• Sherman – The Sherman Development is operated on a peaking, weekly storage basis. The facility consists of an earthfill dam and spillway, intake and penstock, powerhouse, and substation. Sherman Reservoir is roughly 2 miles long and 0.25 miles across at its widest point with a surface area of 218 acres, 1,359 acre-feet of useable storage and gross storage of 3,593 acre-feet. The impoundment also formerly provided once-through cooling water for the now decommissioned Yankee Atomic Electric Power Company’s Rowe Station. Sherman Dam is 110 feet high and 810 feet long with a 179-foot-long concrete gravity spillway and a concrete and brick intake structure. Four feet of flashboards are maintained on the spillway year-round. Water is conveyed from the reservoir either through spillage, or via the powerhouse intake. Water is conveyed to the integral powerhouse via a concrete conduit 98 feet in length with a cross-sectional area of 142 square feet, and a steel penstock 13 feet in diameter and 227 feet long. There are no diversion canals or tunnels. The powerhouse contains one vertical 6 MW Francis unit.
• Deerfield No. 5 – The Deerfield No. 5 Development is operated on a peaking, daily storage basis. The facility consists of two dams, a series of diversion tunnels, canals and penstocks, the powerhouse, and a substation. The impoundment is about 0.75-mile-long and 180 feet across at its widest point with a surface area of 38 acres, and gross storage of 118 acre-feet. It is comprised of a concrete gravity spillway 35 feet high and 90 feet long; a concrete intake structure that directs water to a minimum flow pipe; two low level sluice gates; and a power tunnel located in the west abutment. Water is conveyed from the impoundment by spillage, the minimum flow pipe, the sluice gates, or by the intake tunnel to the powerhouse. Hydraulically controlled steel flap gates are used to maintain normal reservoir elevation along the entire spillway crest. The control gates in the western abutment intake structure are composed of two 8-foot-wide by 7.75-foot-high sluices and a single 12.5-foot by 13-foot intake gate. Two tunnels, two concrete conduits, and three canals crisscross River Road and total 14,941 feet in length. The Deerfield No. 5 tunnel/canal system includes a small concrete gravity diversion structure about 12 feet high and 160 feet long on Dunbar Brook which directs water from the impounded brook (approximately 0.1-mile long and 175 feet across) into the southernmost tunnel. Collectively, these structures create a 3-mile-long bypassed reach and convey water from the dam to a 400-foot-long, 10-foot-diameter steel penstock and then to the powerhouse. The powerhouse is a steel frame and concrete structure constructed in 1974. It replaced the original station which was removed when the Bear Swamp Pumped Storage Project (FERC No. 2669) was built. The powerhouse contains one vertical Francis unit with a capacity of 14 MW. The Dunbar Brook diversion structure was completely redesigned and reconstructed in 1993. Two gates control water level in the canals and can divert flow to the powerhouse or release water into the Deerfield River via Dunbar Brook.
• Deerfield No. 4 – The Deerfield No. 4 Development is operated on a peaking, daily storage basis. The facility consists of an earthfill dam, spillway and sluice gates, intake and tunnel, forebay and penstocks, powerhouse, and substation. The impoundment is roughly 2 miles long and 500 feet across at its widest point, with a surface area of 75 acres, gross storage of 467 acre-feet and usable storage of 432 acre-feet. The dam is comprised of an earthfill embankment with a concrete core approximately 50 feet high and 160 feet long, a 241-foot-long concrete gravity spillway, and three sluice gates located in the east abutment. The dam is equipped with flashboards ranging in height from 6 to 8 feet. Water is conveyed from the impoundment either by spillage or by sluice gates located in the eastern abutment. The intake gates include a 10-foot by 10-foot, an 8-foot by 10-foot, and a single 10-foot by 14-foot surface sluice. In addition, a 6-foot by 12-foot surface sluice gate is located adjacent to, and downstream of, the power tunnel intake racks. This gate discharges into a 10-foot-diameter vertical conduit which in turn, discharges into a 4-foot-diameter pipe that discharges into the tailrace. It has an electric operator used to pass minimum flows into the 1.5-mile-long bypassed reach and was formerly used for downstream fish passage. The power tunnel conveys water from the intake structure at the impoundment via a 12.5-foot-diameter, 1,514-foot-long concrete and brick lined horseshoe shaped tunnel that leads to the powerhouse forebay. The earthen forebay has a 12,000 square foot surface area and a 35-foot depth. From the forebay, water is conveyed through three 10-foot-diameter, 154-foot-long steel penstocks to the powerhouse. The powerhouse is a steel frame and brick structure constructed in 1913. It contains three horizontal Francis units each with a capacity of 2 MW.
• Deerfield No. 3 – The Deerfield No. 3 Development is operated on a peaking, daily storage basis. The facility consists of a concrete gravity dam and sluice gates, intake, tunnel, forebay and penstocks, powerhouse, and substation. The impoundment is roughly 1.3 miles long and 300 feet across at its widest point with a surface area of 42 acres, 221 acre-feet of gross storage and 200 acre-feet of useable storage. The dam is composed of a concrete gravity spillway approximately 15 feet high and 475 feet long equipped with 6-foot flashboards, two sluice gates and a power tunnel intake located in the south abutment. The sluice gates in the south abutment include a 10-foot-wide surface sluice and an 8-foot-wide by 4-foot-high submerged sluice. A six-foot by 10-foot surface sluice gate, located adjacent to, and downstream of the power tunnel intake racks, discharges directly into the tailrace. This gate has an electric operator and is used to pass minimum flows into the 0.2-mile-long bypassed reach and was formerly used for downstream fish passage. The power tunnel exiting the gated intake is a 677-foot-long, 17-foot-wide by 12.5-foot-high concrete conduit. It runs underground to an 880-foot long forebay from which water is conveyed via three 59-foot-long, 10-foot-diameter steel penstocks to the powerhouse. The powerhouse is a steel frame and brick structure built in 1912. It contains three horizontal Francis units each with a capacity of 2.3 MW. The tailwater for Deerfield No. 3 is formed by the headwaters of the Gardner’s Falls Project impoundment (LIHI #80). The Deerfield No. 3 powerhouse discharges into an impounded section of the river even when Gardner’s Falls is maintained at its lowest level.
• Deerfield No. 2 – The Deerfield No. 2 Development is operated on a peaking, daily storage basis. The facility consists of a concrete gravity dam and sluice gates, an inflatable bladder, trip-able flashboards, intake and penstocks, powerhouse, and substation. The impoundment is roughly 1.5 miles long and 500 feet across at its widest point with a surface area of 63.5 acres, 550 acre-feet of gross storage and 500 acre-feet of useable storage. The dam consists of a concrete gravity spillway approximately 70 feet high and 447 feet long, with the inflatable bladder and trip-able flashboards, sluice gates and an integral powerhouse located at the western end of the spillway. Water can be conveyed from the impoundment by spillage, sluice gates, or through the powerhouse. Ten feet of trip-able flashboards on top of the spillway crest and the inflatable bladder (112 feet long by 10 feet high) are used to maintain normal impoundment elevation. When water is at the top of the bladder, it will deflate automatically if inflow exceeds the powerhouse discharge. The two surface sluices are each 10 feet wide. A six-foot by 16-foot surface sluice gate is located between the two 10-foot-wide sluices and the inflatable bladder. It discharges directly into the tailrace, downstream of the dam. This gate has an electric operator and was formerly used for downstream fish passage. The powerhouse, constructed in 1913, is integral to the dam, and includes a gated intake structure with three steel 11-foot-diameter by 35-foot-long penstocks. The powerhouse contains three horizontal Francis units each with a capacity of 2.3 MW.

