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
ALLEGHENY CREEK Pennsylvania Scour Critical — Countermeasures Installed Poor 1956 10,331
CREEK Oklahoma Scour Critical — Countermeasures Installed Poor 1979 10,315
CROSS BAYOU Louisiana Scour Critical — Countermeasures Installed Fair 1960 10,312
MOREAU RVR Missouri Scour Critical — Countermeasures Installed Fair 1969 10,305
MOREAU RVR OVERFLO Missouri Scour Critical — Countermeasures Installed Good 1969 10,305
WATERWAY Puerto Rico Scour Critical — Countermeasures Installed Fair 1930 10,300
ST JOSEPH RIVER Indiana Scour Critical — Countermeasures Installed Fair 1965 10,300
BUCK CREEK Michigan Scour Critical — Countermeasures Installed Fair 1965 10,300
GALLARDO CHANNEL Puerto Rico Scour Critical — Countermeasures Installed Good 1961 10,300
La Vega Creek Puerto Rico Scour Critical — Countermeasures Installed Poor 1940 10,300
CREEK Puerto Rico Scour Critical — Countermeasures Installed Poor 1930 10,300
GRAZE CREEK South Carolina Scour Critical — Countermeasures Installed Fair 1989 10,300
LA MINA RIVER Puerto Rico Scour Critical — Countermeasures Installed Fair 1862 10,300
COFRESI CREEK Puerto Rico Scour Critical — Countermeasures Installed Poor 1940 10,300
UNNAMED CREEK Puerto Rico Scour Critical — Countermeasures Installed Fair 1999 10,300
LA VEGA CREEK Puerto Rico Scour Critical — Countermeasures Installed Poor 1940 10,300
OVER SR 3020 & ELK CK. Pennsylvania Scour Critical — Countermeasures Installed Fair 1969 10,274
DRY CREEK CANAL California Scour Critical — Countermeasures Installed Good 1952 10,269
ROCK RUN Pennsylvania Scour Critical — Countermeasures Installed Poor 1954 10,266
OVERFLOW CHANNEL Oregon Scour Critical — Countermeasures Installed Fair 1985 10,265
INDIAN MILL CREEK Michigan Scour Critical — Countermeasures Installed Good 1984 10,251
STONY BROOK New Jersey Scour Critical — Countermeasures Installed Good 1976 10,248
WATER CHARLES RIVER Massachusetts Scour Critical — Countermeasures Installed Fair 1847 10,216
Natural Corral Wash Arizona Scour Critical — Countermeasures Installed Fair 1961 10,203
Cane Springs Wash Arizona Scour Critical — Countermeasures Installed Fair 1961 10,203
AMITE RIVER Louisiana Scour Critical — Countermeasures Installed Good 2009 10,200
PORTUGUES RIVER Puerto Rico Scour Critical — Countermeasures Installed Poor 1969 10,200
PORTUGUES RIVER Puerto Rico Scour Critical — Countermeasures Installed Poor 1969 10,200
KOLOA STRM-LAIEMALOO Hawaii Scour Critical — Countermeasures Installed Fair 1933 10,200
BARK RIVER Wisconsin Scour Critical — Countermeasures Installed Fair 1957 10,200
HUDSON BAYOU Florida Scour Critical — Countermeasures Installed Good 1916 10,200
CROWDERS CREEK South Carolina Scour Critical — Countermeasures Installed Fair 1957 10,200
North Yamhill River Oregon Scour Critical — Countermeasures Installed Fair 1959 10,193
GRIFFY CREEK Indiana Scour Critical — Countermeasures Installed Fair 1972 10,184
HOLTON CREEK Oregon Scour Critical — Countermeasures Installed Fair 1926 10,152
TEN MILE RIVER Rhode Island Scour Critical — Countermeasures Installed Fair 1946 10,151
HACIENDA WASH California Scour Critical — Countermeasures Installed Poor 1971 10,150
HACIENDA WASH California Scour Critical — Countermeasures Installed Fair 1971 10,150
PAWTUXET RIVER Rhode Island Scour Critical — Countermeasures Installed Fair 1967 10,149
S. BR. PENNSAUKEN CREEK New Jersey Scour Critical — Countermeasures Installed Fair 1909 10,139
TITTABAWASSEE RIVER Michigan Scour Critical — Countermeasures Installed Fair 1976 10,133
ITHAN CREEK Pennsylvania Scour Critical — Countermeasures Installed Poor 1930 10,128
CLOQUALLUM CR Washington Scour Critical — Countermeasures Installed Good 1962 10,124
E FK WILDCAT CR Washington Scour Critical — Countermeasures Installed Good 1962 10,124
E FK WILDCAT CR Washington Scour Critical — Countermeasures Installed Good 1962 10,124
CLOQUALLUM CR Washington Scour Critical — Countermeasures Installed Good 1962 10,124
LACAMAS CREEK Washington Scour Critical — Countermeasures Installed Good 1921 10,107
SAUGATUCKET RIVER Rhode Island Scour Critical — Countermeasures Installed Fair 1920 10,107
JOHNSON CREEK Oregon Scour Critical — Countermeasures Installed Good 1985 10,101
CAMUY RIVER Puerto Rico Scour Critical — Countermeasures Installed Fair 1942 10,100

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.