POTENTIAL AUXILIARY WATER SOURCES FOR MOUNTAIN LAKE, GILES COUNTY, VIRGINIA

Mountain Lake, located in Giles Country, Virginia at an elevation of 4785 feet above sea level is believed to be one of the highest lakes east of the Mississippi River. It is also one of only two naturally formed lakes in Virginia. The lake covers what was an ancient meadow and stream sitting in a water gap formed by the dissection of a plunging anticline. Recent studies by researchers at Kent State University suggest that an earthquake triggered a landslide over 6,000 years ago damming the stream and causing the lake to form. The dam consists of colluvium that allows conduits to form through the dam and these holes control the water level, allowing it to rise and fall. In 2008 the water level dropped to the lowest in historic times. During the winter and spring of 2013, the owners filled the depressions at bottom of the lake with local natural soil and rock, resulting in a partial refilling of the lake.

After completion of this project, the lake reached its highest water levels since 2005 in August 2013. With the lake still not reaching full pond, the owners asked researchers at Radford University for suggestions for supplementing the lake inflow with water from other nearby watersheds. In the spring of 2014 the authors began to investigate those watersheds in search of viable sources of water. The authors also investigated potential sites of water loss at key locations within the watershed currently serving Mountain Lake and its drainage system. Two watersheds were identified as having potential for supplementing flow. A northern watershed did not have enough water to warrant further investigation. A western watershed appears to have the greatest potential as an auxiliary water source. Several sites were identified where water has been diverted away from the lake and out of its natural watershed.