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 |
|---|---|---|---|---|---|
| HURON RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1971 | 102,776 |
| FALL CREEK & TRAIL | Indiana | Scour Critical — Countermeasures Installed | Fair | 1966 | 101,476 |
| MATTABESSET RIVER | Connecticut | Scour Critical — Countermeasures Installed | Fair | 1965 | 99,500 |
| Mason Creek | Texas | Scour Critical — Countermeasures Installed | Good | 2005 | 99,354 |
| FALL CREEK & TRAIL | Indiana | Scour Critical — Countermeasures Installed | Fair | 1966 | 97,835 |
| Willamette River | Oregon | Scour Critical — Countermeasures Installed | Fair | 1970 | 97,105 |
| PIPE MAKERS CANAL | Georgia | Scour Critical — Countermeasures Installed | Good | 1976 | 96,600 |
| JONES FALLS & UNION AVE | Maryland | Scour Critical — Countermeasures Installed | Fair | 1959 | 95,051 |
| CAGUITAS RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Poor | 1964 | 93,200 |
| CARMEL CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1967 | 92,625 |
| CARMEL CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1967 | 92,625 |
| ECHECONNEE CREEK | Georgia | Scour Critical — Countermeasures Installed | Good | 1963 | 92,100 |
| HACKENSACK RIVR & ROAD | New Jersey | Scour Critical — Countermeasures Installed | Poor | 1931 | 92,076 |
| CLEAR CREEK R | Colorado | Scour Critical — Countermeasures Installed | Good | 1980 | 92,000 |
| KEEGANS BAYOU | Texas | Scour Critical — Countermeasures Installed | Fair | 1969 | 89,868 |
| RED RIVER | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1972 | 88,998 |
| FERDUN CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1957 | 88,500 |
| SALT CR | Illinois | Scour Critical — Countermeasures Installed | Fair | 1958 | 87,550 |
| SALT CR | Illinois | Scour Critical — Countermeasures Installed | Fair | 1958 | 87,550 |
| DEEP RUN BROOK | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1940 | 86,421 |
| ST.JOHNS RIV.& MILL COVE | Florida | Scour Critical — Countermeasures Installed | Fair | 1989 | 84,321 |
| HARLEM RVR SHORE | New York | Scour Critical — Countermeasures Installed | Fair | 1966 | 82,471 |
| CST N LEVEE RD MISSOU | Missouri | Scour Critical — Countermeasures Installed | Fair | 1972 | 81,653 |
| Mississippi River | Minnesota | Scour Critical — Countermeasures Installed | Fair | 1963 | 81,500 |
| WATER MERRIMACK RIVER | Massachusetts | Scour Critical — Countermeasures Installed | Poor | 1962 | 79,000 |
| SAN JACINTO RIVER | Texas | Scour Critical — Countermeasures Installed | Fair | 1974 | 78,458 |
| AMERICAN RIVER | California | Scour Critical — Countermeasures Installed | Fair | 1955 | 78,370 |
| GRANDE DE LOIZA RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 2000 | 78,200 |
| WEST COLYELL CR | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1970 | 77,469 |
| HWY 1 | Oregon | Scour Critical — Countermeasures Installed | Fair | 1963 | 76,816 |
| BIG BRANCH | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1969 | 75,867 |
| SANDY RUN | Pennsylvania | Scour Critical — Countermeasures Installed | Good | 1954 | 74,921 |
| MERAMEC RVR BACKWOOD DR | Missouri | Scour Critical — Countermeasures Installed | Fair | 1954 | 74,368 |
| BLOOD RIVER | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1968 | 74,180 |
| ECHO LAKE | New Jersey | Scour Critical — Countermeasures Installed | Poor | 1929 | 73,690 |
| ELIZABETH RIVER | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1928 | 73,243 |
| RIPPOWAM RIVER | Connecticut | Scour Critical — Countermeasures Installed | Fair | 1936 | 73,120 |
| POMPESTON CREEK | New Jersey | Scour Critical — Countermeasures Installed | Poor | 1925 | 72,151 |
| HWY 1 I-5 | Oregon | Scour Critical — Countermeasures Installed | Fair | 1963 | 71,767 |
| SAVANNAH RIVER | Georgia | Scour Critical — Countermeasures Installed | Fair | 1976 | 70,500 |
| EIGHTMILE CREEK | Alabama | Scour Critical — Countermeasures Installed | Fair | 1965 | 69,472 |
| CHICKASAW CREEK | Alabama | Scour Critical — Countermeasures Installed | Fair | 2003 | 69,472 |
| WEPAWAUG RIVER | Connecticut | Scour Critical — Countermeasures Installed | Fair | 1949 | 68,300 |
| BIG INDIAN CREEK | Georgia | Scour Critical — Countermeasures Installed | Good | 1963 | 67,800 |
| CONRAIL RAISIN R FRONT | Michigan | Scour Critical — Countermeasures Installed | Poor | 1955 | 67,800 |
| CLOVER CREEK | Washington | Scour Critical — Countermeasures Installed | Fair | 1957 | 67,232 |
| SWARTZ CREEK | Michigan | Scour Critical — Countermeasures Installed | Fair | 1954 | 66,912 |
| LAUREL RUN | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1963 | 66,529 |
| CLARKS CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1966 | 65,674 |
| WEST FK WHITE LICK CREEK | Indiana | Scour Critical — Countermeasures Installed | Good | 1966 | 65,674 |
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.