The Rolfe Canal Hydroelectric Project (“the Rolfe Project”) is located on the Contoocook River in the City of Concord, New Hampshire. The City of Concord is the state capital of New Hampshire. The project area is located on the extreme northern end of the city of Concord.
|Project Name||Rolfe Canal|
|LIHI Certificate Number||104|
|LIHI Effective and Expiration Dates||December 4, 2012
December 4, 2017
|Owner||Briar Hydro Associates|
|Location||Located at river mile 68 on the Contoocook River in the City of Concord, New Hampshire.|
|Installed Capacity||4.285 MW|
|Average Annual Generation||21.6 GWh|
The project utilizes the previously existing impoundment formed by the state-owned York Dam. Water is diverted from this impoundment to the Rolfe canal, a canal that also existed prior to the construction of the Rolfe Project. A penstock intake structure is located at the end of the canal that conveys water into a penstock that is connected to the Briar powerhouse. Water is returned from the powerhouse to the Contoocook River by means of a tailrace channel. The approximate latitude and longitude of the project area are 43°16’29”N and 71°36’14”W.
Project works consist of: (a) previously existing reservoir with negligible storage capacity, a surface area of 5-acres and a normal surface elevation of 349.0 feel NGVD; (b) the York dam, a 10-foot-high, 130-foot-long granite block dam, (c) a gated concrete canal intake structure leading to a 7,000-foot-long, 75-foot-wide and 9-foot deep wide –foot- power canal; (d) a 130-foot-long concrete penstock intake structure; (e) a 900-foot-long 14 foot diameter steel penstock; (f) a concrete powerhouse containing a single generating unit with an installed nameplate capacity of 4,285 kw; (g) a 100-foot long 4.16KV interconnecting power line; (h) a 4.16/34.5 KV (i) a tailrace, 47 feet wide and 350 feet long; and (j) appurtenant facilities.
The canal banks consist of sections that are riprapped with stone in areas of high flow and earthen banks in the remaining sections of the canal. The tailrace banks immediately downstream of the powerhouse are stabilized with riprap. Other banks are earthen. There have been no observed areas of high erosion during the 24 years that the Project has operated.
The project is located immediately upstream of the Penacook Upper Falls and Penacook Lower Falls projects. These projects, also owned by Briar Hydro Associates, were certified by LIHI in 2010 (LIHI Certificates 52 and 64). The plant is unmanned, but operation is monitored on a 24/7 basis.
The Contoocook River rises on the eastern slopes of Mt. Monadnock in southeastern New Hampshire and ends where it enters the Merrimack River approximately 2.5 miles downstream from the Rolfe Canal Hydroelectric Project. The river, about 66 miles long, flows in a generally north-easterly direction through the towns of Jaffrey, Peterborough, Bennington, Antrim, Hillsboro, Henniker, and Contoocook, and has a total drainage area of 766 square miles. Its major tributaries, the Warner and Blackwater Rivers, both enter from the north, only two miles apart, near the village of Contoocook. The watershed, which is primarily forested, contains numerous other small tributaries and many natural lakes. Elevations in the watershed range from 3165 ft MSL at the top of Mt. Monadnock to 243 ft. MSL at the confluence with the Merrimack. The Contoocook drops about 130 feet in its final 20 miles (6.5 ft/mile), thus explaining the location of the village of Penacook and the development of numerous water-powered mills over the past two centuries.
A gauge, located one-half mile upstream from the mouth, was maintained in the Contoocook from 1928 to 1977. The average flow over the 49 years of record was 1255 cfs. The maximum discharge of record, 46,800 cfs (estimated), occurred on March 20, 1936; the minimum, 38 cfs, occurred August 17, 1965. Daily minimum flows of 57 cfs were recorded on October 12, 1964 and August 16, 1965.
In accordance with its FERC License (project No. 3240-001) the Project is operated as a run of river facility and is required to maintain a continuous minimum flow of 285 cubic feet per second, to be measured at the confluence of the Contoocook River and the outlet of the Rolfe Canal, with at least 50 cfs of this flow released at the York Dam. The project is also required to release at least 5cfs in the reach of the canal that is bypassed by the penstock and powerhouse and FERC letter dated February 28, 1986.
March 12, 2013: The Rolfe Canal Project has been certified as low impact for five year term, effective December 4, 2012 and expiring December 4, 2017.
February 4, 2013: Public comment period on application has closed.
December 4, 2012: Briar Hydro Associates has submitted an application for the certification of its Rolfe Canal Hydroelectric Project. The application was posted and the public comment period was opened.