Holtwood Dam Redevelopment: More Power, Better Fish Passage?

As a result of negotiated agreements with hydroelectric operators on the lower Susquehanna River in the 1990s, upstream anadromous fishways were installed on all four mainstem dams by the year 2000. Although the agreements succeed in getting upstream fishways installed for anadromous fish and provided for fish passage counts at the fishways, they had no provisions to require improvements to the fishways or there operations for detected inefficiencies. Also downstream passage facilities were not included, and catadromous American eel passage was not considered. At the second upstream Holtwood Dam, studies and observation of American shad behavior near and in the Holtwood fishway indicated problems with inadequate fishway entrance attraction flow, false attraction to dead ends at the spillway and in eddies in the tailrace, and inadequate zones of passage below the dam. When the owner of the Holtwood project proposed a hydroelectric expansion that would more than double the electric power output they approached the resource agencies to explore ways to improve fish passage. This presentation will describe the approach and methods to explore fish passage needs and develop facilities and measures to improve fishways and implement additional measures to address American eel passage, resident fish passage, and downstream passage.