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 |
|---|---|---|---|---|---|
| DRAINAGE CANAL 039 | Florida | Scour Critical — Countermeasures Installed | Fair | 1955 | 3,000 |
| BUCK CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1985 | 3,000 |
| EDISTO RIVER SWAMP | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1949 | 3,000 |
| EDISTO RIVER SWAMP | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1949 | 3,000 |
| SHEPAUG RIVER | Connecticut | Scour Critical — Countermeasures Installed | Poor | 1955 | 3,000 |
| CREEK | Oklahoma | Scour Critical — Countermeasures Installed | Poor | 1950 | 3,000 |
| LETORT SPRING RUN | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1978 | 3,000 |
| Canal 100 | Florida | Scour Critical — Countermeasures Installed | Fair | 1949 | 3,000 |
| Canal 101 | Florida | Scour Critical — Countermeasures Installed | Fair | 1949 | 3,000 |
| PEQUONNOCK RIVER | Connecticut | Scour Critical — Countermeasures Installed | Fair | 1965 | 3,000 |
| CANOVANAS RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Good | 1953 | 3,000 |
| _ | Puerto Rico | Scour Critical — Countermeasures Installed | Good | 2018 | 3,000 |
| DRAW | Colorado | Scour Critical — Countermeasures Installed | Fair | 1935 | 3,000 |
| WILLIAMS CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1927 | 3,000 |
| SANTA YNEZ RIVER | California | Scour Critical — Countermeasures Installed | Poor | 1949 | 3,000 |
| LITTLE SCHUYLKILL RIVER | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1893 | 3,000 |
| CREEK | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1955 | 3,000 |
| VIVI RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1973 | 3,000 |
| SWAMP CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Poor | 1939 | 3,000 |
| MAD DOG CREEK | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1973 | 3,000 |
| MEADOW BROOK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1931 | 3,000 |
| SPRING CREEK | Florida | Scour Critical — Countermeasures Installed | Fair | 1953 | 3,000 |
| TOWN CREEK | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1968 | 3,000 |
| CANOVANAS RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Poor | 1953 | 3,000 |
| WATER BR MILLERS RIVER | Massachusetts | Scour Critical — Countermeasures Installed | Fair | 1988 | 3,000 |
| Lil Cypress Bayou | Louisiana | Scour Critical — Countermeasures Installed | Poor | 1965 | 3,000 |
| TRIBUTARY TO WEST BRANCH | Maryland | Scour Critical — Countermeasures Installed | Fair | 1930 | 3,000 |
| S B GLENDENING CK | New York | Scour Critical — Countermeasures Installed | Poor | 1937 | 2,998 |
| WEBB CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1962 | 2,997 |
| NECK RIVER | Connecticut | Scour Critical — Countermeasures Installed | Fair | 1983 | 2,996 |
| DUTCH CREEK | Colorado | Scour Critical — Countermeasures Installed | Fair | 1997 | 2,996 |
| MCNEIL CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1955 | 2,994 |
| FRENCH CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Poor | 1856 | 2,994 |
| KALAMAZOO RIVER | Michigan | Scour Critical — Countermeasures Installed | Poor | 1948 | 2,991 |
| MUSCOOT RIVER | New York | Scour Critical — Countermeasures Installed | Fair | 1960 | 2,991 |
| BEASON CREEK | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1954 | 2,990 |
| OAK CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1958 | 2,987 |
| JENKINS BRANCH | Texas | Scour Critical — Countermeasures Installed | Good | 1979 | 2,987 |
| PIPE CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1965 | 2,987 |
| STURGEON RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1956 | 2,977 |
| CASTOR CREEK | Louisiana | Scour Critical — Countermeasures Installed | Good | 2002 | 2,974 |
| SHERMAN CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1939 | 2,969 |
| LUBBERS RUN | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1986 | 2,968 |
| DUCKABUSH RIVER | Washington | Scour Critical — Countermeasures Installed | Fair | 1934 | 2,967 |
| WOONASQUATUCKET RIVER | Rhode Island | Scour Critical — Countermeasures Installed | Poor | 1949 | 2,965 |
| WHITE RIVER | Indiana | Scour Critical — Countermeasures Installed | Fair | 1990 | 2,965 |
| SKIPPACK CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1908 | 2,965 |
| N BR BLACK RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1988 | 2,962 |
| Bear River | Wyoming | Scour Critical — Countermeasures Installed | Poor | 1941 | 2,961 |
| TROUT RIVER | New York | Scour Critical — Countermeasures Installed | Good | 1932 | 2,960 |
Scour Critical Bridges by State
States ranked by number of scour critical bridges.
| State | Scour Critical | Unaddressed | Countermeasures | Ineffective |
|---|---|---|---|---|
| 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 — Unaddressed | Bridge is scour critical with no countermeasures installed. The foundation is vulnerable and no protective action has been taken. |
| Code 3 — Countermeasures Installed | Protective measures (riprap, sheet piling, etc.) have been installed to reduce scour risk, but the bridge remains classified as scour critical. |
| Code 6 — Countermeasures Ineffective | Protective 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.