LIHI Certificate #141 – Mallison Falls Project, Maine

On the Presumpscot River there are eight hydroelectric facilities between Sebago Lake and the Atlantic Ocean in Portland, Maine. The Mallison Falls project is the sixth hydro project downstream of the Sebago Lake outlet.

The Mallison Falls site has been used for a variety of manufacturing purposes since c. 1740. The site was developed specifically for hydroelectric generation in 1900, when several local businesses formed the Mallison Falls Power Company to generate power for their mills. The site was later owned and operated by the Cumberland Power and Light Company, which was later acquired by Central Maine Power Company (CMP). Mr. Lawrence Keddy, owner of the Mallison Corporation, purchased the site in 1955, using the power generated for his Little Falls steel mill. The site was purchased in 1974 by S.D. Warren, later renamed Sappi North America, Inc.

The Mallison Falls Project operates in a run-of-river mode and consists of the following features:

  • a 358-foot-long, 14-foot-high diversion dam, consisting of a 113.5-foot-long cut granite spillway section, a 174.5-foot-long reinforced concrete spillway section, and a 70-foot-long canal headgate structure;
  • a 675-foot-long, 41-foot-wide, and 6-foot-deep intake canal;
  • a 33-footwide by 51-foot-long powerhouse containing two vertical Francis turbines direct connected to generators, each with an installed capacity of 0.4 MW for a total rated generating capacity of 0.8 MW and a reported annual generation of 4,200 MWh:
  • an 11-kV transmission line tied into the Gambo Project transmission line;
  • a 675-foot-long bypass reach between the dam and powerhouse tailwaters, the lower 375 feet of which is backwatered by discharges from the Mallison Falls powerhouse and by the downstream Saccarappa Project impoundment as noted in the FERC license;
  • a 0.5-mile-long impoundment extending from the Mallison Falls dam upstream to the tailwaters of the Little Falls Project, with a surface area of approximately 8 acres, and a maximum water surface elevation of 90.5 feet mean sea level (msl);
  • an upstream passage for American eel; and
  • a reported average annual flow at the dam of 926 cubic feet per second (cfs).
Project Name Mallison Falls
LIHI Certificate No. 141
LIHI Certificate Term  September 5, 2017 - September 4, 2022
Owner Sappi North America, Inc.
State Maine
Location Windham and Gorham, Cumberland Counties River mile 16.4 Presumpscot River
Installed Capacity 0.8 MW
Average Annual Generation 4,200 MWh
Facility Type run-of-river
FERC No. P 2932 issued 2003, expires 2053

Certification History

March 5, 2018 – The 30-day appeal window closed for the preliminary certification decision of the Mallison Falls Hydroelectric Project closed on March 1, 2018 with no appeals to the decision received. The decision is therefore final and Mallison Falls is LIHI Certificate #141. The Certificate term will be September 5, 2017 – September 4, 2022. The certificate includes the following conditions:

  • Condition 1:The Owner shall provide LIHI with a copy of the 2018 effectiveness study of the upstream eel passage, along with MDMR and USFWS comments on the study results and comments related to whether additional effectiveness testing is required to confirm that eels are safely passing upstream at the Project. If additional testing is required, the schedule and final results along with agency comments on the report, agency recommendations for modifications, and plans and schedule for any needed modifications to shall also be provided to LIHI.
  • Condition 2. The Owner shall update LIHI on the following activities in the annual LIHI compliance statement:
    1. The status of Condition 1 above.
    2. The status of the effectiveness testing of downstream passage of eels.
    3. The status of upstream and downstream anadromous fish passage activities at the Project and at the Saccarappa Project. The updates should include summaries of agency and stakeholder consultation and recommendations made, any changes in the fish passage plans from those described in the LIHI application, and any changes in passage requirements or the timing of implementation at both Projects. LIHI reserves the right to suspend its certification if the agencies do not determine that safe passage at the Project is being provided and that such passage needs have not been waived.
    4. A summary of any consultation with MIF&W and/or USFWS related to state or federally listed species identified as possibly occurring at the site that could be impacted by construction activities or non-routine operations or maintenance activities. This would also include impoundment drawdowns that would expose a significant portion of the river bottom, among other non-routine activities. A summary of the relevant triggering activities and the measures implemented during the year to protect such species shall also be provided.
  • Condition 3: The LIHI Certification term will not expire until September 4, 2022. If upstream anadromous fish passage is not installed at Mallison Falls by May 2021 (the earliest date based on a 2019 fishway operational date at the Saccarappa Project) the Owner shall provide LIHI with a summary of the reasons passage has not yet been installed at Mallison Falls, and a revised schedule for installation based on the information available at that time.
January 30, 2018 – On January 24, 2018, the Low Impact Hydropower Institute (LIHI) preliminarily approved Low Impact Certification for the Mallison Falls project. 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  comments@lowimpacthydro.orgRequests must be received by 5:00 pm Eastern time March 1, 2018.

September 7, 2017 – On September 7, 2017, the Low Impact Hydropower Institute (LIHI) received a complete application from S.D. Warren Company d/b/a Sappi North America for the Low Impact Certification of the Mallison Falls Project, FERC No. P-2932, located on the Presumpscot River in Maine.

LIHI is seeking comment on the Mallison Falls 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 “Mallison Falls 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 7, 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.