LIHI Certificate #65 - Medway Project, Maine


Project Name Medway
LIHI Certificate No. 65
LIHI Certificate Term June 1, 2020 – May 31, 2030
Owner Black Bear Hydro Partners LLC, a subsidiary of Brookfield Renewable Energy Group
State Maine
Location Located at river mile 0.7 on the West Branch of the Penobscot River in Medway, Maine.
Installed Capacity 3.44 MW
Average Annual Generation 29,944 MWh
Facility Type Run-of-river
FERC No. P-2666 issued in 1999, expires 03/31/2029

The Medway Project is located on the West Branch of the Penobscot River in Medway, Maine. The project commenced initial commercial operations in 1923. There are several hydroelectric developments on the Penobscot River and its branches. The closest upstream is the Penobscot Mills Project (including the Millinocket and Dolby developments, LIHI #167) on the West Branch and the closest downstream is the Mattaceunk Project (LIHI #189) on the mainstem Penobscot River.

The Medway project is included in the Penobscot River Restoration Agreement. The overall intent of the Agreement is to provide enhancements to the Penobscot River’s environmental resources, and to lower and minimize the influence of the owner’s hydroelectric projects on those resources while maintaining the levels of renewable hydropower generation from the river. The restoration effort is one of the largest river restoration projects in our nation’s history. In an unprecedented collaboration, a diverse group of stakeholders worked together to restore 11 species of sea-run fish to the Penobscot River, while maintaining energy production.

The project consists of a 343-foot-long concrete gravity dam surmounted by 5.75-foot-high flashboards, a 64-foot-long concrete gravity forebay wall, and a powerhouse that is integral to the dam and containing five generating units with a total installed capacity of 3.44 MW.

The project operates in a run-of-river mode and impounds a 120-acre reservoir. Flows and reservoir water levels are monitored and maintained at a stable level to ensure compliance with run-of-river operations. The flow regime was developed in consultation with Maine Department of Environmental Protection (MDEP).

Waters within the project reach are designated as Class B and impaired for dissolved oxygen and nutrient/eutrophication. MDEP has concluded that these impairments are not caused by project operations and are attributed to discharges from former paper mills upstream of the project. The recent closure of these mills has improved water quality in the river, resulting in the attainment of Class B water standards.

As mentioned above, the Penobscot River Restoration Agreement supports efforts to enhance the Penobscot River’s environmental resources and restore migratory fish passage to the river. The project currently has upstream passage for American eels but no anadromous fish passage facilities. Every five years, the project owner consults with US Fish and Wildlife Service (USFWS), the National Marine Fisheries Service (NMFS), the Penobscot Indian Nation (PIN), Maine Department of Marine Resources (MDMR), and Maine Division of Inland Fisheries and Wildlife (MDIFW) to determine the status of anadromous fish species recovery and to ensure project operations are concurrent with recovery efforts. The upstream eel passage was installed in 2004 and operates seasonally. The downstream eel passage was installed in 2000 and consists of a sluice gate, which was retrofitted with a 3-foot-wide by 6-foot-tall bellmouth weir and flume. The bypass entrance is located at the end of the spillway adjacent to the forebay. The weir constricts down to a 5-inch opening, can pass approximately 15 cfs of flow, and sits in the top portion of the water column. The project’s very short bypass reach receives flows from the downstream eel passage facility, and the powerhouse backwaters to the bypass which remains wetted.

The project lands consist of roughly 4 acres. These lands primarily house project infrastructure and surrounding lands are developed – downtown Medway, industrial sites, roads, and a municipal wastewater treatment plant. Some forested areas exist to the south of the project boundary, but they are actively managed for timber harvesting and are bifurcated by roads and transmission lines. As such, lands within the project boundary are unlikely have significant ecological value.

Threatened or endangered species potentially present in the project vicinity include Atlantic salmon, brook floater, Canada lynx, Northern long-eared bat, little brown bat, and eastern small-footed bat. Though the project area has the potential for Canada lynx, no impacts are expected due to the small footprint and developed nature of the area. Similarly, Northern long-eared bat habitat is not expected to be impacted as vegetation management at the project is done in a manner consistent with USFWS recommendations, though project land management is limited. The other listed bat species are not likely to be impacted for the same reasons. Aquatic species, like the brook floater mussel, are protected by run-of-river operations. However, significant lowering of the headpond could expose the species if present in the impoundment. Thus, consultation with MDIFW is required to ensure impact minimization should lowering events be needed. Atlantic salmon restoration efforts are currently being undertaken and NMFS is collecting data on potential opportunities for restoring river connectivity in the West Branch of the Penobscot River.

Consultation with the Maine Historic Preservation Commission determined that no historic or cultural resources are found in the project area and no properties are eligible for listing on the National Register of Historic Places. Further consultation is required should any sites be discovered in the project area.

Recreational resources at the project include a canoe portage trail and a boat launch on the north shore of the impoundment. The canoe portage leads around the dam and allows for put-in downstream of the powerhouse. Public access is provided free of charge.

Compliance Status

The Certificate includes the following facility-specific conditions:

Condition 1: The facility Owner shall provide LIHI a copy of agency correspondence documenting numerical performance standards that the agencies may establish for upstream and/or downstream passage for the Penobscot River basin that affect the Medway Project, within 60 days of publication of the standards.

Condition 2: In annual compliance statements, the facility Owner shall summarize any new agency or PIN requests for upstream eel passage studies or modifications to the eelway, and/or for provision of upstream passage for anadromous species. Documentation shall include the agency requests and any plans and schedule for implementing the requested activity(ies). Annual updates shall document agency communications, discussion of resolution of disagreements should they occur, and project modifications made or results of studies during the prior year. LIHI reserves the right to modify this condition in light of future Project changes.

