LIHI Certificate #79 - Benton Falls Project, Maine

Project Name Benton Falls
LIHI Certificate No. 79
LIHI Certificate Term
November 23, 2020 –
November 22, 2030
Owner Benton Falls Associates, a subsidiary of Essex Hydro Associates, LLC
State Maine
Location Located at river mile 5.3 on the Sebasticook River in the village of Benton, Maine
Installed Capacity 4.33 MW
Average Annual Generation 14,963 MWh
Facility Type Run-of-river
FERC No. P-5073 issued in 1984, expires 02/28/2034

The Benton Falls Project is located on the Sebasticook River in Benton, Maine and is the first dam on the river, located 5.3 miles upstream the confluence of the Sebasticook and Kennebec Rivers. The Burnham Dam project is located upstream of the project in Pittsfield, ME.

The Sebasticook River has a drainage area of 975 square miles and is the largest subbasin of the Kennebec River System. The current dam was completed in 1984. It is on the same site as a previous dam that was destroyed by flooding in 1936.

Project works consist of a 500-foot-long, 27-foot-high concrete gravity dam with a 300-foot-long integral uncontrolled spillway topped by 4-foot-high flashboards; a powerhouse located near the west dam abutment, constructed integrally with the dam, containing two horizontal Kaplan turbine/generators with a total rated capacity of 4.468 MW; a 350-foot-long tailrace channel; and a fish lift which contains a 600-gallon hopper and a minimum cycle time of approximately seven minutes.

The project operates in a run-of-river mode and impounds an 84-acre reservoir. There is no bypassed reach. Instantaneous run-of-river operations help to protect fish and wildlife resources as well as water quality in the river. A pressure transducer is utilized to monitor water surface elevation and ensure river inflow to the project matches outflow.

Waters within the project reach are designated as Class C, attaining uses such as aquatic biota habitat and secondary recreation. Water quality sampling was conducted in 2017 to determine project impacts on the river system. The Maine Department of Environmental Protection concluded that the project does not cause or contribute to non-attainment of the State’s water quality standards.

The Sebasticook River is host to several migratory fish species. The upstream fish passage facility consists of a fish lift designed to pass alewife, American shad, and Atlantic salmon. Upstream passage for American eel is provided by a ramp located at the eastern side of the concrete spillway. The downstream fish passage facility is designed to pass all species and consists of a surface bypass system (two 3-foot-wide intakes leading to a transition chamber and then a 24-inch bypass pipe with a total capacity of 30 cfs). The upstream and downstream fish passage facilities became operational in the spring of 2006 and have been highly successful. In 2020, the fish lift was in operation from May 7th to June 30th and passed 2,847,171 river herring and 10 American shad. No Atlantic salmon were observed passing the fish lift.  In 2021, 30,067 American eels were counted using the upstream eel ramp and an average of 9,283 have passed annually since 2015. The project owner is currently collaborating with Maine Department of Marine Resources to monitor the effectiveness of the eel passage facility using sonar to record eel species movement and success in traversing the passage facility.

The project lands consist of 27 acres. Benton Village and Benton Falls sit in a broad valley cut through deep marine and lacustrine deposits of gravel, sand, silt, and clay surficial deposits. The generally flat or gently rolling topography of the valley is cut by the steep gully banks of the Sebasticook River. The steep banks and riverbed include prominent outcrops, which periodically resurface upstream to the upper end of the project’s pool. The Sebasticook River is bordered on both shores by bands of relatively steep (8 to 15 percent slope) silty loam. Lands near the river are primarily woodland, with agriculture, residential and small commercial uses. Run-of-river operations mitigate any project impact on the surrounding shoreline.

Threatened or endangered species potentially present in the project vicinity include Atlantic salmon and the Northern long-eared bat. The bat species is likely only transient in the project area and no critical habitat exists in the project reach. Critical habitat for Atlantic salmon is designated in the mainstem Kennebec River both upstream and downstream of the Sebasticook River confluence, but the designation does not extend into the Sebasticook River.  Based on a desktop survival estimate of salmon entrainment, there is a high probability of salmon smolt survival through all downstream passage routes. The project operates in accordance with its Atlantic salmon species protection plan. State-listed species include three species of freshwater mussels and seven additional bat species. Run-of-river operations are unlikely to affect mussels, and any tree cutting needed would be conducted in accordance with the US Fish and Wildlife Service requirements.

Several archaeological sites exist in the project area; thus, a cultural resources management plan was implemented. Erosion monitoring was conducted over a span of twenty years to ensure that project operations would not adversely impact these sites. The Maine Historic Preservation Commission has concluded that the project does not cause any significant erosional damage.

Recreational resources at the project include a canoe portage, fishing access, and boat launch. These recreational opportunities were developed in collaboration with US Department of the Interior, Maine Bureau of Parks and Recreation, and the Town of Benton, Maine. As a result of the successful fish restoration program, the Maine Department of Marine Resources issued an alewife harvesting permit to the Town of Benton. The project owner has a cooperative agreement with the town to use project lands to harvest alewives that are surplus to the state’s upstream migration goals. Public access is provided free of charge.

