Mountain Lake, Virginia

Mountain Lake is the sole example of a natural lake in the southern Appalachians. The lake is located near the top of Salt Pond Mountain in Giles County, Virginia.  Marland (1967) estimated that 9,180 years ago, shortly after the glacial period in North America, the surface soil layer melted and slid downslope over the permafrost beneath it. This landslide dammed a small valley. The dam was fairly leaky until 2,000 years ago, when the permanent lake was formed. The lake reaches a maximum depth of over 30 m and exhibits a dimictic pattern of annual water circulation. Twice a year, in spring and autumn, the lake turns over, mixing the surface and bottom layers of water. Thermal stratification is pronounced in the summer but becomes uniform during the fall overturn (Crisman 1992).

The University of Virginia maintains a research laboratory, Mountain Lake Biological Station, near the lake.