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 |
|---|---|---|---|---|---|
| TOBY CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Poor | 1941 | 29,878 |
| PIGEON RIVER | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1966 | 29,828 |
| PIGEON RIVER | Tennessee | Scour Critical — Countermeasures Installed | Poor | 1966 | 29,828 |
| GILLS CREEK | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1940 | 29,800 |
| TRIB.TO MOSELEM CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1934 | 29,775 |
| DARBY CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Poor | 1950 | 29,754 |
| GREAT SWAMP | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1966 | 29,700 |
| GREAT SWAMP | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1966 | 29,700 |
| MISSOURI RVR UP RR | Missouri | Scour Critical — Countermeasures Installed | Fair | 1955 | 29,666 |
| WILLAMETTE R OFLOW WB | Oregon | Scour Critical — Countermeasures Installed | Fair | 1961 | 29,662 |
| ROUGE RIVER | Michigan | Scour Critical — Countermeasures Installed | Poor | 1932 | 29,650 |
| MIDDLE BR CLINTON RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1966 | 29,646 |
| Cox Creek | Oregon | Scour Critical — Countermeasures Installed | Good | 1940 | 29,551 |
| Calapooia River | Oregon | Scour Critical — Countermeasures Installed | Fair | 1971 | 29,513 |
| Calapooia Overflow | Oregon | Scour Critical — Countermeasures Installed | Fair | 1971 | 29,513 |
| Calapooia Overflow | Oregon | Scour Critical — Countermeasures Installed | Fair | 1971 | 29,513 |
| GLADES CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1939 | 29,452 |
| SEXTON KILFOIL DRAIN | Michigan | Scour Critical — Countermeasures Installed | Good | 1986 | 29,303 |
| SEXTON KILFOIL DRAIN | Michigan | Scour Critical — Countermeasures Installed | Fair | 1964 | 29,303 |
| NEWAUKUM RIVER | Washington | Scour Critical — Countermeasures Installed | Fair | 1952 | 29,186 |
| NEWAUKUM RIVER | Washington | Scour Critical — Countermeasures Installed | Fair | 1952 | 29,186 |
| PR 765 & BEATRIZ CRE | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1972 | 29,150 |
| PR 765 & BEATRIZ CRE | Puerto Rico | Scour Critical — Countermeasures Installed | Poor | 1972 | 29,150 |
| SPRING LAKE CHANNEL | Michigan | Scour Critical — Countermeasures Installed | Fair | 1966 | 29,125 |
| LITTLE DRY CREEK | Colorado | Scour Critical — Countermeasures Installed | Poor | 1965 | 29,000 |
| MILL CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1961 | 28,818 |
| MILL CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1961 | 28,818 |
| MISSOURI RVR CST MOK | Missouri | Scour Critical — Countermeasures Installed | Fair | 1991 | 28,808 |
| CAGUITAS RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1953 | 28,745 |
| BEAR RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1930 | 28,667 |
| SNI-A-BAR CR | Missouri | Scour Critical — Countermeasures Installed | Fair | 1963 | 28,534 |
| HONEY CREEK | Indiana | Scour Critical — Countermeasures Installed | Good | 1994 | 28,504 |
| HONEY CREEK | Indiana | Scour Critical — Countermeasures Installed | Good | 1993 | 28,504 |
| MATADERO CREEK | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1925 | 28,500 |
| WEOWEOPILAU STRM | Hawaii | Scour Critical — Countermeasures Installed | Fair | 1937 | 28,400 |
| WILDCAT CREEK | Indiana | Scour Critical — Countermeasures Installed | Good | 1969 | 28,376 |
| WILDCAT CREEK | Indiana | Scour Critical — Countermeasures Installed | Good | 1969 | 28,376 |
| BRAYS BAYOU | Texas | Scour Critical — Countermeasures Installed | Good | 1986 | 28,257 |
| Dairy Creek | Oregon | Scour Critical — Countermeasures Installed | Fair | 1923 | 28,179 |
| S. FORK FISHING CK | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1979 | 28,150 |
| GREEN RIVER | Washington | Scour Critical — Countermeasures Installed | Fair | 1959 | 28,147 |
| WISCONSIN RIVER 31 | Wisconsin | Scour Critical — Countermeasures Installed | Poor | 1915 | 28,144 |
| RAMBIN BAYOU | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1986 | 28,142 |
| JONHSON CHUTE BAYOU | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1985 | 28,142 |
| SPOKANE RIVER | Washington | Scour Critical — Countermeasures Installed | Fair | 1973 | 28,100 |
| PINE RUN CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1958 | 28,043 |
| PINE RUN CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1958 | 28,043 |
| AMITY DITCH | Indiana | Scour Critical — Countermeasures Installed | Fair | 1970 | 28,018 |
| Dry Bayou | Arkansas | Scour Critical — Countermeasures Installed | Good | 1952 | 28,000 |
| BIG POTTSBURG CREEK | Florida | Scour Critical — Countermeasures Installed | Fair | 1927 | 28,000 |
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.