Lexington, MA (November 20, 2018): The Low Impact Hydropower Institute has received a complete application for Low Impact Certification of the Waterbury Hydroelectric Project (FERC No. 2090). The Project is located on the Little River in the in the town of Waterbury, Washington County, 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 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 “Waterbury 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 on or before 5 pm Eastern time on January 19, 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 Waterbury Hydroelectric Project (FERC No. 2090) (Project) is located at river mile (RM) 2.5 on the Little River in the town of Waterbury, Washington County, Vermont and is the only hydroelectric plant located on the Little River. The Project’s hydroelectric facilities are owned and operated by Green Mountain Power Corporation (GMP).

The Waterbury dam and reservoir were built in 1938 by the U.S. Army Corps of Engineers (USACE) for the purpose of flood control in the Winooski River Valley following the flood of 1927. The dam and reservoir are owned by the State of Vermont and operated by GMP for flood control and power generation. Federal oversight of the Waterbury Dam is continuing and significant.  Because of federal oversight, the dam and reservoir are not part of the Waterbury Hydroelectric Project works or Project boundary.

Hydropower Certification Environmental Safety

Project Name Waterbury
Owner Green Mountain Power Corporation
State Vermont
Location Located at river mile (RM) 2.5 on the Little River in the town of Waterbury, Washington County, Vermont
Installed Capacity 4.102 MW
Average Annual Generation 17,562 MWh
Facility Type Modified peaking, will be year-round run-of-river
FERC No. 2090

The Waterbury Project was issued a new operating license by the Federal Energy Regulatory Commission (FERC or Commission) on February 19, 2016. The Waterbury Project, as licensed, consists of: a concrete intake structure and broom gate; a 825-foot-long, 10.5-foot-high, 14-foot-wide horseshoe shaped reinforced concrete tunnel; two 205-foot-long, 4.5-foot-diameter penstocks; a 25-foot-long, 6.7-foot-diameter penstock with a new 6.5-foot diameter butterfly valve; a 58-foot-long, 35-foot-wide powerhouse containing a 5.52-megawatt turbine-generator unit with a new turbine runner with a minimum and maximum hydraulic capacity of 49 cubic feet per second (cfs) and 391 cfs; a 12-foot-long, 2.0-foot-diameter penstock drain pipe and valve; a new 60-foot-long, 4.0-foot-diameter bypass penstock with a 4.0-foot-diameter butterfly valve connected to a 2.0- foot-diameter Howell-Bunger valve; a 50-foot-long, 33 kilovolt transmission line from the powerhouse to the substation; and appurtenant facilities. The Project works are limited to the powerhouse, penstock, and the transmission lines from the powerhouse to the adjacent substation.

The license includes three Stages of operation. Stage I covered operations before the Project modifications described below. Stage II operations began in Spring 2018 when the modifications were complete. Stage III operations will commence when VT and the USACE complete improvements to the Tainter gates and spillway. In accordance with the conditions included in the 2016 FERC license, GMP designed and constructed a number of modifications at the Project. Project modifications required by the FERC license include:

  1. Installation of a new turbine runner. The new runner will be designed to operate between 49 and 391 cfs.
  2. Installation of a new bypass flow pipe. The new bypass pipe will be a 60-inch diameter pipe designed to pass 250 cfs. The pipe will terminate with an adjustable Howell-Bunger valve to the east of the powerhouse (but west of an existing State-owned bypass pipe).
  3. Installation of a butterfly valve for the bypass pipe.
  4. Installation of a new, automated bypass pipe Programmable Logic Controller (PLC) for transitioning of flow between the unit and bypass pipe.
  5. GMP also provides funds to the USGS for the installation and operation of a new gage on the Little River upstream of the reservoir to monitor inflow. Additionally, funds are provided annually for continued operation of USGS gages 04288500, 04289000, and the newly installed gage upstream of the reservoir. This new gage installation was completed in August 2016.

GMP completed construction of the pipes, valves, and runner replacement described above in Spring 2018.

The Vermont Department of Environmental Conservation issued a Project Water Quality Certificate (WQC) on December 11, 2014. The WQC was conditioned such that drawdowns will no longer occur as part of regular Project operations and that the Project operating mode will become year-round instantaneous run-of-river.