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NHDOT State Route 123

Alstead, New Hampshire



NHDOT - Concord


NHDOT - Concord


Weaver Brothers Construction Co Inc.


April 2012

Technical Description:

  • DuroMaxx® SPRE 144 LF of 72” dia. with low head joints 3 psi

On October 9, 2005, significant rains pummeled southwestern New Hampshire causing widespread damage to roads, bridges, dwellings and significant loss of life. In Alstead, NH, the Warren Lake Dam overflowed causing water levels in Warren Brook to rise rapidly. A 12’ diameter pipe under Cooper Hill Road became plugged with debris resulting in the overtopping and failure of a 30’ embankment. The consequential dam breach and flood wave destroyed many roads and bridges in Alstead, including large sections of Route 123, Route 123A and Route 12A. Overall, 60 miles of state roads were closed, 8 miles were destroyed or deemed impassable including 4.5 miles of Route 123, 6 bridges severely damaged, one bridge destroyed and 15 towns affected. By December 2005, most of the affected roads were reopened. The NHDOT’s rapid and professional response to this disaster resulted in the Department’s award of the 2006 Outstanding Civil Engineering Achievement by the NH Chapter of the American Society of Civil Engineers.

Several years later in 2011-2012, Route 123 was reconstructed as part of the normal road rehabilitation process by NHDOT. Two such culverts in this mountainous area required a 72” diameter plastic pipe with a smooth interior. The NHDOT utilized Contech Engineered Solution’s 72” diameter DuroMaxx®, a steel reinforced high density polyethylene culvert pipe material. Two runs were installed by Weaver Brothers Construction on tributaries to Warren Brook approximately 3/4 mile below the lake.

Technical Description:

  • DuroMaxx® SPRE 144 LF of 72” dia. with low head joints 3 psi

800-338-1122 |


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