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 |
|---|---|---|---|---|---|
| RAISIN RIVER & ELM AVE | Michigan | Scour Critical — Countermeasures Installed | Fair | 1988 | 27,951 |
| N BRANCH WRECK POND | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1941 | 27,928 |
| COBBS CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Poor | 1934 | 27,899 |
| BRANCH OF ROYCES BROOK | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1923 | 27,845 |
| HORSEPEN CREEK | Texas | Scour Critical — Countermeasures Installed | Fair | 1975 | 27,840 |
| BIG WILLS CREEK | Alabama | Scour Critical — Countermeasures Installed | Good | 1992 | 27,802 |
| BIG WILLS CREEK | Alabama | Scour Critical — Countermeasures Installed | Good | 1992 | 27,802 |
| BUCK CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1986 | 27,800 |
| AMITY DITCH | Indiana | Scour Critical — Countermeasures Installed | Good | 1970 | 27,789 |
| CYPRESS SWAMP | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1961 | 27,700 |
| CYPRESS SWAMP | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1961 | 27,700 |
| MIDDLE ROUGE R | Michigan | Scour Critical — Countermeasures Installed | Good | 1959 | 27,634 |
| MIDDLE ROUGE R | Michigan | Scour Critical — Countermeasures Installed | Good | 1959 | 27,634 |
| MIDDLE BR CLINTON RIVER | Michigan | Scour Critical — Countermeasures Installed | Good | 1966 | 27,631 |
| BRNT MEADOW (GRN PD) BRK | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1960 | 27,614 |
| PLEASANT RUN CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1991 | 27,568 |
| NORRIS DITCH NO 2 | Indiana | Scour Critical — Countermeasures Installed | Fair | 1971 | 27,527 |
| WATER CONNECTICUT RIVER | Massachusetts | Scour Critical — Countermeasures Installed | Fair | 1924 | 27,500 |
| SAND CREEK | Idaho | Scour Critical — Countermeasures Installed | Poor | 1994 | 27,500 |
| PR 328 0.03 KM | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1974 | 27,500 |
| LAKE LANSING OUTLET | Michigan | Scour Critical — Countermeasures Installed | Fair | 1931 | 27,408 |
| BUCK CR | Michigan | Scour Critical — Countermeasures Installed | Poor | 1933 | 27,400 |
| UKUMEHAME STRM | Hawaii | Scour Critical — Countermeasures Installed | Fair | 1950 | 27,400 |
| INABON RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Poor | 1970 | 27,300 |
| INABON RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1970 | 27,300 |
| WATER WESTFIELD RIVER | Massachusetts | Scour Critical — Countermeasures Installed | Fair | 1938 | 27,300 |
| SAUCON CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1929 | 27,279 |
| North Channel Toms River | New Jersey | Scour Critical — Countermeasures Installed | Poor | 1928 | 27,261 |
| COW CASTLE CREEK | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1961 | 27,250 |
| COW CASTLE CREEK | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1961 | 27,250 |
| BIG EAGLE CREEK | Indiana | Scour Critical — Countermeasures Installed | Good | 1960 | 27,250 |
| BIG EAGLE CREEK | Indiana | Scour Critical — Countermeasures Installed | Good | 1960 | 27,250 |
| STONY CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Poor | 1878 | 27,202 |
| GRAND RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1927 | 27,197 |
| PIEDRAS RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1965 | 27,100 |
| PIEDRAS RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Poor | 1953 | 27,100 |
| Oak Creek | Oregon | Scour Critical — Countermeasures Installed | Fair | 1958 | 27,073 |
| Oak Creek | Oregon | Scour Critical — Countermeasures Installed | Good | 1958 | 27,073 |
| NORTH CHICKAMAUGA CREEK | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1955 | 27,012 |
| FRENCH BROAD RIVER | North Carolina | Scour Critical — Countermeasures Installed | Fair | 1967 | 27,000 |
| SAMMAMISH R | Washington | Scour Critical — Countermeasures Installed | Fair | 1972 | 27,000 |
| LAUREL CREEK | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1954 | 27,000 |
| UPRR & TRUCKEE RIVER | Nevada | Scour Critical — Countermeasures Installed | Fair | 1990 | 27,000 |
| Albany Ditch | Oregon | Scour Critical — Countermeasures Installed | Fair | 1958 | 26,927 |
| Albany Ditch | Oregon | Scour Critical — Countermeasures Installed | Fair | 1958 | 26,927 |
| North Channel Toms River | New Jersey | Scour Critical — Countermeasures Installed | Poor | 1928 | 26,921 |
| MANATAWNY CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1958 | 26,919 |
| SNAKE R. (HWY 493) | Oregon | Scour Critical — Countermeasures Installed | Good | 1967 | 26,880 |
| UNKNOWN CREEK | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1997 | 26,800 |
| WAIPAHOEHOE STRM | Hawaii | Scour Critical — Countermeasures Installed | Good | 1968 | 26,700 |
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.