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 |
|---|---|---|---|---|---|
| BRONX RIVER | New York | Scour Critical — Countermeasures Installed | Fair | 1926 | 8,381 |
| NORTH FORK BIG CREEK | Kansas | Scour Critical — Countermeasures Installed | Fair | 1965 | 8,367 |
| NORTH FORK BIG CREEK | Kansas | Scour Critical — Countermeasures Installed | Fair | 1965 | 8,367 |
| AU SABLE RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1972 | 8,367 |
| BRANCH | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1962 | 8,367 |
| REESE CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1921 | 8,367 |
| N BR CHIPPEWA RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1934 | 8,359 |
| Slick Rock Creek | Oregon | Scour Critical — Countermeasures Installed | Fair | 1930 | 8,356 |
| BADGER CREEK | Kansas | Scour Critical — Countermeasures Installed | Fair | 1976 | 8,350 |
| BADGER CREEK | Kansas | Scour Critical — Countermeasures Installed | Fair | 1976 | 8,350 |
| SPRING CREEK | Texas | Scour Critical — Countermeasures Installed | Good | 2000 | 8,348 |
| Wilbur Canyon | Arizona | Scour Critical — Countermeasures Installed | Fair | 1963 | 8,346 |
| WEST BR.CHESTER CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1931 | 8,345 |
| INDIAN CREEK | Alabama | Scour Critical — Countermeasures Installed | Fair | 1956 | 8,342 |
| FLAT RIVER | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1982 | 8,332 |
| INDIAN CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1921 | 8,331 |
| OUACHITA RIVER | Louisiana | Scour Critical — Countermeasures Installed | Fair | 2003 | 8,312 |
| MIDDLE FORK BLUE RIVER | Indiana | Scour Critical — Countermeasures Installed | Fair | 1947 | 8,309 |
| Little N. Fk. Santiam R. | Oregon | Scour Critical — Countermeasures Installed | Fair | 1952 | 8,303 |
| WHITE FEATHER CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1938 | 8,300 |
| SKUNGAMAUG RIVER | Connecticut | Scour Critical — Countermeasures Installed | Fair | 1928 | 8,300 |
| KALAMAZOO RIVER | Michigan | Scour Critical — Countermeasures Installed | Poor | 1938 | 8,300 |
| GRANDE DE LOIZA RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Poor | 1940 | 8,300 |
| SPRING BROOK | Wisconsin | Scour Critical — Countermeasures Installed | Fair | 1969 | 8,300 |
| MATON RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Poor | 1927 | 8,300 |
| JUAN ORRACA CREEK | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1929 | 8,300 |
| BOQUERON CREEK | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1933 | 8,300 |
| REEVES CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1926 | 8,286 |
| CLINTON RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1953 | 8,263 |
| BRANCH | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1954 | 8,262 |
| HOLDEN BRANCH | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1954 | 8,262 |
| CREEK | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1954 | 8,262 |
| BOGUE CHITTO RV. RELIEF | Louisiana | Scour Critical — Countermeasures Installed | Good | 1975 | 8,257 |
| BOGUE CHITTO RIVER | Louisiana | Scour Critical — Countermeasures Installed | Good | 1974 | 8,257 |
| PRINGLE CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1930 | 8,251 |
| DRY CREEK | Kansas | Scour Critical — Countermeasures Installed | Good | 1976 | 8,250 |
| DRY CREEK | Kansas | Scour Critical — Countermeasures Installed | Good | 1976 | 8,250 |
| BIG CREEK DRAINAGE | Kansas | Scour Critical — Countermeasures Installed | Good | 1965 | 8,250 |
| BIG CREEK DRAINAGE | Kansas | Scour Critical — Countermeasures Installed | Good | 1965 | 8,250 |
| LOVILLS CREEK | North Carolina | Scour Critical — Countermeasures Installed | Fair | 1969 | 8,250 |
| BARKERS BROOK | New Jersey | Scour Critical — Countermeasures Installed | Poor | 1912 | 8,244 |
| TRIB. BUSHKILL CR. | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1953 | 8,242 |
| PEQUABUCK RIVER | Connecticut | Scour Critical — Countermeasures Installed | Fair | 1983 | 8,240 |
| VERMILION RIVER | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1971 | 8,240 |
| WATER WEWEANTIC RIVER | Massachusetts | Scour Critical — Countermeasures Installed | Poor | 1929 | 8,214 |
| LACKAWANNA RIVER | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1957 | 8,200 |
| PACHAUG RIVER - P & W RR | Connecticut | Scour Critical — Countermeasures Installed | Fair | 1930 | 8,200 |
| MEADOWS CREEK | Wisconsin | Scour Critical — Countermeasures Installed | Fair | 1952 | 8,200 |
| PLATTE RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1927 | 8,172 |
| DRAKES BROOK | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1958 | 8,170 |
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.