(3) GreggsFallsPowerhouseDam

The Gregg’s Falls facility is located on the Piscataquog River near the town of Goffstown, New Hampshire.  The site was historically used for the generation of electrical energy and was decommissioned in the 1970’s. A major refurbishment was undertaken in 1985, which included the installation of two new turbines and generators and the replacement of all electrical and control equipment. The installed capacity of the facility is 3,480 kilowatts.

Project Name  Gregg’s Falls
 LIHI Certificate Number 120
LIHI Effective and Expiration Dates January 26, 2015
January 26, 2020
Owner Greggs Falls Hydroelectric Associates Limited Partnership, a subsidiary of Eagle Creek Renewable Energy, LLC
State New Hampshire
Location Located at River Mile 30 (of 37) on the Piscataquog River in New Hampshire.
Installed Capacity 3.479 MW
Average Annual Generation 10,902 MWh
Facility Type  Run-of-river
FERC No. 3180


On July 21, 1983 the Federal Energy Regulatory Commission (FERC) issued an exemption for the hydroelectric facility at the site of the existing Gregg’s Falls Dam.  FERC amended the Exemption on December 1, 1998.  On June 29, 2013, Eagle Creek Renewable Energy LLC acquired 100% of the Gregg’s Falls project from Algonquin Power Co.’s subsidiary, Gregg’s Falls Hydroelectric Associates Limited Partnership.

The facility has a concrete dam that has a height of approximately 60 feet and a span of 1,360 feet.  The generating station has approximately 53 feet of head.  The site draws flow from a headpond of approximately 136 acres which is part of the Glen Lake recreational waterway. The site has a drainage area of approximately 193.1 square miles. The annual drawdown of the upstream lake provides a boost to energy generation at this site during the fall season.

The powerhouse is integrated into the base of the concrete gravity dam. It is a reinforced concrete structure measuring approximately 98.4 feet wide by 44.3 feet long. The powerhouse has a crane for servicing the generating equipment.  The interconnection point with PSNH grid distribution system is located approximately 98.5 feet from the powerhouse.

The Gregg’s Falls hydroelectric facility consists of: (1) an existing earthfill and concrete gravity dam 1,360 feet long and 60 feet high; (2) a reservoir (Glenn Lake) with a storage capacity of 3,650 acre-feet; (3) existing intake structures; (4) new fish passage facilities; (5) an existing concrete penstock 31.75 feet long and 10 feet by 17.5 feet oblong shape, transitioning to a 7.5 feet diameter circular shape; (6) an existing powerhouse containing 2 turbines and 2 new generators with an installed capacity of 3,479 kW; (7) a switchyard; and (8) a new 100-foot-long transmission line. The concrete spillway crest elevation remains unchanged at 271.1 feet NGVD, and is topped by 1.5-foot-high flashboards which raise the normal maximum surface elevation to 272.6 feet NGVD and increase the reservoir’s storage capacity to approximately 3,650 acre-feet.

Certification History

June 24, 2015 – Executive Director Michael J. Sale, using authority delegated from the LIHI Governing Board and a full review of the Application Reviewer’s report and all public comments and additional materials provided by the Applicant, has determined that the Gregg’s Falls Hydroelectric Project (FERC No. P-3180) satisfies the LIHI Certification Criteria. The effective certification date for the Gregg’s Falls Project is January 26, 2015 for a five (5) year term, which will expire on January 26, 2020, with the following conditions:

Condition satisfied in 2017. Condition 1. To confirm compliance with possible new flow requirements, the Facility Owner shall provide LIHI with documentation of the USFWS’s required flow regime for the Project, the final schedule for implementing the Operations and Flow Monitoring Plan, and approval from USFWS and NHF&GD of this Plan. These shall be provided within 30 days of each item’s completion. In its annual compliance report, the Facility Owner shall provide a statement of compliance with the Operations and Flow Monitoring Plan and an explanation of any deviations from the Plan requirements.

Condition satisfied in 2017. Condition 2. To confirm that the project waters are meeting all numerical state standards for water quality, additional sampling for all parameters, including but not limited to DO, chlorophyll and pH as outlined in a sampling plan to be developed by NHDES, shall be conducted in 2015. The sampling plan, results of these studies and an analysis by NHDES regarding compliance with state standards shall be provided to LIHI within 30 days of completion of NHDES’s determination. All additional water quality sampling required by NHDES shall be completed by December 31, 2015.

Condition satisfied in 2016. Condition 3. To confirm compliance with the MOA regarding fish passage, the Facility Owner shall provide LIHI with copies of any notification that they receive from state or federal resource agencies that require construction of the downstream passage and protection facilities for river herring and American eel. LIHI shall be notified of any such fish passage requirements within 30 days of receipt of that notification. Further, the Facility Owner shall keep LIHI informed on the status of activities conducted to meet these requirements within the designated timeframe, including any interim deadlines (e.g., approval of construction plans, effectiveness testing completion, etc.) in their annual compliance report to LIHI.

January 26, 2015 – The Low Impact Hydropower Institute (LIHI) received an application from Eagle Creek Renewables for Low Impact Certification of the Gregg’s Falls Hydroelectric Project, FERC P-3180, located on the Piscataquog River, in the state of New Hampshire.