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
RAISIN RIVER & ELM AVE Michigan Scour Critical — Countermeasures Installed Fair 1988 27,951
N BRANCH WRECK POND New Jersey Scour Critical — Countermeasures Installed Fair 1941 27,928
COBBS CREEK Pennsylvania Scour Critical — Countermeasures Installed Poor 1934 27,899
BRANCH OF ROYCES BROOK New Jersey Scour Critical — Countermeasures Installed Fair 1923 27,845
HORSEPEN CREEK Texas Scour Critical — Countermeasures Installed Fair 1975 27,840
BIG WILLS CREEK Alabama Scour Critical — Countermeasures Installed Good 1992 27,802
BIG WILLS CREEK Alabama Scour Critical — Countermeasures Installed Good 1992 27,802
BUCK CREEK Michigan Scour Critical — Countermeasures Installed Fair 1986 27,800
AMITY DITCH Indiana Scour Critical — Countermeasures Installed Good 1970 27,789
CYPRESS SWAMP South Carolina Scour Critical — Countermeasures Installed Fair 1961 27,700
CYPRESS SWAMP South Carolina Scour Critical — Countermeasures Installed Fair 1961 27,700
MIDDLE ROUGE R Michigan Scour Critical — Countermeasures Installed Good 1959 27,634
MIDDLE ROUGE R Michigan Scour Critical — Countermeasures Installed Good 1959 27,634
MIDDLE BR CLINTON RIVER Michigan Scour Critical — Countermeasures Installed Good 1966 27,631
BRNT MEADOW (GRN PD) BRK New Jersey Scour Critical — Countermeasures Installed Fair 1960 27,614
PLEASANT RUN CREEK Indiana Scour Critical — Countermeasures Installed Fair 1991 27,568
NORRIS DITCH NO 2 Indiana Scour Critical — Countermeasures Installed Fair 1971 27,527
WATER CONNECTICUT RIVER Massachusetts Scour Critical — Countermeasures Installed Fair 1924 27,500
SAND CREEK Idaho Scour Critical — Countermeasures Installed Poor 1994 27,500
PR 328 0.03 KM Puerto Rico Scour Critical — Countermeasures Installed Fair 1974 27,500
LAKE LANSING OUTLET Michigan Scour Critical — Countermeasures Installed Fair 1931 27,408
BUCK CR Michigan Scour Critical — Countermeasures Installed Poor 1933 27,400
UKUMEHAME STRM Hawaii Scour Critical — Countermeasures Installed Fair 1950 27,400
INABON RIVER Puerto Rico Scour Critical — Countermeasures Installed Poor 1970 27,300
INABON RIVER Puerto Rico Scour Critical — Countermeasures Installed Fair 1970 27,300
WATER WESTFIELD RIVER Massachusetts Scour Critical — Countermeasures Installed Fair 1938 27,300
SAUCON CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1929 27,279
North Channel Toms River New Jersey Scour Critical — Countermeasures Installed Poor 1928 27,261
COW CASTLE CREEK South Carolina Scour Critical — Countermeasures Installed Fair 1961 27,250
COW CASTLE CREEK South Carolina Scour Critical — Countermeasures Installed Fair 1961 27,250
BIG EAGLE CREEK Indiana Scour Critical — Countermeasures Installed Good 1960 27,250
BIG EAGLE CREEK Indiana Scour Critical — Countermeasures Installed Good 1960 27,250
STONY CREEK Pennsylvania Scour Critical — Countermeasures Installed Poor 1878 27,202
GRAND RIVER Michigan Scour Critical — Countermeasures Installed Fair 1927 27,197
PIEDRAS RIVER Puerto Rico Scour Critical — Countermeasures Installed Fair 1965 27,100
PIEDRAS RIVER Puerto Rico Scour Critical — Countermeasures Installed Poor 1953 27,100
Oak Creek Oregon Scour Critical — Countermeasures Installed Fair 1958 27,073
Oak Creek Oregon Scour Critical — Countermeasures Installed Good 1958 27,073
NORTH CHICKAMAUGA CREEK Tennessee Scour Critical — Countermeasures Installed Fair 1955 27,012
FRENCH BROAD RIVER North Carolina Scour Critical — Countermeasures Installed Fair 1967 27,000
SAMMAMISH R Washington Scour Critical — Countermeasures Installed Fair 1972 27,000
LAUREL CREEK South Carolina Scour Critical — Countermeasures Installed Fair 1954 27,000
UPRR & TRUCKEE RIVER Nevada Scour Critical — Countermeasures Installed Fair 1990 27,000
Albany Ditch Oregon Scour Critical — Countermeasures Installed Fair 1958 26,927
Albany Ditch Oregon Scour Critical — Countermeasures Installed Fair 1958 26,927
North Channel Toms River New Jersey Scour Critical — Countermeasures Installed Poor 1928 26,921
MANATAWNY CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1958 26,919
SNAKE R. (HWY 493) Oregon Scour Critical — Countermeasures Installed Good 1967 26,880
UNKNOWN CREEK Puerto Rico Scour Critical — Countermeasures Installed Fair 1997 26,800
WAIPAHOEHOE STRM Hawaii Scour Critical — Countermeasures Installed Good 1968 26,700

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.