A mill, a flood, a dam

Mountain Island Lake was created in 1923, when Duke Power closed a hydroelectric dam across the Catawba River at the site of the old Mountain Island cotton mill. The mill itself was already gone — destroyed in the Great Flood of July 1916. The reservoir that rose behind the new dam has generated electricity for a century and, as Charlotte grew, took on a second job no one planned for in 1923: supplying drinking water to a large share of the region.

Before the lake: gold, a mill and a river community

The name came first. Mountain Island was a river island on the Catawba, and the community that grew up around it on the Gaston side predates the lake by generations. Among its early settlers were Irish immigrants who came to the area to mine gold in the 1800s and helped found St. Joseph's Catholic Church near Mount Holly. In the late 1840s Henry Humphreys and Thomas R. Tate built the Mountain Island Mill on the river, harnessing the falls for cotton spinning, and a mill village followed.

For nearly seventy years the mill and its village were the community. Then, in mid-July 1916, back-to-back tropical storms dropped extraordinary rain across the western Carolinas. The Catawba rose to levels no one living had seen, and the flood destroyed the Mountain Island Mill. It was never rebuilt as a mill.

Building the dam

The Southern Power Company — the utility founded by James B. Duke and engineer William States Lee, renamed Duke Power in 1924 and today Duke Energy — was already turning the Catawba into a staircase of hydroelectric reservoirs to electrify the Piedmont's textile mills. The ruined mill site, with its natural fall in the river, was an obvious rung on that ladder. In 1920 the Virginia contractor Rinehart and Dennis was awarded the contract to build a dam at Mountain Island. Workers' families lived in refurbished brick mill houses on the bluff above the site and in temporary frame housing built for the job. When the dam closed in 1923, the water rose over the old riverbed, low farmland and the former mill grounds.

A power lake becomes a water-supply lake

For its first decades the reservoir was simply part of the hydro system. As Charlotte and the surrounding towns grew through the twentieth century, Mountain Island Lake became one of the region's principal drinking-water sources. The N.C. Forest Service now describes it as providing water for one out of every twelve North Carolina residents. That role is why so much of the shoreline carries watershed protections, why there is no commercial marina strip, and why large tracts — Latta Nature Preserve on the Mecklenburg shore and conservation land on the Gaston and Lincoln side — remain wooded. Read more in our water quality guide.

Upstream, Cowans Ford Dam was completed in 1963 and created Lake Norman, which now controls most of the flow arriving at Mountain Island. On the Gaston shore, Duke's coal-fired Riverbend Steam Station ran for decades before it was retired in 2013 and its coal ash was excavated and removed. In 2015 the Federal Energy Regulatory Commission issued Duke a new operating license for the Catawba-Wateree hydro project, which includes Mountain Island, following a comprehensive relicensing agreement signed by Duke and dozens of stakeholders in 2006.

Timeline

Why the history still shapes the market

Because the lake was engineered rather than discovered, its shoreline was drawn by a utility rather than by developers. The project boundary, the buffers, and the absence of a commercial waterfront all descend from decisions made in the 1920s and from the water-supply role added later. That is the origin of the scarcity described in the real estate guide, and it is why shoreline questions on any individual lot — a dock, a path, tree removal — go through Duke Energy review; see dock permits.

Two older landscapes survive close by. Latta Plantation, a house built around 1800, sits inside Latta Nature Preserve, and Historic Rural Hill preserves a Scots-Irish farmstead landscape that predates the lake entirely — see parks and nature. For the dam and powerhouse today, read Mountain Island Dam; for the river system it belongs to, read the Catawba River.