The Wild Ammonoosuc Dam in Landaff NH Has Been Removed

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The river restoration project creates 71 miles of free-flowing aquatic habitat in the White Mountain National Forest.

Wild Ammonoosuc dam removal in progress, taken in August 2026. River in foreground, machine with a red drill in center, trees in background. — Wild Ammonoosuc dam removal in progress, taken in August 2026.

The Wild Ammonoosuc Dam in Landaff, owned by the Woodsville Water and Light Department, was removed in August 2026, restoring a stretch of one of the Connecticut River’s important cold-water tributaries.

Built in 1929 as part of a water supply system for the village of Woodsville, the 10-foot-high concrete dam had not been used for decades but continued to block fish passage and disrupt natural river processes. The project included removal of the dam and associated infrastructure, management of impounded sediments, and restoration of the adjacent floodplain, allowing the river to once again flow naturally through the White Mountain National Forest. A planting of over 500 native trees and shrubs is also scheduled for this fall to further stabilize the riverbank.

The Wild Ammonoosuc is part of the larger Ammonoosuc watershed, a roughly 60 square mile river system that begins on the slopes of Mount Washington and flows west to the Connecticut River. It has long been recognized for its high-quality habitat, outstanding recreational value, and ecological importance.

The removal reconnects approximately 71 miles of mainstem and tributary habitat, opening access to some of New Hampshire's highest-quality cold-water streams. The project is expected to benefit eastern brook trout, a Species of Greatest Conservation Need in New Hampshire, by improving access to spawning habitat, increasing genetic exchange among populations, and providing connections to cool-water refuge areas that help fish withstand warming temperatures. Returning the river to a more natural condition will also improve sediment transport, oxygen levels, and overall ecosystem resilience, while supporting other native aquatic species that depend on connected river systems.

Wild Ammonoosuc Dam before removal in June 2026.
Wild Ammonoosuc River after dam removal in September 2026.

Wild Ammonoosuc dam before removal (left), and free-flowing river after removal (photo on the right taken in September 2026 when the river was running low).

The project was made possible through a partnership among the Woodsville Water & Light Department, Connecticut River Conservancy, U.S. Fish and Wildlife Service, New Hampshire Department of Environmental Services Dam Removal and River Restoration Program, New Hampshire Fish and Game, American Rivers, and the U.S. Forest Service. Funding support was provided by the New Hampshire Charitable Foundation Upper Connecticut River Mitigation and Enhancement Fund, U.S. Forest Service, and NH State Conservation Committee Conservation Moose Plate Grant Program. Lynch Construction Co. and Base Flow LLC contractors also provided engineering and construction work.

This achievement represents another important step toward restoring the connectivity of the Connecticut River watershed and supporting a critical refuge for cold-water species in a changing climate.

Additional background, habitat, and historic information was published during the permitting phase here.