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 |
|---|---|---|---|---|---|
| TROUT CREEK | Oregon | Scour Critical — Countermeasures Installed | Good | 1988 | 5,160 |
| COW CREEK | Oregon | Scour Critical — Countermeasures Installed | Good | 2008 | 5,155 |
| LIMESTONE CREEK | Alabama | Scour Critical — Countermeasures Installed | Fair | 1952 | 5,154 |
| BLACK OTTER CREEK | Wisconsin | Scour Critical — Countermeasures Installed | Fair | 1892 | 5,151 |
| POORMANS CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1975 | 5,143 |
| COAST FORK WILLAMETTE R | Oregon | Scour Critical — Countermeasures Installed | Fair | 1960 | 5,141 |
| BEAN CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1947 | 5,136 |
| BEAN CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1947 | 5,136 |
| FIVE MILE RIVER | Connecticut | Scour Critical — Countermeasures Installed | Poor | 1910 | 5,120 |
| BEAVER BROOK | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1900 | 5,114 |
| SW BR RANCOCAS CREEK | New Jersey | Scour Critical — Countermeasures Installed | Poor | 1908 | 5,114 |
| TRIB SCHUYLKILL RIV | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1949 | 5,108 |
| TRIB SCHUYLKILL RIV | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1949 | 5,108 |
| DAYS CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1992 | 5,105 |
| MILL CREEK | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1977 | 5,102 |
| Mill Creek | Louisiana | Scour Critical — Countermeasures Installed | Good | 1976 | 5,102 |
| ELK CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1958 | 5,101 |
| MARSHY CREEK | Wisconsin | Scour Critical — Countermeasures Installed | Fair | 1932 | 5,100 |
| MOSHER CREEK | Wisconsin | Scour Critical — Countermeasures Installed | Fair | 1932 | 5,100 |
| SNAKE RIVER;PAYETTE BR. | Idaho | Scour Critical — Countermeasures Installed | Poor | 1953 | 5,100 |
| INTRACOASTAL WATERWAY | Florida | Scour Critical — Countermeasures Installed | Fair | 1964 | 5,100 |
| POKAGON CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1931 | 5,100 |
| WILLAMETTE RIVER | Oregon | Scour Critical — Countermeasures Installed | Fair | 1952 | 5,100 |
| SNAKE RIVER(NYSSA) | Oregon | Scour Critical — Countermeasures Installed | Fair | 1957 | 5,100 |
| MILWAUKEE RIVER | Wisconsin | Scour Critical — Countermeasures Installed | Fair | 1955 | 5,100 |
| Wilson River | Oregon | Scour Critical — Countermeasures Installed | Poor | 1939 | 5,092 |
| BULLIT RUN | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1966 | 5,091 |
| MID FK CHARITON RV | Missouri | Scour Critical — Countermeasures Installed | Fair | 1956 | 5,085 |
| HUNTER BROOK | New York | Scour Critical — Countermeasures Installed | Fair | 1931 | 5,080 |
| ANDERSON CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1949 | 5,076 |
| BITTERROOT RIVER | Montana | Scour Critical — Countermeasures Installed | Fair | 1954 | 5,076 |
| BRANCH | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1940 | 5,073 |
| NORTH ORE CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1961 | 5,060 |
| PIRNIE CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1930 | 5,057 |
| FLORAS CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1967 | 5,056 |
| POTATO CREEK | Indiana | Scour Critical — Countermeasures Installed | Good | 1973 | 5,055 |
| TOUCHET RIVER | Washington | Scour Critical — Countermeasures Installed | Fair | 1931 | 5,054 |
| COPPER MINE BROOK | Connecticut | Scour Critical — Countermeasures Installed | Fair | 1956 | 5,054 |
| CARICABOA RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1989 | 5,053 |
| FARM DRAIN | Michigan | Scour Critical — Countermeasures Installed | Fair | 1937 | 5,052 |
| FOURMILE BAYOU | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1953 | 5,051 |
| BISHOP MANOR CREEK | Alabama | Scour Critical — Countermeasures Installed | Fair | 1958 | 5,041 |
| MISTEQUAY CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1940 | 5,039 |
| LINESVILLE CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1966 | 5,034 |
| BAKER RIVER | Washington | Scour Critical — Countermeasures Installed | Poor | 1972 | 5,032 |
| MILL CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1937 | 5,031 |
| THREE BROOK STREAM | Maine | Scour Critical — Countermeasures Installed | Fair | 1948 | 5,030 |
| MUNCIE CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1973 | 5,026 |
| NATALBANY RIVER | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1963 | 5,026 |
| L NATALBANY RIVER | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1962 | 5,026 |
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.