Power Plant and Dam No. 4 is a historic hydroelectric power generation station on the Potomac River, located near Shepherdstown on the county line between Berkeley and Jefferson County, West Virginia. The power plant is a tall one-story, limestone building on a high stone foundation.

The seven dams on the Potomac River were originally built to divert water into the canal. Dam #4 provided water for 22 miles of the canal, from Milepost 84.6 downstream to Milepost 62.3, just above Harpers Ferry.

The dam was a major source of water for the canal, and supplied water power to aid in moving heavy canal boats. Since 1913, it has supplied hydroelectric power. The dam was modified in 1994 to improve its hydroelectric capacity, with a height of 20 feet and a length of 715 feet.

Map of sites near Dam No. 4 -- a Canal Site, one of many historic and recreation sites on the Potomac River.

Jun 3, 2024 · The Potomac River between Dam 4 and Lock 41 (Mile 88.9) is known as the Big Slackwater. Because it would have been near impossible to construct a canal through the limestone cliffs that hugged the Potomac River in this area, the Chesapeake and Ohio Canal engineers decided to build Dam 4 so that the river could be backed up to create a deep pool ...

Dams on the Potomac River Operational. Little Falls Dam (Potomac River) aka Brookmont Dam (at C&O Canal milepost 5.6, upstream of Chain Bridge) Potomac Aqueduct Dam (at C&O Canal milepost 17.5, upstream of Great Falls) C&O Feeder Dam No. 4 (at C&O Canal milepost 84, downstream of Williamsport, MD)

Dam 4 spans the Potomac River and impounds water in a 13-mile-long upriver pool known as “Big Slackwater.” It provided water for the canal between here and Dam 3 at Milepost 62.2 near Harper’s Ferry.

Potomac River Dam #4 is a gravity dam located in Williamsport, Md, Washington, Maryland. The dam, which is on the Potomac River, was primarily built for Hydroelectric purposes, but also serves for benefits.

Power Plant and Dam No. 4 is a historic hydroelectric power generation station on the Potomac River, located near Shepherdstown on the county line between Berkeley and Jefferson County, West Virginia.

The department received a request to create a new speed zone in the Potomac River below Dam Number 5, approximately 10 miles above Dam Number 4, and approximately 1/2 mile above Potomac Fish and Game (near the Falling Waters, WV River Lots).