Baker River Site 8 Dam Rehabilitation

Grafton, New Hampshire | New Hampshire Department of Environmental Services

The Baker River Site 8 dam is a 1,462-ft-long by 63-ft-high dam with a maximum storage capacity of 4,750 acre-ft and is fed by a 15.58-sq.-mi. drainage area. The dam uses a vegetated auxiliary spillway to pass high flows, and the main spillway system consists of a concrete riser and a small stilling basin. Constructed in 1968, the dam embankment and the auxiliary spillway no longer meet current NRCS guidance for slope stability and for hydraulic capacity and integrity. In addition, components such as the internal toe drain have reached the end of their service lives. D&K performed topographic, bathymetric, and sediment surveys, evaluated the structure, performed H&H analyses, evaluated the stability of the structure (including for seismic liquefaction), designed improvements to the embankment for stability, toe drains, and spillways, and added St. Anthony’s Falls Stilling Basin.

Markets:

Project Elements

• 1,462-ft-long by 63-ft-high earthen flood control dam
• 4,750-acre-ft maximum storage capacity
• 15.58-sq.-mi. drainage area