The South Milton Hydroelectric Project is located on the Salmon Falls River in the town of Milton, New Hampshire. The Salmon Falls River originates at Great East Lake about twelve miles due north of the Project site. The river flows principally southeast from the Project site to join the Cochecho River, which flows in from the west in the town of Dover, New Hampshire. Together they form the Piscataqua River, which is a tidal river that enters the Atlantic Ocean twelve miles downstream in Portsmouth, New Hampshire and Kittery, Maine. The Salmon Falls River, with a length of 38 miles, forms a portion of the southern border between New Hampshire and Maine. Except for the Project dam, all Project infrastructure is located in New Hampshire.

Project Name South Milton
LIHI Certificate Number 100
LIHI Effective and Expiration Dates September 6, 2012
September 6, 2017(extended to April 6, 2018)
Owner Salmon Falls River Hydro Corporation
State New Hampshire
Location Located on the Salmon Falls River in the town of Milton, New Hampshire.
Installed Capacity 2.05 MW
Average Annual Generation
Facility Type Run-of-river
FERC No. 3984

The Project dam is one of fifteen dams located on the Salmon Falls River. Six federally licensed or exempted hydroelectric projects are located between the Project and South Berwick, Maine: North Rochester (FERC Project No. 3985), Boston Felt (FERC Project No. 4542), Somersworth (FERC Project No. 3820), Lower Great Falls (FERC Project No. 4451), Rollinsford (FERC Project No. 3777), and South Berwick (FERC Project No. 11163). Below South Berwick, the river becomes tidal for its last three miles before entering the Piscataqua River.

The mills on the upper Salmon Falls River were initially developed in the early 1900’s by the Jonas Spaulding, a partner in Spaulding Fiber, a manufacturer of leatherboard, transformer board, and vulcanized fibre founded in 1873 in Townsend Harbor, Massachusetts. The New Hampshire mills were operated for leatherboard manufacture under the name the J. Spaulding and Sons. Dams related to this manufacturing enterprise persist.

Project works consist of: (1) a 164-foot-long concrete-capped timber crib dam which is 16.4 feet high at its highest point; (2) a 6-foot 6-inch-diameter, 3,800-foot-long steel penstock; (3) a powerhouse located in the former Spaulding Fiber Company Mill 4,600 feet downstream of the dam; (4) three turbines, with Units 1, 2, and 4 located in Mill Building No. 1 and Unit 3 located in adjacent Mill Building No. 2. Mill building No. 1 is considered the primary powerhouse with the controls and electrical cubicles situated within. Each of the generating units has individual draft tubes which discharge flow into a common tailrace. The Project dam forms a 100-acre impoundment with an average depth of 15 feet and a gross storage capacity of about 768 acre-feet. The FERC exemption application indicates that the headpond elevation is 340 feet and the tailwater 238 feet, presumably referenced to sea level.

The dam was completed in 1893. The upper six feet of the dam consists of stanchion stoplogs. Two 10.5 feet wide by 6.5 feet high wooden wastegates were incorporated in the structure in 1999. The gates are motorized. The intake structure is comprised of a trashrack, a custom built trash rake system, a manually operated headgate, and a transition section which feeds thee penstock. The trashrack rake system is operated manually on a daily basis and more frequently during specific times of the year such as during the fall and during ice break-up periods.

The station has a capacity of 2.05 MW.

2017 Recertification

October 26, 2017: On October 26, 2017, the Low Impact Hydropower Institute (LIHI) received a complete application from Salmon Falls River Hydro Corporation for the Low Impact Certification of the South Milton Hydroelectric Project, located in Milton, NH (FERC 3984).

LIHI is seeking public comment on this application. Specifically, we are interested in knowing whether you think the South Milton project meets the LIHI Low Impact Certification Criteria. The South Milton application is subject to review using the Criteria in the LIHI Certification Handbook of 2016.  Please review the program and criteria in LIHI’s 2016 Handbook and then review the Project’s 2017 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 comments@lowimpacthydro.org with “South Milton Project Comments” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, 329 Massachusetts Ave, Suite 2, Lexington, MA 02420. The 60 day public comment period begins on October 26, 2017.  Comments must be received at the Institute on or before 5 pm Eastern time on December 26, 2017 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.

Certification History

January 30, 2013: The South Milton Hydroelectric Project has been certified as low impact for a five year term, effective September 6, 2012 and expiring September 6, 2017, with the following conditions:

  • (1) SFR Hydro shall maintain a minimum flow of 58 cfs, or inflow if less, in the penstock-bypassed reach of river.  This condition is deemed satisfied by LIHI on consultation with Certificate Holder- 9/2/15
  • (2) After consultation with the USFWS, the N.H. Department of Fish and Game, and the N.H. Department of Environmental Services, SFR Hydro shall revise the Project flow monitoring plan to address the method for releasing the bypass minimum flow and how records will be supplemented to enable demonstration of compliance with the bypass minimum flow. The revised plan will be filed with FERC for approval within 90 days of LIHI’s grant of certification; SFR Hydro shall copy LIHI on the filing.  This condition is deemed satisfied by LIHI on consultation with Certificate Holder- 9/2/15.  See Flow Monitoring Plan posted in Files below.  
  • (3) By October 1, 2013, SFR Hydro shall enter into, and provide LIHI with a copy of, an agreement reached between the USFWS, the New Hampshire Department of Fish and Game, and SFR Hydro for providing both interim and permanent downstream passage and permanent upstream passage, that are safe, timely, and effective, for American eel, including a description of the planned passage and protection measures and the implementation schedule for design, installation, and operations. Said permanent facilities for upstream and downstream passage shall be in place and operational by August 1, 2015, and SFR Hydro shall notify LIHI within two weeks of completion. Pending the agreement, SFR Hydro shall continue providing downstream passage by maintaining the exclusionary trashracks and passing eels through the opening in one sluicegate during the period August 15 to November 15. In the event that the USFWS and the New Hampshire Department of Fish and Game determine prior to the installation of permanent downstream passage that the above-described interim downstream passage measure is not providing safe, timely and effective interim passage for outmigrating eels, SFR Hydro shall implement other reasonable interim measures as requested by these agencies.  In August 2015 SFR completed Eel Passage construction, see Eel Passage Design in files below.  Agency approval is pending.
  • (4) In the event that the facility owner decides to undertake any new activities that may have an adverse effect on historic properties, such as new excavation, demolition, and structural alteration, the facility owner shall notify LIHI within 30 days of such decision.  The facility owner shall then consult with, and obtain approval from, the State Historic Preservation Office of such activities and send LIHI a copy of that approval when it is obtained.

September 30, 2012: The public comment period on the application has closed.

July 30, 2012: SFR Hydro, Inc. has submitted an application for the certification of its South Milton Project. The application was posted and the public comment period was opened.


2017 Recertification

2012 Certification