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 |
|---|---|---|---|---|---|
| RATTLESNAKE WASH | New Mexico | Scour Critical — Countermeasures Installed | Fair | 1951 | 4,813 |
| CLIFTY CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1983 | 4,809 |
| HARRISON CREEK | Oklahoma | Scour Critical — Countermeasures Installed | Poor | 1940 | 4,800 |
| DRAIN #73 | Michigan | Scour Critical — Countermeasures Installed | Fair | 1930 | 4,800 |
| WADDELL CREEK | California | Scour Critical — Countermeasures Installed | Fair | 1947 | 4,800 |
| GOOSE RIVER | North Dakota | Scour Critical — Countermeasures Installed | Fair | 1966 | 4,800 |
| CIALITOS RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1973 | 4,800 |
| CHATFIELD HOLLOW BROOK | Connecticut | Scour Critical — Countermeasures Installed | Fair | 1935 | 4,800 |
| GRAYS CREEK | South Carolina | Scour Critical — Countermeasures Installed | Good | 1983 | 4,800 |
| BARRANCAS CREEK | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1965 | 4,800 |
| CAYAGUAS RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1969 | 4,800 |
| CREEK | Oklahoma | Scour Critical — Countermeasures Installed | Poor | 1984 | 4,800 |
| Wet Beaver Creek | Arizona | Scour Critical — Countermeasures Installed | Good | 1972 | 4,800 |
| LITTLE RIVER | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1964 | 4,800 |
| SALTO ARRIBA CREEK | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1925 | 4,800 |
| VIVI RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1925 | 4,800 |
| BIG CHOCONUT CREEK | New York | Scour Critical — Countermeasures Installed | Fair | 1930 | 4,793 |
| N FORK NINNESCAH RIVER | Kansas | Scour Critical — Countermeasures Installed | Good | 1969 | 4,792 |
| N FORK NINNESCAH RIVER | Kansas | Scour Critical — Countermeasures Installed | Good | 1969 | 4,792 |
| KIIKII STREAM | Hawaii | Scour Critical — Countermeasures Installed | Fair | 1950 | 4,790 |
| BAYOU SAN PATRICIO | Louisiana | Scour Critical — Countermeasures Installed | Good | 2006 | 4,790 |
| BAYOU SAN MIGUEL | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1963 | 4,790 |
| MIDDLE RELIEF | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1963 | 4,790 |
| ABERNATHY CREEK | Washington | Scour Critical — Countermeasures Installed | Fair | 1930 | 4,787 |
| INDIAN RUN | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1910 | 4,787 |
| ROCK CREEK | Kansas | Scour Critical — Countermeasures Installed | Fair | 1961 | 4,785 |
| HCFCD DITCH | Texas | Scour Critical — Countermeasures Installed | Fair | 1982 | 4,784 |
| SAN ANTONIO RIVER | Texas | Scour Critical — Countermeasures Installed | Good | 2000 | 4,782 |
| CARY BAYOU | Texas | Scour Critical — Countermeasures Installed | Fair | 1967 | 4,780 |
| E HIND DR/WAILUPE STRM | Hawaii | Scour Critical — Countermeasures Installed | Fair | 1949 | 4,780 |
| TRIB TO CROOKED CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1923 | 4,777 |
| H W CHANNEL METHOW R | Washington | Scour Critical — Countermeasures Installed | Good | 1945 | 4,775 |
| PERE MARQUETTE RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1922 | 4,771 |
| Laprele Creek | Wyoming | Scour Critical — Countermeasures Installed | Fair | 1958 | 4,769 |
| COBB DITCH | Indiana | Scour Critical — Countermeasures Installed | Fair | 1952 | 4,768 |
| S.COLONEL CREEK | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1948 | 4,763 |
| Little Boxelder Creek | Wyoming | Scour Critical — Countermeasures Installed | Fair | 1958 | 4,762 |
| Little Boxelder Creek | Wyoming | Scour Critical — Countermeasures Installed | Fair | 1958 | 4,762 |
| RICKETTS BRANCH TRIB | Texas | Scour Critical — Countermeasures Installed | Fair | 1986 | 4,762 |
| RICKETTS BRANCH TRIB | Texas | Scour Critical — Countermeasures Installed | Good | 1986 | 4,762 |
| WILDCAT CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1961 | 4,758 |
| WILDCAT CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1961 | 4,758 |
| WILDCAT CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1961 | 4,758 |
| ELM CREEK | Texas | Scour Critical — Countermeasures Installed | Fair | 1942 | 4,757 |
| FENHOLLOWAY RIVER | Florida | Scour Critical — Countermeasures Installed | Fair | 1934 | 4,750 |
| Pinal Creek | Arizona | Scour Critical — Countermeasures Installed | Good | 1957 | 4,750 |
| DRAIN | Louisiana | Scour Critical — Countermeasures Installed | Good | 1982 | 4,748 |
| IRONSTONE CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1907 | 4,748 |
| SWEETWATER CREEK | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1970 | 4,748 |
| TANGIPAHOA RIVER | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1965 | 4,748 |
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.