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 |
|---|---|---|---|---|---|
| DUEY RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1949 | 3,600 |
| UNNAMED CREEK | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1950 | 3,600 |
| TRIB TO PACOLET RIVER | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1973 | 3,600 |
| KINGS CREEK | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1950 | 3,600 |
| SANTIAGO RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1954 | 3,600 |
| CERCADA CREEK | Puerto Rico | Scour Critical — Countermeasures Installed | Poor | 1927 | 3,600 |
| FAJARDO RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1961 | 3,600 |
| UNNAMED WATERWAY | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1939 | 3,600 |
| DAGUAO RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1923 | 3,600 |
| CERRO GORDO CREEK | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1939 | 3,600 |
| BOTIJAS RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Poor | 1940 | 3,600 |
| DUNCAN CREEK | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1952 | 3,600 |
| RIVIERA BAY | Florida | Scour Critical — Countermeasures Installed | Fair | 1962 | 3,600 |
| PORTER BROOK | Connecticut | Scour Critical — Countermeasures Installed | Fair | 1871 | 3,600 |
| COVE SOUND CREEK | Florida | Scour Critical — Countermeasures Installed | Fair | 1976 | 3,600 |
| OSSIPEE RIVER | New Hampshire | Scour Critical — Countermeasures Installed | Good | 1956 | 3,594 |
| BRUSHY BAYOU | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1987 | 3,594 |
| BIG CEDAR RIVER | Michigan | Scour Critical — Countermeasures Installed | Good | 1933 | 3,591 |
| WASHOUGAL RIVER | Washington | Scour Critical — Countermeasures Installed | Fair | 1954 | 3,589 |
| SOUHEGAN RIVER | New Hampshire | Scour Critical — Countermeasures Installed | Good | 1987 | 3,589 |
| SHIAWASSEE RIVER | Michigan | Scour Critical — Countermeasures Installed | Poor | 1930 | 3,587 |
| BOULDER CREEK | Washington | Scour Critical — Countermeasures Installed | Good | 1962 | 3,586 |
| BAYOU SAN PATRICIO | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1977 | 3,585 |
| CONEWAGO CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1934 | 3,584 |
| DUCK CREEK | Texas | Scour Critical — Countermeasures Installed | Fair | 1970 | 3,583 |
| KEEN BRANCH | Texas | Scour Critical — Countermeasures Installed | Good | 1967 | 3,583 |
| SO. BR. SWATARA CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Poor | 1920 | 3,582 |
| SMOKY HILL RIVER | Kansas | Scour Critical — Countermeasures Installed | Fair | 1970 | 3,581 |
| N BR PRESQUE ISLE STREAM | Maine | Scour Critical — Countermeasures Installed | Fair | 1929 | 3,581 |
| DRAINAGE CANAL | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1926 | 3,574 |
| MARYS CREEK | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1959 | 3,574 |
| DRAINAGE CANAL | Tennessee | Scour Critical — Countermeasures Installed | Poor | 1926 | 3,574 |
| DRAIN | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1954 | 3,571 |
| BRIGGS CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1953 | 3,566 |
| HILL CREEK | Oregon | Scour Critical — Countermeasures Installed | Good | 1938 | 3,562 |
| BRANCH LITTLE NESHAMINY | Pennsylvania | Scour Critical — Countermeasures Installed | Poor | 1927 | 3,559 |
| PLUM CREEK | Kansas | Scour Critical — Countermeasures Installed | Good | 1982 | 3,558 |
| PARADISE CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1932 | 3,554 |
| STONY RUN | Pennsylvania | Scour Critical — Countermeasures Installed | Poor | 1958 | 3,554 |
| TRIBUTARY ELK CREEK | Ohio | Scour Critical — Countermeasures Installed | Fair | 1994 | 3,552 |
| SWAN RIVER | New York | Scour Critical — Countermeasures Installed | Good | 1988 | 3,549 |
| SANDY CREEK | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1957 | 3,548 |
| DIRICKSON CREEK | Delaware | Scour Critical — Countermeasures Installed | Fair | 1961 | 3,548 |
| Fern Creek | Oregon | Scour Critical — Countermeasures Installed | Poor | 1953 | 3,545 |
| COQUILLE RIVER | Oregon | Scour Critical — Countermeasures Installed | Fair | 1962 | 3,545 |
| SASCO BROOK | Connecticut | Scour Critical — Countermeasures Installed | Poor | 1973 | 3,540 |
| OVER SAGE RUN | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1942 | 3,539 |
| BRANCH MARTINS CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1955 | 3,539 |
| OVER SAGE RUN | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1942 | 3,539 |
| OVER SAGE RUN | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1942 | 3,539 |
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.