Condition satisfied in 2022 – Condition 3: The facility Owner shall provide LIHI a copy of the 2021 downstream eel passage study results, agency and PIN comments, and plans and schedules for any agreed upon modifications needed as a result of the study. Should the Owner not agree to make all requested modifications, the rationale for these decisions shall be provided. LIHI reserves the right to modify this condition based on the study results and assessment of the effectiveness of downstream passage.

Condition 4 (added in 2022):

a) The facility Owner shall report to LIHI on a quarterly basis with detailed documentation of all activities, FERC actions, consultation, and/or studies related to downstream eel passage until a plan and schedule for passage is finalized.  Reports will be due by the 15th of the month following the calendar quarter.

b) Until a new license is issued, annual LIHI compliance submittals shall include a summary of all relicensing activities, consultation, stakeholder comments, study plans and studies, and FERC actions.

LIHI reserves the right to reassess, suspend, or revoke certification based on the information provided.

2023: No material changes or compliance issues were identified.  The project remains in compliance based on the annual review, pending resolution of downstream eel passage issues   For Conditions 1 and 2, the project reported no changes.  For Condition 4, the project submitted quarterly reports indicating no activity, and awaiting FERC response to downstream eel passage plan filed august 1, 2022 but indicated that the project will initiate the proposed plans as voluntary measures for the 2023 eel passage season.

2022: No material changes or compliance issues were identified.  The project remains in compliance based on the annual review, pending resolution of downstream eel passage issues   For Conditions 1 and 2, the project reported no changes.  For Condition 3, the project submitted the 2021 eel passage report and a proposal for operational changes in 2022, thus satisfying the condition.  Condition 4 was added in December 2022. 

2021: Annual reporting for the current Certificate has not yet taken effect.

Certification History

January 1, 2022: The LIHI Certificate term has been extended in accordance with Revision 2.05 of the LIHI 2nd Edition Certification Handbook issued January 1, 2022. Refer to the facility table above for the new term.

April 26, 2021: The decision to recertify the Medway Project became final after the close of the appeals period on April 17, 2021 with no valid appeals filed. The Certification term is from June 1, 2020 through May 31, 2025.

March 18, 2021: The Low Impact Hydropower Institute (LIHI) has preliminarily approved recertification of the Medway Project for a new 5-year terms of Low Impact Certification. This decision is preliminary pending the 30-day appeal window. Only those who commented on the initial application during the 60-day comment period are eligible to file an appeal. Such appeal needs to include an explanation as to how the Project does not meet the LIHI criteria. Appeal requests can be submitted by email to with “Medway Project” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, 1167 Massachusetts Ave, Arlington MA 02476. All requests will be posted to the website. The applicant will have an opportunity to respond and any response will also be posted. Requests must be received by 5 pm Eastern time on April 17, 2021. The full application and reviewer’s report is available below. If no appeal requests are received and the decision becomes final, the Certification term for the Project will be June 1, 2020 through May 31, 2025.

December 1, 2020: The Low Impact Hydropower Institute has received a complete application for Low Impact recertification of the Medway Project. The complete application can be found below. LIHI is seeking public comment on these applications. 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 “Medway Project Comments” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, 1167 Massachusetts Avenue, Arlington MA 02476. Comments must be received on or before 5 pm Eastern time on January 30, 2021 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.

August 5, 2016: LIHI Executive Director Michael J. Sale, using authority delegated from the LIHI Governing Board, has issued a Preliminary Certification Decision that the Medway Hydroelectric Project (FERC No. P-2666) satisfies the LIHI Certification Criteria.  This Preliminary Certification Decision includes one facility-specific condition, as follows:

  • Condition 1.  The Owner shall be proactive in contacting the MIFWS a minimum of 30 days prior to any planned drawdown of the impoundment that would expose a significant portion of the river bottom, to determine if any special measures are needed to avoid or minimize adverse impacts to state-threatened mussels that may be in the impoundment. The Owner shall work with the MIFWS to implement appropriate mitigation measures should they be needed.  The Owner shall advise LIHI of any such events, including the results of any activities conducted to minimize such impacts. Such notification shall be provided as part of the annual compliance statement to LIHI.

As provided for in Section 4.2.5 of the LIHI 2nd Edition, the Preliminary Certification Decision to certify, along with the Application Reviewer’s report and (if prepared) report of the Executive Director, will be posted on the Institute’s Web page for 30 days.  Notice of the posting will be provided to all individuals or organizations that commented on the initial Application Package.Any Commenter may submit a letter to the Executive Director requesting an appeal within the 30-day period.  The appeal request must state specific reasons why the hydropower facility should have failed one or more criteria.  If an individual or organization did not comment on the initial Application Package, they may not file an appeal.  Further information about the LIHI appeal process is available in the LIHI Handbook, available at If no appeal is requested within the 30-day period, the Executive Director will issue LIHI Certification for the facility and post a notification of certification on the Institute’s website.  Once final, the effective certification date for the Medway Project is June 1, 2015 for a five (5) year term, which will expire on June 1, 2020.

December 11, 2015: The Low Impact Hydropower Institute has received a complete application for a new term of Low Impact Certification for the Medway Hydroelectric project.  The application materials can be found in the Files section below.

The public comment period for this application closed on February 12, 2016.

January 28, 2011: The Medway Hydroelectric Project has been certified as low impact for a five year term, effective June 1, 2010 and expiring June 1, 2015.

August 2, 2010: Public comment period for the application for certification has been closed.

June 2, 2010: Black Bear Hydro Partners has submitted an application for certification of the Medway Hydroelectric Project. The public comment period on the application will remain open for 60 days.

Certification Files

2020 Recertification

2015 Recertification

2010 Certification

Key Documents