LIHI Certificate #142 – Lowell Project, Massachusetts

March 24, 2020 – COVID-19 update: Central Rivers Power has notified LIHI that the Lowell Project visitors center will remain closed until further notice.  The facility is only open by appointment, and the company will not accept any requests until it is safe to allow group access.

Project Name Lowell
LIHI Certificate No. 142
LIHI Certificate Term August 23, 2017 – August 22, 2027
Owner Boott Hydropower, LLC, a subsidiary of Central Rivers Power USA
State Massachusetts
Location Merrimack River

River mile 40.8

Installed Capacity 22.635 MW
Average Annual Generation 88,530 MWh
Facility Type diversion, run-of-river
FERC No. P-2790 issued 1983, expires 2023

The Lowell Project is located on the Merrimack River in the City of Lowell, Massachusetts. The Merrimack River originates at the confluence of two major rivers, the Pemigewasset and Winnipesaukee, in Franklin, N.H. From its origin, the river travels 115 miles to the Atlantic Ocean at Newburyport, Massachusetts. The project is the second dam on the mainstem, located 10 miles upstream of the Lawrence Hydroelectric Project.

The project dam was originally constructed in 1847, with a second spillway added in 1875. Expansion of the project was conducted in 1985 with the construction of a new powerhouse on the Northern Canal. Four other power plants are operated out of existing mill buildings along the canal system. The Pawtucket gatehouse was constructed to control flow from behind the Pawtucket Dam into the Northern Canal. Notably, it was the site of the first Francis turbine which operated the ten wooden gates that controlled the flow of the Merrimack into the canal. Now the gates are electronically controlled. Historically, Lowell housed many hydroelectric and hydromechanical power generators throughout the many mill buildings along the canal. Most of these units have been inoperable or decommissioned for quite some time.

The project includes Pawtucket Dam, the E.L. Field powerhouse on the river and four smaller power stations in the canal system, with a total installed capacity of 22.463 MW, upstream fish passage systems, and the canal system running through downtown Lowell. The dam is a 1,093 foot-long, 15-foot-high stone-masonry gravity structure. Construction of the new powerhouse included excavation of a 1,000-foot-long tailrace channel. The tailrace is separated from the river by a five-foot-high training wall. The canal system consists of two tiers, the Northern Canal, controlled by the gatehouse at the dam, and the Pawtucket Canal, controlled by the Francis Gate and Guard Locks.

The project operates in run-of-river mode and creates a 720-acre reservoir. The project provides a minimum flow of 1,990 cfs downstream of the E.L. Field powerhouse. Flows are also provided seasonally in the bypassed reach below Pawtucket Dam for migratory fish passage. Flow control and habitat enhancement are being provided by a pneumatic crest gate. The flow regime was developed using the summer Aquatic Base Flow derived from the US Fish and Wildlife Service recommendation for New England stream flow.

Waters within the project reach are designated impaired for several designated uses including fish consumption (mercury from atmospheric deposition), primary contact recreation (coliform bacteria), and aquatic life. Additional impairments include lead, PCBs, and DDT in the bypass and though sources are unknown, it is likely that their presence is due to historical contamination from mills and industrial facilities on the canal system. Massachusetts Department of Environmental Protection notes that the impairments are due to other sources and not within the project’s control.

Anadromous fish historically found in the project area include Atlantic salmon, American shad, and river herring. Construction of the Essex Dam in 1847 in Lawrence extirpated Atlantic salmon and diminished herring and shad populations. Upstream and downstream fish passage facilities at the project include a fish elevator and downstream fish bypass at the E.L. Field powerhouse, and a vertical-slot fish ladder at the Pawtucket Dam. The facilities were designed in consultation with US Fish and Wildlife Service and is now monitored and evaluated by both federal and state fishery agencies.

The project property consists of 40 acres not including the impoundment. The surrounding lands are urbanized and not owned by the project. A new crest gate system reduces impoundment drawdowns, a feature that may reduce riverbank erosion.

Threatened and endangered species potentially within project vicinity include: Northern long-eared bat, bald eagle, peregrine falcon, red knot, cobra clubtail, umber shadowdragon, Blanding’s turtle, small whorled pogonia, and sandplain gerardia. The primary concern for bat species is habitat destruction, however the project does not plan to remove trees in the project area. Multi-year telemetry studies have found that the project does not impact riverine fish species and further, no impact on listed species occurs. No critical habitats for listed species occur in the project area.

Historic properties include the Pawtucket Dam and the canal system and associated mill buildings. The Lowell Act recognizes the historical value of this area and established the Lowell National Historical Park and Lowell Historic Preservation District. No cultural or historic management plan is required for the project as any activities with the potential to threaten cultural resources at the project are regulated by the license, Lowell Act, and National Historic Preservation Act. The project maintains an operating agreement with the National Park Service to provide flows for tour boat operations.

Recreational resources at the project include a visitor facility at the powerhouse, Northern Canal Walkway, and National Park Service boat tours. Public access is provided free of charge.

