Howland Dam Bypass Channel

The Penobscot River Restoration Project (PRRP) in Maine includes the removal of the two most-downstream dams on the Penobscot River and construction of a bypass channel at Howland Dam on the Piscataquis River at its confluence with the Penobscot River.  The bypass channel option was proposed for use at Howland Dam as a means achieve upstream fish passage goals and as a means to address interests of the local community regarding the upstream impoundment.  This presentation presents the proposed bypass channel design and evaluations of upstream fish passage for a suite of anadromous fish species.

 The proposed bypass channel design includes a channel approximately 800 feet (ft) long with an approximate hydraulic drop of 12 ft, resulting in an average grade of 67:1 (horizontal:vertical).  The channel bottom width is approximately 60 ft.  The project design and evaluation process included two-dimensional (depth-averaged) hydraulic studies and a high-level of state and federal agency reviews for upstream passage of the target fish species.