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 |
|---|---|---|---|---|---|
| LONG BRANCH BAYOU | Louisiana | Scour Critical — Countermeasures Installed | Poor | 1954 | 4,612 |
| LONG BRANCH BAYOU | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1954 | 4,612 |
| LITTLE INDIAN CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1990 | 4,610 |
| Laprele Creek | Wyoming | Scour Critical — Countermeasures Installed | Fair | 1958 | 4,607 |
| ARKANSAS RIVER DRAINAGE | Kansas | Scour Critical — Countermeasures Installed | Good | 1909 | 4,605 |
| BECKETS RUN | Pennsylvania | Scour Critical — Countermeasures Installed | Poor | 1915 | 4,603 |
| SILVER CREEK | Maryland | Scour Critical — Countermeasures Installed | Fair | 1940 | 4,601 |
| ST. MARYS RIVER | Georgia | Scour Critical — Countermeasures Installed | Fair | 1927 | 4,600 |
| BARK RIVER | Wisconsin | Scour Critical — Countermeasures Installed | Fair | 1964 | 4,600 |
| EAST FORK WHITE RIVER | Indiana | Scour Critical — Countermeasures Installed | Fair | 1994 | 4,600 |
| YAMPA RIVER | Colorado | Scour Critical — Countermeasures Installed | Good | 1976 | 4,600 |
| DELAWARE River | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1926 | 4,600 |
| GRANDE DE JAYUYA RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1972 | 4,600 |
| LUCY POINT CREEK | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1965 | 4,600 |
| WALLOOMSAC RIVER | Vermont | Scour Critical — Countermeasures Installed | Fair | 1926 | 4,600 |
| ST. MARYS RIVER | Florida | Scour Critical — Countermeasures Installed | Fair | 1927 | 4,600 |
| JEFFERSON DITCH | Wisconsin | Scour Critical — Countermeasures Installed | Fair | 1998 | 4,600 |
| CENTRAL CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1941 | 4,598 |
| BLACK BAYOU | Louisiana | Scour Critical — Countermeasures Installed | Poor | 1967 | 4,595 |
| Willamette River | Oregon | Scour Critical — Countermeasures Installed | Fair | 1958 | 4,595 |
| LITTLE CANEY BAYOU | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1978 | 4,595 |
| WARRIOR RIVER RELIEF | Alabama | Scour Critical — Countermeasures Installed | Fair | 1927 | 4,587 |
| IRON ORE CREEK | Texas | Scour Critical — Countermeasures Installed | Fair | 1999 | 4,585 |
| MUD CREEK | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1925 | 4,572 |
| THUNDER BAY RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1927 | 4,572 |
| WATER TEN MILE RIVER | Massachusetts | Scour Critical — Countermeasures Installed | Fair | 1905 | 4,571 |
| E. FORK BEAVER CK CANAL | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1923 | 4,571 |
| DEUEL HOLLOW BRK | New York | Scour Critical — Countermeasures Installed | Fair | 1932 | 4,566 |
| CARPENTER CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1929 | 4,557 |
| TOUCHET RIVER | Washington | Scour Critical — Countermeasures Installed | Good | 1966 | 4,556 |
| BIG COVE CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1930 | 4,554 |
| TITTABAWASSEE RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1900 | 4,550 |
| BOGGS RUN | Pennsylvania | Scour Critical — Countermeasures Installed | Good | 1920 | 4,550 |
| RYAN CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1968 | 4,542 |
| SOUTH UMPQUA RIVER | Oregon | Scour Critical — Countermeasures Installed | Poor | 1946 | 4,541 |
| A-2 CHANNEL | Oregon | Scour Critical — Countermeasures Installed | Fair | 1981 | 4,539 |
| LITTLE RIVER RELIEF | Louisiana | Scour Critical — Countermeasures Installed | Fair | 2008 | 4,538 |
| LITTLE RIVER | Louisiana | Scour Critical — Countermeasures Installed | Good | 2008 | 4,538 |
| COCKERHAM CREEK | Louisiana | Scour Critical — Countermeasures Installed | Good | 2008 | 4,538 |
| DYAS CREEK | Alabama | Scour Critical — Countermeasures Installed | Fair | 1951 | 4,535 |
| AMAZON CANAL | Oregon | Scour Critical — Countermeasures Installed | Fair | 1973 | 4,535 |
| CANAL | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1973 | 4,534 |
| Church Rock Wash | Arizona | Scour Critical — Countermeasures Installed | Fair | 1961 | 4,533 |
| North Santiam River | Oregon | Scour Critical — Countermeasures Installed | Fair | 1973 | 4,530 |
| BLACKWELL CR | Missouri | Scour Critical — Countermeasures Installed | Fair | 1964 | 4,527 |
| NINE MILE CREEK | New York | Scour Critical — Countermeasures Installed | Fair | 1921 | 4,527 |
| PAWLOWSKI CREEK DRAIN | Michigan | Scour Critical — Countermeasures Installed | Fair | 1978 | 4,525 |
| N. FORK HUMBOLDT RIVER | Nevada | Scour Critical — Countermeasures Installed | Good | 1962 | 4,525 |
| N. FORK HUMBOLDT RIVER | Nevada | Scour Critical — Countermeasures Installed | Good | 1962 | 4,525 |
| MUDDY CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1950 | 4,523 |
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.