LIHI Certificate #122 – Downer’s Mill Project, Vermont

Project Name  Downer’s Mill
LIHI Certificate No.  122
LIHI Certificate Term
March 3, 2020 – March 2, 2030
Owner Simon Pearce (U.S.) Inc.
State Vermont
Location Located at River Mile 7 on the Ottauquechee River in Vermont.
Installed Capacity 0.645 MW
Average Annual Generation 2,000 MWh
Facility Type Run-of-river
FERC No. P-5195 exempt 1982

The Downer’s Mill Project is located on the Ottauquechee River in Quechee Village in the town of Hartford, Vermont approximately seven miles upstream of the confluence with the Connecticut River. With a watershed area of 223 square miles and a length of about 38 miles, the Ottauquechee River is a major tributary of the Connecticut River.  The river descends from the Green Mountains near Killington Peak and flows generally in an easterly direction to its outlet in the town of Hartland.  The project is the fourth dam upstream of the confluence.

The project was constructed at the site of the existing Emory Mill dam (a.k.a. Downer’s Mill). The dam was built in the early 1800s to power a grist mill. The project generating unit was put back into service in the 1980s to provide power for Simon Pearce Inc.’s glass blowing business. Excess power is sold to Green Mountain Power Corporation.

The concrete gravity dam is 150 feet long with an uncontrolled spillway. The crest elevation of the dam is 562 feet NGVD and is about 14 feet above the bedrock streambed at the downstream toe. A 57-foot-long steel penstock conveys water from the impoundment to the powerhouse, located in the basement of the mill building.  The powerhouse contains a single vertical Kaplan turbine/generator with a capacity of 645 kW. At full pool, the impoundment extends about 0.4 miles upstream to an island and covers approximately nine acres with an average depth of about six feet. The dam creates a short bypassed reach, about 105 feet long with a high gradient and limited habitat value being composed primarily of ledge, as is the downstream reach.

The project operates in a run-of-river mode. Inflow to the project is controlled by the discharge from the upstream Taftsville project along with inflow from small tributaries. The project provides a minimum flow of 22 cfs into the bypass reach by maintaining a 0.5-inch minimum depth of water across the entire face of the dam. The flow regime was developed via a flow demonstration study in consultation with the Vermont Agency of Natural Resources, and is intended to protect aquatic biota and water quality.

Waters within the project reach are designated as Class B(2), suitable for aquatic biota, primary contact recreation, public water supply after treatment, and aesthetic quality. The river downstream of the project is considered stressed for several uses due to nutrients, organic enrichment, temperature, sediment, and E. coli. The project is not contributing to these stressors which are likely caused from runoff from roads and developed land, and from a nearby golf course, septic systems, and fertilized turf. Water quality monitoring confirmed that dissolved oxygen and water temperature are within state standards.

Migratory fish species are not present in the Ottauquechee River as downstream dams create barriers to passage in the river and the downstream Quechee Gorge also precludes fish access as does the project’s bypass reach which has a steep gradient. Resident fish species include wild populations of rainbow trout, brown trout, common shiner, golden shiner, white sucker, black bullhead, rock bass, longnose dace, blacknose dace, bluntnose minnow, creek chub, fallfish, white sucker, smallmouth bass, slimy sculpin, and stocked trout populations. The turbine intake is equipped with 1.5-inch trash racks that exclude most large fish and the bypass flow provides a route of passage for resident fish that may move downstream.

The project lands consist of 1.7 acres with only 0.6 acres in fee ownership. The project is located in the developed Quechee village with surrounding land uses including developed areas, a golf course, steep banks and rock outcroppings, and a rocky downstream reach. A vegetated buffer is located in the less developed area farther from the river. Some residences and mill buildings are located nearby. No lands of significant ecological value or critical habitat exist in the project vicinity.

Threatened or endangered species potentially present in the project vicinity include the Northern long-eared bat, bald eagle, and rusty blackbird. No critical habitat for the species exists in the project area and the project does not impact potential roosting or nesting habitat for bats or birds.

The mill building in which the project is located is a contributing feature in the Quechee Historic Mill District which is listed on the National Register of Historic Places. The history of the mill building was provided in the project’s 2021 LIHI recertification application:

“John Downer & Co. bought the land around the mill in 1825 and built a six-story brick building overlooking the dam. But the mill failed financially and changed hands several times. In 1840, Francis K. Nichols & Co. became the first mill in the country to manufacture a fabric of reused soft rags and new wool, known as “shoddy.” J.C. Parker owned the mill from 1857 to 1906 which reportedly became the largest United States producer of fine, white, soft flannel for baby clothes. The mill building underwent several structural changes over the years. High water caused the north wing to collapse in 1869. It was rebuilt in 1870, including a three-story brick addition. Harris, Emery Company enlarged the mill in 1915, replacing the wing attached to the1870 addition with a new drying room and sales area and enlarging the weaving room. In 1926, a cement dam was built to replace the wooden crib dam. Harris, Emery closed the mill in 1951. It changed hands a few times and ended up owned by John Cone, Sr. in the 1950s. Cone considered the upper floors of the building and the eastern wing a safety hazard and had them demolished. Quechee Lakes Corporation bought the building in 1969 and added the wooden annex on the east end. In 1980, Simon Pearce bought the building, renovated the inside for a glass blowing operation, and added the hydroelectric plant in 1982.”

