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 |
|---|---|---|---|---|---|
| ABERNETHY CREEK | Oregon | Scour Critical — Countermeasures Installed | Poor | 1933 | 9,700 |
| MATTABESSET RIVER | Connecticut | Scour Critical — Countermeasures Installed | Fair | 1942 | 9,700 |
| ARROYATA CREEK | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1950 | 9,700 |
| SONOMA CREEK | California | Scour Critical — Countermeasures Installed | Good | 1949 | 9,700 |
| BACK SWAMP | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1931 | 9,700 |
| BACK SWAMP | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1974 | 9,700 |
| S BR TOBACCO RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1962 | 9,699 |
| S BR TOBACCO RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1962 | 9,699 |
| WATER FIRST LEVEL CANAL | Massachusetts | Scour Critical — Countermeasures Installed | Poor | 1919 | 9,698 |
| KOLB CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1950 | 9,690 |
| TROWBRIDGE CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1961 | 9,678 |
| PAPAKATING CREEK | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1980 | 9,676 |
| BEAL-TAYLOR DITCH | Indiana | Scour Critical — Countermeasures Installed | Fair | 1978 | 9,672 |
| FURNACE RUN | Pennsylvania | Scour Critical — Countermeasures Installed | Poor | 1930 | 9,664 |
| COLUMBIA RIVER | Washington | Scour Critical — Countermeasures Installed | Fair | 1978 | 9,651 |
| BOIS DE SIOUX RIVER | Minnesota | Scour Critical — Countermeasures Installed | Fair | 1930 | 9,650 |
| RIO GRANDE | New Mexico | Scour Critical — Countermeasures Installed | Fair | 1940 | 9,647 |
| USQUEPAUG RIVER | Rhode Island | Scour Critical — Countermeasures Installed | Fair | 1931 | 9,628 |
| DOUGLAS CREEK | Washington | Scour Critical — Countermeasures Installed | Poor | 1957 | 9,626 |
| INTRACOASTAL WATERWAY | Florida | Scour Critical — Countermeasures Installed | Good | 1967 | 9,625 |
| GRAND RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1960 | 9,625 |
| BEAVER RUN | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1940 | 9,622 |
| OVER BULL RUN | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1937 | 9,622 |
| SLOUGH OF YAKIMA R | Washington | Scour Critical — Countermeasures Installed | Fair | 1935 | 9,615 |
| South Fork Ash Creek | Oregon | Scour Critical — Countermeasures Installed | Fair | 1950 | 9,615 |
| BLACK BAYOU | Louisiana | Scour Critical — Countermeasures Installed | Poor | 1983 | 9,608 |
| LAKE VILLAR | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1983 | 9,608 |
| AGUAS LARGAS CREEK | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1949 | 9,600 |
| ARROYO GRANDE CREEK | California | Scour Critical — Countermeasures Installed | Fair | 1932 | 9,600 |
| CREEK | Oklahoma | Scour Critical — Countermeasures Installed | Poor | 1965 | 9,600 |
| BAIROA RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Poor | 1961 | 9,600 |
| SANTA FE RIVER | Florida | Scour Critical — Countermeasures Installed | Fair | 1932 | 9,600 |
| CANOVANILLAS RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1953 | 9,600 |
| BAYAMON RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1949 | 9,600 |
| CYPRESS CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1969 | 9,600 |
| GRAND RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1957 | 9,599 |
| GRAND RIVER | Michigan | Scour Critical — Countermeasures Installed | Poor | 1957 | 9,599 |
| SWEDE RUN | New Jersey | Scour Critical — Countermeasures Installed | Good | 1934 | 9,596 |
| ROCKY RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1951 | 9,588 |
| ROCKY RIVER | Michigan | Scour Critical — Countermeasures Installed | Fair | 1956 | 9,588 |
| HOLDEN DRAIN | Michigan | Scour Critical — Countermeasures Installed | Fair | 1923 | 9,585 |
| Luckiamute River | Oregon | Scour Critical — Countermeasures Installed | Fair | 1954 | 9,582 |
| MILL CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1965 | 9,578 |
| BRANCH OF MILL CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1966 | 9,578 |
| West Fork Dairy Creek | Oregon | Scour Critical — Countermeasures Installed | Poor | 1940 | 9,574 |
| BRUSHY BROOK | Rhode Island | Scour Critical — Countermeasures Installed | Fair | 1922 | 9,567 |
| WOOD RIVER | Rhode Island | Scour Critical — Countermeasures Installed | Fair | 1923 | 9,567 |
| MOREAU RVR | Missouri | Scour Critical — Countermeasures Installed | Poor | 1984 | 9,565 |
| INGRAMS THOROFARE | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1967 | 9,560 |
| S. FK. FORKED DEER RIVER | Tennessee | Scour Critical — Countermeasures Installed | Good | 1959 | 9,555 |
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.