Each development operates in a different operational mode. Most operate as peaking facilities with varying amounts of storage (i.e., seasonal, weekly, or daily). Additionally, the seasonal and weekly storage project facilities limit impoundment elevation changes (except for Sherman reservoir) and all projects have minimum flow requirements. These requirements were developed to support fisheries and wildlife resources in the area as well as maintain state water quality standards. The minimum flows and other requirements of the facilities are explained further in the 2021 Recertification Report found in the Files section below.

Waters within the project reach are located in Vermont and Massachusetts, each of which has different standards of water quality classification. For the facilities located in Vermont, the water classifications are designated as Class A (1) and B (1) in terms of aquatic habitat and Class A(2) and B(2) for aquatic habitat or recreation. These designations indicate that the waters are managed to support aquatic biota, wildlife, and flora, as well as fishing, primary contact recreation, and as a public water source. The Somerset Reservoir, East Branch Deerfield River below Somerset Dam, Searsburg Reservoir, Upper Deerfield River below Searsburg Dam, Harriman Reservoir, and the Vermont portion of Sherman Reservoir are impaired for mercury in fish tissue due to polluted runoff and from atmospheric deposition. The Somerset Reservoir is also listed as impaired for pH due to atmospheric deposition. The Massachusetts waters are designated as Class B, best suited for aquatic biota and habitat, primary and secondary contact recreation, and public water supply. The lower Massachusetts portion of Sherman Reservoir is listed as impaired for mercury in fish tissue, and two contiguous sections from the confluence with the North River to the confluence with the Connecticut River below Deerfield No. 2 are listed for E. coli contamination. The mercury impairment is due to atmospheric deposition and E. coli contamination is caused by municipal point source discharges, combined sewer overflows, and stormwater runoff. Neither impairment is contributed to by the project.

