LIHI Certificate #118 – Webster Pembroke Project, New Hampshire
Webster-Pembroke Project is located on River Mile 34 (of 36) on the Suncook River near Pembroke, New Hampshire. The project is located approximately one half mile upstream of the China Mill Dam and confluence of Suncook and Merrimack Rivers and approximately 16 miles downstream of the Pittsfield Mill Dam. The river runs for 35.7 miles, from the outlet of Crystal Lake in Gilmantown, New Hampshire through several small towns and rural areas to its confluence with the Merrimack in the town of Suncook. The river experienced heavy flooding in 2006, establishing a new route in several areas and resulting in the largest channel change in a New Hampshire river in systematic topographic mapping history. The flood also resulted in several safety changes, including the removal of several unoccupied dams on the river. The river is characterized by very high flow variations, from average lows of 3 CFS to record high of 13,000 CFS, with an average mean flow of 390 CFS. Fishing and kayaking (recreational, not whitewater,) are the two primary recreation uses of the Suncook River.
A series of active dam sites occur along the length of the Suncook River prior to its confluence with the Merrimack River. Although it is unclear exactly how many are active, their appears to be as many as 14 dam sites along the entire 36 miles of the river’s watershed, with the Webster-Pembroke facility being the second to last downstream prior to the confluence. Immediately downstream is the China Mill facility, a privately-owned 1.7 MW facility also located at a former mill site.
The Webster-Pembroke project technically consists of two dams, the Webster Dam as the primary impoundment and the Pembroke, a stone masonry dam located on the bypass section of the Suncook River receiving the minimum flow release and any spillage from the Webster Dam. The Pembroke Dam is located 1800 feet downstream of the Webster Dam, and the powerhouse is currently adjacent to the Pembroke Dam. The reservoir at Webster-Pembroke has a volume of 147 acre-feet, and a total surface area of 26 acres. Approximately 4.5 acres are occupied by non-reservoir facilities, including a 460 foot long, 8 foot diameter penstock and a powerhouse containing one horizontal Voith Kaplan turbine/generator that produces approximately 10 million kilowatt-hours of clean energy in a typical year.
|Project Name||Webster Pembroke|
|LIHI Certificate No.||118|
|LIHI Certificate Term||February 23, 2020 - February 22, 2025|
|Owner||Pembroke Hydro Associates Limited Partnership, a subsidiary of Eagle Creek Renewable Energy, LLC|
|Location||Located at River Mile 34.25 on the Suncook River in New Hampshire.|
|Installed Capacity||2.6 MW|
|Average Annual Generation||10,100 MWh|
|FERC No.||P-3185 exempt 1983|
Partial removal of the Pembroke Dam is currently being proposed, as detailed in a letter provided by Kleinschmidt Associates:
“The reason for the partial removal is to sufficiently eliminate any hazard from dam failure or damage to adjacent property resulting from impounded levels during high flow events. The proposed partial removal addresses the upstream impact caused by the dam during the project design flood flow (100- year storm). Further, analyses has indicated that failure of the remaining portion of the dam under flood flow conditions would not have any significant downstream impact.” Any impact of flow from this removal process will be studied under the flow requirements study in the MOA to be conducted in 2015.
The Pembroke project consists of utilizing the total hydrostatic head available between the headwater of the Webster Dam, with 4 feet of flashboards (elevation 278 NGVD), and the tailwater of the Pembroke Dam (elevation 226 NGVD) which utilizes a gross head of about 52 feet. Flows are diverted through the existing Webster Canal, through a 460-foot-long, 8-foot diameter, 3/8” welded steel penstock to a full Kaplan Turbine rated at 2,600 MW, located in the old Pembroke Powerhouse which is immediately downstream of the Pembroke Dam.
The Pembroke project is operated as a run-of-river facility. Outflows from the project equal inflows on an instantaneous basis, and water levels above the dam are maintained at the crest of the dam and are not drawn down for the purposes of generating power. The Pembroke project consists of a stone masonry gravity dam, a 460-foot-long penstock, a powerhouse, one generation unit and appurtenant project equipment. The exemptee is required to maintain a minimum flow of 9 cfs or inflow, whichever is less at all times through the roughly 1,400-foot-long bypass.
