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
MENOMINEE RIVER Michigan Scour Critical — Countermeasures Installed Fair 1973 5,620
TACONY CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1929 5,619
SEVENTEEN MILE CREEK Indiana Scour Critical — Countermeasures Installed Good 1996 5,613
MIDDLE CREEK Tennessee Scour Critical — Countermeasures Installed Poor 1951 5,610
RICHLAND CREEK Mississippi Scour Critical — Countermeasures Installed Poor 1939 5,600
S.FK.COEUR DALENE RIVER Idaho Scour Critical — Countermeasures Installed Fair 1976 5,600
SAW MILL RUN Pennsylvania Scour Critical — Countermeasures Installed Fair 1932 5,600
SAW MILL RUN Pennsylvania Scour Critical — Countermeasures Installed Fair 1900 5,600
SALMON CANAL Florida Scour Critical — Countermeasures Installed Fair 1968 5,600
KAIPOIOI STRM Hawaii Scour Critical — Countermeasures Installed Fair 1933 5,600
REEDY RIVER South Carolina Scour Critical — Countermeasures Installed Fair 1975 5,600
CANAL L Florida Scour Critical — Countermeasures Installed Good 1982 5,600
KOLEKOLE STRM Hawaii Scour Critical — Countermeasures Installed Fair 1950 5,600
JAMES RIVER North Dakota Scour Critical — Countermeasures Installed Fair 1939 5,600
HARRIGAN BRANCH Indiana Scour Critical — Countermeasures Installed Fair 1933 5,597
Mill Creek Oregon Scour Critical — Countermeasures Installed Fair 1961 5,594
South Santiam River Oregon Scour Critical — Countermeasures Installed Fair 1973 5,594
ROCK CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1942 5,593
SHATZLEY DITCH Indiana Scour Critical — Countermeasures Installed Fair 1992 5,585
Yellow Water River Louisiana Scour Critical — Countermeasures Installed Fair 1976 5,582
SAM BISHOP DITCH Tennessee Scour Critical — Countermeasures Installed Poor 1958 5,579
N. FORK WHITE OAK CREEK Tennessee Scour Critical — Countermeasures Installed Poor 1958 5,579
STEMILT CR. Washington Scour Critical — Countermeasures Installed Fair 1951 5,578
SNAKE RIVER Minnesota Scour Critical — Countermeasures Installed Poor 1976 5,576
ALLEN DRAIN Michigan Scour Critical — Countermeasures Installed Fair 1985 5,571
WISNER DRAIN Michigan Scour Critical — Countermeasures Installed Fair 1985 5,571
CARPENTERS BAYOU Texas Scour Critical — Countermeasures Installed Fair 1975 5,570
Marquam Creek Oregon Scour Critical — Countermeasures Installed Good 1985 5,569
HENSLEY CREEK Indiana Scour Critical — Countermeasures Installed Fair 1990 5,566
HARBERTS CREEK Indiana Scour Critical — Countermeasures Installed Fair 1993 5,566
CALAPOOIA RIVER Oregon Scour Critical — Countermeasures Installed Fair 1940 5,562
OVER FOUR MILE CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1941 5,562
PAWCATUCK RIVER Connecticut Scour Critical — Countermeasures Installed Fair 1953 5,562
EAST POND CREEK Michigan Scour Critical — Countermeasures Installed Fair 1964 5,560
WATER BOUND BROOK Massachusetts Scour Critical — Countermeasures Installed Good 2008 5,560
N FORK TAYLOR BAYOU Texas Scour Critical — Countermeasures Installed Fair 1937 5,555
FOURMILE CREEK Oregon Scour Critical — Countermeasures Installed Fair 1929 5,551
LA PLATA RIVER Puerto Rico Scour Critical — Countermeasures Installed Fair 1997 5,550
NORTHEAST CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1967 5,547
WATERWAY CANAL Michigan Scour Critical — Countermeasures Installed Good 2021 5,546
PILGRIM RIVER Michigan Scour Critical — Countermeasures Installed Fair 1916 5,543
N BR DEVIL RIVER Michigan Scour Critical — Countermeasures Installed Fair 1933 5,537
HCFCD DITCH Texas Scour Critical — Countermeasures Installed Fair 1987 5,536
SEALS GULLY Texas Scour Critical — Countermeasures Installed Fair 1995 5,533
LITTLE KLICKITAT RIVER Washington Scour Critical — Countermeasures Installed Fair 1956 5,532
BRANCH CEDAR CREEK Indiana Scour Critical — Countermeasures Installed Fair 1976 5,530
LITTLE MANATAWNY CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1962 5,524
MILL CREEK Georgia Scour Critical — Countermeasures Installed Good 1981 5,520
CASS RIVER Michigan Scour Critical — Countermeasures Installed Fair 1941 5,516
BEAN CREEK Michigan Scour Critical — Countermeasures Installed Fair 1934 5,505

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.