Mammoth Cave National Park officially closed two of its most popular attractions Monday to begin work rehabilitating two miles of cave trails.
For the next year and a half, parts of the cave will be closed to the public as the park improves the pedestrian paths from the Snowball Room to Grand Avenue Station.
The Grand Avenue Tour will remain closed for the entirety of the project, which is expected to run through at least the spring of 2021.
The Wild Cave Tour will be closed for the first 12 months of the project, and the Domes and Dripstones and Frozen Niagara tours will be closed for the remaining duration of the work.
The Grand Avenue Tour covers four miles in four hours, and the Wild Cave Tour involves “crawling, stooping and squeezing through holes” for an approximately six-mile spelunking route over about six hours. ”It’s not for the faint of heart,” park spokeswoman Molly Schroer said.
In the spring, people seeking an adventurous route can sign up for the Introduction to Caving Tour, which is a moderately strenuous spelunking path that is open to people ages 12 and older. And for folks seeking a longer hiking experience, Schroer recommends the Violet City Lantern Tour, which is a three-hour route by lantern light from the historic entrance.
The Accessible Tour will also be limited to weekends during the first year of construction, as the contractor, Global Specialty Contractors, will be using the elevator to move supplies into the cave.
“We’re excited to get the cave trail project going,” Schroer said. “These trails haven’t been touched for many years.”
In the 1930s, the Civilian Conservation Corps created 12 miles of pedestrian paths leveled with cave sediment, which required either using more cave sediment from inside or outside the cave for maintenance. Neither practice has been sustainable to repair a growing number of potholes, which are hard to spot in low-light conditions, according to the National Park Service environmental assessment published in 2009.
Walking on dirt trails creates clouds of dust that scatter across sensitive cultural and natural resources in the cooler, drier months. And visitors also track in lint, which coats the limestone, provides an unnatural source of energy for cave biota and ultimately disrupts the underground environment, according to the assessment.
The new work will involve constructing durable walkways and lint-collecting curbs as well as improving the handrails, seating and resource issues. An additional benefit will be keeping visitors on the physical trails, which were previously poorly defined.
Two years ago, the park began repairing about two miles of the Historic Route. They added new walkways and guardrails and removed a boardwalk area.
During construction, the cave will offer more tours through the renovated Historic Route. For the remainder of the winter season, the park will offer the following: Frozen Niagara Tour, Mammoth Passage Tour, Historic Tour, Extended Historic Tour, Domes & Dripstones Tour, Gothic Avenue Tour, River Styx Tour, Heritage Walk and the Exhibit Talk.
In addition to the cave work, the park is constructing new ramps for an upgraded Green River Ferry to accommodate changing river levels. The work was initially expected to be concluded by the fall, but the contractor asked for an extension and now expects to finish by the spring.
The old ferry has officially been removed, and the new ferry will be installed once the Green River water level rises enough to safely launch the upgraded boat.