LIHI Certificate #94 - Gage Project, Vermont

The Gage Project is located approximately 2.5 miles downstream of Arnold Falls at river mile 7.2. It was built in 1919-1920 by the Twin state Gas & Electric Company. The dam was destroyed in the flood of 1927, although the powerhouse was largely undamaged. A concrete dam was constructed in 1929. The facility is significant because it is among the very few genuinely low head stations featuring an open channel and generating units in an open pit setting. The powerhouse is also among the limited number of such buildings constructed entirely of steel and concrete, without the brick facade typical of the 1920's powerhouses. The remains of the first hydroelectric station in St. Johnsbury, reportedly built in 1898, are tied into the north abutment of the dam and support the cableway tower.
The Project impounds a 15.2-acre reservoir extending 3,400 feet upstream with a water surface elevation of 539.9 feet msl and 13.8 acre-feet of usable storage. The concrete gravity dam consists of a three sections: (1) a north section which is 176 feet long by maximum height of 13 feet with a crest elevation of 534.2 feet msl and topped with 6-foot-high flashboards; (2) a center section 30 feet long, with a crest elevation of 542.1 feet msl; and (3) a south section which is 43 feet long by 18 feet high with a crest elevation of 538.9 feet msl and a 6 foot wide sluice topped with 1-foot flashboards. The dam is equipped with a 51-foot wide headgate structure with four headgates.

The power canal is 90 feet long by 44 feet wide by 16 feet deep and conveys flow to the powerhouse via an integral intake with an inclined trashrack. The powerhouse contains two vertical shaft turbines rated at 365 kW (Unit 1) and 522 kW (Unit 2), and generators rated at 300 kW (Unit 1) and 400 kW (Unit 2, along with appurtenant structures. A substation is situated adjacent to the power canal. The downstream fish passage facility consists of a sluiceway in the spillway adjacent to the canal headworks.

The bypassed reach at Gage includes a 2-acre plunge pool and about 120 feet of riffle habitat.  The project has a hydraulic range of 170 to 700 cfs and an average annual generation of about 3,040 MWh.
Project Name Gage
LIHI Certificate No. 94
LIHI Certificate Term February 6, 2017 - February 5, 2022
Owner Green Mountain Power Corporation
State Vermont
Location Located at river mile 7.2 on the Passumpsic River, a tributary of the Connecticut River, approximately 2.5 miles downstream of the Arnold Falls project.
Installed Capacity 700 kW
Average Annual Generation 2,535 MWh
Facility Type Run-of-river
FERC No. P-2397 issued 1994, expires 2034

Certification History

August 15, 2018: The decision to recertify the Gage Hydroelectric Project is final. No appeals were received during the appeal period which closed on August 11, 2018. The new term for the Gage Project is from February 6, 2017 through February 5, 2022.

July 12, 2018: The Low Impact Hydropower Institute (LIHI) preliminarily approved the Gage Hydroelectric Project for a new 5-year term of Low Impact Certification.

This decision is preliminary pending the 30-day appeal window. Only those who commented in 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 projects do not meet the LIHI criteria. Appeal requests can be submitted by email to with “Gage 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 and any response will also be posted. Requests must be received by 5 pm Eastern time on August 11, 2018.  The full application and reviewer’s report are available below.

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

June 11, 2018: The Gage Project's certification term has been extended again to September 30, 2018.

April 3, 2018: The Gage Project's certification term has been extended again to June 30, 2018.

November 28, 2017: The Gage  Project's certification term has been extended to March 31, 2018.

December 30, 2016: The Low Impact Hydropower Institute has received a complete application for a new term of Low Impact Certification for the Gage 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 Gage 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 “Gage 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 March 4, 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 Gage Hydroelectric project has been granted an extension of the current certificate term. The new expiration date is May 6, 2017. See extension letter for explanation below.

September 5, 2012: The Gage Project has been certified as low impact for a five year term, effective February 6, 2012 and expiring February 6, 2017.

April 6, 2012: Public comment period on the application has closed.

February 6, 2012: The Central Vermont Public Service Corporation has submitted an application for the certification of the Gage Project. Public comment period has been opened.