LIHI Certificate #10 - Worumbo Hydroelectric Project, Maine

The Worumbo Project is located on the Androscoggin River in Lisbon Falls and Durham, Maine.  It is the third dam on the Androscoggin River, upstream from the Pejepscot Project (FERC No.4784) and the Brunswick Project (FERC No.2284).

The Worumbo Project consists of a dam/spillway, consisting of a gated flood spillway, a concrete ogee spillway with crest elevation at 97 feet msl with two-foot-high hinged flashboards, a center rock ledge section containing a concrete dike with a crest elevation at 97 feet msl with two-foot-high hinged flashboards, and an approximately 520-foot-long concrete spillway with three independently operable pneumatic flasboard sections of seventeen (17) 2.17 ft panels, eight (8) 1.75 ft. panels, and twenty one (21) 2.25 ft. panels; an intake section; and an integral powerhouse equipped with two (2) turbine-generator units having a rated total capacity of 19.4 MW at a net operating head of 30.5 feet.

The crest gate/flashboard system is designed to fail when overtopped by two (2) feet of water.  The dam creates an impoundment with a surface area of 190 acres at a normal full pond elevation of 98.5 feet msl.

The project is currently operated as a run-of-river facility, with outflow approximately equal to inflow on an instantaneous basis, with the exception of power system emergencies when the project is called upon for maximum output.  The project is also operated to provide seasonally-varied minimum flow releases into the 850-foot-long bypassed river reach between the Durham-side dam and the end of the tailrace training wall.  Current operation permits the impoundment to be drawn down by a maximum of 1.5 feet to allow the owner to maximize the energy and capacity of the project, to provide short-term reserve capacity to the interstate power grid, and to provide ancillary services (i.e., Automatic Generation Control) to the power grid under deregulated market conditions.  Minimum flow releases from the project are maintained at 1,700 cfs or inflow, whichever is less, during impoundment refilling.

Project Name Worumbo
LIHI Certificate No. 10
LIHI Certificate Term March 3, 2018 - March 2, 2023
Owner Brown Bear II Hydro, Inc
State Maine
Location Located at river mile 14.1 on the Androscoggin River at Lisbon Falls, Maine
Installed Capacity 19.4 MW
Average Annual Generation 93,000 MWh
Facility Type Run-of-river
FERC No. P-3428 issued 1985, expires 2025

Certification History

October 25, 2018: The decision to recertify the Worumbo Hydroelectric Project is final. No appeals were received during the appeal period which closed on October 13, 2018. The new certification term for the Project is from March 3, 2018 through March 2, 2023.

September 13, 2018: On September 13, 2018, the Low Impact Hydropower Institute (LIHI) preliminarily approved the Worumbo Hydroelectric Project for a new 5-year term of Low Impact Certification, with the following conditions:

  • Condition partially satisfied 2019. Condition 1 (Modified):  The Owner shall make initial contact with the MEDEP by December 31, 2018 and seek to initiate consultation with the MEDEP by March 31, 2019 in an effort to resolve the agency concern in their email to the LIHI reviewer that the dam may be increasing the contaminant bio-accumulation in fish and non-attainment of the water quality standards from mercury and legacy PCB and dioxin pollutants from upstream sources. The Owner shall notify LIHI as to the results of this consultation within 60 days of the consultation. Active Condition part: The Owner shall provide updates on any consultation with MEDEP on this issue that occur during the upcoming FERC relicensing process, to LIHI as part of their annual compliance reports.
  • Condition 2:To ensure that requirements identified by NMFS that are deemed necessary to protect the endangered Atlantic salmon are conducted, the Owner shall confirm that the activities under the Terms and Conditions of the Biological Opinion have been conducted, as needed and applicable, each year. This update shall be provided in the annual compliance reports to LIHI.
  • Condition 3:If the Owner undertakes any construction or maintenance activities that may affect lands not already developed, or structures/tree removal that may provide roosting habitat for listed state and federal bat species, LIHI shall be notified of such actions, along with the results of any mitigation measures that may be conducted to minimize species impacts, should they be found to be necessary based on agency consultation. Such LIHI notification shall be provided as part of the annual compliance reports to LIHI.

This decision is preliminary pending the 30-day appeal window. Only those who commented in 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 projects do not meet the LIHI criteria. Appeal requests can be submitted by email to with “Worumbo Hydroelectric Project” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, 329 Massachusetts Ave, Suite 2, Lexington, MA 02420. All requests will be posted to the website and 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 October 13, 2018.  The full application and reviewers report are available HERE.

If no appeal requests are received and the decision becomes final, the new term for the Worumbo Project will be March 3, 2018 through March 2, 2023.

July 12, 2018:The Low Impact Hydropower Institute has received a complete application for a new term of Low Impact Certification for the Worumbo Hydroelectric Project (LIHI # 10).

LIHI is seeking public comment on this application.  Specifically, we are interested in knowing whether you think the Project meets the LIHI Low Impact Certification Criteria, as revised in the 2nd Edition Handbook.  Please review the program and criteria in LIHI’s revised Handbook and then review the Project’s 2018 application materials posted below.

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 “Worumbo 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 September 10, 2018 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.

July 5, 2018: The Worumbo Hydroelectric Project has been granted an extension of the current term through September 30, 2018.

March 13, 2018: The Worumbo Hydroelectric Project has been granted an extension of the current term through July 31, 2018.

August 27, 2014: The Worumbo Hydroelectric Project has been certified as low impact for a third five year term, effective March 3, 2013 and expiring March 3, 2018.

May 5, 2014: The certificate term for the Worumbo Project has been extended by the Executive Director to June 30, 2014, in order to allow time to finalize the review of the application for recertification.

May 23, 2013: The Low Impact Hydropower Institute has received an application for recertification of the Worumbo Project.

July 3, 2008: The Worumbo Project was recertified for a second five year term. Miller Hydro Group requested to have the expiration date of their current certification accelerated and to file right away for a renewal of their project. The request was accepted and the existing certificate will expire on the effective date of the new certificate.

May 24, 2004: The Worumbo Project was certified as low impact for a five year term, effective February 19, 2004 and expiring February 19, 2009.