeasures Installed Fair 1980 9,676
BEAL-TAYLOR DITCH Indiana Scour Critical — Countermeasures Installed Fair 1978 9,672
FURNACE RUN Pennsylvania Scour Critical — Countermeasures Installed Poor 1930 9,664
COLUMBIA RIVER Washington Scour Critical — Countermeasures Installed Fair 1978 9,651
BOIS DE SIOUX RIVER Minnesota Scour Critical — Countermeasures Installed Fair 1930 9,650
RIO GRANDE New Mexico Scour Critical — Countermeasures Installed Fair 1940 9,647
USQUEPAUG RIVER Rhode Island Scour Critical — Countermeasures Installed Fair 1931 9,628
DOUGLAS CREEK Washington Scour Critical — Countermeasures Installed Poor 1957 9,626
INTRACOASTAL WATERWAY Florida Scour Critical — Countermeasures Installed Good 1967 9,625
GRAND RIVER Michigan Scour Critical — Countermeasures Installed Fair 1960 9,625
BEAVER RUN Pennsylvania Scour Critical — Countermeasures Installed Fair 1940 9,622
OVER BULL RUN Pennsylvania Scour Critical — Countermeasures Installed Fair 1937 9,622
SLOUGH OF YAKIMA R Washington Scour Critical — Countermeasures Installed Fair 1935 9,615
South Fork Ash Creek Oregon Scour Critical — Countermeasures Installed Fair 1950 9,615
BLACK BAYOU Louisiana Scour Critical — Countermeasures Installed Poor 1983 9,608
LAKE VILLAR Louisiana Scour Critical — Countermeasures Installed Fair 1983 9,608
AGUAS LARGAS CREEK Puerto Rico Scour Critical — Countermeasures Installed Fair 1949 9,600
ARROYO GRANDE CREEK California Scour Critical — Countermeasures Installed Fair 1932 9,600
CREEK Oklahoma Scour Critical — Countermeasures Installed Poor 1965 9,600
BAIROA RIVER Puerto Rico Scour Critical — Countermeasures Installed Poor 1961 9,600
SANTA FE RIVER Florida Scour Critical — Countermeasures Installed Fair 1932 9,600
CANOVANILLAS RIVER Puerto Rico Scour Critical — Countermeasures Installed Fair 1953 9,600
BAYAMON RIVER Puerto Rico Scour Critical — Countermeasures Installed Fair 1949 9,600
CYPRESS CREEK Indiana Scour Critical — Countermeasures Installed Fair 1969 9,600
GRAND RIVER Michigan Scour Critical — Countermeasures Installed Fair 1957 9,599
GRAND RIVER Michigan Scour Critical — Countermeasures Installed Poor 1957 9,599
SWEDE RUN New Jersey Scour Critical — Countermeasures Installed Good 1934 9,596
ROCKY RIVER Michigan Scour Critical — Countermeasures Installed Fair 1951 9,588
ROCKY RIVER Michigan Scour Critical — Countermeasures Installed Fair 1956 9,588
HOLDEN DRAIN Michigan Scour Critical — Countermeasures Installed Fair 1923 9,585
Luckiamute River Oregon Scour Critical — Countermeasures Installed Fair 1954 9,582
MILL CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1965 9,578
BRANCH OF MILL CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1966 9,578
West Fork Dairy Creek Oregon Scour Critical — Countermeasures Installed Poor 1940 9,574
BRUSHY BROOK Rhode Island Scour Critical — Countermeasures Installed Fair 1922 9,567
WOOD RIVER Rhode Island Scour Critical — Countermeasures Installed Fair 1923 9,567
MOREAU RVR Missouri Scour Critical — Countermeasures Installed Poor 1984 9,565
INGRAMS THOROFARE New Jersey Scour Critical — Countermeasures Installed Fair 1967 9,560
S. FK. FORKED DEER RIVER Tennessee Scour Critical — Countermeasures Installed Good 1959 9,555

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.