Operational Plan for the Restoration of Diadromous Fishes to the ...

Authors: Norm Dubé and Gail Wippelhauser
Introduction
The National Research Council (NRC 2004) listed dams as a major threat to Atlantic
salmon populations since dams prevent or impede upstream and downstream fish
migrations and alter or destroy habitat. The Strategic Plan for the Restoration of
Diadromous Fishes to the Penobscot River also listed dams as a major contributor
to the decline of many fish species in the Penobscot River.
Whereas effects of structures such as dams upon diadromous fish species are fairly
evident, there are other structures that may appear innocuous to diadromous fish at
first glance but may not be in the long term. Road crossings may seasonally be an
impediment to instream fish movements or prevent movement altogether. For
example, hanging culverts may prevent juvenile salmon from reaching summer
refugia and bridges whose abutments are narrower than the stream width form a
pinch point causing hydraulic barriers to the upstream movements of weaker
swimming diadromous species such as smelt. In order to obtain recovery of the
target diadromous fish species in the Penobscot River, affects upon inriver
migrations and movements by the various life stages of a the target species needs
to be as benign as possible.
There are 14 hydroelectric projects located on the mainstem Penobscot River and its
major tributaries (Table 8). Of these, nine hydro projects have been issued licenses
by the Federal Energy Regulatory Commission (FERC) and five smaller projects
have been issued license exemptions. In addition, one project never completed
installation of generating equipment and was never granted a license or exemption
(Guilford); one dam (Matagamon) was deemed non-jurisdictional by FERC because
of the lack of headwater benefits to downstream hydro generation; and one project
surrendered its license exemption (West Winterport) in anticipation of project
removal.
There are several avenues available to improve or correct passage problems. The
most obvious remedy is removal of the impediment but this strategy is best suited to
small barriers at this time. However, removal of the first (Veazie) and second (Great
Works) dams on the lower mainstem Penobscot River and installation of an
innovative natural bypass around the first dam (Howland) on the lower Piscataquis
River as part of the unprecedented Penobscot River Restoration Project has the
potential to radically decrease upstream and downstream passage effects on
migrating fish.
One strategy allowing fish to migrate around hydro projects is to install upstream and
downstream fish passage facilities. All the major dams in the Penobscot River
drainage (exclusive of the West Branch, Penobscot River) currently have upstream
fish passage facilities (Table 9). Most of the upstream fish passage facilities were
constructed in the 1960s and early 1970s as part of the early restoration program for
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