- New Hampshire Department of Environmental Services
- State & Local
- Effingham and Freedom, New Hampshire
Project Overview
Charter replaced the deteriorated historic dam at the outlet of Berry Bay on Ossipee Lake in Effingham and Freedom, New Hampshire. The original dam had an undermined foundation, deteriorated concrete, a manual stop-log system and not enough capacity to safely pass flood events.
The new dam was built about 50 feet downstream of the original. It is designed to current standards, with greater discharge capacity, improved flood control and remote monitoring and operation.
Charter’s Role
- Water control with an upstream cofferdam throughout construction
- Construction of the new reinforced-concrete dam and extended wing walls
- Installation of two hydraulically actuated crest gates with side-seal heaters to prevent freezing
- A new control building with hydraulic controls, programmable logic controller and emergency generator
- Instrumentation and SCADA connections, plus stop logs, removable stanchions and a catwalk for maintenance
- Demolition of the original dam and restoration of the riverbed with placed boulders for scour control and fish passage
Outcomes & Benefits
The State of New Hampshire now has a modern, remotely controlled dam with greater flood capacity and better control of lake levels, delivered about two months ahead of schedule.
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