LIHI Certificate #124 – Comtu Falls Project, Vermont

The Comtu Falls Project is located on the Black River in the City of Springfield, Vermont. The Black River is a tributary of the Connecticut River and the project is the third dam on the Black River with three more dams upstream. The downstream dams are the Lovejoy Dam and Slack Dam (LIHI #78) while upstream of the project are the Gilman, Fellows, and US Army Corps of Engineers North Springfield dams. The project dam was built in 1902 and hydropower was added in 1987.

The project includes a 4-foot-high, 128-foot-long concrete gravity dam, tapering from 5.5 feet high at its western side to zero feet high at its eastern side with irregular bedrock comprising the last 17-18 feet, situated on the top of a natural falls. Two-foot-high flashboards are installed on 74 feet of the dam. The flashboards consist of steel pins and wooden boards. The boards are designed to fail when there is 3.17 feet of overtopping at the boards. The boards are maintained in place unless they are damaged from debris, or the pins bent from overtopping. The intake structure is located at the west side of the dam with 1.5-inch clear bar spacing trash racks set at a 45-degree angle to the intake. The penstock is 6 by 6 foot-diameter and 65 feet long made of reinforced concrete. The powerhouse houses one vertical Kaplan turbine/generator with a capacity of 460 kW.

The project operates in a run-of-river mode and impounds a 0.4-acre reservoir. There is a very short, 100-foot-long bypassed reach between the dam and the powerhouse tailrace. A 4-cfs minimum flow is provided downstream of the project to ensure aesthetic flow for the natural falls found there. Impoundment levels are monitored using a pressure transducer that sends water level information to the project’s Programmable Logic Controller (PLC). The PLC automatically adjusts the turbine blade settings or powers down the turbine depending on the readings from the pressure transducer, ensuring run-of-river operations.

Waters within the project reach are designated as Class A2, suitable for fish and aquatic biota habitat, wildlife support, and primary/secondary contact recreation. The waters are also listed as impaired for E. coli due to combined sewer overflows. The project does not contribute to this impairment which is likely due to the downstream wastewater treatment plant.

Project Name Comtu Falls
LIHI Certificate No. 124
LIHI Certificate Term July 10, 2020 to July 9, 2025
Owner Comtu Falls Corporation, a subsidiary of Gravity Renewables, Inc.
State Vermont
Location Located at river mile 4.4 on the Black River in Windsor County, Vermont.
Installed Capacity 0.46 MW
Average Annual Generation 2,300 MWh
Facility Type Run-of-river
FERC No. P-7888 issued 1986, expires 2026

Downstream dams prevent upstream fish passage at the project. Migratory species have not been observed in the project vicinity due to passage barriers in the Connecticut River. Consultation with the Vermont Agency of Natural Resources concluded that the natural falls at the project has historically been a natural barrier to upstream passage. The project provides 20 cfs into a downstream fish passage facility which consists of a 2.5-foot-wide by 2.0-foot-high discharge weir at the west abutment of the dam and trashrack, leading to a 3-foot-deep plunge pool. The project operates the passage facilities from April 1 – June 15 annually and voluntarily operates passage in the fall from September 15 – November 15.

The project lands consist of roughly 2 acres. The project does not have any natural shoreline, most of the shore is developed. Run-of-river operations further minimize any potential for shoreline erosion or adverse impacts.

Threatened or endangered species potentially present in the project vicinity include the Northern long-eared bat and Northeastern bulrush. The bulrush is a flowering plant found in emergent wetlands, of which there are none in the project area, thus it is unlikely to occur at the project. Similarly, the project area does not provide any roosting habitat or hibernacula for the bat species.

The Comtu Falls Dam is included in the Springfield Downtown Historic District, listed on the National Register of Historic Places.

The project is very small, and the reservoir is not safely accessible. The shoreline is developed with industrial and commercial buildings. Access is not available and thus no recreational amenities are provided.


Certification History

August 6, 2021: The Low Impact Hydropower Institute has issued a final decision on the recertification of the Comtu Falls Project located on the Black River in Vermont. The 30-day appeal window closed on August 5, 2021 and no appeals were filed. Therefore, the decision to certify the project is now final. The new term is July 10, 2020 through July 9, 2025.

July 6, 2021: The Low Impact Hydropower Institute (LIHI) has preliminarily approved the Comtu Falls Project for a new 5-year term of Low Impact Certification. The Certification includes two conditions:

    Condition 1: If either the USF&WS or the state fisheries management agency requires the facility to provide upstream eel passage in the future, the facility Owner shall notify LIHI within 30 days of receipt of such a notification. The Owner shall then consult with the requesting agency(ies) to develop plans to implement upstream passage and shall provide LIHI with a copy of these plans pursuant to the schedule required by the requesting agency(ies), but no later than one year after receiving the notification.

    Condition 2: For the full term of the LIHI certification, the facility Owner shall continue to operate the downstream fishway in the spring from April 1 through June 15 and in the fall from September 15 through November 15 or as otherwise requested by the state fisheries agency.

This decision is preliminary pending the 30-day appeal window. Only those who commented on 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 Project does not meet the LIHI criteria. Appeal requests can be submitted by email to comments@lowimpacthydro.org with "Comtu Falls Project” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, 1167 Massachusetts Ave, Office 407, Arlington, MA 02476. All requests will be posted to the website. 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 5, 2021. The full application and reviewer's report are available below.

If no appeal requests are received and the decision becomes final, the Certification term for the Project will be July 10, 2020 through July 9, 2025.

April 19, 2021:The Low Impact Hydropower Institute (LIHI) has received a complete recertification application from Comtu Falls Corp. for the Comtu Falls Project located on the Black River in Vermont.

LIHI is seeking comment on this application. 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 "Comtu Falls Project Comments” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, 1167 Massachusetts Avenue, Office 407, Arlington, MA 02476. Comments must be received at the Institute on or before 5 pm Eastern time on June 18, 2021 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.

The project description and complete application can be found below.

December 23, 2015 – LIHI Executive Director Michael J. Sale, using authority delegated from the LIHI Governing Board and a full review of the Application Reviewer’s report and all public comments and additional materials provided by the Applicant, has certified that the Comtu Falls Hydroelectric Project (FERC No. P-7888) satisfies the LIHI Certification Criteria.  A Preliminary Decision was announced on October 12, 2015, and a 30-day appeal period was open through November 12, 2015. No requests for appeal were received. This Certification Decision includes one facility-specific condition, as follows:

  • Condition 1. The Owner shall operate the downstream fish passage facilities annually from April 1 through June 15 and from September 15 through November 15.

The effective certification date for the Comtu Falls Project is July 10, 2015 for a five (5) year term, which will expire on July 10, 2020.

July 13, 2015 – On July 10, 2015, the Low Impact Hydropower Institute (LIHI) received a complete application from Comtu Falls Corporation, on behalf of Gravity Renewables Inc.,  for the Low Impact Certification of the Comtu Falls Hydroelectric Project, FERC P-7888, located on the Black River in Windsor County, Vermont.