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 |
|---|---|---|---|---|---|
| BENS CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1953 | 5,265 |
| YOUNGS CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1946 | 5,263 |
| HURON RIVER | Michigan | Scour Critical — Countermeasures Installed | Good | 2006 | 5,259 |
| CUB CREEK | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1973 | 5,257 |
| CASS RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1934 | 5,255 |
| NECANICUM RIVER | Oregon | Scour Critical — Countermeasures Installed | Fair | 1957 | 5,250 |
| ARKANSAS RIVER | Colorado | Scour Critical — Countermeasures Installed | Fair | 1963 | 5,240 |
| MILL CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1948 | 5,239 |
| LITTLE LEHIGH CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 2013 | 5,235 |
| SHIAWASSEE RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1988 | 5,232 |
| SAN JACINTO RIVER | Texas | Scour Critical — Countermeasures Installed | Fair | 1977 | 5,232 |
| CASTILE CR | Missouri | Scour Critical — Countermeasures Installed | Fair | 1966 | 5,231 |
| BEAR CREEK | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1963 | 5,228 |
| GR RONDE R (ISLAND CITY) | Oregon | Scour Critical — Countermeasures Installed | Good | 1976 | 5,223 |
| Rillito Creek | Arizona | Scour Critical — Countermeasures Installed | Fair | 1963 | 5,205 |
| SUWANNEE RIVER RELIEF | Florida | Scour Critical — Countermeasures Installed | Fair | 1947 | 5,200 |
| AU TRAIN RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1932 | 5,200 |
| CASTAÑON CHANNEL | Puerto Rico | Scour Critical — Countermeasures Installed | Poor | 1927 | 5,200 |
| NORTH FORK OGDEN RIVER | Utah | Scour Critical — Countermeasures Installed | Fair | 1947 | 5,200 |
| SOUTH BR. FLINT RIVER | Michigan | Scour Critical — Countermeasures Installed | Good | 1935 | 5,200 |
| FEATHER RIVER | California | Scour Critical — Countermeasures Installed | Fair | 1965 | 5,200 |
| CASEI RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1902 | 5,200 |
| SAW MILL RUN CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1983 | 5,200 |
| SHUNOCK RIVER | Connecticut | Scour Critical — Countermeasures Installed | Fair | 1954 | 5,200 |
| BR DUTCH GAP CANAL | Wisconsin | Scour Critical — Countermeasures Installed | Poor | 1941 | 5,200 |
| ARROYATA RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1991 | 5,200 |
| BEAR CREEK | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1978 | 5,200 |
| BR TO LITTLE RIVER | South Carolina | Scour Critical — Countermeasures Installed | Good | 1980 | 5,200 |
| MOUNGERS CREEK | Mississippi | Scour Critical — Countermeasures Installed | Good | 1994 | 5,200 |
| MORTON CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1925 | 5,197 |
| HICKS CREEK | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1973 | 5,192 |
| BAYOU SAN MIGUEL | Louisiana | Scour Critical — Countermeasures Installed | Good | 2002 | 5,192 |
| Niger Canyon | Arizona | Scour Critical — Countermeasures Installed | Fair | 1942 | 5,190 |
| LAMINE RVR | Missouri | Scour Critical — Countermeasures Installed | Fair | 1972 | 5,190 |
| DESCHUTES RIVER | Washington | Scour Critical — Countermeasures Installed | Fair | 1943 | 5,190 |
| SIUSLAW RIVER(MAPLETON) | Oregon | Scour Critical — Countermeasures Installed | Fair | 1970 | 5,185 |
| KALAMAZOO RIVER | Michigan | Scour Critical — Countermeasures Installed | Poor | 1930 | 5,183 |
| TAMARACK CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1932 | 5,181 |
| AMMONOOSUC RIVER | New Hampshire | Scour Critical — Countermeasures Installed | Fair | 1972 | 5,178 |
| BIRDSONG CREEK OVERFLOW | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1975 | 5,176 |
| BIRDSONG CREEK | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1975 | 5,176 |
| TURKEY RUN GULLY | Texas | Scour Critical — Countermeasures Installed | Fair | 1958 | 5,175 |
| TRIB TO FISHING CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1938 | 5,174 |
| RICHLAND CREEK | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1974 | 5,170 |
| BIG SANDY RIVER | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1986 | 5,165 |
| TICKLE CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1961 | 5,162 |
| Pinal Creek | Arizona | Scour Critical — Countermeasures Installed | Poor | 1920 | 5,162 |
| WALLOWA RIVER (RAILROAD) | Oregon | Scour Critical — Countermeasures Installed | Good | 1966 | 5,160 |
| BILLS BRANCH | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1977 | 5,160 |
| TROUT CREEK | Oregon | Scour Critical — Countermeasures Installed | Good | 1988 | 5,160 |
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.