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 |
|---|---|---|---|---|---|
| ALLEGHENY CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Poor | 1956 | 10,331 |
| CREEK | Oklahoma | Scour Critical — Countermeasures Installed | Poor | 1979 | 10,315 |
| CROSS BAYOU | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1960 | 10,312 |
| MOREAU RVR | Missouri | Scour Critical — Countermeasures Installed | Fair | 1969 | 10,305 |
| MOREAU RVR OVERFLO | Missouri | Scour Critical — Countermeasures Installed | Good | 1969 | 10,305 |
| WATERWAY | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1930 | 10,300 |
| ST JOSEPH RIVER | Indiana | Scour Critical — Countermeasures Installed | Fair | 1965 | 10,300 |
| BUCK CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1965 | 10,300 |
| GALLARDO CHANNEL | Puerto Rico | Scour Critical — Countermeasures Installed | Good | 1961 | 10,300 |
| La Vega Creek | Puerto Rico | Scour Critical — Countermeasures Installed | Poor | 1940 | 10,300 |
| CREEK | Puerto Rico | Scour Critical — Countermeasures Installed | Poor | 1930 | 10,300 |
| GRAZE CREEK | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1989 | 10,300 |
| LA MINA RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1862 | 10,300 |
| COFRESI CREEK | Puerto Rico | Scour Critical — Countermeasures Installed | Poor | 1940 | 10,300 |
| UNNAMED CREEK | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1999 | 10,300 |
| LA VEGA CREEK | Puerto Rico | Scour Critical — Countermeasures Installed | Poor | 1940 | 10,300 |
| OVER SR 3020 & ELK CK. | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1969 | 10,274 |
| DRY CREEK CANAL | California | Scour Critical — Countermeasures Installed | Good | 1952 | 10,269 |
| ROCK RUN | Pennsylvania | Scour Critical — Countermeasures Installed | Poor | 1954 | 10,266 |
| OVERFLOW CHANNEL | Oregon | Scour Critical — Countermeasures Installed | Fair | 1985 | 10,265 |
| INDIAN MILL CREEK | Michigan | Scour Critical — Countermeasures Installed | Good | 1984 | 10,251 |
| STONY BROOK | New Jersey | Scour Critical — Countermeasures Installed | Good | 1976 | 10,248 |
| WATER CHARLES RIVER | Massachusetts | Scour Critical — Countermeasures Installed | Fair | 1847 | 10,216 |
| Natural Corral Wash | Arizona | Scour Critical — Countermeasures Installed | Fair | 1961 | 10,203 |
| Cane Springs Wash | Arizona | Scour Critical — Countermeasures Installed | Fair | 1961 | 10,203 |
| AMITE RIVER | Louisiana | Scour Critical — Countermeasures Installed | Good | 2009 | 10,200 |
| PORTUGUES RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Poor | 1969 | 10,200 |
| PORTUGUES RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Poor | 1969 | 10,200 |
| KOLOA STRM-LAIEMALOO | Hawaii | Scour Critical — Countermeasures Installed | Fair | 1933 | 10,200 |
| BARK RIVER | Wisconsin | Scour Critical — Countermeasures Installed | Fair | 1957 | 10,200 |
| HUDSON BAYOU | Florida | Scour Critical — Countermeasures Installed | Good | 1916 | 10,200 |
| CROWDERS CREEK | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1957 | 10,200 |
| North Yamhill River | Oregon | Scour Critical — Countermeasures Installed | Fair | 1959 | 10,193 |
| GRIFFY CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1972 | 10,184 |
| HOLTON CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1926 | 10,152 |
| TEN MILE RIVER | Rhode Island | Scour Critical — Countermeasures Installed | Fair | 1946 | 10,151 |
| HACIENDA WASH | California | Scour Critical — Countermeasures Installed | Poor | 1971 | 10,150 |
| HACIENDA WASH | California | Scour Critical — Countermeasures Installed | Fair | 1971 | 10,150 |
| PAWTUXET RIVER | Rhode Island | Scour Critical — Countermeasures Installed | Fair | 1967 | 10,149 |
| S. BR. PENNSAUKEN CREEK | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1909 | 10,139 |
| TITTABAWASSEE RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1976 | 10,133 |
| ITHAN CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Poor | 1930 | 10,128 |
| CLOQUALLUM CR | Washington | Scour Critical — Countermeasures Installed | Good | 1962 | 10,124 |
| E FK WILDCAT CR | Washington | Scour Critical — Countermeasures Installed | Good | 1962 | 10,124 |
| E FK WILDCAT CR | Washington | Scour Critical — Countermeasures Installed | Good | 1962 | 10,124 |
| CLOQUALLUM CR | Washington | Scour Critical — Countermeasures Installed | Good | 1962 | 10,124 |
| LACAMAS CREEK | Washington | Scour Critical — Countermeasures Installed | Good | 1921 | 10,107 |
| SAUGATUCKET RIVER | Rhode Island | Scour Critical — Countermeasures Installed | Fair | 1920 | 10,107 |
| JOHNSON CREEK | Oregon | Scour Critical — Countermeasures Installed | Good | 1985 | 10,101 |
| CAMUY RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1942 | 10,100 |
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.