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 |
|---|---|---|---|---|---|
| QUAKER BROOK | Connecticut | Scour Critical — Countermeasures Installed | Fair | 1957 | 2,900 |
| WATERWAY | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1969 | 2,900 |
| CARR BROOK | Connecticut | Scour Critical — Countermeasures Installed | Fair | 1938 | 2,900 |
| KENAI RIVER (SCHOONERS) | Alaska | Scour Critical — Countermeasures Installed | Fair | 1954 | 2,900 |
| SWIFT RIVER | New Hampshire | Scour Critical — Countermeasures Installed | Fair | 1975 | 2,900 |
| APPLE CREEK | North Dakota | Scour Critical — Countermeasures Installed | Fair | 1914 | 2,900 |
| SURVEYOR CREEK | Colorado | Scour Critical — Countermeasures Installed | Fair | 1935 | 2,900 |
| BUCKHEAD CREEK | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1931 | 2,900 |
| BUTLER DITCH | Wisconsin | Scour Critical — Countermeasures Installed | Fair | 1924 | 2,900 |
| NORTH LABOVE BAYOU | Louisiana | Scour Critical — Countermeasures Installed | Fair | 2013 | 2,899 |
| VALLEY CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1912 | 2,897 |
| POPLAR CREEK | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1951 | 2,897 |
| OVERFLOW | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1951 | 2,897 |
| OVERFLOW | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1951 | 2,897 |
| OVERFLOW | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1951 | 2,897 |
| OVERFLOW | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1951 | 2,897 |
| BEAR CREEK | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1951 | 2,897 |
| OVERFLOW | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1951 | 2,897 |
| OVERFLOW | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1951 | 2,897 |
| OVERFLOW | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1949 | 2,897 |
| OVERFLOW | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1951 | 2,897 |
| OVERFLOW | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1951 | 2,897 |
| OVERFLOW | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1951 | 2,897 |
| BUCK RUN | Pennsylvania | Scour Critical — Countermeasures Installed | Poor | 1926 | 2,896 |
| CREEK | Louisiana | Scour Critical — Countermeasures Installed | Poor | 1960 | 2,894 |
| FERN CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1964 | 2,893 |
| TAPPAN LAKE | New York | Scour Critical — Countermeasures Installed | Fair | 1967 | 2,892 |
| SUMNER BROOK | Connecticut | Scour Critical — Countermeasures Installed | Poor | 1920 | 2,892 |
| BELLDEAU BAYOU | Louisiana | Scour Critical — Countermeasures Installed | Poor | 1973 | 2,890 |
| BAYOU DEVIEW | Arkansas | Scour Critical — Countermeasures Installed | Fair | 1956 | 2,889 |
| TRIB TO PENNS CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1934 | 2,889 |
| HOSENSACK CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Poor | 1933 | 2,882 |
| MIDDLE FK COQUILLE RIVER | Oregon | Scour Critical — Countermeasures Installed | Fair | 1983 | 2,879 |
| MIDDLE FK COQUILLE RIVER | Oregon | Scour Critical — Countermeasures Installed | Fair | 1984 | 2,879 |
| MIDDLE FK COQUILLE RIVER | Oregon | Scour Critical — Countermeasures Installed | Good | 1984 | 2,879 |
| MIDDLE FK COQUILLE RIVER | Oregon | Scour Critical — Countermeasures Installed | Good | 1984 | 2,879 |
| HOLMES CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1984 | 2,879 |
| MIDDLE FK COQUILLE RIVER | Oregon | Scour Critical — Countermeasures Installed | Fair | 1984 | 2,879 |
| COQUILLE RIVER MIDDLE FK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1976 | 2,879 |
| MIDDLE FK COQUILLE RIVER | Oregon | Scour Critical — Countermeasures Installed | Fair | 1976 | 2,879 |
| MENOMINEE RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1966 | 2,875 |
| WEST BRANCH CROTON RIVER | New York | Scour Critical — Countermeasures Installed | Fair | 1929 | 2,874 |
| SHOAL CREEK | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1973 | 2,874 |
| NISQUALLY R OVERFLOW | Washington | Scour Critical — Countermeasures Installed | Good | 1945 | 2,872 |
| JUMPOFF JOE CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1940 | 2,871 |
| LONGS BRANCH | Indiana | Scour Critical — Countermeasures Installed | Good | 1955 | 2,870 |
| KAWKAWLIN RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1987 | 2,870 |
| Parc Perdu Bayou | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1960 | 2,868 |
| Parc Perdu Bayou | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1960 | 2,868 |
| E CANADA CREEK | New York | Scour Critical — Countermeasures Installed | Poor | 1931 | 2,866 |
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.