LIHI Pending Application - Silver Lake Hydroelectric Project
Central Vermont Public Service (CVPS) Applies for LIHI Certification for their Silver Lake Hydroelectric Project
Portland, Maine (February 6, 2012) – The Low Impact Hydropower Institute (LIHI) announced today that Central Vermont Public Service (“CVPS” or“Applicant”) has submitted an application for certification of the Silver Lake Hydroelectric Project (“Silver Lake”).
The Silver Lake Project includes the Sugar Hill storage reservoir and the Goshen Dam on Sucker Brook in the town of Goshen; a downstream diversion dam (Sucker Brook diversion dam) that shunts water to Silver Lake; the dam and penstock headworks on Silver Lake in the town of Leicester; and the surge tank, pipe, powerhouse and appurtenant structures located adjacent to Vermont Route 53 in the town of Salisbury. Much of the Project is located within the Green Mountain National Forest. The development was constructed in 1916-1917, with Goshen Dam added in 1922-1923 to create the Sugar Hill reservoir.
The 74-acre Sugar Hill reservoir is impounded by Goshen Dam with an earthen dam section 60 feet high, by 680 feet long, a concrete spillway section that is 50 feet wide on the eastern side, and a concrete spillway section on the western side that is 100 feet wide. The storage reservoir has a normal water surface elevation of 1,763 feet United States Geological Survey datum (USGS). The intake structure is 14 feet wide and is equipped with wooden trashracks and a concrete gate.
Flow is released from Sugar Hill reservoir through a 232-foot long, 4-foot square conduit outlet structure equipped with two 6-inch diameter, two 8-inch diameter, and one 10-inch diameter steel gate valves, that discharge into Sucker Brook. The Sucker Brook diversion dam is located about 2.6 miles downstream of Goshen Dam. It consists of a 38-foot high 665-foot long earthen section, and a 60-foot long concrete spillway section that impounds a 0.25-acre reservoir with a normal water surface elevation of 1,288 feet USGS. The dam’s intake structure is equipped with a timber headgate and trashracks. The reservoir discharges into a 7,000 foot long penstock consisting of a 36-inch diameter corrugated and galvanized steel section (4400 feet), a 48-inch diameter wood-stave section (1000 feet), a 42-inch diameter steel section (700 feet), and a 42-inch diameter concrete section (910 feet). The penstock discharges into a concrete raceway that extends 380 feet to Silver Lake.
The Silver Lake Development consists of a 30-foot high, 257-foot long buttressed concrete wall with an earth backfill dam that includes an 8-foot wide concrete spillway section and an 18.5-foot wide intake structure. The dam impounds the110-acre Silver Lake, which has a normal surface elevation of 1,250 feet USGS. The intake structure is 60 feet long and is equipped with a slide gate and steel trashracks. The intake conducts water into a 5,200-foot long penstock to the powerhouse.
The powerhouse contains one 2.2-MW turbine generating unit. The powerhouse discharges into a 450-foot long tailrace that leads back to Sucker Brook. An 11,700-foot long reach of Sucker Brook is bypassed from the Sucker Brook diversion dam to the powerhouse tailrace. Project power is transmitted through a 6.9 kilovolt buried transmission cable connected to the regional grid. The powerhouse discharges back into Sucker Brook approximately 450 yards upstream of where the brook enters Lake Dunmore.
Public Comments
We encourage public comments on this application. Specifically, we are interested in knowing whether you think this Project meets our LIHI criteria. Review the program and criteria in greater detail and then review the Project’s 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 info@lowimpacthydro.org; or by mail addressed to LIHI, 34 Providence Street, Portland, ME, 04103. Comments must be received at the Institute on or before April 6, 2012 Eastern time 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.