Scour Critical Bridges in Alaska
159 bridges in Alaska 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 159 bridges in Alaska have been identified as vulnerable to scour damage.
| Bridge | State | Scour Status | Condition | Year Built | ADT |
|---|---|---|---|---|---|
| GOLD CREEK | Alaska | Scour Critical — Countermeasures Installed | Fair | 1938 | 280 |
| SWANSON RIVER | Alaska | Scour Critical — Countermeasures Installed | Fair | 1966 | 260 |
| INDIAN RIVER | Alaska | Scour Critical — Countermeasures Installed | Good | 1984 | 260 |
| GRAND CENTRAL RIVER | Alaska | Scour Critical — Countermeasures Installed | Good | 1982 | 249 |
| GUNNY SACK CREEK | Alaska | Scour Critical — Countermeasures Installed | Fair | 1954 | 240 |
| MONASHKA CREEK | Alaska | Scour Critical — Countermeasures Installed | Fair | 1972 | 220 |
| JOHNSON RIVER | Alaska | Scour Critical — Countermeasures Installed | Poor | 1944 | 180 |
| GERSTLE RIVER | Alaska | Scour Critical — Countermeasures Installed | Poor | 1944 | 180 |
| TAYLOR CREEK | Alaska | Scour Critical — Countermeasures Installed | Poor | 1977 | 160 |
| MOOSE CREEK | Alaska | Scour Critical — Countermeasures Installed | Poor | 1974 | 160 |
| MAMMOTH CREEK | Alaska | Scour Critical — Countermeasures Installed | Fair | 1971 | 140 |
| FT. HAMLIN HILLS CREEK | Alaska | Scour Critical — Countermeasures Installed | Fair | 1982 | 140 |
| TREVOR CREEK | Alaska | Scour Critical — Countermeasures Installed | Fair | 1982 | 130 |
| DAN CREEK | Alaska | Scour Critical — Countermeasures Installed | Fair | 1982 | 130 |
| DEADWOOD CREEK | Alaska | Scour Critical — Countermeasures Installed | Fair | 1975 | 120 |
| SOURDOUGH CREEK | Alaska | Scour Critical — Countermeasures Installed | Good | 1983 | 120 |
| KETCHUM CREEK | Alaska | Scour Critical — Countermeasures Installed | Good | 1975 | 120 |
| BIRCH CREEK | Alaska | Scour Critical — Countermeasures Installed | Fair | 1957 | 110 |
| MID FORK KOYUKUK RIVER 2 | Alaska | Scour Critical — Countermeasures Installed | Fair | 1972 | 110 |
| GOLD CREEK | Alaska | Scour Critical — Countermeasures Installed | Good | 1982 | 110 |
| WEST FORK N FK CHANDALAR | Alaska | Scour Critical — Countermeasures Installed | Fair | 1982 | 110 |
| BEAVER SPRINGS CREEK | Alaska | Scour Critical — Countermeasures Installed | Fair | 2003 | 100 |
| GLACIER FK OF SALMON CR | Alaska | Scour Critical — Countermeasures Installed | Fair | 1986 | 100 |
| COPPER DELTA | Alaska | Scour Critical — Countermeasures Installed | Good | 1977 | 94 |
| CHILKOOT RIVER | Alaska | Scour Critical — Countermeasures Installed | Fair | 1979 | 90 |
| GOLD CREEK | Alaska | Scour Critical — Countermeasures Installed | Poor | 1972 | 86 |
| PERRYVILLE CREEK | Alaska | Scour Critical — Countermeasures Installed | Good | 1981 | 77 |
| MINERAL CREEK | Alaska | Scour Critical — Countermeasures Installed | Poor | 1970 | 75 |
| HUMBOLT SLOUGH | Alaska | Scour Critical — Countermeasures Installed | Poor | 1998 | 75 |
| TOLSTOI CREEK NO. 2 | Alaska | Scour Critical — Countermeasures Installed | Good | 1996 | 70 |
| GILAHINA RIVER | Alaska | Scour Critical — Countermeasures Installed | Fair | 1991 | 70 |
| TOLSTOI CREEK NO. 1 | Alaska | Scour Critical — Countermeasures Installed | Good | 1996 | 70 |
| TOLSTOI CREEK TRIBUTARY | Alaska | Scour Critical — Countermeasures Installed | Good | 1996 | 70 |
| MILLION DOLLAR BRIDGE | Alaska | Scour Critical — Countermeasures Installed | Poor | 1910 | 65 |
| SUSITNA RIVER | Alaska | Scour Critical — Countermeasures Installed | Poor | 1956 | 60 |
| COTTONWOOD CREEK | Alaska | Scour Critical — Countermeasures Installed | Fair | 2008 | 50 |
| PILGRIM RIVER | Alaska | Scour Critical — Countermeasures Installed | Good | 1982 | 50 |
| NINILCHIK RIV BRODY LN | Alaska | Scour Critical — Countermeasures Installed | Good | 2003 | 50 |
| NORTH FORK ALEXCY CREEK | Alaska | Scour Critical — Countermeasures Installed | Fair | 1985 | 50 |
| UNNAMED CREEK KOLIGANEK | Alaska | Scour Critical — Countermeasures Installed | Poor | 1980 | 50 |
| CROOKED CREEK | Alaska | Scour Critical — Countermeasures Installed | Fair | 2006 | 50 |
| TATALINA RIVER | Alaska | Scour Critical — Countermeasures Installed | Fair | 1947 | 45 |
| YANKEE CREEK | Alaska | Scour Critical — Countermeasures Installed | Fair | 1937 | 45 |
| CALIFORNIA CREEK | Alaska | Scour Critical — Countermeasures Installed | Poor | 1937 | 45 |
| GANES CREEK | Alaska | Scour Critical — Countermeasures Installed | Fair | 1937 | 45 |
| SPRUCE CREEK | Alaska | Scour Critical — Countermeasures Installed | Poor | 1964 | 45 |
| CHIGNIK CREEK | Alaska | Scour Critical — Countermeasures Installed | Fair | 2002 | 45 |
| INDEPENDENCE CREEK | Alaska | Scour Critical — Countermeasures Installed | Fair | 1969 | 45 |
| INDIAN CREEK | Alaska | Scour Critical — Countermeasures Installed | Poor | 1985 | 45 |
| PACKERS CREEK | Alaska | Scour Critical — Countermeasures Installed | Fair | 1986 | 41 |
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.