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 |
|---|---|---|---|---|---|
| CULEBRINAS RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Poor | 1955 | 9,000 |
| ARENAS CREEK | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1939 | 9,000 |
| TANGIPAHOA RIVER | Mississippi | Scour Critical — Countermeasures Installed | Fair | 1960 | 9,000 |
| PUGET SOUND @ EAGLE HRBR | Washington | Scour Critical — Countermeasures Installed | Fair | 1972 | 9,000 |
| TANGIPAHOA RIVER | Mississippi | Scour Critical — Countermeasures Installed | Fair | 1960 | 9,000 |
| SAN ANTONIO RIVER | Texas | Scour Critical — Countermeasures Installed | Fair | 1954 | 8,973 |
| QUASSAIC CREEK | New York | Scour Critical — Countermeasures Installed | Poor | 1975 | 8,970 |
| SWARTZ CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1981 | 8,961 |
| LITTLE EAGLE CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1977 | 8,956 |
| AU SABLE RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1984 | 8,950 |
| W FK Dairy Creek | Oregon | Scour Critical — Countermeasures Installed | Good | 1941 | 8,934 |
| BLUFF CREEK | Texas | Scour Critical — Countermeasures Installed | Fair | 1947 | 8,932 |
| THOMAS CREEK | New York | Scour Critical — Countermeasures Installed | Fair | 1968 | 8,932 |
| LEY CREEK | New York | Scour Critical — Countermeasures Installed | Fair | 1950 | 8,922 |
| MIDDLE CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1940 | 8,918 |
| Detrital Wash | Arizona | Scour Critical — Countermeasures Installed | Fair | 1982 | 8,908 |
| BEACON HILL BROOK | Connecticut | Scour Critical — Countermeasures Installed | Fair | 1966 | 8,900 |
| CROOKED OAK CREEK | Oklahoma | Scour Critical — Countermeasures Installed | Poor | 1972 | 8,900 |
| UNIBON RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1921 | 8,900 |
| AIBONITO RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Poor | 1970 | 8,900 |
| COOPER RIVER | New Jersey | Scour Critical — Countermeasures Installed | Poor | 1924 | 8,890 |
| Detrital Wash | Arizona | Scour Critical — Countermeasures Installed | Fair | 1982 | 8,855 |
| LOWER LOOKINGGLASS CRK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1949 | 8,853 |
| CK | South Dakota | Scour Critical — Countermeasures Installed | Fair | 1961 | 8,815 |
| CK | South Dakota | Scour Critical — Countermeasures Installed | Fair | 1961 | 8,815 |
| PHILLIPSE BROOK | New York | Scour Critical — Countermeasures Installed | Fair | 1929 | 8,815 |
| OSWEGO CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1930 | 8,805 |
| TANK FARM DITCH | California | Scour Critical — Countermeasures Installed | Good | 1988 | 8,803 |
| MILL RIVER | Connecticut | Scour Critical — Countermeasures Installed | Fair | 1955 | 8,800 |
| SUGAR CREEK | North Carolina | Scour Critical — Countermeasures Installed | Fair | 1980 | 8,800 |
| AGUACATE CREEK | Puerto Rico | Scour Critical — Countermeasures Installed | Poor | 1920 | 8,800 |
| COROZAL RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1966 | 8,800 |
| THOMPSON CREEK | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1931 | 8,800 |
| BRANCH RANCOCAS CREEK | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1949 | 8,793 |
| CLEAR CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1972 | 8,790 |
| CLEARFIELD CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1937 | 8,758 |
| SHIAWASSEE RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1983 | 8,752 |
| MILL CREEK | Kansas | Scour Critical — Countermeasures Installed | Good | 1966 | 8,750 |
| TRUCKEE RVR | Nevada | Scour Critical — Countermeasures Installed | Fair | 1971 | 8,750 |
| ROGUE RIVER | Oregon | Scour Critical — Countermeasures Installed | Fair | 2006 | 8,744 |
| Trask River | Oregon | Scour Critical — Countermeasures Installed | Fair | 1949 | 8,740 |
| TUALATIN RIVER | Oregon | Scour Critical — Countermeasures Installed | Fair | 1924 | 8,728 |
| SYCAMORE CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1962 | 8,725 |
| FLINT RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1928 | 8,725 |
| CLEAR CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1972 | 8,720 |
| WALKER CREEK | Kansas | Scour Critical — Countermeasures Installed | Good | 1965 | 8,718 |
| WALKER CREEK | Kansas | Scour Critical — Countermeasures Installed | Good | 1965 | 8,718 |
| CHIMACUM CREEK | Washington | Scour Critical — Countermeasures Installed | Fair | 1916 | 8,718 |
| GUADALUPE RIVER | Texas | Scour Critical — Countermeasures Installed | Fair | 1962 | 8,716 |
| SADDLE RIVER | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1940 | 8,710 |
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.