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
POCOTALIGO SWAMP (NO. 3) South Carolina Scour Critical — Countermeasures Installed Fair 1967 18,100
POCOTALIGO SWAMP (NO. 3) South Carolina Scour Critical — Countermeasures Installed Fair 1967 18,100
BEAVER CREEK Michigan Scour Critical — Countermeasures Installed Fair 1919 18,099
CRUM CREEK Pennsylvania Scour Critical — Countermeasures Installed Poor 1926 18,095
FOUNTAIN CREEK Colorado Scour Critical — Countermeasures Installed Fair 1972 18,073
PLATTE RVR Missouri Scour Critical — Countermeasures Installed Fair 1950 18,026
PLATTE RVR OVRFL Missouri Scour Critical — Countermeasures Installed Poor 1950 18,026
BLACK CREEK Michigan Scour Critical — Countermeasures Installed Good 1984 18,011
TAR RIVER North Carolina Scour Critical — Countermeasures Installed Fair 1977 18,000
SNAKE RIVER;W.BLACKFOOT Idaho Scour Critical — Countermeasures Installed Fair 1965 18,000
TOISNOT SWAMP North Carolina Scour Critical — Countermeasures Installed Good 1977 18,000
TOISNOT SWAMP North Carolina Scour Critical — Countermeasures Installed Good 1977 18,000
DRY CREEK California Scour Critical — Countermeasures Installed Good 1928 18,000
TAR RIVER North Carolina Scour Critical — Countermeasures Installed Fair 1977 18,000
MUSKEGON RIVER Michigan Scour Critical — Countermeasures Installed Fair 1983 18,000
BOULDER CREEK Colorado Scour Critical — Countermeasures Installed Fair 1960 18,000
TOWN CR Mississippi Scour Critical — Countermeasures Installed Fair 1962 18,000
BOULDER CREEK Colorado Scour Critical — Countermeasures Installed Poor 1952 18,000
BRAZOS RIVER Texas Scour Critical — Countermeasures Installed Fair 1965 17,960
ROCK CREEK Oregon Scour Critical — Countermeasures Installed Fair 1957 17,900
PROVIDENCE SWAMP South Carolina Scour Critical — Countermeasures Installed Fair 1973 17,900
CAÑAS RIVER Puerto Rico Scour Critical — Countermeasures Installed Fair 1970 17,900
PROVIDENCE SWAMP South Carolina Scour Critical — Countermeasures Installed Fair 1973 17,900
CA¥AS RIVER Puerto Rico Scour Critical — Countermeasures Installed Fair 1970 17,900
Intracoastal Waterway Florida Scour Critical — Countermeasures Installed Fair 1967 17,900
CLINTON RIVER Michigan Scour Critical — Countermeasures Installed Good 1967 17,835
CLINTON RIVER Michigan Scour Critical — Countermeasures Installed Good 1967 17,835
SANTA ANA RIVER California Scour Critical — Countermeasures Installed Fair 1953 17,821
Whippany River New Jersey Scour Critical — Countermeasures Installed Fair 1891 17,820
13th & Shelton Ditch Oregon Scour Critical — Countermeasures Installed Good 1988 17,817
ROCK CREEK Arkansas Scour Critical — Countermeasures Installed Fair 1963 17,814
WHEELER BRANCH Texas Scour Critical — Countermeasures Installed Fair 1948 17,806
N. EDISTO RIVER South Carolina Scour Critical — Countermeasures Installed Fair 1970 17,800
BRANCH CANAL BAYOU Florida Scour Critical — Countermeasures Installed Good 1988 17,800
N. EDISTO RIVER South Carolina Scour Critical — Countermeasures Installed Fair 1970 17,800
CANAL MAIN B Florida Scour Critical — Countermeasures Installed Good 1988 17,800
MANISTEE RIVER Michigan Scour Critical — Countermeasures Installed Fair 1933 17,789
POHATCONG CREEK New Jersey Scour Critical — Countermeasures Installed Fair 1984 17,779
HONEY RUN Indiana Scour Critical — Countermeasures Installed Good 1959 17,764
MYAKKA RIVER Florida Scour Critical — Countermeasures Installed Fair 1977 17,750
MYAKKA RIVER Florida Scour Critical — Countermeasures Installed Good 1977 17,750
SALT CREEK Florida Scour Critical — Countermeasures Installed Fair 1977 17,750
SALT CREEK Florida Scour Critical — Countermeasures Installed Fair 1977 17,750
PENNYPACK CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1918 17,735
LITTLE CACOOSING CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1947 17,731
CLEAR CREEK Tennessee Scour Critical — Countermeasures Installed Fair 1926 17,719
MOANALUA STRM Hawaii Scour Critical — Countermeasures Installed Fair 1961 17,692
OUACHITA RIVER-LOUISVILL Louisiana Scour Critical — Countermeasures Installed Fair 1936 17,683
YAKIMA RIVER Washington Scour Critical — Countermeasures Installed Fair 1962 17,681
YAKIMA RIVER Washington Scour Critical — Countermeasures Installed Fair 1917 17,681

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.