Recreational resources at the project include a natural canoe portage via Quechee Main Street which parallels the river above and below the dam. The put-in and take-out are located outside the project boundary. Other recreational areas near the Project include Quechee Falls Park, a town-owned pocket park with views of the dam, the covered bridge just downstream, and the downstream reach.  The Ottauquechee Trail is a footpath that runs from the covered bridge downstream along the river.  It connects to the Quechee Gorge Trail which leads to Quechee Gorge State Park. Public access is provided free of charge where safety concerns do not preclude access.

Compliance Status

There are no facility-specific conditions in the current Certificate.

2024: No material changes or compliance issues were identified. The project remains in compliance based on the annual review. The project reported flooding damage to the generating unit in 2023.

2023: No material changes or compliance issues were identified. The project remains in compliance based on the annual review.

2022: No material changes or compliance issues were identified. The project remains in compliance based on the annual review.

2021: There were no reported changes or compliance issues. The project remains in compliance based on the annual review.

2020: Annual reporting for the current Certificate has not yet taken effect.

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.

August 10, 2021: The Low Impact Hydropower Institute has issued a final decision on the recertification of the Downer’s Mill Project located on the Ottauquechee River in Vermont. The 30-day appeal window closed on August 7, 2021 and no appeals were filed. Therefore, the decision to recertify the project is now final. The new term is March 3, 2020 through March 2, 2025.

July 8, 2021: The Low Impact Hydropower Institute (LIHI) has preliminarily approved the Downer’s Mill 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 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 with “Downer’s Mill 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 7, 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 March 3, 2020 through March 2, 2025.

April 20, 2021: The Low Impact Hydropower Institute (LIHI) has received a complete recertification application from Simon Pearce (U.S.), Inc. for the Downers Mill Project located on the Ottauquechee River in Vermont. The complete application can be found below. 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 with “Downers Mill 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 19, 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.

July 27, 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 determined that the Downer’s Mills Hydroelectric Project (FERC No. 5195-001) satisfies the LIHI Certification Criteria. The Downer’s Mill certification is effective as of March 3, 2015 for a five (5) year term, which will expire on March 3, 2020, with the following conditions:

  • Condition satisfied in 2015. Condition 1. The facility owner shall cooperate with the Vermont Agency of Natural Resources (VANR) in scheduling and completing a flow demonstration study for the bypassed reach to determine an appropriately protective minimum flow for aquatic habitat support. The outcome of the study, including VANR recommendations, shall be reported to LIHI within 90 days of the issuance of LIHI certification. Since this certification is being granted without the minimum bypass flow having been deemed appropriately protective by the resource agencies, LIHI may withdraw certification if it determines that the owner is failing to make a good faith effort to cooperate with the resource agencies in determining a final minimum bypass flow. Any increase in the bypass minimum flow to meet the appropriately protective standard shall be implemented within 14 days of receipt of the VANR recommendation.
  • Condition satisfied in 2016. Condition 2. The facility owner shall develop a system for producing and maintaining records sufficient to demonstrate compliance with the headpond elevation and flow management limitations for an instantaneous run-of-river operation and bypass conservation flows. Within 90 days of the issuance of LIHI certification, the facility owner shall provide LIHI with a copy of the operations and flow monitoring plan. Prior to filing the plan, the facility owner shall obtain plan approval from U.S. Fish and Wildlife Service (USFWS) and VANR; written confirmation of the approvals will be filed with the plan. Should the minimum bypass flow be increased after the plan is completed, the plan shall be revised accordingly and resubmitted to VANR, USFWS, and LIHI.
  • Condition waived in 2021 with recertification.Condition 3. During the term of this certification, should a resource agency request implementation of upstream and/or downstream fish passage at the Facility, the owner shall notify LIHI of this new requirement within 14 days and provide LIHI with a copy of the request and its response.

March 6, 2015: On March 3, 2015, the Low Impact Hydropower Institute (LIHI) received a timely and complete application from Simon Pearce (U.S.) Inc., for the Low Impact Certification of the Downer’s Mills Project, FERC P-5195-001, located on the Ottauquechee River in Vermont.

Certification Files

2021 Recertification

2015 Certification

Key Documents