Milford Powerhouse Photo

The Milford Project consists of two dams, the Milford Dam, on the main stem of the Penobscot River (“River) at river mile 33.25, and the Gilmans Falls Dam, located on the Stillwater Branch. The Project is in Milford and Old Town, Penobscot County, Maine. The Penobscot River Basin (“Basin”) is New England’s second largest river system with a drainage area of 8,570 square miles. Upstream storage dams on both the West and East Branches control a large portion of flows within the drainage area. The Basin includes the East and West Branches of the Penobscot River, the Piscataquis River, the Sebec River, the Pleasant River, the Mattawamkeag River, the Passadumkeag River, the Stillwater Branch and the main stem of the Penobscot River, as illustrated on the following page. The Milford Project is located approximately 22 miles downstream of the West Enfield Hydro Project (FERC P-2600). Two dams that had been located downstream of the Milford Dam (Great Works Dam and Veazie Dam) have been removed as part of the 2004 Settlement Agreement. The Milford Dam is now the most downstream dam on the Penobscot River. The Mattawamkeag River remains free-flowing, while there are a total of 20 run-of river dams located on the other Basin waterways.

Project Name Milford
LIHI Certificate Number 113
LIHI Effective and Expiration Dates November 13, 2013
November 13, 2018 extended to May 31, 2019
Owner Black Bear Hydro Partners, LLC
State Maine
Location Located on the main stem of the Penobscot River at river mile 33.25, and the Gilmans Falls Dam, located on the Stillwater Branch, in Milford and Old Town, Penobscot County, Maine.
Installed Capacity 8.23 MW
Average Annual Generation 59,400 MWh
Facility Type Run-of-river
FERC No. 2534

BBHP owns and operates the Stillwater, West Enfield, Milford, Medway and Orono Projects. Under the June 2004 Settlement Agreement, the ownership  of the Veazie, Great Works and Howland Projects were sold to the Penobscot River Restoration Trust (PRRT). In addition to removal of the Great Works and Veazie Dams, PRRT is planning to construct a fish bypass at the Howland Dam.

The Milford Project was originally licensed to Bangor Hydro Electric Company. That license expired in December 1990. The project was operated under an annual license until a new license was issued on April 20, 1998. Ownership of the facility changed in 2000 to Penobscot Hydro LLC, which later became PPL Maine, LLC, and was subsequently purchased by BBHP with the license transfer on September 17, 2009. The Project is licensed by the Federal Energy Regulatory Commission (FERC) as Project Number 2534.  The current license expires on March 31, 2038.

The Milford Project consists of both an existing  facility, plus 1.4 MW of generation capacity which was added in 2011 for a total of 8.23 MW. Pursuant to the Lower Penobscot River Multiparty Settlement Agreement and a FERC order dated April 18, 2005, two new units were added to the Milford Project, which commenced commercial operation in November 2011. The 2004 Settlement Agreement involved five hydropower projects owned and operated by BBHP located within the Penobscot River Basin. Three of these other sites have received LIHI certification: the Orono Project, Midway Project and both the original units and Powerhouse B of the Stillwater Project. The Milford Project has an estimated annual production of 59,400 MWh.

The Milford Project consists of (1) a 1,159-foot-long, 30-foot-high, concrete gravity Milford dam located across the main stem of the Penobscot River, topped with 4.5-foot-high flashboards, (2) a 397 feet long concrete gravity spillway, (3) a concrete sluiceway and 25 foot gate, and (4) a 226 foot by 85 foot powerhouse. The powerhouse contains four original and two new 700 kilowatt (kW) turbine/generator units. The new units went operational in 2011. The original units have an installed capacity of 6.4 megawatts (MW) and the new units are rated at 1.4 MW. The units operate over a range of flows from the minimum hydraulic capacity of 500 cfs to 6,730 cfs).

The Gilman Falls dam, at the head of the Stillwater Branch, consists of (1) a 49-foot-wide non-overflow section; (2) a 311-foot-long primary spillway with 4.4 foot high flashboards; (3) a 6-foot-wide sluice gate with a top at elevation 100.8 feet; and (4) two taintor gates, one 30 feet wide and the other 20 feet wide.

