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
TRUCKEE RVR Nevada Scour Critical — Countermeasures Installed Fair 1921 13,000
KOOTENAI R;UPRR;BNNRS FY Idaho Scour Critical — Countermeasures Installed Fair 1984 13,000
CEDAR RIVER Iowa Scour Critical — Countermeasures Installed Fair 1920 13,000
PEACE CREEK RELIEF Florida Scour Critical — Countermeasures Installed Good 1951 13,000
Spout Spring Br. - Fay. Arkansas Scour Critical — Countermeasures Installed Poor 1940 13,000
WATER SUDBURY RIVER Massachusetts Scour Critical — Countermeasures Installed Fair 1967 13,000
NEUSE RIVER North Carolina Scour Critical — Countermeasures Installed Fair 1961 13,000
LITTLE CREEK North Carolina Scour Critical — Countermeasures Installed Poor 1979 13,000
BOOKER CREEK Florida Scour Critical — Countermeasures Installed Good 1965 13,000
TOWAMENCIN CREEK Pennsylvania Scour Critical — Countermeasures Installed Poor 1928 12,986
MAURICE RIVER New Jersey Scour Critical — Countermeasures Installed Fair 1970 12,950
POST OAK CREEK Texas Scour Critical — Countermeasures Installed Fair 1971 12,948
POST OAK CREEK Texas Scour Critical — Countermeasures Installed Fair 1971 12,948
Larimer Co. Canal No. 2 Colorado Scour Critical — Countermeasures Installed Fair 1920 12,947
GAYHEAD POND INLT New York Scour Critical — Countermeasures Installed Fair 1935 12,935
MANOA PALOLO STRM Hawaii Scour Critical — Countermeasures Installed Fair 1937 12,921
MEADOW STREAM New York Scour Critical — Countermeasures Installed Fair 1930 12,909
CROSS BAYOU CANAL Florida Scour Critical — Countermeasures Installed Good 1984 12,900
SWARTZ CREEK Michigan Scour Critical — Countermeasures Installed Fair 1918 12,900
SELSERS CREEK Louisiana Scour Critical — Countermeasures Installed Fair 1938 12,900
PENNYPACK CREEK Pennsylvania Scour Critical — Countermeasures Installed Poor 1930 12,877
PENNYPACK CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1930 12,877
WAXHAW CREEK South Carolina Scour Critical — Countermeasures Installed Fair 1973 12,850
ANAHULU STRM Hawaii Scour Critical — Countermeasures Installed Poor 1921 12,850
CANE CREEK South Carolina Scour Critical — Countermeasures Installed Fair 1974 12,850
KALAMAZOO RIVER Michigan Scour Critical — Countermeasures Installed Fair 1973 12,841
PEQUANNOCK RIVER New Jersey Scour Critical — Countermeasures Installed Fair 1925 12,830
LA NANA BAYOU Texas Scour Critical — Countermeasures Installed Fair 1962 12,825
PASCACK BROOK New Jersey Scour Critical — Countermeasures Installed Fair 1975 12,821
WATERWAY Delaware Scour Critical — Countermeasures Installed Fair 1925 12,820
WATER SPICKET RIVER Massachusetts Scour Critical — Countermeasures Installed Poor 1900 12,808
WAGNER CREEK Oregon Scour Critical — Countermeasures Installed Fair 1937 12,804
E FORK CARSON RVR Nevada Scour Critical — Countermeasures Installed Fair 1951 12,800
BIG DUTCHMAN CREEK South Carolina Scour Critical — Countermeasures Installed Fair 1979 12,800
TRUCKEE RIVER Nevada Scour Critical — Countermeasures Installed Poor 1966 12,800
JAGUEYES CREEK Puerto Rico Scour Critical — Countermeasures Installed Fair 1967 12,800
COTTONWOOD SLOUGH Nevada Scour Critical — Countermeasures Installed Good 1952 12,800
JAGUEYES CREEK Puerto Rico Scour Critical — Countermeasures Installed Fair 1955 12,800
HAKIPUU STRM Hawaii Scour Critical — Countermeasures Installed Fair 1922 12,800
COAST FK WILLAMETTE RIV Oregon Scour Critical — Countermeasures Installed Fair 1953 12,757
DUNCAN CREEK South Carolina Scour Critical — Countermeasures Installed Fair 1960 12,750
DUNCAN CREEK South Carolina Scour Critical — Countermeasures Installed Fair 1960 12,750
BUCK CREEK Pennsylvania Scour Critical — Countermeasures Installed Poor 1930 12,743
COBBS CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1909 12,715
CUIVRE RVR CRD DYER RD Missouri Scour Critical — Countermeasures Installed Fair 1985 12,712
LAUHULU STRM Hawaii Scour Critical — Countermeasures Installed Fair 1937 12,700
VALENCIANO RIVER Puerto Rico Scour Critical — Countermeasures Installed Fair 1947 12,700
KAWAILOA STRM Hawaii Scour Critical — Countermeasures Installed Good 1929 12,700
LITTLE OTTER CREEK Vermont Scour Critical — Countermeasures Installed Fair 1959 12,700
MILLSTONE RIVER New Jersey Scour Critical — Countermeasures Installed Fair 1970 12,700

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.