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 |
|---|---|---|---|---|---|
| WATER MILL BROOK | Massachusetts | Scour Critical — Countermeasures Installed | Fair | 1920 | 2,800 |
| ROCKY CREEK | South Carolina | Scour Critical — Countermeasures Installed | Poor | 1962 | 2,800 |
| MIDDLE BRANCH BUSHY CK | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1982 | 2,800 |
| SNAKE RIVER | Idaho | Scour Critical — Countermeasures Installed | Fair | 1967 | 2,800 |
| SHAMONA CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1965 | 2,800 |
| SANTA CATALINA CREEK | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1980 | 2,800 |
| SALKEHATCHIE RIVER SWAMP | South Carolina | Scour Critical — Countermeasures Installed | Fair | 2002 | 2,800 |
| GUAMANI RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1925 | 2,800 |
| TRIB TO KEOWEE RIVER | South Carolina | Scour Critical — Countermeasures Installed | Poor | 1958 | 2,800 |
| BURNT FORK | West Virginia | Scour Critical — Countermeasures Installed | Poor | 1959 | 2,800 |
| TRIB TO RICES CREEK | South Carolina | Scour Critical — Countermeasures Installed | Fair | 1967 | 2,800 |
| SANTANA CREEK | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1900 | 2,800 |
| FIFTEEN MILE CREEK | South Carolina | Scour Critical — Countermeasures Installed | Poor | 1965 | 2,800 |
| MORGAN CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Poor | 1922 | 2,800 |
| BEAR RIVER;RIVERDALE BR | Idaho | Scour Critical — Countermeasures Installed | Fair | 1960 | 2,800 |
| WHIPPY SWAMP | South Carolina | Scour Critical — Countermeasures Installed | Good | 2002 | 2,800 |
| BRANNIN CREEK | California | Scour Critical — Countermeasures Installed | Poor | 1914 | 2,799 |
| RICE CREEK | California | Scour Critical — Countermeasures Installed | Fair | 1914 | 2,799 |
| CLEAR CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1988 | 2,798 |
| OVER SPRUCE RUN | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1948 | 2,792 |
| LITTLE QUILCENE RIVER | Washington | Scour Critical — Countermeasures Installed | Fair | 1938 | 2,792 |
| ALLOWAYS CREEK | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1930 | 2,787 |
| RHINEBECK KILL | New York | Scour Critical — Countermeasures Installed | Poor | 1919 | 2,787 |
| WATER NASKETUCKET BAY | Massachusetts | Scour Critical — Countermeasures Installed | Fair | 1920 | 2,785 |
| EAGLE CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1952 | 2,781 |
| E BRANCH NAUGATUCK RIVER | Connecticut | Scour Critical — Countermeasures Installed | Fair | 1961 | 2,780 |
| CREEK | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1954 | 2,778 |
| BULL BRANCH | Louisiana | Scour Critical — Countermeasures Installed | Poor | 1957 | 2,778 |
| WEST BRANCH RUSSIAN RIV | California | Scour Critical — Countermeasures Installed | Poor | 1958 | 2,776 |
| OVER LITTLE SUGAR CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1985 | 2,773 |
| OVER LITTLE SUGAR CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1985 | 2,773 |
| ASSISCONG CREEK | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1923 | 2,771 |
| DRY CREEK | California | Scour Critical — Countermeasures Installed | Fair | 1987 | 2,769 |
| PUCHYAN RIVER | Wisconsin | Scour Critical — Countermeasures Installed | Poor | 1929 | 2,769 |
| BUCK RUN | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1929 | 2,763 |
| ALEXANDER CREEK | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1948 | 2,761 |
| WATNONG BROOK | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1944 | 2,761 |
| MARAIS DES CYGNES RIVER | Kansas | Scour Critical — Countermeasures Installed | Fair | 1973 | 2,760 |
| SPRING GARDEN BROOK | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1936 | 2,760 |
| S BR CASS RIVER I/C DRN | Michigan | Scour Critical — Countermeasures Installed | Poor | 1930 | 2,754 |
| SCATTER CREEK | Washington | Scour Critical — Countermeasures Installed | Fair | 1965 | 2,751 |
| SUGAR CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1919 | 2,748 |
| SUGAR CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1923 | 2,748 |
| SUGAR CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1919 | 2,748 |
| SUGAR CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1923 | 2,748 |
| LONG TOM RIVER | Oregon | Scour Critical — Countermeasures Installed | Fair | 1978 | 2,746 |
| PIPE CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1942 | 2,741 |
| SHILOH BRANCH | Texas | Scour Critical — Countermeasures Installed | Fair | 1990 | 2,735 |
| LITTLE ANDERSON CREEK | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1921 | 2,732 |
| THORNAPPLE RIVER | Michigan | Scour Critical — Countermeasures Installed | Good | 1970 | 2,730 |
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.