Compliance Status

The Certificate includes the following facility-specific conditions:

  • Condition 1: The Owner shall continue to maintain the current voluntary seasonal attraction flows in the bypass reach and full season fish ladder operation (See LIHI Reviewer Report, Appendix – Agency Letters) and proactively consult with the resource agencies regarding possible interim opportunities to enhance flows in the bypass reach and in the canal system (if needed) while the upcoming FERC relicensing activities are underway. Such opportunities may involve study of habitat quantity/quality, alternative flow regimes, and/or water quality monitoring so that modifications can be implemented more quickly once a new license is issued, or even prior to a new license if agreed to by all parties. During the term of this LIHI Certification, should a resource agency request implementation of enhanced bypass and/or canal flow measures as part of their recommendations or jurisdictional mandates under the relicensing proceedings, the Owner shall provide to LIHI in the annual compliance report a copy of the request, and describe the Owner’s plans to address these requests along with a schedule and progress toward implementation.
  • Condition 2. The Owner shall provide to LIHI as part of the annual compliance report, a status report of the FERC licensing progress listing significant agency interactions that have occurred in the past year that are relevant to any of LIHI’s Certification criteria, and highlighting major topics of agreement or disagreement. LIHI reserves the right to request additional details if necessary, if highlighted topics are relevant to LIHI Certification criteria and their associated goals. LIHI also reserves the right to modify the Certificate conditions again if needed.
  • Condition 3. The Owner shall work toward removing the state’s water quality impairment listing for hydromodification in the combined bypass and downstream reach of the Project. This may be accomplished by working proactively with Massachusetts DEP and: a) ensuring that any water quality studies conducted as part of relicensing adhere to state quality control/quality assurance (QA/QC) protocols and that results are submitted to the state timely and in the proper format for use by the state in its biennial review(s) of the State’s Clean Water Act Integrated List of Waters; b) providing results of other relicensing studies (e.g., instream flow studies) to the state for inclusion in upcoming biennial reviews of the state’s impairment listings; and c) by submitting public comments relative to results from flow and water quality studies in that reach during the public comment process when the state’s draft lists are made available. Activities and any changes in the impairment listing for the reach shall be summarized and reported to LIHI in the annual compliance reports.
  • Condition 4. The Merrimack River basin is highly developed for water resources and the operation of multiple hydropower facilities and other water uses in the basin are interconnected to a degree that requires a systematic approach for future management. Solutions for individual facilities are insufficient to achieve the environmental protection and restoration needed for long-term, sustainable water uses. Therefore, the Owner of the Lowell facility shall continue to play a constructive, supportive role in promoting integrative water management in the basin, both in the Project’s upcoming FERC relicensing and in other regulatory proceedings and voluntary activities that may develop in the basin. The Owner shall report to LIHI on its activities relative to this condition each year in its annual compliance report. LIHI reserves the right to modify the Certificate conditions again if needed.


2021: There were no reported changes or compliance issues. The project remains in compliance based on the annual review. For Condition 1, the project reported continued voluntary measures and noted its proposal to replace the fish lift with a fish ladder, its proposal to institute enhanced bypass flows, and its proposal to decommission the canal hydro units. For Condition 2, the project reported filing its license application with all studies completed except for the whitewater boating study, expected to be completed in 2021. For Condition 3, the project reported taking water quality grab samples during bypass reach instream flow studies that showed compliance with water quality standards. For Condition 4, the project reported continued proactive engagement with the Merrimack River Technical Committee.

2020: There were no reported changes or compliance issues. The project remains in compliance based on the annual review. For Condition 1, the project reported continued voluntary measures and noted that fishery studies being conducted for relicensing. For Condition 2, the project reported filing its initial study report for 7 of 13 studies conducted in 2019; and that modifications to improve fish lift effectiveness was delayed to allow for pre-existing baseline study conditions. For Condition 3, the project reported no change. For Condition 4, the project reported that Central Rivers Power purchased the Lowell and Lawrence projects making them the owner of all the hydro projects on the Merrimack and Pemigewasset rivers which contributes significantly to integrative management of the resource.

2019: There were no reported changes or compliance issues. The project remains in compliance based on the annual review. For Condition 1, the project reported continued voluntary measures and noted that fishery studies would be conducted for relicensing. For Condition 2, the project reported on FERC’s study plan determination that agency-requested balloon tag studies were not necessary given the other fishery related studies; however, the project made voluntary modifications to improve fish lift effectiveness in consultation with resource agencies. For Condition 3, the project reported no change. For Condition 4, the project reported that the relicensing process and coordination between the Lowell and Lawrence (LIHI # 121) Projects contributes to integrative management.

2018: There were no reported changes or compliance issues. The project remains in compliance based on the annual review. For Condition 1, the project reported continued voluntary measures. For Condition 2, the project reported no issues and submitted the relicensing proposed study plan. For Condition 3, the project reported no change and no study requests for water quality although a bypass reach minimum flow study will be conducted. For Condition 4, the project reported that the relicensing process contributes to integrative management.

2017: 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 17, 2018 The 30-day appeal window closed for the preliminary certification decision of the Lowell Hydroelectric Project closed on April 11th, 2018 with no appeals to the decision received. The decision is therefore final and the Lowell Hydroelectric Project is LIHI Certificate #142. The Certificate term will be August 23, 2017 – August 22, 2022.

March 12, 2018– On March 9, 2018, the Low Impact Hydropower Institute (LIHI) preliminarily approved Low Impact Certification for the Lowell project. The reviewer’s report and the report of the Executive Director are attached at the bottom of this page. This decision is preliminary pending the 30-day appeal window. Only those who commented in the initial application 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 to Requests must be received by 5:00 pm Eastern time April 11, 2018.

September 22, 2017 – On August 25, 2017, the Low Impact Hydropower Institute (LIHI) received a complete application from Enel Green Power North America, Inc. for the Low Impact Certification of the Lowell Hydroelectric Project, FERC No. 2790, located on the Merrimack River in Massachusetts. LIHI is seeking comment on the Lowell application for certification. 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 “Lowell Project Comments” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, 329 Massachusetts Avenue, Suite 2, Lexington, MA 02420.  Comments must be received at the Institute on or before 5 pm Eastern time on November 22, 2017 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.


2017 Certification