LIHI Certificate #137 – Eel Weir Project, Maine

On the Presumpscot River there are eight hydroelectric facilities between Sebago Lake and the Atlantic Ocean in Portland, Maine. The headgate of the Eel Weir hydroelectric project is located at the outlet of Sebago Lake in the towns of Windham and Standish, Maine. The Presumpscot River originates from this point and extends roughly 25 miles southeast to the Atlantic Ocean at Casco Bay.

The Eel Weir Project headgates were installed in the mid-1800s while the generating facilities were commissioned in 1903 by the Presumpscot Electric Company, a subsidiary of S.D. Warren, later renamed Sappi North America, Inc.

The Eel Weir Project is operated in a store-and-release mode to achieve the lake elevations and flow releases established by the FERC license and Water Quality Certificate. The lake levels are intended to protect aquatic resources and minimize erosion along the shoreline, while providing adequate conditions for recreation and boating. Project works consist of:

  • a 1,350-foot-long dam, that includes: a 900-foot-long, non-overflow concrete retaining wall and earth-fill east embankment; a 115-foot-long, 22-foot-high stone masonry and concrete spillway; a 35-foot-long, 17-foot-wide stone masonry and concrete river gatehouse with five 6.4-foot-high, 4.8-foot-wide wooden gates; and a 260-foot-long stone masonry and earth-fill west embankment;
  • a 90-foot-long fish screen with ¾-inch clear-bar spacing located immediately upstream of the canal intake gatehouse;
  • a 40-foot-long, 19-foot-high canal waste gate structure with three 17-foot-wide, 11-foot-high steel slide gates;
  • a minimum flow gate located within each steel slide gate;
  • a 3.5-mile-long, 11-kilovolt transmission line connecting the powerhouse to S.D. Warren’s Dundee Project (P-2942); and
  • both upstream and downstream eel passage measures.

The only reported major repairs to the power equipment includes a 2009 rewind of the #1 Generator and the addition of digital metering and relaying; neither increased the capacity of the units. Alteration of the canal waste gates to satisfy the increased required minimum flows under the new license under are scheduled for completion by April 1, 2019.

Project Name Eel Weir
LIHI Certificate No. 137
LIHI Certificate Term September 5, 2017 - September 4, 2022
Owner Sappi North America, Inc.
State Maine
Location Located at Windham & Gorham, Cumberland Counties River mile 25 on the Presumpscot River
Installed Capacity 1.8 MW
Average Annual Generation 12,300 MWH
Facility Type store-and-release
FERC No. P-2984 issued 2015, expires 2055

 Certification History

March 23, 2018 – The 30-day appeal window for the preliminary certification decision of the Eel Weir Hydroelectric Project closed on March 1, 2018 with no appeals to the decision received. The decision is therefore final and Eel Weir is LIHI Certificate #137. The Certificate term will be September 5, 2017 – September 4, 2022. The certificate includes the following condition:

  • Condition 1. The Owner shall update LIHI on the following activities and provide requested documentation in the annual LIHI compliance statement:
    1. Satisfied 2019. Status of completion of releasing the 125 cfs minimum flow to the bypass reach, expected to begin April 1, 2019, in accordance with the current agency approvals.
    2. The status of downstream eel passage testing. Once testing is completed, the Owner shall forward to LIHI a copy of the final report, agency comments on the report, any agency recommendations made as a result of the testing, and any plans and schedule for any needed modifications to downstream passage facilities or measures.
    3. Receipt of formal agency notification by USFWS or any state resource agency that conditions have changed and it is appropriate that upstream and/or downstream passage for anadromous species is installed at the Project;
    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. A summary of the relevant triggering activities and the measures implemented during the year to protect such species shall also be provided.
    5. Status of completion of the Phase 0 archeological studies by the 2021 deadline specified in the HPMP; and
    6. Status of completion of the report on improvements for public access to Sebago Lake by the June 30, 2022 deadline, including comments and concurrence of resource agencies of the report findings.

January 30, 2018 – On January 24, 2018, the Low Impact Hydropower Institute (LIHI) preliminarily approved Low Impact Certification for the Eel Weir 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.

LIHI is seeking comment on the Eel Weir 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 “Eel Weir 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.