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
BENS CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1953 5,265
YOUNGS CREEK Indiana Scour Critical — Countermeasures Installed Fair 1946 5,263
HURON RIVER Michigan Scour Critical — Countermeasures Installed Good 2006 5,259
CUB CREEK Tennessee Scour Critical — Countermeasures Installed Fair 1973 5,257
CASS RIVER Michigan Scour Critical — Countermeasures Installed Fair 1934 5,255
NECANICUM RIVER Oregon Scour Critical — Countermeasures Installed Fair 1957 5,250
ARKANSAS RIVER Colorado Scour Critical — Countermeasures Installed Fair 1963 5,240
MILL CREEK Oregon Scour Critical — Countermeasures Installed Fair 1948 5,239
LITTLE LEHIGH CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 2013 5,235
SHIAWASSEE RIVER Michigan Scour Critical — Countermeasures Installed Fair 1988 5,232
SAN JACINTO RIVER Texas Scour Critical — Countermeasures Installed Fair 1977 5,232
CASTILE CR Missouri Scour Critical — Countermeasures Installed Fair 1966 5,231
BEAR CREEK Louisiana Scour Critical — Countermeasures Installed Fair 1963 5,228
GR RONDE R (ISLAND CITY) Oregon Scour Critical — Countermeasures Installed Good 1976 5,223
Rillito Creek Arizona Scour Critical — Countermeasures Installed Fair 1963 5,205
SUWANNEE RIVER RELIEF Florida Scour Critical — Countermeasures Installed Fair 1947 5,200
AU TRAIN RIVER Michigan Scour Critical — Countermeasures Installed Fair 1932 5,200
CASTAÑON CHANNEL Puerto Rico Scour Critical — Countermeasures Installed Poor 1927 5,200
NORTH FORK OGDEN RIVER Utah Scour Critical — Countermeasures Installed Fair 1947 5,200
SOUTH BR. FLINT RIVER Michigan Scour Critical — Countermeasures Installed Good 1935 5,200
FEATHER RIVER California Scour Critical — Countermeasures Installed Fair 1965 5,200
CASEI RIVER Puerto Rico Scour Critical — Countermeasures Installed Fair 1902 5,200
SAW MILL RUN CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1983 5,200
SHUNOCK RIVER Connecticut Scour Critical — Countermeasures Installed Fair 1954 5,200
BR DUTCH GAP CANAL Wisconsin Scour Critical — Countermeasures Installed Poor 1941 5,200
ARROYATA RIVER Puerto Rico Scour Critical — Countermeasures Installed Fair 1991 5,200
BEAR CREEK South Carolina Scour Critical — Countermeasures Installed Fair 1978 5,200
BR TO LITTLE RIVER South Carolina Scour Critical — Countermeasures Installed Good 1980 5,200
MOUNGERS CREEK Mississippi Scour Critical — Countermeasures Installed Good 1994 5,200
MORTON CREEK Oregon Scour Critical — Countermeasures Installed Fair 1925 5,197
HICKS CREEK Tennessee Scour Critical — Countermeasures Installed Fair 1973 5,192
BAYOU SAN MIGUEL Louisiana Scour Critical — Countermeasures Installed Good 2002 5,192
Niger Canyon Arizona Scour Critical — Countermeasures Installed Fair 1942 5,190
LAMINE RVR Missouri Scour Critical — Countermeasures Installed Fair 1972 5,190
DESCHUTES RIVER Washington Scour Critical — Countermeasures Installed Fair 1943 5,190
SIUSLAW RIVER(MAPLETON) Oregon Scour Critical — Countermeasures Installed Fair 1970 5,185
KALAMAZOO RIVER Michigan Scour Critical — Countermeasures Installed Poor 1930 5,183
TAMARACK CREEK Michigan Scour Critical — Countermeasures Installed Fair 1932 5,181
AMMONOOSUC RIVER New Hampshire Scour Critical — Countermeasures Installed Fair 1972 5,178
BIRDSONG CREEK OVERFLOW Tennessee Scour Critical — Countermeasures Installed Fair 1975 5,176
BIRDSONG CREEK Tennessee Scour Critical — Countermeasures Installed Fair 1975 5,176
TURKEY RUN GULLY Texas Scour Critical — Countermeasures Installed Fair 1958 5,175
TRIB TO FISHING CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1938 5,174
RICHLAND CREEK Tennessee Scour Critical — Countermeasures Installed Fair 1974 5,170
BIG SANDY RIVER Tennessee Scour Critical — Countermeasures Installed Fair 1986 5,165
TICKLE CREEK Oregon Scour Critical — Countermeasures Installed Fair 1961 5,162
Pinal Creek Arizona Scour Critical — Countermeasures Installed Poor 1920 5,162
WALLOWA RIVER (RAILROAD) Oregon Scour Critical — Countermeasures Installed Good 1966 5,160
BILLS BRANCH Louisiana Scour Critical — Countermeasures Installed Fair 1977 5,160
TROUT CREEK Oregon Scour Critical — Countermeasures Installed Good 1988 5,160

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.