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
TOBY CREEK Pennsylvania Scour Critical — Countermeasures Installed Poor 1941 29,878
PIGEON RIVER Tennessee Scour Critical — Countermeasures Installed Fair 1966 29,828
PIGEON RIVER Tennessee Scour Critical — Countermeasures Installed Poor 1966 29,828
GILLS CREEK South Carolina Scour Critical — Countermeasures Installed Fair 1940 29,800
TRIB.TO MOSELEM CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1934 29,775
DARBY CREEK Pennsylvania Scour Critical — Countermeasures Installed Poor 1950 29,754
GREAT SWAMP South Carolina Scour Critical — Countermeasures Installed Fair 1966 29,700
GREAT SWAMP South Carolina Scour Critical — Countermeasures Installed Fair 1966 29,700
MISSOURI RVR UP RR Missouri Scour Critical — Countermeasures Installed Fair 1955 29,666
WILLAMETTE R OFLOW WB Oregon Scour Critical — Countermeasures Installed Fair 1961 29,662
ROUGE RIVER Michigan Scour Critical — Countermeasures Installed Poor 1932 29,650
MIDDLE BR CLINTON RIVER Michigan Scour Critical — Countermeasures Installed Fair 1966 29,646
Cox Creek Oregon Scour Critical — Countermeasures Installed Good 1940 29,551
Calapooia River Oregon Scour Critical — Countermeasures Installed Fair 1971 29,513
Calapooia Overflow Oregon Scour Critical — Countermeasures Installed Fair 1971 29,513
Calapooia Overflow Oregon Scour Critical — Countermeasures Installed Fair 1971 29,513
GLADES CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1939 29,452
SEXTON KILFOIL DRAIN Michigan Scour Critical — Countermeasures Installed Good 1986 29,303
SEXTON KILFOIL DRAIN Michigan Scour Critical — Countermeasures Installed Fair 1964 29,303
NEWAUKUM RIVER Washington Scour Critical — Countermeasures Installed Fair 1952 29,186
NEWAUKUM RIVER Washington Scour Critical — Countermeasures Installed Fair 1952 29,186
PR 765 & BEATRIZ CRE Puerto Rico Scour Critical — Countermeasures Installed Fair 1972 29,150
PR 765 & BEATRIZ CRE Puerto Rico Scour Critical — Countermeasures Installed Poor 1972 29,150
SPRING LAKE CHANNEL Michigan Scour Critical — Countermeasures Installed Fair 1966 29,125
LITTLE DRY CREEK Colorado Scour Critical — Countermeasures Installed Poor 1965 29,000
MILL CREEK Michigan Scour Critical — Countermeasures Installed Fair 1961 28,818
MILL CREEK Michigan Scour Critical — Countermeasures Installed Fair 1961 28,818
MISSOURI RVR CST MOK Missouri Scour Critical — Countermeasures Installed Fair 1991 28,808
CAGUITAS RIVER Puerto Rico Scour Critical — Countermeasures Installed Fair 1953 28,745
BEAR RIVER Michigan Scour Critical — Countermeasures Installed Fair 1930 28,667
SNI-A-BAR CR Missouri Scour Critical — Countermeasures Installed Fair 1963 28,534
HONEY CREEK Indiana Scour Critical — Countermeasures Installed Good 1994 28,504
HONEY CREEK Indiana Scour Critical — Countermeasures Installed Good 1993 28,504
MATADERO CREEK Puerto Rico Scour Critical — Countermeasures Installed Fair 1925 28,500
WEOWEOPILAU STRM Hawaii Scour Critical — Countermeasures Installed Fair 1937 28,400
WILDCAT CREEK Indiana Scour Critical — Countermeasures Installed Good 1969 28,376
WILDCAT CREEK Indiana Scour Critical — Countermeasures Installed Good 1969 28,376
BRAYS BAYOU Texas Scour Critical — Countermeasures Installed Good 1986 28,257
Dairy Creek Oregon Scour Critical — Countermeasures Installed Fair 1923 28,179
S. FORK FISHING CK South Carolina Scour Critical — Countermeasures Installed Fair 1979 28,150
GREEN RIVER Washington Scour Critical — Countermeasures Installed Fair 1959 28,147
WISCONSIN RIVER 31 Wisconsin Scour Critical — Countermeasures Installed Poor 1915 28,144
RAMBIN BAYOU Louisiana Scour Critical — Countermeasures Installed Fair 1986 28,142
JONHSON CHUTE BAYOU Louisiana Scour Critical — Countermeasures Installed Fair 1985 28,142
SPOKANE RIVER Washington Scour Critical — Countermeasures Installed Fair 1973 28,100
PINE RUN CREEK Michigan Scour Critical — Countermeasures Installed Fair 1958 28,043
PINE RUN CREEK Michigan Scour Critical — Countermeasures Installed Fair 1958 28,043
AMITY DITCH Indiana Scour Critical — Countermeasures Installed Fair 1970 28,018
Dry Bayou Arkansas Scour Critical — Countermeasures Installed Good 1952 28,000
BIG POTTSBURG CREEK Florida Scour Critical — Countermeasures Installed Fair 1927 28,000

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.