LIHI Certificate #100 - South Milton Project, New Hampshire

Project Name South Milton
LIHI Certificate No. 100
LIHI Certificate Term
September 6, 2017 – September 5, 2027
Owner Salmon Falls River Hydro Corporation
State New Hampshire
Location Located at river mile 26 on the Salmon Falls River in the town of Milton, New Hampshire.
Installed Capacity 1.55 MW
Average Annual Generation 6,200 MWh
Facility Type Run-of-river
FERC No. P-3984 exempt 1981

The South Milton Project is located on the Salmon Falls River in the town of Milton, New Hampshire on the border with Lebanon, Maine. 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 City of Dover, New Hampshire. Except for the dam, all project infrastructure is located in New Hampshire.

The Project 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. Below South Berwick, the river once joined with the Cochecho 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 Jonas Spaulding, a partner in Spaulding Fiber, a manufacturer of leatherboard, transformer board, and vulcanized fiber founded in 1873 in Townsend Harbor, Massachusetts. The New Hampshire mills were operated for leatherboard manufacture under the name ‘J. Spaulding and Sons.’ Dams related to this manufacturing enterprise persist to this day.
The project includes: a timber crib dam, penstock, powerhouse, three turbines, and wastegates.

The dam is a 164-foot-long concrete-capped timber crib structure which is 16.4 feet high at its highest point. The steel penstock measures 6.5 feet in diameter and is 3,800 feet long. The powerhouse is located in the former Spaulding Fiber Company Mill 4,600 feet downstream of the dam and houses three turbines, with Units 1, 2, and 4 located in Mill Building No. 1 and Unit 3 located in adjacent Mill Building No. 2. The project’s total installed capacity is 1.55 MW. 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 dam was completed in 1893. The upper six feet of the dam consists of stanchion stoplogs. Two 10.5-foot-wide by 6.5-foot-high wooden motorized wastegates were incorporated in the structure in 1999. The intake structure is comprised of a trashrack, a custom-built trash rake system, a manually operated headgate, and a transition section which feeds the 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 project operates in a run-of-river mode and impounds a 100-acre reservoir. The project provides a 58 cfs minimum flow into the 0.87-mile-long bypass reach. This flow regime was developed in consultation with US Fish and Wildlife Service and New Hampshire Department of Fish and Game (NHFG).

Waters within the project reach were sampled in 2016 as requested by the New Hampshire Department of Environmental Services (NHDES). NHDES concluded that the project was meeting the water quality criteria for dissolved oxygen, phosphorus, and chlorophyll-a. The Salmon Falls River is not Section 303(d) listed in the project reach.

The Salmon Falls River historically supported migratory fish, but passage has since been precluded by multiple downstream dams. The project is not required to provide passage for migratory or riverine fish. In 2015, the project owner finished installing permanent passage facilities for American eel for both upstream and downstream migration. Effectiveness monitoring is currently being undertaken in consultation with NHFG, USFWS, and Maine Department of Marine Resources.

The project lands consist of roughly 100 acres. The riparian area associated with the project is heavily forested and assist in protection of the shoreline as well as aquatic biota, wildlife, and water quality.

Threatened or endangered species potentially present in the project vicinity include the Northern long-eared bat and small whorled pogonia. The primary concern for Northern long-eared bat is disturbance of critical habitat. This bat species is found all over New England and roosts in trees during the summer. The project does not plan to perform tree-cutting activities. The small-whorled pogonia is unlikely to be located with areas affected by project operations or maintenance activities as it is typically found in upland hardwood forest understory.

While the project is not currently eligible for listing on the National Register of Historic Places, the project has a rich history associated with mill development. In consultation with the New Hampshire Division of Historical Resources, the site may become eligible at a future date which would then necessitate architectural inventory. The project was purchased by the current owner in 2000 and no changes to the site that would alter or adversely affect cultural or historic resources have been made. The project owner must consult with the State Historic Preservation Office prior to conducting any activities that may have such an effect.

Recreational resources at the project include informal fishing access. The project lands are open to the public free of charge where safe.

Certification History

January 1, 2022: The LIHI Certificate term has been extended in accordance with Revision 2.05 of the LIHI 2nd Edition Certification Handbook issued January 1, 2022. Refer to the facility table above for the new term.

March 13, 2018:  On March 11, 2018, the 30-day appeal window for the preliminary decision to recertify the South Milton Hydroelectric Project ended with no appeals filed. The recertification decision is therefore final.

The term of Low Impact Certification for the South Milton Hydroelectric Project is from September 6, 2017 until September 5, 2022.

February 9, 2018: The South Milton Hydroelectric Project has received preliminary approval for a new 5-year term of Low Impact Certification.  The Certification includes the following conditions:

  • Condition 1: The Owner shall continue to maintain a minimum flow of 58 cfs, or inflow if less, in the bypassed reach of river.
  • Condition satisfied 2018. Condition 2: The Owner shall revise the Project flow monitoring plan to clarify and specify the method for releasing into the bypassed reach the required minimum flow (58 cfs, or instantaneous inflow if less), and true run-of-river operation, and how records will be maintained to demonstrate compliance with the bypass reach minimum flow and true run-of-river operation.  The Owner shall submit the final plan revision to U.S. Fish and Wildlife Service, the N.H. Department of Fish and Game, and the N.H. Department of Environmental Services and obtain agency concurrence on the revised plan. The Owner shall submit the final plan as an update to FERC within 90 days of agency concurrence and copy LIHI on the filing in the following annual compliance report filed with LIHI.
  • Condition 3: The Owner shall continue to operate and maintain safe, timely, and effective upstream passage facilities for American eel in coordination with the N.H. Department of Fish and Game, the Maine Department of Marine Resources, and the U.S. Fish and Wildlife Service. The Owner shall monitor effectiveness using means acceptable to the agencies and report results annually to the agencies and in the annual compliance reports filed with LIHI. If, during the LIHI Certification term, agencies determine that eel passage is not effective, the Owner shall consult with agencies to develop and implement modifications to the passage facility. The status of consultation and any modifications to eel passage will also be reported to LIHI in the annual compliance reports.

As provided for in the LIHI 2nd Edition Certification Handbook, the Preliminary Decision, along with the Application Reviewer’s report and (if prepared) report of the Executive Director, will be posted on the Institute’s web page for 30 days during which time those who provided comments during the application’s 60-day public comment period can appeal the decision. Any appeal must include specific reasons why the appellant believes the hydropower facility does not meet one or more criteria. Appeal requests can be submitted by email to with “South Milton Hydroelectric Project” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, 329 Massachusetts Ave, Suite 2, Lexington, MA 02420. All requests will be posted to the website and the applicant will have an opportunity to respond. Any response will also be posted. Requests must be received by 5 pm Eastern time on March 11, 2018. 

If no appeal requests are received and the decision becomes final, the new term for the South Milton Project will be September 6, 2017 through September 5, 2022.

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 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.

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:

  • Condition 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
  • Condition 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.
  • Condition 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.
  • Condition 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