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 |
|---|---|---|---|---|---|
| RED BRANCH | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1979 | 3,124 |
| LICKING CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1935 | 3,124 |
| MAMARONECK RIVER | New York | Scour Critical — Countermeasures Installed | Poor | 1900 | 3,122 |
| FLATROCK RIVER | Indiana | Scour Critical — Countermeasures Installed | Fair | 1992 | 3,120 |
| SLOUGH | Louisiana | Scour Critical — Countermeasures Installed | Good | 1974 | 3,120 |
| TERRYS CREEK | Louisiana | Scour Critical — Countermeasures Installed | Good | 1974 | 3,120 |
| TANG. R. W.RELIEF | Louisiana | Scour Critical — Countermeasures Installed | Good | 1975 | 3,120 |
| TANGIPAHOA RIVER | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1974 | 3,120 |
| TANGIPAHOA RIVER E RELIE | Louisiana | Scour Critical — Countermeasures Installed | Good | 1975 | 3,120 |
| Chehulpum Creek | Oregon | Scour Critical — Countermeasures Installed | Fair | 1919 | 3,115 |
| BUTTERNUT CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1927 | 3,115 |
| LITTLE WHITE OAK BAYOU | Texas | Scour Critical — Countermeasures Installed | Fair | 1955 | 3,115 |
| HUNLOCK CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Poor | 1925 | 3,114 |
| OVERFLOW | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1968 | 3,114 |
| OBION RIVER | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1968 | 3,114 |
| LTI CREEK | Louisiana | Scour Critical — Countermeasures Installed | Fair | 2015 | 3,111 |
| NORTH SUGAR CREEK | Kansas | Scour Critical — Countermeasures Installed | Good | 1982 | 3,109 |
| WEST BR.CHESTER CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1973 | 3,108 |
| E BR PEMIGEWASSET RIVER | New Hampshire | Scour Critical — Countermeasures Installed | Fair | 1938 | 3,107 |
| SHOTGUN CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1964 | 3,106 |
| EAST BR PEQUEST RIVER | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1939 | 3,105 |
| PAWCATUCK RIVER | Rhode Island | Scour Critical — Countermeasures Installed | Fair | 1926 | 3,102 |
| DEER CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1933 | 3,101 |
| DRY CREEK CANAL | California | Scour Critical — Countermeasures Installed | Fair | 1935 | 3,101 |
| ST CATHERINE CREEK | Mississippi | Scour Critical — Countermeasures Installed | Good | 1998 | 3,100 |
| GROVE CREEK | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1971 | 3,100 |
| TRIB CARPENTER CK (1) | South Carolina | Scour Critical — Countermeasures Installed | Poor | 1959 | 3,100 |
| TRIB CARPENTER CK (2) | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1959 | 3,100 |
| REEDY RIVER | South Carolina | Scour Critical — Countermeasures Installed | Good | 1988 | 3,100 |
| COOSAWHATCHIE RIVER | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1996 | 3,100 |
| LYMAN BROOK | Vermont | Scour Critical — Countermeasures Installed | Fair | 1929 | 3,100 |
| PRIEST RIVER | Idaho | Scour Critical — Countermeasures Installed | Poor | 1962 | 3,100 |
| BR CEDAR CREEK | Wisconsin | Scour Critical — Countermeasures Installed | Fair | 1940 | 3,100 |
| STURGEON CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1981 | 3,100 |
| SLEEPY CREEK | West Virginia | Scour Critical — Countermeasures Installed | Poor | 1900 | 3,100 |
| LA MINA CREEK | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1961 | 3,100 |
| MINETTA BRANCH | Florida | Scour Critical — Countermeasures Installed | Poor | 1924 | 3,100 |
| LA MANUELA CREEK | Puerto Rico | Scour Critical — Countermeasures Installed | Poor | 1955 | 3,100 |
| SANTIAGO RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1955 | 3,100 |
| ONION RIVER | Wisconsin | Scour Critical — Countermeasures Installed | Fair | 1936 | 3,100 |
| DE NEVEU CREEK | Wisconsin | Scour Critical — Countermeasures Installed | Poor | 1965 | 3,100 |
| ST LUCIE CANAL | Florida | Scour Critical — Countermeasures Installed | Good | 1980 | 3,100 |
| GUAYNABO RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Poor | 1985 | 3,100 |
| MUSKEGO CANAL | Wisconsin | Scour Critical — Countermeasures Installed | Fair | 1925 | 3,100 |
| PATILLAS RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1956 | 3,100 |
| ALAMO ALTO DRAIN | Texas | Scour Critical — Countermeasures Installed | Good | 2011 | 3,095 |
| DRAINAGE CANAL | Louisiana | Scour Critical — Countermeasures Installed | Good | 2007 | 3,094 |
| MUD CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1976 | 3,093 |
| MUD CREEK | Indiana | Scour Critical — Countermeasures Installed | Good | 1971 | 3,093 |
| SANDY CREEK | Louisiana | Scour Critical — Countermeasures Installed | Poor | 1979 | 3,092 |
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.