The project is located at the Slack Dam in Springfield, Vermont.  The dam is one of five existing concrete gravity dams on the Black River.  (Comtu Falls site is immediately upstream, and the Lovejoy site is just downstream.)  The project was reconstructed in 1986 and has an installed capacity of 400 KW.  Annual energy production has averaged 2,000,000 KWH.

Project Name Slack Dam
LIHI Certificate Number 78
LIHI Effective and
Expiration Dates
February 28, 2011
February 28, 2016
(extended to July 31, 2017)
Owner Springfield Hydroelectric Company
State Vermont
Location Located at the Slack Dam in Springfield, Vermont.
Installed Capacity 400 KW
Average Annual Generation 2,000,000 KWh
Facility Type Run-of-river deminimus bypass
FERC No. 8014

The project is strict run-of-river utilizing 21’ of gross head, between the headwater and tailwater.  There is no bypass reach.  The project is served by a 190 square mile drainage area on the Black River, 75% of which is controlled by the U.S. Army Corps of Engineers Flood Control Project in N. Springfield, 4.5 miles upstream.  A steel penstock 8’ in diameter and 80’ in length conducts water from the intake to the powerhouse.

The power house is 20’ x 20’ square and houses one horizontal full Kaplan turbine driving a vertical induction generator by means of an internal bevel gear, together with associated hydraulic, mechanical, electrical and electronic equipment.  The powerhouse is constructed of reinforced concrete to an elevation greater than the 100 year flood level.  A pad mounted transformer connects the station to 3-phase 4,160 V electrical service.  A fishway, constructed in 2007 provides for downstream fish passage.


Fish chute looking downstream.

(Below): fish chute looking upstream

Fish chute looking upstream

Certification History

March 13, 2017: LIHI received a comment letter from Eric Davis of the Vermont Department of Environmental Conservation regarding the recertification of the Slack Dam project. The letter can be found in the Files section below.

March 8, 2017: The Low Impact Hydropower Institute has received a complete application for a new term of Low Impact Certification for the Slack Dam Hydroelectric project. The application materials can be found in the Files section below.

LIHI is seeking public comment on this application.  Specifically, we are interested in knowing whether you think the Slack Dam project meets the LIHI Low Impact Certification Criteria, as revised in the 2nd Edition Handbook released in March 2016.  Please review the program and criteria in LIHI’s revised Handbook and then review the Project’s 2016 application materials posted on the project page.

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 “Slack Dam Project Comments” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, PO Box 194, Harrington Park, New Jersey 07640.  Comments must be received at the Institute on or before 5 pm Eastern time on May 7, 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.

December 16, 2016: The Slack Dam Project has been granted a third extension of the current certificate term. The new expiration date is July 31, 2017. See the extension letter for explanation below.

September 9, 2016:  The Slack Dam Project has been granted an additional extension of the current certificate term as it prepares to apply for a new term.  The new expiration date is December 31, 2016. See the extension letter for explanation below.

December 22, 2015: The Slack Dam Project has been granted an extension of the current certificate term. The new expiration date is August 26, 2016. See the extension letter for explanation below.

October 27, 2011: The Slack Dam Hydroelectric Project has been certified as low impact for a five year term, effective February 28, 2011 and expiring February 28, 2016.

April 28, 2011: Public comment period has been closed.

February 28, 2011: Springfield Hydroelectric Company has submitted an application for the certification of the Slack Dam Project. Public comment period will be open for 60 days.

Slack Dam Hydroelectric Project (FERC No. 8014 )

Slack Dam Hydroelectric Project (FERC No. 8014 )


2016 Re-certification

2011 Certification