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
DUEY RIVER Puerto Rico Scour Critical — Countermeasures Installed Fair 1949 3,600
UNNAMED CREEK Puerto Rico Scour Critical — Countermeasures Installed Fair 1950 3,600
TRIB TO PACOLET RIVER South Carolina Scour Critical — Countermeasures Installed Fair 1973 3,600
KINGS CREEK South Carolina Scour Critical — Countermeasures Installed Fair 1950 3,600
SANTIAGO RIVER Puerto Rico Scour Critical — Countermeasures Installed Fair 1954 3,600
CERCADA CREEK Puerto Rico Scour Critical — Countermeasures Installed Poor 1927 3,600
FAJARDO RIVER Puerto Rico Scour Critical — Countermeasures Installed Fair 1961 3,600
UNNAMED WATERWAY Puerto Rico Scour Critical — Countermeasures Installed Fair 1939 3,600
DAGUAO RIVER Puerto Rico Scour Critical — Countermeasures Installed Fair 1923 3,600
CERRO GORDO CREEK Puerto Rico Scour Critical — Countermeasures Installed Fair 1939 3,600
BOTIJAS RIVER Puerto Rico Scour Critical — Countermeasures Installed Poor 1940 3,600
DUNCAN CREEK South Carolina Scour Critical — Countermeasures Installed Fair 1952 3,600
RIVIERA BAY Florida Scour Critical — Countermeasures Installed Fair 1962 3,600
PORTER BROOK Connecticut Scour Critical — Countermeasures Installed Fair 1871 3,600
COVE SOUND CREEK Florida Scour Critical — Countermeasures Installed Fair 1976 3,600
OSSIPEE RIVER New Hampshire Scour Critical — Countermeasures Installed Good 1956 3,594
BRUSHY BAYOU Louisiana Scour Critical — Countermeasures Installed Fair 1987 3,594
BIG CEDAR RIVER Michigan Scour Critical — Countermeasures Installed Good 1933 3,591
WASHOUGAL RIVER Washington Scour Critical — Countermeasures Installed Fair 1954 3,589
SOUHEGAN RIVER New Hampshire Scour Critical — Countermeasures Installed Good 1987 3,589
SHIAWASSEE RIVER Michigan Scour Critical — Countermeasures Installed Poor 1930 3,587
BOULDER CREEK Washington Scour Critical — Countermeasures Installed Good 1962 3,586
BAYOU SAN PATRICIO Louisiana Scour Critical — Countermeasures Installed Fair 1977 3,585
CONEWAGO CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1934 3,584
DUCK CREEK Texas Scour Critical — Countermeasures Installed Fair 1970 3,583
KEEN BRANCH Texas Scour Critical — Countermeasures Installed Good 1967 3,583
SO. BR. SWATARA CREEK Pennsylvania Scour Critical — Countermeasures Installed Poor 1920 3,582
SMOKY HILL RIVER Kansas Scour Critical — Countermeasures Installed Fair 1970 3,581
N BR PRESQUE ISLE STREAM Maine Scour Critical — Countermeasures Installed Fair 1929 3,581
DRAINAGE CANAL Tennessee Scour Critical — Countermeasures Installed Fair 1926 3,574
MARYS CREEK Tennessee Scour Critical — Countermeasures Installed Fair 1959 3,574
DRAINAGE CANAL Tennessee Scour Critical — Countermeasures Installed Poor 1926 3,574
DRAIN Louisiana Scour Critical — Countermeasures Installed Fair 1954 3,571
BRIGGS CREEK Oregon Scour Critical — Countermeasures Installed Fair 1953 3,566
HILL CREEK Oregon Scour Critical — Countermeasures Installed Good 1938 3,562
BRANCH LITTLE NESHAMINY Pennsylvania Scour Critical — Countermeasures Installed Poor 1927 3,559
PLUM CREEK Kansas Scour Critical — Countermeasures Installed Good 1982 3,558
PARADISE CREEK Oregon Scour Critical — Countermeasures Installed Fair 1932 3,554
STONY RUN Pennsylvania Scour Critical — Countermeasures Installed Poor 1958 3,554
TRIBUTARY ELK CREEK Ohio Scour Critical — Countermeasures Installed Fair 1994 3,552
SWAN RIVER New York Scour Critical — Countermeasures Installed Good 1988 3,549
SANDY CREEK Louisiana Scour Critical — Countermeasures Installed Fair 1957 3,548
DIRICKSON CREEK Delaware Scour Critical — Countermeasures Installed Fair 1961 3,548
Fern Creek Oregon Scour Critical — Countermeasures Installed Poor 1953 3,545
COQUILLE RIVER Oregon Scour Critical — Countermeasures Installed Fair 1962 3,545
SASCO BROOK Connecticut Scour Critical — Countermeasures Installed Poor 1973 3,540
OVER SAGE RUN Pennsylvania Scour Critical — Countermeasures Installed Fair 1942 3,539
BRANCH MARTINS CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1955 3,539
OVER SAGE RUN Pennsylvania Scour Critical — Countermeasures Installed Fair 1942 3,539
OVER SAGE RUN Pennsylvania Scour Critical — Countermeasures Installed Fair 1942 3,539

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.