June 24,2019: The Low Impact Hydropower Institute has received a complete application for Low Impact Certification of the Quinebaug – Five Mile Pond Hydroelectric Project.  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 application materials 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 comments@lowimpacthydro.org with “Quinebaug – Five Mile Pond Project Comments” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, 329 Massachusetts Avenue, Suite 6, Lexington, MA 02420.  Comments must be received on or before 5 pm Eastern time on August 23, 2019 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.

Project Description:

The Quinebaug – Five Mile Pond Hydroelectric Project is located at the confluence of the Five Mile River and Quinebaug River in the Towns of Brooklyn and Killingly in Windham County, Connecticut.  It consists of two developments, Quinebaug and Five Mile Pond located in close proximity, but on different rivers, and authorized under the same FERC license.  The Project is owned by Quinebaug Associates, LLC, a subsidiary of Gravity Renewables, Inc.

Project Name Quinebaug – Five Mile Pond
Owner Quinebaug Associates, LLC (Gravity Renewables Inc.)
State Connecticut
Location Quinebaug: River mile 26.2 on the Quinebaug River.

Five Mile Pond: River mile 0.2 on the Five Mile River.

Installed Capacity Total: 2.59 MW

Quinebaug: 2.24 MW

Five Mile Pond: 0.35 MW

Average Annual Generation Total: 7,945 MWh

Quinebaug: 6,925 MWh

Five Mile Pond: 1,020 MWh

Facility Type Run of river
FERC No. 5062

The Quinebaug Development consists of the Rojak dam, approximately 250 ft long with a 30 ft wide, 7 ft deep and 900 ft long power canal intake structure toward the right and spillway on the left (looking downstream). The dam is a stone masonry gravity structure with an overflow spillway section approximately 130 ft long. The maximum height of the dam is 14 ft.  The reservoir created from the dam is approximately 85 acres. The development is operated in instantaneous run-of-river mode therefore, no reservoir storage is utilized for power generation.  An axial flow propeller turbine is located inside a steel pressure case on the non-overflow section of the dam and provides minimum flows into the 0.3-mile bypassed reach.  The turbine is rated for 77 cfs of flow (to meet bypass flow requirements) and a maximum power of 75 KW. Water from the minimum flow unit draft tube enters a channel which conveys water directly to the Quinebaug River.  Immediately upstream of the powerhouse is a canal and an approximately 200 ft long reinforced concrete overflow/auxiliary spillway. The powerhouse contains two Kaplan/bulb turbines. Unit 1 is rated at 1,347 KW and Unit 2 is rated at 889 KW.

The Five Mile Pond Development consists of a stone masonry gravity dam approximately 135 ft long and 16.5 ft high, with a 100-ft-long spillway.  The reservoir created from the Five Mile Dam is approximately 65 acres with a storage capacity of 260 ac-ft.  There is a canal intake structure toward the right and spillway on the left (looking downstream) and is approximately 30 ft wide, 12 ft deep and 280 ft long. The left side of the canal is formed by the natural elevation of the surrounding terrain and lined with concrete and stone. The right side of the canal is formed by stone lined earthen embankment.  The Project creates a bypassed reach, approximately 158 feet long. Immediately upstream of the powerhouse is a canal overflow spillway. The spillway is concrete lined and approximately 80 ft long.  The powerhouse contains a single double regulated Kaplan turbine rated for 350 KW.  The development is operated in instantaneous run-of-river mode with no pondage or storage. A minimum bypass flow of 15 cfs is released to the bypass reach through a notch in the flashboards.

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