LIHI Certificate #39 - Fifteen Mile Falls Project, Vermont and New Hampshire

The Fifteen Mile Falls store-and-release project in the upper Connecticut River watershed is comprised of three developments spanning a 26-mile reach of the Connecticut River between river miles (RM) 268.6 and 294.5 at the top of Moore Reservoir.
Moore Development

The Moore development is located at RM 283, and includes: (1) an 11-mile-long reservoir with a surface area of 3,490 acres and 223,722 acre-feet of gross storage at a normal maximum operating level of 809 feet msl; (2) an earth and concrete gravity dam with an overall length of 2,920 feet and a height of 178 feet; (3) a 373-foot-long concrete spillway with a 15-foot-wide by 20-foot-high sluice gate, four 50-foot bays of 17-foot-high stanchions, and three bays of 36 foot-wide by 30-foot-high tainter gates; (4) four steel penstocks each 296 feet long; and (5) a powerhouse with four Francis type turbine-generator units. The turbines have a combined power rating of 225,600 horsepower (56,400 horsepower each) under a design head of 150 feet and a combined rated discharge of 13,300 cubic feet per second (cfs). Each generator is rated at 35,100 kilowatts (kW), yielding an overall rated capacity for the station of 140,400 kW. Maximum output at full load is 191,960 kW under a net head of 158 feet with a combined turbine discharge of 18,300 cfs.

Comerford Powerhouse and Tailrace

The Comerford development is located at RM 275 and consists of: (1) an 8-mile-long reservoir with a surface area of 1,093 acres and 32,270 acre-feet of gross storage at a normal maximum operating level of 650 feet msl; (2) an earth and concrete gravity dam with an overall length of 2,253 feet and a height of 170 feet; (3) an 850-foot-long concrete spillway with six 7-foot-wide by 9-foot-high sluice gates, four bays of 8-foot-high flashboards and seven 10-foot-high stanchion bays; (4) four steel penstocks each 150 feet long; and (5) a powerhouse with four Francis type turbine-generator units. The turbines have a combined power rating of 216,800 horsepower (54,200 horsepower each) under a design head of 180 feet and a combined rated discharge of 12,010 cfs. Each generator is rated at 35,100 kW, yielding an overall rated capacity for the station of 140,400 kW. Maximum output at full load is 163,960 kW under a net head of 174 feet with a combined turbine discharge of 13,300 cfs.

McIndoes Forebay, Dam and Powerhouse

The McIndoes development is located at RM 268 and consists of: (1) a 5-mile-long reservoir with a surface area of 543 acres and 5,988 acre-feet of gross storage at a normal maximum operating level of 454 feet msl; (2) a concrete gravity dam with an overall length of 730 feet and a height of 25 feet; (3) a 520-foot-long concrete spillway with a 12-foot-wide by 13-foot-high skimmer gate, three 24-foot-wide by 25-foot-high tainter gates, a 300-foot long spillway flashboard section with 6-foot flashboards, and two 50-foot-wide by 18-foot-high stanchion bays; and (4) a powerhouse with four Kaplan type turbine-generator units. The turbines have a combined power rating of 15,200 horsepower (3,800 horsepower each) under a design head of 29 feet and a combined rated discharge of 5,800 cfs. Each generator is rated at 2,640 kW, yielding an overall rated capacity for the station of 10,560 kW. Maximum output at full load is 13,000 kW under a net head of 26 feet with a combined turbine discharge of 5,800 cfs.

There is a roughly 1.5-mile riveine reach between Comerford and McIndoes reservoirs.

Settlement Agreements

In August 1997 a dozen organizations signed a settlement agreement intended to address a number of objectives, including “…improving water quality, enhancing habitat for fish and other aquatic biota; improving wildlife habitat; protecting threatened and endangered plant and animal species; protecting wetlands; protecting cultural resources; preserving undeveloped lands; enhancing public recreation; protecting aesthetic values; fostering economic development and preserving the local tax base; and maintaining the energy and system reliability benefits of New England's largest hydropower project.”[1] The signatories were the project’s owner at the time, New England Power Company, and the following stakeholders:

  • New Hampshire Fish and Game Department (NHFGD)
  • New Hampshire Department of Environmental Services (NHDES)
  • Vermont Agency of Natural Resources (VANR)
  • United States Fish and Wildlife Service (USFWS)
  • United States Environmental Protection Agency (EPA)
  • National Park Service (NPS)
  • Appalachian Mountain Club (AMC)
  • Connecticut River Joint Commissions (CRJC)
  • Connecticut River Watershed Council (CRWC)
  • New Hampshire Rivers Council (NHRC)
  • North Country Council (NCC)
  • Northeastern Vermont Development Association (NVDA)
  • New Hampshire Council of Trout Unlimited (TU)

[1] Final Fifteen Mile Falls Settlement Agreement, August 6, 1997 (Signed August 14, 1997).

The provisions of the settlement agreement, most, but not all of which are reflected in the project’s FERC license, require the following:
  • Flows and Reservoir Levels: Water management protection, mitigation, and enhancement measures, including changes to operational modes, and minimum flow releases for the three developments.
  • Direct Donation of Conservation Easements: Dedication by the project owner of easements on 4,000 acres of project land and 4,200 acres of non-project land to protect the scenic, forestry, and natural resources values of the lands. (The FERC license requires dedication only of the acreage on project land.)
  • Mitigation and Enhancement Fund: Establishment of an Upper Connecticut River Mitigation and Enhancement Fund to address impacts of the project, financed from project revenues capped at $15 million, and available to fund:  river and wetland restoration, protection, and enhancement; acquisition of conservation easements; and mitigation of tax revenue impacts to communities. (The FERC license establishes the fund but limits its enforcement to activities directly tied to project impacts.) Note that this fund, which allocates grants, is separate from a pool of money set aside for studies and management plans (see following).
  • Studies and Management Plans and Study Fund: Studies and/or the development of management plans related to fisheries mitigation, water quality, wildlife management, rare and unusual plant communities, threatened and endangered animal and plant species or communities, recreation, and cultural resources. Under the settlement agreement the applicant set aside a total of $3 million for a “Study Fund” to underwrite the costs of conducting pre- and post-licensing studies, developing plans, and implementation (except for fish passage implementation).

