Scour Critical Bridges in District of Columbia

5 bridges in District of Columbia 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 5 bridges in District of Columbia have been identified as vulnerable to scour damage.

Clear
Bridge State Scour Status Condition Year Built ADT
Anacostia River Outlet District of Columbia Scour Critical — Countermeasures Ineffective Fair 1984 200
ANACOSTIA RIVER District of Columbia Scour Critical — Countermeasures Installed Fair 1953 131,500
WATTS BRANCH District of Columbia Scour Critical — Countermeasures Installed Fair 1956 122,000
WATTS BRANCH District of Columbia Scour Critical — Countermeasures Installed Good 1956 13,000
WATTS BRANCH District of Columbia Scour Critical — Countermeasures Installed Fair 1950 2,000

Scour Critical Rating Codes

Code 2 — UnaddressedBridge is scour critical with no countermeasures installed. The foundation is vulnerable and no protective action has been taken.
Code 3 — Countermeasures InstalledProtective measures (riprap, sheet piling, etc.) have been installed to reduce scour risk, but the bridge remains classified as scour critical.
Code 6 — Countermeasures IneffectiveProtective 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.