Why is the 'Dirty Dancing' Lake Continually Drying Up?

If you've never heard of Mountain Lake, given its remote location outside of Blacksburg, Virginia, at an elevation of nearly 4,000 feet (1,219 meters) above sea level, it's understandable. Still, you've probably seen it. It's the lake from the 1987 film 'Dirty Dancing,' where Johnny Castle (Patrick Swayze) and Frances 'Baby' Houseman (Jennifer Grey) experience a passionate summer romance at Kellerman's Resort.

If you are familiar with Mountain Lake, then you're likely aware of its current state. And you probably know that the once expansive lake from the film is now less than half full, resembling more of a dried-up pond than a lake.

Mountain Lake's remaining land is now part of the Mountain Lake Lodge, a grand hotel located at the southern edge of the lake. This is the location where the iconic Kellerman's was portrayed in the film. Once a popular vacation spot for boating and swimming, the lake area now focuses on land activities, including archery, hiking, a ropes course, and events based on 'Dirty Dancing'.

I first visited the lake in 2016 while living in Blacksburg, and returned in October 2019 with Radford University geologist Chester 'Skip' Watts. He has been studying the lake for over ten years, having been fascinated by it since his undergraduate days at Virginia Tech. While the lake may no longer resemble its former self, the surrounding area is still breathtaking, especially in the fall when the trees are adorned in vibrant colors and the cool mountain air fills the atmosphere.

As you walk around the lake's edge, you can still make out the original basin and imagine how high the water would have risen when the lake was full. Nowadays, a long white dock stretches from the famous gazebo at the lodge, but it doesn't quite reach the water. Old boats lie abandoned on the dry land where the water used to be.

What's So Unusual About Mountain Lake?

Mountain Lake is one of only two natural lakes in Virginia and the sole natural lake in the southern Appalachian Mountains. What makes it truly unique is its ability to empty and refill nearly completely every few centuries. Even between these events, the lake experiences dramatic changes in its water levels.

While Watts and I were sitting in the lodge, he shared an intriguing tale about how, during the early 1900s, the water level in the lake became so low that hotel staff covered the holes at the lake's bottom with mattresses to prevent the water from draining out.

What sets Mountain Lake apart is the presence of numerous small holes at its bottom — holes that continuously drain water from the lake and, based on a dye test conducted by Watts's team, disperse the water about a mile away. These holes have existed since the lake's creation, which, according to the sediment record, dates back at least 6,000 years.

Why Does the Lake Continually Empty?

For much of the 20th century, the lake resembled a typical body of water. However, starting in 2002, its water levels noticeably decreased.

"Water levels fluctuate," explains Watts. "But the lowest points were consistently lower year after year." Though there was a brief rebound in 2005 due to a wetter season, by 2008, the lake had nearly dried up, remaining mostly empty from then until 2012.

In 1999, Jon Cawley, in his doctoral thesis on Mountain Lake, predicted that the lake, which had only experienced four complete dry spells over 6,000 years according to his research, would face another significant low. Just three years later, his prediction came true.

"It's rare in geology to make such an accurate forecast, and then witness it unfold, especially so soon after the prediction," remarks Cawley, a biologist and geologist with over 20 years of study on the lake. He currently serves as a research geologist at the Smithsonian Institution.

As the situation unfolded, scientists gathered at the lake, eager to uncover the cause. Meanwhile, the staff at Mountain Lake Lodge were left scrambling as their hotel's namesake had transformed into little more than a mud puddle.

The holes were definitely a factor; the drains became increasingly visible as the lake level dropped. However, the holes had always existed. The real question people had was why the lake drained so completely this time and if there was any way to address it.

Watts explains that the timing of the lake's drying can be understood by looking at the water budget. He compares it to a bank account: "You want your bank account to grow," he says. "You have your expenses, which in this case is the lake's outflow, but there's also an inflow. As long as your inflow is greater than your outflow, your balance will increase until it's full." But in 2008, the outflow was clearly greater than the inflow.

Impact of Drought, Climate Change, and Construction

There are several contributing factors. One key reason is the drought from 1997 to 2002, which led to a 30% reduction in average rainfall compared to the previous period (1982-1996). This drought was probably influenced, at least partially, by climate change, according to Cawley and Watts.

During his research on Mountain Lake, Cawley often remarked, "Mountain Lake serves as the canary in the coal mine for this region of Appalachia. The effects of climate change will be visible here before they appear in many other places," due to the Appalachian Mountains hosting one of the world’s most diverse ecosystems in terms of plant and animal species per square mile.

Around the same time, Mountain Lake Lodge was constructing a conference center on the land above the lake. To meet state regulations, the Lodge built stormwater management basins. This was a routine measure, and Watts suggests that little attention was given to the potential consequences at the time. When he first heard about the project, he assumed that the water would still reach the lake as groundwater. However, a few years later, after his students modeled the groundwater profile of Mountain Lake, they discovered that the water being diverted by the basins wasn't flowing into the lake at all. Instead, much of it was being redirected underground to a nearby creek.

Since this construction occurred in 2001, just before the water levels began to decline, Watts believes it's likely that the basins played a significant role in the lake's shrinking.

Cawley also highlights other local factors, such as nearby homes, the University of Virginia biological station, and the hotel. Another possible contributor, he suggests, is the sediment cycle. Occasionally, sediment can become trapped in the system, reducing the size of the drainage pipe, which slows the water's outflow. Other times, sediment washes away, causing the water to drain more rapidly. This variation in sediment accumulation can affect the water flow over time.

"All these factors are intertwined," Cawley says. "You can't simply attribute the lake's disappearance to one single cause."

Can Mountain Lake Ever Become a Lake Again?

In 2013, the hotel took steps to address the situation and began sealing the holes in Mountain Lake where the water had been draining out. Watts and his team provided maps for the project, but ultimately, they were excluded from the process, which was carried out in a manner that Watts believes differed from his recommendations.

"Our recommendation was to take a staged approach because you can't predict exactly how things will unfold," Watts explains. "You could block off one section, and then the water level would rise, allowing you to prepare for the next phase."

However, the repair work was done all at once, using a mixture of dirt and materials removed from the lake’s edge, along with bentonite, a clay that swells when wet. Although the lake refilled quickly after the repairs, new holes appeared higher up, allowing water to continue escaping. In the end, the water level never returned to its previous high, much to the disappointment of the hotel. While the lake currently holds more water than it did in 2008, guests can no longer swim or use paddleboats in it.

If the hotel remains interested in attempting to refill the lake, Watts suggests that the best option would be to redirect water from a nearby watershed using a gravity-fed pipeline. This could potentially restore the inflow that was lost when the conference center was constructed in 2001.

"I’m pretty sure that would work," Watts says. "However, it would need to be done with great care due to potential environmental concerns."

Currently, however, Mountain Lake Lodge has rebranded itself. It now emphasizes land-based activities and integrates the lake's distinctive hydrology and ecology into its tourism offerings. As far as Watts is aware, the lodge is no longer focused on restoring the lake to its full capacity.

That’s perfectly fine with Cawley, who is content with the lake as it is. "The lake will take care of itself," he says. "It's not broken. It's doing exactly what it's supposed to do."