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 |
|---|---|---|---|---|---|
| MENOMINEE RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1973 | 5,620 |
| TACONY CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1929 | 5,619 |
| SEVENTEEN MILE CREEK | Indiana | Scour Critical — Countermeasures Installed | Good | 1996 | 5,613 |
| MIDDLE CREEK | Tennessee | Scour Critical — Countermeasures Installed | Poor | 1951 | 5,610 |
| RICHLAND CREEK | Mississippi | Scour Critical — Countermeasures Installed | Poor | 1939 | 5,600 |
| S.FK.COEUR DALENE RIVER | Idaho | Scour Critical — Countermeasures Installed | Fair | 1976 | 5,600 |
| SAW MILL RUN | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1932 | 5,600 |
| SAW MILL RUN | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1900 | 5,600 |
| SALMON CANAL | Florida | Scour Critical — Countermeasures Installed | Fair | 1968 | 5,600 |
| KAIPOIOI STRM | Hawaii | Scour Critical — Countermeasures Installed | Fair | 1933 | 5,600 |
| REEDY RIVER | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1975 | 5,600 |
| CANAL L | Florida | Scour Critical — Countermeasures Installed | Good | 1982 | 5,600 |
| KOLEKOLE STRM | Hawaii | Scour Critical — Countermeasures Installed | Fair | 1950 | 5,600 |
| JAMES RIVER | North Dakota | Scour Critical — Countermeasures Installed | Fair | 1939 | 5,600 |
| HARRIGAN BRANCH | Indiana | Scour Critical — Countermeasures Installed | Fair | 1933 | 5,597 |
| Mill Creek | Oregon | Scour Critical — Countermeasures Installed | Fair | 1961 | 5,594 |
| South Santiam River | Oregon | Scour Critical — Countermeasures Installed | Fair | 1973 | 5,594 |
| ROCK CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1942 | 5,593 |
| SHATZLEY DITCH | Indiana | Scour Critical — Countermeasures Installed | Fair | 1992 | 5,585 |
| Yellow Water River | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1976 | 5,582 |
| SAM BISHOP DITCH | Tennessee | Scour Critical — Countermeasures Installed | Poor | 1958 | 5,579 |
| N. FORK WHITE OAK CREEK | Tennessee | Scour Critical — Countermeasures Installed | Poor | 1958 | 5,579 |
| STEMILT CR. | Washington | Scour Critical — Countermeasures Installed | Fair | 1951 | 5,578 |
| SNAKE RIVER | Minnesota | Scour Critical — Countermeasures Installed | Poor | 1976 | 5,576 |
| ALLEN DRAIN | Michigan | Scour Critical — Countermeasures Installed | Fair | 1985 | 5,571 |
| WISNER DRAIN | Michigan | Scour Critical — Countermeasures Installed | Fair | 1985 | 5,571 |
| CARPENTERS BAYOU | Texas | Scour Critical — Countermeasures Installed | Fair | 1975 | 5,570 |
| Marquam Creek | Oregon | Scour Critical — Countermeasures Installed | Good | 1985 | 5,569 |
| HENSLEY CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1990 | 5,566 |
| HARBERTS CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1993 | 5,566 |
| CALAPOOIA RIVER | Oregon | Scour Critical — Countermeasures Installed | Fair | 1940 | 5,562 |
| OVER FOUR MILE CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1941 | 5,562 |
| PAWCATUCK RIVER | Connecticut | Scour Critical — Countermeasures Installed | Fair | 1953 | 5,562 |
| EAST POND CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1964 | 5,560 |
| WATER BOUND BROOK | Massachusetts | Scour Critical — Countermeasures Installed | Good | 2008 | 5,560 |
| N FORK TAYLOR BAYOU | Texas | Scour Critical — Countermeasures Installed | Fair | 1937 | 5,555 |
| FOURMILE CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1929 | 5,551 |
| LA PLATA RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1997 | 5,550 |
| NORTHEAST CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1967 | 5,547 |
| WATERWAY CANAL | Michigan | Scour Critical — Countermeasures Installed | Good | 2021 | 5,546 |
| PILGRIM RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1916 | 5,543 |
| N BR DEVIL RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1933 | 5,537 |
| HCFCD DITCH | Texas | Scour Critical — Countermeasures Installed | Fair | 1987 | 5,536 |
| SEALS GULLY | Texas | Scour Critical — Countermeasures Installed | Fair | 1995 | 5,533 |
| LITTLE KLICKITAT RIVER | Washington | Scour Critical — Countermeasures Installed | Fair | 1956 | 5,532 |
| BRANCH CEDAR CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1976 | 5,530 |
| LITTLE MANATAWNY CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1962 | 5,524 |
| MILL CREEK | Georgia | Scour Critical — Countermeasures Installed | Good | 1981 | 5,520 |
| CASS RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1941 | 5,516 |
| BEAN CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1934 | 5,505 |
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.