Compliance Status

The Certificate includes the following facility-specific condition:

Condition 1: The facility Owner shall design and conduct downstream passage effectiveness studies if requested by, and in consultation with the resource agencies. Along with annual compliance statements, the facility Owner shall submit copies of the annual Fish and Eel Passage Facility Operating Report and Proposed Operating Plan and if applicable, any plans, schedules, and reports including agency comments for any downstream passage studies that are conducted.

2023: No material changes or compliance issues were identified. The project remains in compliance based on the annual review. For Condition 1, the project reported no requests for studies and submitted the annual report.  The project also reported receiving a Biological Opinion from NOAA/NMFS related to Atlantic salmon and sturgeon.

2022: No material changes or compliance issues were identified. The project remains in compliance based on the annual review. For Condition 1, the project reported no requests for studies and submitted the annual report.

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

Certification History

January 14, 2022: The Low Impact Hydropower Institute has issued a final decision on the recertification of the Benton Falls Project. The 30-day appeal window closed on January 13, 2022 and no appeals were filed. Therefore, the decision to recertify the project is now final. The new term is October 23, 2020 through October 22, 2030, reflecting the extended terms for Certificates that became effective on January 1, 2022.

December 14, 2021: The Low Impact Hydropower Institute (LIHI) has preliminarily approved the Benton Falls Project for a new term 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 “Benton Falls Project” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, 1167 Massachusetts Ave, Office 407, 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 January 13, 2022. The full application and reviewer’s report are available below. If no appeal requests are received and the decision becomes final, the Certification term for the Project will be November 23, 2020 through November 22, 2025.

October 5, 2021: The Low Impact Hydropower Institute (LIHI) has received a complete recertification application from Benton Falls Associates, LP for the Benton Falls Project located on the Sebasticook River in Maine. LIHI is seeking comment on this application. 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 LIHI by e-mail at with “Benton Falls Project Comments” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, 1167 Massachusetts Avenue, Office 407, Arlington, MA 02476. Comments must be received at the Institute on or before 5 pm Eastern time on December 4, 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. The complete application can be found below.

June 6, 2016: LIHI Executive Director Michael J. Sale, using authority delegated from the LIHI Governing Board, has certified that the Benton Falls Hydroelectric Project (FERC No. P-5073) satisfies the LIHI Certification Criteria.  A Preliminary Certification Decision was announced on May 4, 2016, and a 30-day appeal period was open through June 5, 2016. No requests for appeal were received. This Certification Decision includes three facility-specific conditions, as follows:

  • Continued with modifications into 2021 recertification. Condition 1.  If resource management agencies (MDMR, MIFWS, USFWS and/or NMFS) determine that a sufficient number of Atlantic Salmon and/or American Shad have been passed upstream of the facility, or other appropriate trigger has occurred, the Owner shall conduct fish passage effectiveness studies to demonstrate that Atlantic Salmon and/or American Shad are being safely passed downstream of the facility during outmigration.  The Owner shall notify LIHI within 30 days of when the applicable resource agency(ies) determine that such fish passage effectiveness testing is required.  The Owner shall then consult with the agencies in the design and implementation of these studies, allowing the agencies to participate in the testing if they so desire.  The Owner shall provide LIHI the testing results along with an assessment made by the agencies as to whether or not they find that safe and effective passage is being provided by the current downstream passage methods. This condition can be satisfied by providing LIHI with a copy of the annual Fish and Eel Passage Facility Operating Report and Proposed Operating Plan, as long as appropriate data and agency positions regarding fish passage are contained in that report.
  • Satisfied in 2021 with initiation of ESA consultation. Condition 2.  As part of the Annual Compliance statement to LIHI, the Owner should include documentation of ongoing consultation with NMFS regarding Atlantic Salmon pursuant to the Endangered Species Act. The schedule for these ESA consultations shall be set through agreement of the Owner and NMFS.  LIHI shall be notified of this schedule within 30 days of its establishment. LIHI shall also be provided a copy of any studies or authorizations issued during the course of this certification period on this issue.
  • Condition satisfied 2017. Condition 3.  To contribute to water quality management on the lower Sebasticook River, the owner shall implement a MEDEP-approved water quality sampling plan that evaluates the role of Benton Falls dam and impoundment in the nonattainment status of the river and report back to LIHI and MDEP on the findings. In addition to new water quality data, the Owner shall describe other point-source discharges in the vicinity of the facility to provide context for the facility’s potential effects.  The owner shall obtain a letter from MDEP on their assessment of whether or not the Benton Falls facility is the cause of the nonattainment status, and submit that letter to LIHI within 30 days of its receipt.

The effective certification date for the Benton Falls Project is November 23, 2015 for a five (5) year term, which will expire on November 23, 2020.

November 12, 2015: The Low Impact Hydropower Institute has received a complete application for a new term of Low Impact Certification for the Benton Falls Hydroelectric project.  The application materials can be found in the Files section below.

The public comment period for this application closed on January 11, 2015.

October 31, 2011: The Benton Falls Hydroelectric Project has been certified as low impact for a five year term, effective November 23, 2010 and expiring November 23, 2015.

November 23, 2010: Benton Falls Associates has submitted an application for certification of the Benton Falls Hydroelectric Project. A public comment period on the application will remain open for 60 days.

Certification Files

2021 Recertification

2015 Recertification

2010 Certification

Key documents