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 |
|---|---|---|---|---|---|
| Brawley Wash | Arizona | Scour Critical — Countermeasures Installed | Poor | 1960 | 3,531 |
| BIG QUILCENE RIVER | Washington | Scour Critical — Countermeasures Installed | Poor | 1936 | 3,525 |
| WESTERN RUN | Maryland | Scour Critical — Countermeasures Installed | Fair | 1893 | 3,524 |
| Fine Wash | Arizona | Scour Critical — Countermeasures Installed | Fair | 1932 | 3,521 |
| SUCKER CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1967 | 3,520 |
| MIDDLE FK COQUILLE RIVER | Oregon | Scour Critical — Countermeasures Installed | Fair | 1984 | 3,518 |
| LICK CREEK | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1966 | 3,516 |
| Canal 092 | Florida | Scour Critical — Countermeasures Installed | Good | 1941 | 3,515 |
| Canal 088 | Florida | Scour Critical — Countermeasures Installed | Fair | 1949 | 3,515 |
| Canal 087 | Florida | Scour Critical — Countermeasures Installed | Fair | 1949 | 3,515 |
| Canal 086 | Florida | Scour Critical — Countermeasures Installed | Good | 1955 | 3,515 |
| WALNUT RIVER | Kansas | Scour Critical — Countermeasures Installed | Fair | 1953 | 3,509 |
| WALNUT RIVER DRAINAGE | Kansas | Scour Critical — Countermeasures Installed | Fair | 1953 | 3,509 |
| BIRCH CREEK OVERFLOW | Indiana | Scour Critical — Countermeasures Installed | Fair | 1986 | 3,508 |
| Icehouse Canyon | Arizona | Scour Critical — Countermeasures Installed | Good | 1920 | 3,504 |
| Normandy Waterway | Florida | Scour Critical — Countermeasures Installed | Good | 1983 | 3,503 |
| JOHNSON CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1938 | 3,502 |
| FORESTER CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1934 | 3,500 |
| TRIB. TO ROCKY RIVER | South Carolina | Scour Critical — Countermeasures Installed | Good | 1992 | 3,500 |
| WARRIOR RIVER RELIEF | Alabama | Scour Critical — Countermeasures Installed | Fair | 1927 | 3,500 |
| SAMMY SWAMP CREEK | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1946 | 3,500 |
| WATER N NASHUA RIVER | Massachusetts | Scour Critical — Countermeasures Installed | Fair | 1900 | 3,500 |
| LA MINA CREEK | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1981 | 3,500 |
| GROVE CREEK | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1976 | 3,500 |
| MUSCATINE SLOUGH | Iowa | Scour Critical — Countermeasures Installed | Good | 2002 | 3,500 |
| TCHOUTACABOUFFA RIVER | Mississippi | Scour Critical — Countermeasures Installed | Fair | 1998 | 3,500 |
| MUSCATINE SLOUGH | Iowa | Scour Critical — Countermeasures Installed | Good | 2002 | 3,500 |
| GARCIA CREEK | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1941 | 3,500 |
| FRIENDSHIP CREEK | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1900 | 3,494 |
| SALT CREEK | Washington | Scour Critical — Countermeasures Installed | Fair | 1952 | 3,493 |
| INDIAN CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1984 | 3,490 |
| SAND CREEK | Georgia | Scour Critical — Countermeasures Installed | Good | 1976 | 3,490 |
| NESTUCCA RIVER | Oregon | Scour Critical — Countermeasures Installed | Fair | 1973 | 3,489 |
| STEWART CREEK | Kansas | Scour Critical — Countermeasures Installed | Fair | 1953 | 3,488 |
| STEWART CREEK DRAINAGE | Kansas | Scour Critical — Countermeasures Installed | Fair | 1953 | 3,488 |
| Calapooia Bottoms No. 5 | Oregon | Scour Critical — Countermeasures Installed | Fair | 1963 | 3,487 |
| JOHNSON BRANCH | Delaware | Scour Critical — Countermeasures Installed | Fair | 1947 | 3,486 |
| SPRING BRANCH | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1952 | 3,482 |
| GRASSY COVE CREEK | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1951 | 3,482 |
| LICK CREEK | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1948 | 3,482 |
| GRASSY COVE CREEK | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1951 | 3,482 |
| CHOCTAW CREEK | Texas | Scour Critical — Countermeasures Installed | Fair | 1994 | 3,479 |
| EAST BR BRANDYWINE CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1931 | 3,479 |
| CASS RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1957 | 3,478 |
| LITTLE BAYOU | Florida | Scour Critical — Countermeasures Installed | Fair | 1961 | 3,477 |
| BLUE JACKET CREEK | Ohio | Scour Critical — Countermeasures Installed | Good | 1965 | 3,475 |
| Wolf Creek | Pennsylvania | Scour Critical — Countermeasures Installed | Poor | 1981 | 3,473 |
| BOONE CREEK | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1991 | 3,472 |
| DORCHEAT BAYOU RELIEF | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1982 | 3,472 |
| DORCHEAT BAYOU | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1981 | 3,472 |
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.