The Passumpsic Project is the furthest downstream of the four CVPS Projects on the Passumpsic River. It is located approximately 1.7 miles downstream of the Gage Project, at river mile 5.5. It was built in 1905-1906 for the St. Johnsbury Electric Company. The powerhouse was completely destroyed in the flood of 1927. Portions of its foundation and those of its associated power canal remain buried on the other side of the existing canal. The plant was rebuilt in 1929 in the location of the Chase leatherboard mill water wheel, which was also destroyed in the flood. The building behind the powerhouse (not owned by CVPS) is the remainder of the former leatherboard mill.

Project Name Passumpsic
LIHI Certificate Number 95
LIHI Effective and
Expiration Dates
February 6, 2012
February 6, 2017
(extended to August 31, 2018)
Owner Green Mountain Power Corporation
State Vermont
Location Located at river mile 5.5 on the Passumpsic River, a tributary of the Connecticut River, approximately 1.7 miles downstream of the Gage Project.
Installed Capacity 700 kW
Average Annual Generation 2.3 GWH
Facility Type Run-of-river
FERC No. 2400

The Project impounds an 18.3-acre reservoir which extends 4,600 feet upstream with a water surface elevation of 521.0 feet msl and a usable storage of 18.4 acre-feet. The concrete gravity dam consists of two sections: (1) a south section 122 feet long by maximum height of 10 feet, with a crest elevation of 519.98 feet msl and topped with 1-foot-high flashboards; and (2) a north section 126 feet long by maximum height of 10 feet, with a crest elevation of 519.98 feet msl topped with 1-foot flashboards. The dam is equipped with a 27-foot wide headgate structure with two gates.

The power canal conveys flow to the powerhouse via an integral intake with an inclined trashrack. The canal is 19 to 22 feet wide and 87 feet long. There is also a sluice and a 24-foot long overflow spillway.

The powerhouse contains one vertical shaft turbine rated at 708 kW and a generator rated at 700kW, as well as appurtenant equipment. A substation is located 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 is about 350 feet long. The project has a hydraulic range of 195 to 460 cfs and an average annual generation of about 2,349 MWh.

Passumpsic dam 2

Passumpsic Dam

Certification History

June 12, 2018: The Low Impact Hydropower Institute has received a complete application for a new term of Low Impact Certification for the Passumpsic Hydroelectric Project (LIHI # 95). The Project is located on the Passumpsic River in St. Johnsbury, Vermont.

LIHI is seeking public comment on this application.  Specifically, we are interested in knowing whether you think the Project meets the LIHI Low Impact Certification Criteria, as revised in the 2nd Edition Handbook.  Please review the program and criteria in LIHI’s revised Handbook and then review the Project’s 2018 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 “Passumpsic Project Comments” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, 329 Massachusetts Avenue, Suite 2, Lexington, MA 02420.  Comments must be received at the Institute on or before 5 pm Eastern time on August 11, 2018 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.

November 28, 2017 – The Passumpsic Hydroelectric project has been granted another extension of the current certificate term. The new expiration date is March 31, 2018.

December 16, 2016: The Passumpsic Hydroelectric project has been granted an extension of the current certificate term. The new expiration date is August 6, 2017. See extension letter for explanation below.

September 13, 2012: The Passumpsic 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 Passumpsic  Project. Public comment period has been opened.


2018 Recertification

2012 Certification