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Winnicut Dam Removal Feasibility Study
Woodlot Alternatives, INC.
Date Created and/or Issued
Contributing Institution
UC Riverside, Library, Water Resources Collections and Archives
Clearinghouse for Dam Removal Information (CDRI)
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Scope/Content: Abstract: The purpose of the Winnicut Dam Removal Feasibility Study (Feasibility Study) is to evaluate options for the restoration of native diadromous and resident fisheries, including alewife and blueback herring, in the Winnicut River ecosystem. The primary objective for achieving this restoration goal would be to improve upstream and downstream fish passage within the Winnicut River, with a secondary objective of enhancing the overall function of the Winnicut River ecosystem. The feasibility of each option was assessed with respect to its impacts to adjacent infrastructure, groundwater and wells, recreational use, natural resources, and historical and archeological resources. The Winnicut Dam is owned by the New Hampshire of Fish and Game Department (NHFGD). It is situated at the head-of-tide on the Winnicut River in Greenland, New Hampshire, and represents the only anthropogenic barrier to upstream fish movement along the main stem of the river. The dam currently restricts fish movement within the Winnicut River, which in turn affects other ecological systems that are dependent upon the fish populations for dispersal within the ecosystem. Although a fish ladder was incorporated into the dam at the time of its construction in 1957, its design has proven to be inefficient in providing upstream passage for most diadromous and resident fish species. Because the fish ladder is currently only operated to accommodate upstream migration of anadromous river herring in the spring, it is of limited utility in providing a means of upstream passage for anadromous rainbow smelt and catadromous American eel. Cumulatively, the poor performance and limited window of operation of the existing fish ladder combined with lack of dedicated downstream fish passage has adversely impacted the use of the Winnicut River by diadromous and resident fish. Three primary alternatives for achieving the project goals are presented in this Feasibility Study. Alternative A is the "No Action" alternative. Alternatives B and C present differing approaches intended to achieve the project goals. Alternative A, the No Action alternative, does not meet the basic project goals of restoring resident and diadromous fisheries in the Winnicut River, but is included as a baseline for the purpose of comparing the affects of the other alternatives. This alternative avoids some short- term, temporary impacts associated with the other alternatives, but does not address impacts to fisheries associated with the Winnicut Dam, with the primary impact being the poor performance WINNICUT DAM REMOVAL FEASIBILITY STUDY of the existing fish ladder. Under the No Action alternative, adverse impacts associated with the presence of the dam and the existing fish ladder would continue and would constitute a long-term impact to the natural resources dependent upon upstream and downstream fish passage and factors such as the loss of riverine habitat resulting from the presence of the Winnicut Dam. Alternative B would involve the construction of an Alaska Steeppass technical fishpass in place of the existing Canadian step weir fish ladder at the Winnicut Dam. This alternative meets some of the projects needs through the implementation of improved fish passage at the Winnicut Dam, but does not provide for increased free-flowing riverine habitat or enhanced downstream fish passage. Alternative C would involve the removal of the Winnicut Dam and the construction of a technical fishpass under the State Route 33 Bridge (Rte 33 Bridge). The alternative would meet the project goal through the improvement of upstream and downstream fish passage and the restoration of approximately 250 feet of the Winnicut River below the Rte 33 Bridge to riverine conditions. The restoration of the riverine habitat is particularly important for achieving project objectives associated with the restoration of rainbow smelt populations in the Winnicut River, as this species is dependent upon riverine habitat for spawning and is not capable of asce
Scope/Content: Date constructed: 1957. Date removed: 2010.
Alternative analysis (e.g., feasibility studies, EIRs)
Dam retirement
Winnicut River, NH
Winnicut Dam

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