May 20, 2019: The Low Impact Hydropower Institute has received a complete application for Low Impact Certification of the Hooksett Hydroelectric Project.  LIHI is seeking public comment on this application.  Specifically, we are interested in knowing whether you think the Project meets the LIHI Low Impact Certification Criteria, as revised in the 2nd Edition Handbook.  Please review the program and criteria in LIHI’s revised Handbook and then review the Project’s application materials below.

Comments that are directly tied to specific LIHI criteria (flows, water quality, fish passage, etc.) will be most helpful, but all comments will be considered.  Comments may be submitted to the Institute by e-mail at with “Hooksett Project Comments” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, 329 Massachusetts Avenue, Suite 6, Lexington, MA 02420.  Comments must be received on or before 5 pm Eastern time on July 19, 2019 to be considered.  All comments will be posted to the web site and the applicant will have an opportunity to respond.  Any response will also be posted.

Project Description:

The Hooksett Development is one of three developments that comprise the Merrimack River Project (FERC No. 1893), located along 21 miles of the Merrimack River. The development is in the towns of Hooksett and Bow, Merrimack County, New Hampshire. The development is approximately 8 miles upstream of the Amoskeag development and approximately 5.6 miles downstream of the Garvin Falls development. The Merrimack River Project is owned by HSE Hydro NH, LLC and operated by Central Rivers Power NH, LLC.

The Hooksett development’s impoundment extends upstream approximately 5.5 miles and has a surface area of 350 acres.  The dam has two spillway sections. A stone masonry section, approximately 340 feet long, extends from the west bank of the river. The second section is approximately 250 feet long and made of concrete. This section runs longitudinally up and down the river near the east bank of the river and forms a canal that extends to the powerhouse; each section topped with 2-foot- high wooden flashboards. There is a 13-foot-by 20-foot steel Tainter wastegate located between the second spillway section and the powerhouse.  A 200-foot-long power canal is located at the east of the dam.  The powerhouse contains a single vertical propeller turbine generator with an installed capacity of 1,600 KW. The development has an approximate110-foot long tailrace and a bypassed reach approximately 430 feet long.   Hooksett is operated in run-of-river mode with a minimum flow of 64 cfs at all times into the bypassed reach for the protection of aquatic life.

Project Name Hooksett
Owner Central Rivers Power NH, LLC
State New Hampshire
Location River Mile 81.1 on the Merrimack River
Installed Capacity 1.6 MW
Average Annual Generation 8,020 MWh
Facility Type Run of river
FERC No. 1893

The U.S. Fish and Wildlife Service fishway prescription requires the installation of upstream passage facilities for anadromous fish at the Hooksett dam, to be operational within three years after passage of either 9,500 or more shad or 22,500 or more river herring in any given year at the Amoskeag development. The trigger number for river herring was reached during the 2016 migration season. As such, the former owner, Eversource, initiated consultation with state and federal agencies to begin preliminary design work and HSE continues to consult with the agencies to determine the most feasible design in terms of size, location, target species, project operations, cost, and constructability.  The existing downstream fish passage is a gate between the Tainter gate and the powerhouse.


LIHI Application Hooksett 20190508 Reduced