Early travelers once believed Virginia’s Mountain Lake was bottomless - or, at least, up to 300 feet deep. In reality, the mountaintop pond extends about 100 feet from the surface. And there’s a hole in it. Water comes into the natural 55-acre basin from a 500-acre watershed, but it escapes at a rate of 600 gallons per minute, slipping through rock crevices in the lakebed. One hole on the lakebed measures a little more than two feet wide.
“The water definitely doesn’t slow down,” said Bruce Parker, a retired Virginia Tech biologist who has studied Mountain Lake since 1969. “The reason why it’s low today is because more than 50 percent of the water that comes in is leaking through holes that are natural holes - crevices between rocks and boulders.”
This natural wonder seems like a lake in limbo. And, again, it has many asking, “How low will it go?” “It’s really quite interesting,” said Dave Deshler, the director of the Wilderness Conservancy at Mountain Lake. “It’s a fascinating lake.” It’s also one of only two natural freshwater lakes in Virginia. The other is swampy Lake Drummond, lying on the Suffolk-Chesapeake line. In recent months, Mountain Lake has lost so much of its pool that it has shrunk to nearly half its size atop Salt Pond Mountain in Giles County, about a half-hour drive from Blacksburg.
Many visitors to the mountain lake Resort Hotel want to see the same level of the lake that they saw when it was at full pool in 1986, the year Vestron Pictures filmed the hit movie “Dirty Dancing” at the site.
“That’s what they look for,” Deshler said. “People come back up and say, ‘Hey, this is Mountain Lake. I only see a puddle.’” Earlier, from the late 1990s to 2003, the lake also slipped into a lower stage - until heavy rains suddenly made the water rise, refilling the lake at the end of a drought. Another time, in 1959, Parker said, the low-level lake rose rapidly after an earthquake hit the Giles County area.
“Earthquakes are definitely factored into the lake,” Deshler said. “We’re in a very active fault line area. It changes in what goes on with the fault line. We never know how much water is going to be led into the lake or be led out of the lake.” According to theory, a landslide formed the lake after damming a stream at the end of a small valley about 9,000 years ago. Who knows how that really happened.
“It’s still up to study,” Deshler said. “The rocks did slide down at the north end of the lake, due to the earthquakes, but it may have been a longer process rather than a shorter process.”
Taking a tour of the lake, Parker showed off a tree stump salvaged from the lakebed when the lake was 32 feet below full pool. This stump, according to carbon dating, is a southern yellow pine that dates to 1655. “That tree stump has roughly 25 growth rings,” Parker added. “And that tells us that the lake was at more than 32 feet lower for a period of at least 25 years. Pine trees do not put their roots in water. They cannot survive. They die as soon as they have been inundated.” More recently, when the lake was low in 2002, Parker suggested pumping water into the basin. Trouble was, the water in an experimental pump didn’t flow fast enough to make refilling the lake successful. Then it rained. And, as it turns out, Mother Nature took care of the refill, all on her own. Today, that’s what Parker and Deshler suggest - leave this alone to its own cycles. “A lot of people that coming here nowadays don’t know that the lake is normally up and down,” Deshler said. “Right now, they see a shoreline, and they see natural grasses and things growing. They don’t necessarily ask about the lake.”
BUT MANY ASK ABOUT THE TREELINE - specifically, the hemlocks that have perished along the shoreline, due to attacks by the woolly adelgid. About 60 percent of the trees around the lake have died, Deshler said. “But, in less fragile systems on this mountaintop, the hemlocks are doing OK.” In 2001, the resort hotel began asking for donations to “Adopt-A- Hemlock.” Soon after, a hotel newsletter bragged about the program’s success.
In time, too, the Wilderness Conservancy at Mountain Lake began working on a plan to combat the woolly adelgid. Over 300 specimen trees were treated with an insecticide called Merit, Deshler said. “It’s actually the same type of chemical that you put on your dogs and cats, on the back of their neck, to keep the flea and ticks off. There was a fair amount of success with it.”
Still, several trees in the hotel property’s 2,600 acres died very quickly, due to stress, Deshler added.
“Old trees - ancient, slow-growing trees - get stressed very quickly,” Deshler said. “And then any trees that are in an insecure area, like the lake itself, the periphery of the lake ... There is no solid substrate there. It’s an ideal area for hemlocks to grow, but it’s not as stable as other habitats are. It needs to be around water, but it’s very precarious up there in terms of where a hemlock could grow.”
FOR MORE INFORMATION: Wilderness Conservancy at Mountain Lake, 115
Hotel Circle, Pembroke, Va. (800) 346-3334. www.mountainlakehotel.com
Joe Tennis is the author of Southwest Virginia Crossroads: An Almanac of Place Names and Places to See (The Overmountain Press).