Ann Jackson Dam Removal

Hollis, New Hampshire

DuBois & King designed and planned the removal of a 12-ft tall aging concrete and masonry dam and restoration of the stream channel through the former impoundment. Owned by the Girl Scouts of the Green and White Mountains, the dam was deemed structurally deficient by State regulators and the owners could not justify the expense of reconstructing it. D&K connected the owners with the Natural Resource Conservation Service (NRCS), who funded the construction. Design included removal and disposal of the dam and restoration of 180 ft of stream channel that had been previously obliterated. Restored stream channel to mimic existing channel upstream and downstream of the dam. Design included imported cobble and gravel substrate and constructed wood clusters to promote stability and habitat. Design also included passive restoration areas where the channel was populated with woody material to facilitate habitat features while the streamside woody vegetation establishes. Professional services included:

Dam and site inspection
Stream channel geomorphic assessment
Topographic and cross section survey
Coordination with stakeholders and project partners
State wetland permit
Coordination with Section 106 historic consultant
Design of dam removal and channel restoration
Plans and specifications
Bid phase services
Construction observation and administration