In July 2000 the then-owner of the facility and a subset of stakeholders also signed a Mercury Settlement to fund studies, plans, and mitigation measures to reduce bio-accumulation of mercury in fish in the facility area. Implementation has consisted of ongoing monitoring of fish tissue and posting of consumption advisories.

Project Name  Fifteen Mile Falls
LIHI Certificate No. 39
LIHI Certificate Term December 15, 2013 - December 14, 2021
Owner Great River Hydro, LLC
State New Hampshire, Vermont
Location Dams are located between river mile 268.6 and 83.5 on the Connecticut River in Grafton County, New Hampshire and Caledonia County, Vermont.
Installed Capacity 291.2 MW
Average Annual Generation 729,089 MWh
Facility Type Store-and-release
FERC No. P-2077 issued 2002, expires 2042

Certification History

January 24, 2017: Having reviewed information provided by the applicant as required in Condition 3 (text below), LIHI's Executive Director has determined that Condition 3 is satisfied and Fifteen Mile Falls has earned an additional three years of Certification term. The Certificate term is therefore December 15, 2013 through December 14, 2021. (The decision letter is posted below under Files.)

May 15, 2016: LIHI has received notice that TransCanada Hydro Northeast Inc. was converted to a limited liability company on April 7, 2017, becoming TransCanada Hydro Northeast LLC.  On April 19, 2017, the name of the company was changed from TransCanada Hydro Northeast LLC to Great River Hydro, LLC.

July 10, 2015: Executive Director Michael J. Sale, using authority delegated from the LIHI Governing Board, has determined that the Fifteen Mile Falls Hydroelectric Project (FERC No. P-2077) continues to satisfy the LIHI Certification Criteria. The effective certification date for the Fifteen Mile Falls Project is December 15, 2013 for a five (5) year term, which will expire on December 15, 2018, with the following conditions:

  • Condition satisfied 2016. Condition 1:Pertaining to the trap and truck operation for downstream passage of Atlantic salmon smolts stocked upstream of the Moore Dam, the facility owner shall remain in full compliance with its FERC license and the associated Settlement Agreement (SA) and Water Quality Certificate. If the licensee requests to amend the FERC license or the WQC, or reopen the SA, with regard to use of this operation, the facility owner shall notify LIHI within seven days, including a description of the proposed changes and schedules for pursuing them. LIHI shall also be provided a copy of any amendments, along with resource agency comments, to confirm continued compliance with LIHI’s criterion.
  • Condition 2: As part of the required annual Compliance Statement to LIHI, the facility owner shall identify any violations of FERC operating requirements and will include copies of all agency and FERC notifications and reports of deviations of said operating requirements that have occurred in the previous year. This report shall be submitted by March 31 for the previous year’s events. This report shall reference and include copies of all notifications made to the FERC during the previous year. Unless otherwise included in the FERC notifications themselves, the report to LIHI shall describe for each instance:
    1. The cause of the event/deviation;
    2. The date, duration and magnitude of the deviation;
    3. Confirmation that the required 24-hour notices have been made to NHDES and VTDEC of such events (list the date of and to whom all notifications were sent);
    4. Ways to minimize future repeat occurrences to the extent possible by the Licensee;
    5. Any proposed mitigation measures and a schedule by which such measures will be implemented; and
    6. Status or confirmation that the previously developed mitigation measures (for the previous year) have been implemented according to the proposed schedule.
    The owner shall maintain a proactive approach to reducing the frequency and severity of such deviations to the extent reasonably possible. LIHI shall be informed of the capital improvement projects that are underway and planned for the future to minimize the occurrence of deviations or plant outages. The annual compliance report to LIHI will be used as confirmation that the facility owner is conducting the necessary actions to minimize such events and ensure compliance with LIHI’s flow and water quality criteria.
  • Condition satisfied 2018, extended term granted. Condition 3:The facility owner shall provide LIHI with a description of the current status and use of funds from the Mitigation and Enhancement Fund that was part of the Settlement Agreement for the most recent FERC licensing.  In particular, this description shall identify the lands and waters that are benefiting from the funds, the current fund balance, and continuing payment schedule, and be sufficient to determine if these funds are achieving the ecological and recreational equivalent of land protection of the buffer zone referred to in Question D.1.  This information will be used by LIHI staff to determine if the Fifteen Mile Falls certification qualifies for three additional years in its term.  The facility owner may or may not take advantage of this opportunity to request an extended term of their new certificate; if they do not provide this additional information, it will not affect the new five-year term.

January 27, 2014: The Low Impact Hydropower Institute has received an application from TransCanada for a second term of certification of the Vernon Station Hydroelectric Project. The 2013 application was received on December 5th, but due to administrative backlog, the certificate has been granted a three month extension beyond the date of December 15th. The application materials can be found in the “Files” section below.

June 25, 2009: The 15-Mile Falls Hydroelectric Project has been certified as low impact for a five year term, effective December 15, 2008 and expiring December 15, 2013.