Going Deep Into Mountain Lake Mystery

A voice crackling over the “underwater com” told the researchers that something was there and may be the largest one yet.  Ken Dunker, owner and instructor of Diving Enterprises in Salem, is surveying the bottom of one of four mapped depressions in Mountain Lake, in Giles County, Va. As principal investigator and geology professor Skip Watts and geology faculty members Beth McClellan and Paki Stephenson wait, the bright pink string attached to a white wooden “bowtie” unravels from the large metal bolt Dunker placed in the “piping hole.”  Dunker donated his time to help survey the depression using classic search and rescue diving techniques.  The excitement on the retrofitted pontoon boat floods over when the white marker pops to the surface of the lake and the team waits for more news from Dunker.

As Dunker breaks the surface he exclaims “this is the biggest hole yet.  It was this big and the water flow looked significant,” as he holds his hands and arms above the water in a circle the size of a large beach ball.  Dunker says he placed a pole about three feet into the hole before he felt any closure or reduction of diameter.  “That is great and definitely the largest hole that we have found yet,” says Watts.

The trio of researchers along with co-principal investigator Parvinder Sethi, have spent the summer measuring, analyzing and diving for hours at a time from a pontoon research vessel converted from a vintage “lake cruiser.” Pulleys, ropes, and a catacanoe assembled from two canoes bolted together, help make it all possible.  Watts, Sethi, McClellan and Stephenson are in the process of investigating the reason for Mountain Lake’s cyclical draining, to help the Mountain Lake Conservancy and Mountain Lake Hotel management find and implement eco-friendly solutions to preserve the water level in the popular tourist destination.

The researchers have mapped the lake, which is fed by springs and mountain streams, and now are searching for “piping holes” through which the water is disappearing.  They have been studying the rise and fall of the lake for more than a year.  They have collected sediment samples, studied the documented history and geology of the lake and the region, and monitored the water level of the lake.  Now thanks to grant funds, the group is finding and mapping where the water may be draining.

“There is so much to do,” says Watts, “we could have students working here on many geological and hydrogeological studies for a long time.”  Watts has incorporated Radford University undergraduate students, Virginia Tech Ph.D. students and graduate students from Kent State in his examination of the draining phenomenon.  As they find the “piping holes,” they then attempt to measure the velocity of water disappearing down each hole.  This may lead to an environmentally friendly way to begin the process of closing the holes that allow the most water to escape.

However the group has challenges ahead, many of the holes close and then open elsewhere on their own.  And the lake is on track to fully drain by the end of the year.  These diving expeditions will need to be completed before the lake fully recedes.  This winter, the research team will be applying for grants to purchase an unmanned underwater vehicle to monitor and revisit the holes.  They hope to gather photographic and video evidence of what exactly is happening when the water escapes from the lake. Then after the spring thaw, they will be back on their retrofitted research pontoon boat to again quantify the volume of water leaving the lake.

Sep 18, 2012
Ann Brown