A hydro dam built at Lyman Falls between Bloomfield, Vermont, and Stratford, New Hampshire, in 1903 (breached in the early 1960s) may have been small, but it played a big role in local history bringing the first electric power to Bloomfield the rural hamlets on both sides of the river. Log drives moved through this stretch using a boom which caught the timber just upstream from the dam, siding the wood until it could be funneled through a narrow path of booms leading to a sluiceway on of the dam.
New England's largest river naturally attracted attention of those who would capture its power. "Speed bumps" in the river, in place as early as 1792 at Turner's Falls, Massachusetts, have proliferated over the last two centuries, with eleven dams now harnessing its power on the mainstream in New Hampshire and Vermont and impounding 144 miles, or slightly over half the river between the two states.
Several, such as the Wyoming Valley Dam between Guildhall and Northumberland, have evolved full circle from an early timber crib structure, later reinforced with concrete and a powerhouse, reverting once more to a falls as the river crushed the dam in the 1980s and slowly rediscovered its old riverbed. Others, such as the massive 178-foot Moore Dam between Waterford and Littleton, have barred the river only since 1957. The impoundment behind it amounts to the fourth largest lake in New Hampshire. Beyond these behemoths, many of their smaller brethren are at work on tributaries large and small, some directly powering industry, others producing electricity to run one household or a hundred.
Some dams are "run of river," and simply pass water through a turbine as it moves downstream, and others are "peaking" facilities, which capture and store water to generate power at a later time. Unlike other power sources, which need a spark or other electrical stimulus to initiate generation, a tannin river is ready to deliver power whether the switches are on or off. A hydroelectric dam is able to supply power instantaneously at times of high demand, and even to provide a "cold start" to a dead electrical grid. During the widespread blackout in the North eastern U.S. in 1965, Wilder Dam started the process that turned the lights back on throughout this darkened corner of the nation.
Fifteen Mile Falls, which consists of the Moore, Comerford, and McIndoe Falls hydroelectric generating stations on the Connecticut River between Littleton/Monroe, New Hampshire and Waterford/Barnet, Vermont, is the site of a former series of powerful and legendary waterfalls. Now buried beneath towering dams and miles of captured river, the biggest hydroelectric site in all of New England is critical source of power for the region.