The lake has been drained so that necessary engineering work can be completed to finish the design of a new concrete spillway, along with a plan to rehabilitate the earthen portion of the dam. In 2018 the drain failed causing it to leak and slowly drain the lake. Work is slated to start in 2025.
See the the poster explaining the project.
Four alternatives for reconstruction were considered:
1. Repair the existing dam outlet works.
2. Replace the existing outlet works in-kind.
3. Utilize the existing Agri Drain outlet works.
4. Construct a new unregulated overflow concrete spillway.
The recommended alternative is the option that best satisfies the Dam Bureau’s dam safety criteria, involves the least amount of construction and environmental disturbance to the site and involves minimal operation and maintenance. Based on the analysis of the alternatives, the unregulated overflow spillway constructed of reinforced concrete is the recommended dam repair alternative.
The plan set shows the features of the construction of the new concrete overflow spillway and low-level outlet gate and pipe, existing channel widening and protection of the emergency spillway channel to accommodate the new overflow spillway and concrete abutments, a new prefabricated pedestrian bridge to span over the new overflow spillway to maintain the existing walking trail connectivity that crosses the dam, new protection at normal pond level on the upstream side of the earth dam to minimize wave and ice scour, a new, partial height “blanket drain” on the downstream side of the earth dam to collect, control and direct earth dam seepage to a perforated pipe at the toe of the dam to be safely discharged to the wetland, and the structural stabilization of the existing drop inlet pipe outlet works and low-level drain pipe by filling the entire system with loose concrete; flowable fill.
Funding for this project is a combination of an appropriation through the State of New Hampshire Capital Budget and a grant from the Land and Water Conservation Program. Construction is expected to begin in the spring of 2026 and be completed by the fall of 2026.
See Northwood Meadows Dam Project Plans
