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 |
|---|---|---|---|---|---|
| POCOTALIGO SWAMP (NO. 3) | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1967 | 18,100 |
| POCOTALIGO SWAMP (NO. 3) | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1967 | 18,100 |
| BEAVER CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1919 | 18,099 |
| CRUM CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Poor | 1926 | 18,095 |
| FOUNTAIN CREEK | Colorado | Scour Critical — Countermeasures Installed | Fair | 1972 | 18,073 |
| PLATTE RVR | Missouri | Scour Critical — Countermeasures Installed | Fair | 1950 | 18,026 |
| PLATTE RVR OVRFL | Missouri | Scour Critical — Countermeasures Installed | Poor | 1950 | 18,026 |
| BLACK CREEK | Michigan | Scour Critical — Countermeasures Installed | Good | 1984 | 18,011 |
| TAR RIVER | North Carolina | Scour Critical — Countermeasures Installed | Fair | 1977 | 18,000 |
| SNAKE RIVER;W.BLACKFOOT | Idaho | Scour Critical — Countermeasures Installed | Fair | 1965 | 18,000 |
| TOISNOT SWAMP | North Carolina | Scour Critical — Countermeasures Installed | Good | 1977 | 18,000 |
| TOISNOT SWAMP | North Carolina | Scour Critical — Countermeasures Installed | Good | 1977 | 18,000 |
| DRY CREEK | California | Scour Critical — Countermeasures Installed | Good | 1928 | 18,000 |
| TAR RIVER | North Carolina | Scour Critical — Countermeasures Installed | Fair | 1977 | 18,000 |
| MUSKEGON RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1983 | 18,000 |
| BOULDER CREEK | Colorado | Scour Critical — Countermeasures Installed | Fair | 1960 | 18,000 |
| TOWN CR | Mississippi | Scour Critical — Countermeasures Installed | Fair | 1962 | 18,000 |
| BOULDER CREEK | Colorado | Scour Critical — Countermeasures Installed | Poor | 1952 | 18,000 |
| BRAZOS RIVER | Texas | Scour Critical — Countermeasures Installed | Fair | 1965 | 17,960 |
| ROCK CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1957 | 17,900 |
| PROVIDENCE SWAMP | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1973 | 17,900 |
| CAÑAS RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1970 | 17,900 |
| PROVIDENCE SWAMP | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1973 | 17,900 |
| CA¥AS RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1970 | 17,900 |
| Intracoastal Waterway | Florida | Scour Critical — Countermeasures Installed | Fair | 1967 | 17,900 |
| CLINTON RIVER | Michigan | Scour Critical — Countermeasures Installed | Good | 1967 | 17,835 |
| CLINTON RIVER | Michigan | Scour Critical — Countermeasures Installed | Good | 1967 | 17,835 |
| SANTA ANA RIVER | California | Scour Critical — Countermeasures Installed | Fair | 1953 | 17,821 |
| Whippany River | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1891 | 17,820 |
| 13th & Shelton Ditch | Oregon | Scour Critical — Countermeasures Installed | Good | 1988 | 17,817 |
| ROCK CREEK | Arkansas | Scour Critical — Countermeasures Installed | Fair | 1963 | 17,814 |
| WHEELER BRANCH | Texas | Scour Critical — Countermeasures Installed | Fair | 1948 | 17,806 |
| N. EDISTO RIVER | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1970 | 17,800 |
| BRANCH CANAL BAYOU | Florida | Scour Critical — Countermeasures Installed | Good | 1988 | 17,800 |
| N. EDISTO RIVER | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1970 | 17,800 |
| CANAL MAIN B | Florida | Scour Critical — Countermeasures Installed | Good | 1988 | 17,800 |
| MANISTEE RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1933 | 17,789 |
| POHATCONG CREEK | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1984 | 17,779 |
| HONEY RUN | Indiana | Scour Critical — Countermeasures Installed | Good | 1959 | 17,764 |
| MYAKKA RIVER | Florida | Scour Critical — Countermeasures Installed | Fair | 1977 | 17,750 |
| MYAKKA RIVER | Florida | Scour Critical — Countermeasures Installed | Good | 1977 | 17,750 |
| SALT CREEK | Florida | Scour Critical — Countermeasures Installed | Fair | 1977 | 17,750 |
| SALT CREEK | Florida | Scour Critical — Countermeasures Installed | Fair | 1977 | 17,750 |
| PENNYPACK CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1918 | 17,735 |
| LITTLE CACOOSING CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1947 | 17,731 |
| CLEAR CREEK | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1926 | 17,719 |
| MOANALUA STRM | Hawaii | Scour Critical — Countermeasures Installed | Fair | 1961 | 17,692 |
| OUACHITA RIVER-LOUISVILL | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1936 | 17,683 |
| YAKIMA RIVER | Washington | Scour Critical — Countermeasures Installed | Fair | 1962 | 17,681 |
| YAKIMA RIVER | Washington | Scour Critical — Countermeasures Installed | Fair | 1917 | 17,681 |
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.