Mountain Lake (Virginia)
Mountain Lake is a freshwater lake located in Giles County near Newport, Virginia, in the United States. Along with Lake Drummond in the Great Dismal Swamp, it is one of only two natural lakes in Virginia. It was originally known as Salt Pond, as it was where cattle were given salt.
The Lake
Mountain Lake typically covers about 50 acres (200,000 m²), and its level was largely constant at an elevation of 3,875 feet (1,181m) during the 19th and 20th centuries. Since 2002 it has been subject to dry-season level drops of as much as 15 feet (5 m). The last such level fluctuations occurred between 1751 and 1804 as historical accounts give widely different accounts of the lake size.
The first known written evidence of the lake was by Christopher Gist of the Ohio Land Surveying Company, in 1751. It subsequently became known as Salt Pond.
Natural lakes are common well to the north, where the Appalachian Range was subject to geologically recent glacial activity. But the basis on which this lake—the only natural one in the southern Appalachians—exists has been the source of much speculation. Recent scientific studies indicate that an unusual combination of natural processes created the lake, which is maintained by a fissure at the bottom that provides an outlet for both sediment and water and prevents the lake from otherwise simply becoming a bog. Replenishment of the water lost depends on rain levels, and apparent washing-out of sediment from the fissured bedrock bottom is causing the unstable lake levels.