The lower Deerfield River presently supports migratory fish species including American shad, blueback herring, sea lamprey, American eel, and shortnose sturgeon. The states of Vermont and Massachusetts both stock trout species in the project area. Vermont stocks brown and brook trout in the mainstem of the Deerfield River, brook trout in the Somerset and Searsburg reservoirs, brown trout in Sherman reservoir, and Harriman reservoir supports brook, brown, rainbow, and lake trout. The Massachusetts portion of the river is stocked with brown, brook, and rainbow trout at various locations. Other resident fish species reported to occur in the upper Deerfield River include blacknose dace, bluegill, brown bullhead, chain pickerel, common shiner, creek chub, fallfish, golden shiner, largemouth bass, longnose dace, longnose sucker, mimic shiner, pumpkinseed, rainbow smelt, rock bass, slimy sculpin, smallmouth bass, white sucker, and yellow perch.

The project lands consist of over 17,700 acres and are largely undeveloped and protected by perpetual conservation easements. These areas are managed for multiple uses including high quality timber, passive recreation, and wildlife resources. The lands provide wildlife habitat, protections for the natural resources therein, as well as scenic and recreational access.

PLUS-Standard: The project owner established the Deerfield River Basin Environmental Enhancement Fund to finance watershed conservation, recreational and educational opportunities, and the maintenance and monitoring of such activities. Additionally, the conservation lands in the project area cover well over 50% of project owned lands.

Threatened or endangered species potentially present in the project vicinity include the common loon, tubercled orchid, Northern long-eared bat, little brown bat, tricolored bat, American bittersweet, muskflower, sandbar cherry, and bald eagle.

The common loon has seen a dramatic population increase and the project owner has continued to collaborate with Vermont Department of Fish and Wildlife (VDFW) to support the nesting activities of the species within the project boundary. The orchid species was present in the Searsburg and Harriman bypassed reaches and an increase in minimum flows in the late 1990s threatened the existence of the species. The project owner implemented a plan that relocated the species and monitored the health of the population after the relocation. VDFW has commended the success of such work and the orchid population has successfully repopulated the area. Periodic tree trimming and maintenance have the potential to impact the Northern long eared bat. VDFW is consulted to ensure no adverse impacts to bat roosting habitat. The project coordinates with Massachusetts Division of Fisheries and Wildlife to minimize impacts to the listed plant species.

PLUS-Standard: The project owner has implemented a comprehensive operations and management compliance plan under the Massachusetts Natural Heritage Endangered Species Program. The plan specifies routine operations and maintenance tasks, maps Project areas and the activities that occur within each area, discusses avoidance and minimization of impacts to threatened, endangered and rare species, and priority habitats. The plan identifies control measures in place to mitigate. Areas of impact are minimized, approved methods are employed, and updated tools and techniques are used. Erosion and siltation control measures are used as needed to protect regulated resources. Timing restrictions or seasonal work windows may be developed if there are any species-related requirements.

The hydroelectric facilities which comprise the project are all eligible for listing on the National Register of Historic Places. The properties that contribute to its eligibility include 27 historic sites including nineteenth and twentieth century residences, mill/factory complexes, mining complexes, schoolhouses, bridge abutments, and a cemetery. A cultural resources management plan was developed in consultation with the Vermont and Massachusetts State Historic Preservation Offices and the Advisory Council on Historic Preservation. The plan includes mitigation measures to preserve and protect the historic features at the project.

Recreational resources at the project include 16 trails, 15 picnic areas, eight boat launches, four carry-in/out access areas, one angler access area, and whitewater put-in and take-out facilities. Whitewater releases from Deerfield No. 5 Dam are scheduled each year. The project also has online and telephone access listing the anticipated flow release schedules for the following day. Real-time information is also provided in 10-minute intervals. Public access is provided free of charge except where safety concerns preclude access.