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 |
|---|---|---|---|---|---|
| Dania Cut-Off Canal | Florida | Scour Critical — Countermeasures Installed | Fair | 1931 | 53,000 |
| Drainage Ditch | Texas | Scour Critical — Countermeasures Installed | Fair | 1961 | 52,733 |
| CR 632 & MUSCONET RIV | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1959 | 52,610 |
| TURKEY CR MILL STREET | Kansas | Scour Critical — Countermeasures Installed | Good | 1961 | 52,500 |
| TURKEY CR MILL STREET | Kansas | Scour Critical — Countermeasures Installed | Good | 1961 | 52,500 |
| LA PLATA RIVER & PR | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1985 | 52,500 |
| OLD WM PENN HWY LEAK RUN | Pennsylvania | Scour Critical — Countermeasures Installed | Poor | 1962 | 52,457 |
| Grand Canal | Arizona | Scour Critical — Countermeasures Installed | Fair | 1979 | 52,404 |
| PENNYPACK CRK;PATHS | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1920 | 52,330 |
| HARRIS CREEK | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1965 | 52,149 |
| SEQUATCHIE RIVER | Tennessee | Scour Critical — Countermeasures Installed | Poor | 1965 | 52,102 |
| SEQUATCHIE RIVER | Tennessee | Scour Critical — Countermeasures Installed | Poor | 1965 | 52,102 |
| ELM CREEK | Texas | Scour Critical — Countermeasures Installed | Good | 1934 | 52,065 |
| CLEAR CREEK | Oregon | Scour Critical — Countermeasures Installed | Fair | 1930 | 51,600 |
| BRANCH MCCRACKEN CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1966 | 51,175 |
| BRANCH MCCRACKEN CREEK | Indiana | Scour Critical — Countermeasures Installed | Fair | 1966 | 51,175 |
| N BRANCH MCCRACKEN CREEK | Indiana | Scour Critical — Countermeasures Installed | Good | 1966 | 51,175 |
| CLARKS CREEK | Indiana | Scour Critical — Countermeasures Installed | Good | 1966 | 51,175 |
| STONY BROOK | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1929 | 50,500 |
| ROARING BROOK | Connecticut | Scour Critical — Countermeasures Installed | Fair | 1955 | 50,400 |
| S. BR. RARITAN RIVER | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1958 | 49,741 |
| SOUTH BR. RARITAN RIVER | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1957 | 49,741 |
| CLINTON RIVER N&S RDS | Michigan | Scour Critical — Countermeasures Installed | Fair | 1947 | 49,601 |
| CLINTON RIVER N&S RDS | Michigan | Scour Critical — Countermeasures Installed | Fair | 1963 | 49,601 |
| BRADEN RIVER EAST BRANCH | Florida | Scour Critical — Countermeasures Installed | Good | 1988 | 49,500 |
| CROSS BAYOU | Florida | Scour Critical — Countermeasures Installed | Fair | 1976 | 49,500 |
| MATTABESSET RIVER | Connecticut | Scour Critical — Countermeasures Installed | Fair | 1965 | 49,200 |
| MILL BROOK | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1932 | 48,987 |
| IRRIGATION CHANNEL | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1986 | 48,600 |
| HIWASSEE RIVER | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1968 | 48,545 |
| HIWASSEE RIVER | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1968 | 48,545 |
| SOUTH PLATTE RIVER | Colorado | Scour Critical — Countermeasures Installed | Poor | 1969 | 48,500 |
| HAT CREEK | Georgia | Scour Critical — Countermeasures Installed | Good | 1958 | 48,500 |
| JUAN GONZALEZ CREEK | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1976 | 48,100 |
| FEATHER RIVER K ST UP RR | California | Scour Critical — Countermeasures Installed | Fair | 1947 | 48,000 |
| NVRR NAPA RIVER STANLY | California | Scour Critical — Countermeasures Installed | Poor | 1977 | 48,000 |
| ASHLEY RIVER | South Carolina | Scour Critical — Countermeasures Installed | Poor | 1953 | 47,800 |
| MOUSE CREEK | Tennessee | Scour Critical — Countermeasures Installed | Good | 1971 | 47,306 |
| MOUSE CREEK | Tennessee | Scour Critical — Countermeasures Installed | Fair | 1971 | 47,306 |
| PASSAIC RIVER | New Jersey | Scour Critical — Countermeasures Installed | Fair | 1940 | 47,094 |
| I 25 ML FOUNTAIN CRK | Colorado | Scour Critical — Countermeasures Installed | Fair | 1990 | 47,000 |
| NESHAMINY CR & SR 2027 | Pennsylvania | Scour Critical — Countermeasures Installed | Fair | 1964 | 46,995 |
| LICK CREEK | Indiana | Scour Critical — Countermeasures Installed | Good | 1963 | 46,611 |
| CA¥AS RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1953 | 46,400 |
| CLEAR CREEK BP R | Colorado | Scour Critical — Countermeasures Installed | Fair | 1981 | 46,000 |
| STILLAGUAMISH RIVER | Washington | Scour Critical — Countermeasures Installed | Fair | 1933 | 45,626 |
| STILLAGUAMISH R | Washington | Scour Critical — Countermeasures Installed | Fair | 1971 | 45,626 |
| ABITA RIVER | Louisiana | Scour Critical — Countermeasures Installed | Fair | 1975 | 45,574 |
| CANOVANAS RIVER | Puerto Rico | Scour Critical — Countermeasures Installed | Fair | 1956 | 45,200 |
| Willamette River | Oregon | Scour Critical — Countermeasures Installed | Fair | 1953 | 45,083 |
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.