September 14, 2020: The decision to recertify the Webster-Pembroke Project became final after the close of the appeals period on September 5, 2020 with no appeals filed. The Certification term is from February 23, 2020 – February 22, 2025. The Certificate includes the following conditions:
- Condition 1: The facility Owner shall provide the revised Operations and Flow Monitoring Plan and the amended or extended USFWS MOA within 90 days of finalization of each document with resource agencies. Any changes in operations or required fish passage measures shall be reported to LIHI in annual compliance submittals.
- Partially satisfied 2020 Condition 2: The facility Owner shall report to LIHI on the status and completion of the partial dam removal and mitigation measures under the SHPO MOA in annual compliance submittals until all work is completed and approved by the SHPO and FERC.
August 6, 2020:The Low Impact Hydropower Institute (LIHI) has preliminarily approved the Webster Pembroke Project (LIHI #118) for a new 5-year term of Low Impact Certification.
This decision is preliminary pending the 30-day appeal window. Only those who commented on 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 Project does not meet the LIHI criteria. Appeal requests can be submitted by email to email@example.com with “Webster Pembroke Project” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, 329 Massachusetts Ave, Suite 6, Lexington, MA 02420. All requests will be posted to the website. 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 September 5, 2020. The full application and reviewer’s report are available below. If no appeal requests are received and the decision becomes final, the Certification term for the Project will be February 23, 2020 through February 22, 2025.
May 19, 2020: The Low Impact Hydropower Institute has received a complete application for Low Impact recertification of the Webster Pembroke Hydroelectric Project. The complete application can be found below.
LIHI is seeking public comment on this application. 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 firstname.lastname@example.org with “Webster Pembroke Project Comments” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, 329 Massachusetts Avenue, Suite 6, Lexington, MA 02420. Comments must be received on or before 5 pm Eastern time on July 18, 2020 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.
May 11, 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 Webster Pembroke Hydroelectric Project (FERC No. 3185) satisfies the LIHI Certification Criteria. The effective certification date for the Webster Pembroke Project is February 23, 2015 for a five (5) year term, which will expire on February 23, 2020, with the following conditions:
- Condition Satisfied in 2018. Condition 1: Facility owner shall complete the agreed upon water quality sampling in 2015, receive satisfactory determination from New Hampshire Department of Environmental Services (NHDES) that facility does not negatively impact water quality, and provide results to LIHI by December 31, 2015.
- Condition Satisfied in 2017. Condition 2: Facility owner will comply with updated fish passage installation plants in 2015 as specified in the MOA with USFWS, obtain written approval of any required modifications, and report results to LIHI by December 31, 2015.
- See 2020 Condition 2. Condition 3: Facility owner will perform bypass flow study in consultation with USFWS and NHFG in 2015 and provide results to LIHI by December 31, 2015.
- Condition Satisfied in 2018. Condition 4: Facility owner will complete the Operations and Flow Monitoring Plan as required by MOA, obtain written approval by USFWS, and provide results to LIHI by December 31, 2015.
February 25, 2015 – The Low Impact Hydropower Institute (LIHI) received a timely and complete application on February 23, 2015 from Eagle Creek Renewable Energy LLC, for the Low Impact Certification of the Webster Pembroke Project, FERC P-3185.
- Webster Pembroke Recertification Review Report
- Webster Pembroke Recertification Application 2020
- Webster Pembroke Exemption Amendment 2020
- Webster Pembroke Certification Review Report 2015
- Webster Pembroke Certification Application
- Application Appendix - Order Granting Exemption 1983
- Application Appendix - Change of Ownership
- Application Appendix - Location of Other Dams
- Application Appendix - Project Map
- Application Appendix -Minimum Flow Compliance 2008-2012
- Application Appendix - US Fish and Wildlife Service & New Hampshire Fish & Game Comment Requests
- Application Appendix - New Hampshire Department of Historic Resources Review Request
- Application Appendix - New Hampshire Department of Historic Resources Comment Letter
- Application Appendix - New Hampshire Department of Fish and Game Recreational Access Request
- US Fish and Wildlife Service Threatened & Endangered Species Letter 2013
- Natural Heritage Bureau Threatened & Endangered Project Review
- New Hampshire Department of Fish and Game Request for Threatened & Endangered Species Review
- New Hampshire Department of Fish & Game Comment Letter
- Propose Revision of Dam Removal 2014