The Project presently includes a downstream bypass that discharges to the tailrace, a 4-foot Denil style upstream fishway located at the outboard side of the powerhouse tailrace and a downstream bypass fishway. Additional upstream and downstream fish passage facilities are being installed.  After construction of the new facilities, the Denil will remain in place as a backup fishway for emergency purposes, and the expanded downstream bypass will incorporate the existing system.

The Milford Project is operated as a run-of-river development with discharge from the turbines and spillway equivalent to inflow. Flows are reallocated between the main stem of the Penobscot River and the Stillwater Branch through operation of the Milford Project. To accommodate the installation of new generation at the downstream Stillwater and Orono projects, more water now flows to the Stillwater Branch. The flow reallocation is within the range of operations allowed by the current licenses for these Projects. The Project also provides a minimum flow of 3,800 cfs or inflow, whichever is less, and a headpond elevation limit of one foot of the normal full pond when flashboards are in place.

There is a 235 acre reservoir with a gross storage of 2,250 acre-feet. Land area occupied by the features described above is estimated at 1.2 acres.  Approximately 145.4 acres of land, of which only a small portion is owned by BBHP, is contained in a 200-foot zone extending around the impoundment.

In summary, modifications at the Milford Project consist of:

  • Installation of two new 700 kw turbine/generator in the existing powerhouse;
  • installation of trashracks with angled 1-in clear spacing;
  • installation of upstream passage for eels, upstream anadroumous passage through a lift system and trap and truck facility, a downstream passage structure, and a rubber dam on the 390 foot spillway to enhance passage at the lift; and
  • improvements at the log sluice and adjacent ledge area to enhance lift attraction flows.

The original FERC license was issued to Bangor Hydro Electric Company (Bangor Hydro) and expired in December 1990. The project was operated under an annual license until license renewal was approved on April 20, 1998.  A 40-year term was approved by FERC to coordinate expiration dates for projects on the same river basin, in support of their policy to consider cumulative impacts of projects in the same river basin collectively at relicensing.  Thus, the Milford license was issued with the same expiration date as the Stillwater and Veazie Projects. The Milford license was transferred to Penobscot Hydro LLC, which later became PPL Maine, LLC, (PPL Maine) in October 2000. The Milford Project was subsequently purchased by BBHP and the license transferred on September 17, 2009.

Certification History

March 7, 2019: The Low Impact Hydropower Institute has received a complete application for Low Impact Recertification of the Milford 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 “Milford 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 May 6, 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.

February 12, 2014: The Milford Project is certified as low impact for a five-year term, effective November 13, 2013 and expiring November 13, 2018, with the following conditions:

Condition 1: Fish passage effectiveness studies, including numerical performance on specific standards for Atlantic salmon, are scheduled for the next three years (downstream passage) and two years (upstream passage) to confirm adequacy of the fishways installed.  The owner shall report to LIHI on the results of all fish passage effectiveness testing conducted within thirty (30) days of conclusion of each year’s studies, including reporting on any changes in operation of the passage facilities, as recommended or required by the resource agencies and/or the Penobscot Indian Nation (PIN). This reporting shall summarize the opinions (if rendered) of The United States Fish and Wildlife Service (USFWS), National Marine Fisheries Service (NMFS), Maine Department of Marine Resources (MDMR) and PIN on the results of the effectiveness studies.

Condition 2: Three state threatened mussel species may be present in the vicinity of the Milford facility and these could be impacted during significant impoundment lowering.  If significant drawdowns are scheduled (other than those needed for normal maintenance activities) that may adversely affect mussels, the owner shall notify LIHI of the license-required consultation with FERC and applicable state resource agencies, along with mitigation actions developed to ensure impacts to sensitive mussel species are  minimized.

Condition Satisfied in 2018. Condition 3: The owner shall report to LIHI on the status and results of the consultations regarding the canoe portage trail, as well as the status of development of the trail.

January 13, 2014: Public comment period for the application has closed.

November 12, 2013: Black Bear Hydro Partners, LLC submitted an application for the certification of the Milford Project; application was posted to website and public comment period opened.


2019 Recertification:

2013 Certification: