Scour Critical Bridges in New Hampshire

86 bridges in New Hampshire 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 86 bridges in New Hampshire have been identified as vulnerable to scour damage.

Clear

Bridge	State	Scour Status	Condition	Year Built	ADT
LAMPREY RIVER	New Hampshire	Scour Critical — Unaddressed	Poor	1914	547
STEARNS BROOK	New Hampshire	Scour Critical — Unaddressed	Poor	1950	96
SO. BR. GALE RIVER	New Hampshire	Scour Critical — Countermeasures Ineffective	Good	2011	99
SCARFACE BROOK	New Hampshire	Scour Critical — Countermeasures Ineffective	Good	2011	99
COLD BROOK	New Hampshire	Scour Critical — Countermeasures Ineffective	Good	2006	99
N.BR. GALE RIVER	New Hampshire	Scour Critical — Countermeasures Ineffective	Fair	1971	50
E.BR. MILL BROOK	New Hampshire	Scour Critical — Countermeasures Ineffective	Fair	1982	50
SO. BR. GALE RIVER	New Hampshire	Scour Critical — Countermeasures Ineffective	Good	2011	50
MERRIMACK RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Fair	1959	25,855
MERRIMACK RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Fair	1959	25,801
CONNECTICUT RIVER NECRR	New Hampshire	Scour Critical — Countermeasures Installed	Poor	1966	22,288
CONNECTICUT RIVER NECRR	New Hampshire	Scour Critical — Countermeasures Installed	Poor	1966	21,268
MERRIMACK RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Fair	1970	17,275
CONTOOCOOK RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Fair	1961	17,117
ISINGLASS RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Poor	1951	14,407
HAMPTON RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Poor	1949	9,402
SOUCOOK RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Fair	1936	8,465
AMMONOOSUC RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Good	1950	7,962
ELLIS RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Good	1938	6,773
BEAVER BROOK	New Hampshire	Scour Critical — Countermeasures Installed	Fair	1920	6,622
MILL BROOK	New Hampshire	Scour Critical — Countermeasures Installed	Fair	1928	6,478
SOUHEGAN RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Fair	1917	6,406
SALMON FALLS RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Poor	1950	6,132
BEAVER BROOK	New Hampshire	Scour Critical — Countermeasures Installed	Poor	1900	6,111
N BRANCH RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Good	1988	5,929
CLARKS RR PEMIGEWASSET R	New Hampshire	Scour Critical — Countermeasures Installed	Good	1973	5,785
CONTOOCOOK RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Poor	1942	5,773
CLARKS RR PEMIGEWASSET R	New Hampshire	Scour Critical — Countermeasures Installed	Good	1981	5,456
AMMONOOSUC RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Fair	1972	5,178
PEABODY RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Fair	1950	4,148
OSSIPEE RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Good	1956	3,594
SOUHEGAN RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Good	1987	3,589
WINNIPESAUKEE RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Fair	1982	3,412
E BR PEMIGEWASSET RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Fair	1938	3,107
PISCATAQUA ESTUARY	New Hampshire	Scour Critical — Countermeasures Installed	Fair	1955	3,041
SWIFT RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Fair	1975	2,900
MAD RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Poor	1979	2,828
PEMIGEWASSET RIVER NHRR	New Hampshire	Scour Critical — Countermeasures Installed	Fair	1937	2,666
LAMPREY RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Fair	1932	2,642
CONTOOCOOK RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Fair	1981	2,615
WINNIPESAUKEE RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Good	1988	2,602
COHAS BROOK	New Hampshire	Scour Critical — Countermeasures Installed	Good	1900	2,560
COCHECO RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Good	1978	2,189
AMEY BROOK	New Hampshire	Scour Critical — Countermeasures Installed	Good	1938	1,984
ASHUELOT RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Fair	1940	1,937
PEMIGEWASSET RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Poor	1928	1,917
BERRY BROOK	New Hampshire	Scour Critical — Countermeasures Installed	Good	1986	1,673
SUGAR RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Fair	1959	1,345
CONNECTICUT RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Fair	1931	1,342
ASHUELOT RIVER	New Hampshire	Scour Critical — Countermeasures Installed	Fair	1976	1,336

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.

All Bridges Poor Condition Historic Bridges Bridge Stats