The project is located 5.3 miles from the confluence of the Sebasticook and Kennebec Rivers. Within the watershed area, the west shore consists of thin beds of alternating greenish gray pelite and micaceous quartzite. The steep banks and riverbed include prominent outcrops, which periodically resurface upstream to the upper end of the project’s pool. The Sebasticook is bordered on both shores by bands of relatively steep (8 to 15 percent slope) silty loam. On the east and west shores north of the project, most of the river within the watershed area is bordered by gravel and clay. Lands near the river are primarily woodland, although some pasture and some hay land are included.

The Sebasticook River has a drainage area of 975 square miles and is the largest subbasin of the Kennebec River System. Almost 90 percent of the total drainage area (860 miles) is upstream of the site. The project is operated as a run of river plant. The downstream release through the turbine-generators plus the excess spill over the dam equals the inflow to the reservoir.  Streamflows at the project site are based on daily flow data recorded at U.S. Geological Survey (USGS) surface water Stream Gauging Station No. 01049000. The gauge is located approximately 14 miles upstream of the project site in Pittsfield, Maine, and has a period of record extending back to 1929.  The Benton Falls Project works consists of: (1) a 500-foot long, 27-foot high concrete gravity dam with a 300-foot long integral uncontrolled spillway topped by 4-foot high flashboards; (2) a powerhouse located near the west dam abutment, constructed integrally with the dam, containing two turbine generators with a total rated capacity of 4.468MW; (3) a 350-foot long tailrace channel; (4) the 4.16-kV generator leads, 4.16/12-kV step-up transformers and a 170-foot long, 12-kV transmission line; and (5) a fish lift which contains a 600-gallon hopper and a minimum cycle time of approximately seven minutes.

The project discharges a continuous minimum flow of 100 cfs from the Benton Falls Project of the inflow to the reservoir, whichever is less, for the purpose of protecting fish and wildlife resources and water quality of the Sebasticook River.  Construction of the Benton Falls project was completed in 1984. The powerhouse contains two turbine generators with a total rated hydraulic capacity of 2115 cfs under a gross head of 29.5 feet. The project utilizes all of the available head and about 79% of the streamflow.

FERC licensed the Benton Falls project without requiring fish or eel passage facilities. On January 25, 1989, as part of the Kennebec Hydro Developers Agreement (“the KHDG Agreement”), the Applicant’s FERC license was amended to require installation of upstream and downstream fish passage facilities.

Both upstream and downstream fish passage facilities were installed in 2006. The upstream fish passage facility consists of an elevator designed to pass alewives, shad and salmon. The downstream fish passage facility consists of two conduits that maintain a minimum flow of 350 cfs or project inflow that bypass the turbines. The upstream and downstream facilities became operational in the spring of 2006 and now have operated during five upstream and downstream fish migration seasons. These facilities have been highly successful. A record 1,319,137 alewives were transported upstream during the 2009 migratory season using the fish elevator. An even greater number were transported during the 2010 upstream migration season.

Layout and landscaping of the powerhouse grounds was designed in a manner to minimize visual impact and mitigate that project’s impact on the surrounding shoreline. As a condition of issuance, the FERC License requires that BFA comply with any terms and conditions that the Federal or State fish and wildlife agencies have determined appropriate to prevent loss of, or damage to, fish and wildlife resources. There have been no deficiencies noted by any agency with jurisdiction for the plant.