Waterpower & Dams

Waterpower and Dams. . , The force of falling water can turn wheels and other devices to power machinery. Capturing that force requires a dam to divert water's natural path, artificial channels or raceways to lead water through a power-creating wheel, and a tailrace below the wheel to return water to a stream or river. Valley Falls was perhaps the best potential site for waterpowered mills on the Blackstone. The marsh upriver could be turned into a storage pond and relatively low banks on either side of the tails provided mill sites. A sequence of three dams at Valley Falls and the raceways running through this park tell much of the water power story here., Water Power Sites on the Blackstone , The Blackstone River drops 438 feet in 46 miles. Mill owners once used almost all of the energy., The Mill Pond's Changing Shape , The first Wilkinson dam, built c1813, was on the bedrock near the upper end of the falls. The Wilkinsons built a dam 5 or 6 feet higher, about 40 feet downstream, in 1828. The 1828 dam created a larger pond in the Valley Falls marsh than the earlier dam. Higher pond levels flooded waterwheels at mills upriver. A lawsuit required lowering the dam crest 16 inches in 1835. The large pond created by the higher 1828 dam appears on an 1831 map. An 1838 map, made after the dam was lowered, shows a smaller pond. Siltation behind the Valley Falls dam has further reduced the pond size., Gatehouse Site , The rack-and-pinion operator in front of you is one of three that [unreadable] gates in the arches below. These gates controlled the flow from the river into the raceways. A gatehouse like this one across the river sheltered the machinery., Archaeological investigations in February 1991 located the buried headrace from the 1813 and 1828 dams., Much of the timber framing from both Wilkinson dams remains underwater. These sections were last exposed when the water behind the stone dam was lowered in 1940.