Planned Removal of the Wild Ammonoosuc Dam and Opportunity to Comment on Historic Signage

Wild Ammonoosuc Dam in Landaff, New Hampshire.

The White Mountain National Forest (WMNF) is proposing to issue a permit to dismantle and remove the Wild Ammonoosuc Dam, and restore the natural floodplain. The project is expected to be completed in 2026.

Project Overview 

The Wild Ammonoosuc River Dam, owned by the Woodsville Water and Light Department, blocks fish passage to 71 miles of cold-water habitat and disrupts natural riverine processes. The ten-foot-high concrete dam and associated water system previously served as a water supply but has not been used for decades. Rehabilitation of the dam for water supply purposes would be prohibitively expensive, so owners wish to pursue removal to alleviate the cost, maintenance, and liability burden. The project will include removal of structures and impounded sediment, and restoration of the adjacent floodplain.

The project is located in a designated brook trout catchment within the White Mountain National Forest. Removal of the dam will reconnect approximately 71 miles of mainstem and tributary streams benefiting eastern brook trout.

Currently, the Ammonoosuc River is suitable for wild, self-sustaining populations of brook trout (NH Fish and Game) and the area is identified as capable of sustaining brook trout populations under predicted climate conditions. Barrier removal will increase access to tributaries for spawning, increase genetic diversity, and provide thermal refuge allowing brook trout to persist and maintain healthy populations. The project will also plant native riparian tree and shrub species at the site, providing shade and further enhancing water quality for brook trout. 

The dam facility includes a straight gravity dam built on ledge, an intake structure, a north/right abutment set into ledge, and a south/left abutment. A wood-framed gatehouse sits above the south abutment, next to the intake, and the abutment extends to the south as an underground dike. There is also a pedestrian bridge above the dam, providing access from the parking area to the gatehouse. 

Project Partners 

Project partners include the Woodsville Water & Light Department/Owner (“WWL”), Connecticut River Conservancy, U.S. Fish and Wildlife Service, NHDES Dam Removal and River Restoration Program, NH Fish and Game, American Rivers, and the U.S. Forest Service.

Facing east toward Woodsville Dam and Woodsville Water & Light Department Water Treatment Plant

Facing southeast toward spillway, left abutment and intake, and gatehouse.

Facing northwest from atop intake bay, outlet gate on left.

Habitat Benefits 

Dam removal has an immediate benefit to the river system by permanently returning the Ammonoosuc River to its free-flowing state and improving sediment transport, oxygen levels, and temperatures which all contribute to ecosystem health and resilience. The vast majority of the Wild Ammonoosuc River and its tributaries are located within the White Mountain National Forest and are mapped as the highest-ranking habitat in the state by NH Fish and Game. The removal of this dam will reconnect 71 miles of cold-water stream for eastern brook trout. According to the NH Fish & Game, the Ammonoosuc River is suitable for wild, self-sustaining populations of brook trout.  

Brook trout are one of the most highly sought fish in New Hampshire and are included in the NH Wildlife Action Plan as a “Species of Greatest Conservation Need” (Ammonoosuc River Local Advisory Committee Corridor Management Plan, 2013). Eastern Brook Trout Joint Venture (EBTJV) notes the area as high priority habitat, and the Northeast CPA Map tool for Brook Trout Climate Persistence lists the watershed as 90-100%. USGS EcoSheds model shows this catchment is predicted to have 88% likelihood of brook trout occupancy given an air temperature increase of 2 degrees Celsius.

Other species of conservation concern will also benefit from management actions that improve the overall health and connectivity of the river. Streams in northern New Hampshire are and will continue to be a stronghold against climate-related disruption for these and other cold water native species. Additionally, the project will restore scenic views along the Lost River Road and improve recreational access and safety at this site. 

1929 sign at north bridge support tower.

History and Signage 

The dam was built in 1929 as part of a water works system for the village of Woodsville in the town of Haverhill under a permit issued by the WMNF. The dam has been determined eligible for listing in the National Register of Historic Places. The dam has distinctive engineering and characteristics of an early 20th century waterworks complex. The dam is located adjacent to Route 112 in the town of Landaff, about 11 miles west of the village of Woodsville in Grafton County, New Hampshire. 

The WMNF is issuing this public notice as a part of its responsibilities under 36 CFR Part 800, the regulations implementing Section 106 of the National Historic Preservation Act (NHPA) of 1966, as amended. Section 106 consultation under the NHPA requires federal agencies, including the USDA Forest Service, to identify and consider the potential effects of their actions on historic properties through a collaborative framework for seeking, discussing, and considering the views of the public on addressing adverse effects to historic properties resulting from proposed Federal action. The removal of the Wild Ammonoosuc Dam will result in the loss of all characteristics that qualify it for eligibility in the National Register, and the WMNF has determined in consultation with the New Hampshire’s State Historic Preservation Office that this will be an adverse effect.  

As mitigation for the adverse effect, the WMNF and project proponents, including the Connecticut River Conservancy and the Woodsville Water & Light Department, are proposing to preserve the history of the dam through public information describing the dam and its history, potentially as a sign panel or on the internet. In addition, the dam has been documented with recent photographs, and its history is captured in the New Hampshire Division of Historic Resources evaluation document. The original 1929 design drawings will be maintained in the permanent files of the WMNF.  

For a full description of the dam's features, history, and historic significance, including maps, photos, and drawings, please see the historical documentation here.  

If you would like to comment on the proposed mitigation measures or receive more information, please contact Sarah Jordan, White Mountain National Forest Heritage Program Manager, at sarah.jordan@usda.gov or 603-536-6240 by February 5, 2026. Comments may also be sent by mail to Sarah Jordan, 71 White Mountain Dr., Campton, NH 03223.