Gregg's Falls Impoundment Drawdown

Posted Date
Wednesday, July 27, 2022
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September 1, 2022

Subject:  Glen Lake Drawdown - Notification of Change in Drawdown Start Date and Schedule for Special Kayaking Discharge Release

The start date of the Glen Lake Drawdown has been moved from Tuesday September 6th to Saturday September 10th.  This schedule change has been made in consultation with the New Hampshire Fish and Game Department (NHFGD) and other State Agencies in order to facilitate an annual kayaking event.

On the morning of Saturday, September 10th, Gregg’s Falls Hydroelectric Associates (GFHA) will gradually ramp up project discharges. At 11:00 AM, the project is scheduled to begin releasing approximately 700 CFS to provide adequate flows for the planned kayaking event. Discharges will remain at approximately 700 CFS until 2:00 PM at which time GFHA will gradually reduce discharges to rates appropriate to maintain a daily reservoir drawdown rate of 6-inches per day.

GFHA is making this schedule change in an effort to appropriately balance different project stakeholder interests. The change is not expected to affect the remainder of the Glen Lake Drawdown schedule and we apologize for any inconvenience that the schedule change may cause.




Gregg’s Falls Hydroelectric Associates (GFHA) is the owner, operator and license exemption holder of the Gregg’s Falls Hydroelectric Project (FERC No. 3180) (the Project). The Project is located on the Piscataquog River in Goffstown, NH and includes Glen Lake as its Project impoundment. GFHA is scheduled to conduct a drawdown of Glen Lake between September 6 and December 24, 2022 to perform a safety inspection of the dam at the direction of the Federal Energy Regulatory Commission (FERC). Over the course of the drawdown, the impoundment will be lowered approximately 30 feet.
Impoundment lowering operations will commence on September 6 and continue until October 16, 2022. During this period, the impoundment will be drawn down in two stages. Between September 6-26 (Stage I), the impoundment will be drawn down a total of approximately 10 feet over a period of 20 days at a rate of 6-inches per day. Between September 27 and October 16 (Stage II), the impoundment will be lowered an additional 20 feet over a period of 20 days at a rate of 1-foot per day. GFHA will then conduct dam safety inspections for a period of 5 days between October 17-21, 2022. The dam safety inspections are the result of consultation with FERC to address non-emergent Project maintenance. Refill operations will commence on October 22 and are expected to be completed by December 24, 2022. Drawdown and refill operations will not impact the Project’s ability to maintain its downstream minimum flow requirements.

GFHA has developed the Glen Lake Reservoir Proposed Drawdown Plan (the Drawdown Plan) in consultation with the New Hampshire Department of Environmental Services, New Hampshire Fish and Game Department, and the U.S. Fish and Wildlife Service to identify measures to protect environmental resources and notify the public of the drawdown. In accordance with the Drawdown Plan, GFHA will be holding a public meeting virtually via Microsoft Teams on August 9, 2022 at 7:00 p.m. to provide additional information and answer questions.

In addition, GFHA is currently compiling an email distribution list for those interested in receiving updates about the drawdown. Please contact Melissa Sonnleitner at to be added to the email distribution list, for additional information, or to RSVP for the public meeting.