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
WEST FK WHITE LICK CREEK Indiana Scour Critical — Countermeasures Installed Fair 1966 65,674
TOWAMENCIN CREEK Pennsylvania Scour Critical — Countermeasures Installed Good 1955 65,329
COLUMBIA RIVER Washington Scour Critical — Countermeasures Installed Fair 1916 65,013
COLUMBIA RIVER Washington Scour Critical — Countermeasures Installed Fair 1958 65,013
Columbia River Oregon Scour Critical — Countermeasures Installed Fair 1958 65,013
Columbia River Oregon Scour Critical — Countermeasures Installed Fair 1916 65,013
SABALOS CHANNEL Puerto Rico Scour Critical — Countermeasures Installed Fair 1997 64,800
CITY STREETS Louisiana Scour Critical — Countermeasures Installed Fair 1970 64,059
GILKEY CREEK Michigan Scour Critical — Countermeasures Installed Fair 1976 63,400
PEQU RIV RR HMBG TPK SB New Jersey Scour Critical — Countermeasures Installed Poor 1934 63,188
WALNUT CREEK Georgia Scour Critical — Countermeasures Installed Good 1967 62,400
Clackamas River Oregon Scour Critical — Countermeasures Installed Fair 1962 62,210
Clackamas River Oregon Scour Critical — Countermeasures Installed Fair 1962 62,210
BIG DRY CREEK Colorado Scour Critical — Countermeasures Installed Fair 1939 62,000
NO.BR.RARITAN RIVER New Jersey Scour Critical — Countermeasures Installed Fair 1934 61,761
PIPE MAKERS CANAL Georgia Scour Critical — Countermeasures Installed Good 1976 61,100
SAVANNAH RIVER Georgia Scour Critical — Countermeasures Installed Fair 1976 60,800
WATER MERRIMACK RIVER Massachusetts Scour Critical — Countermeasures Installed Poor 1964 60,056
MDOT RR COR & HURON RVR Michigan Scour Critical — Countermeasures Installed Fair 1956 59,888
SCHUY.RIVER SERVICE RD. Pennsylvania Scour Critical — Countermeasures Installed Fair 1963 59,527
CLEAR CREEK R Colorado Scour Critical — Countermeasures Installed Fair 1980 59,000
THREAD CREEK Michigan Scour Critical — Countermeasures Installed Fair 1971 59,000
CROOKFALL BROOK Rhode Island Scour Critical — Countermeasures Installed Fair 1924 58,520
SANDY RUN / 3257-H10 Pennsylvania Scour Critical — Countermeasures Installed Fair 1958 58,495
ROGUE RIVER Michigan Scour Critical — Countermeasures Installed Fair 1969 58,420
YELLOW WATER RIVER REL. Louisiana Scour Critical — Countermeasures Installed Good 1970 58,377
Indian Bend Wash Arizona Scour Critical — Countermeasures Installed Fair 1979 57,843
MILFORD BROOK New Jersey Scour Critical — Countermeasures Installed Fair 1938 57,832
ROUGE RIVER Michigan Scour Critical — Countermeasures Installed Fair 1967 57,795
FLAT CREEK Georgia Scour Critical — Countermeasures Installed Good 1963 57,600
SIX MILE CYPRESS CREEK Florida Scour Critical — Countermeasures Installed Good 1981 57,000
FOUNTAIN CREEK Colorado Scour Critical — Countermeasures Installed Good 1990 56,500
UNNAMED CREEK Puerto Rico Scour Critical — Countermeasures Installed Fair 1970 56,300
ROUGE RIVER Michigan Scour Critical — Countermeasures Installed Good 2024 56,238
WATER MERRIMACK RIVER Massachusetts Scour Critical — Countermeasures Installed Fair 1954 56,200
CASS RIVER Michigan Scour Critical — Countermeasures Installed Good 1961 56,192
FLINT R W BLVD&R SIDE DR Michigan Scour Critical — Countermeasures Installed Fair 1976 56,000
BEAVER CREEK Michigan Scour Critical — Countermeasures Installed Good 1964 55,558
SANTA CATALINA CREEK Puerto Rico Scour Critical — Countermeasures Installed Fair 1943 55,551
WILLAMETTE RIVER Oregon Scour Critical — Countermeasures Installed Fair 1967 55,375
WILLAMETTE RIVER Oregon Scour Critical — Countermeasures Installed Fair 1958 55,335
CROW CREEK Oregon Scour Critical — Countermeasures Installed Fair 1964 55,046
SIX MILE CREEK Florida Scour Critical — Countermeasures Installed Good 1981 55,000
HEDDON CANAL Florida Scour Critical — Countermeasures Installed Good 1997 55,000
MILL CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1959 54,739
CONVERSE POND BROOK Connecticut Scour Critical — Countermeasures Installed Fair 1934 53,800
MEDFORD VIADUCT Oregon Scour Critical — Countermeasures Installed Fair 1962 53,404
SELSERS CREEK Louisiana Scour Critical — Countermeasures Installed Fair 1975 53,386
PASSAIC RIVER New Jersey Scour Critical — Countermeasures Installed Fair 1968 53,207
POMPTON RIVER New Jersey Scour Critical — Countermeasures Installed Fair 1935 53,150

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.