The trip from Bumpus Mills to Bowling Green brought us into Kentucky, although the trip was virtually straight east along the state border. At the Corps of Engineers campground at Barren River Lake outside of Bowling Green, we were just a half hour from Tennessee. The campground is called Tailwater, at it is a medium sized campground immediately below the dam. This meant we had a very nice river flowing past the campground instead of the other, larger campgrounds on the lake itself. Tailwater is a very nice, well-maintained campground in comparison to the older and smaller campground at Bumpus Mills. Most campsites are along the river giving good views of the flowing water with the backdrop of a bluff on the other bank. Nearly all of the sites are back-in but with the large grassy bank of the river, it was a simple matter to back the RV into the site. It certainly makes a difference when there is not trees in the way of swinging the truck around!!
Tuesday was once again time to do laundry and cleaning so Kal took off to find a laundromat in town while I cleaned the RV. It was sure nice to have a full closet of clean clothes again. Wednesday was another beautiful day so we headed north to Mammoth Cave. This was our second time visiting Mammoth Cave, although the last time was over 30 years ago while Kal was pregnant with Jenny and I was in graduate school. Neither of us remember much from this visit and it sure did not diminish the awe of seeing the huge cave. We bought tickets for the Historic Tour, however, we had over 2 hours before the tour. So we spent the first hour in the museum at the Visitor Center, which is well worth the time. They have a number of interactive exhibits covering the geology, history, and culture of the caves. I was amazed to find out that the cave complex consists of over 400 miles of explored and mapped caves, already making it the longest known cave complex in the world and it is estimated there are over 600 more miles of undiscovered caves still to be found. The cave complex extends well beyond the over 52,000 acres of the National Park on the surface. It was also fun to discover that mapping of the tunnels use many tools I am familiar with from measuring trees. Among these were Suunto clinometers, which I taught many students over 25 years to use to measure the height of trees. They also had exhibits of the many unique animal species that have evolved to live in the dark cave environment. This still left us time to eat lunch before gathering for the tour.
The Historic Tour is one of the longer tours offered while we were there. It was over two miles in length, would take over 2 hours, and had over 600 steps. While it sounded like it could be a challenge, it also sound very interesting. As the name implies, this tour follows much of the path that has been used for tours since the 1800s. The entrance is HUGE with the ceiling over 30 feet above your head and a small waterfall off to one side. After walking a quarter mile into this huge cave you come to the Rotunda which is the convergence of two subterranean rivers. As expected, this cave system is through a deep limestone layer of rock. What makes the geology so unique is the sandstone overlaying the limestone. This relatively impervious rock protects the caves and is critical to their creation. It also makes the surface different then I have ever encountered. Simply put, there are almost no creeks on the surface. Instead rainwater exits the surface through sink holes that pockmark the entire area. This also leads to a number of shallow springs that disappear back underground. For this reason this part of Kentucky is relatively poor for agriculture due to lack of water. Instead this water slowly dissolves the underlying limestone creating a vast complex of caves. Over time the Green River, which drains this part of the area, cuts a deeper path in the limestone thereby lowering the water table. As this happens the underground rivers drain into lower reaches cutting dissolving new courses through the limestone. Thus there are now five levels of caves and this entrance is into the area between the first and second layers. You can actually see where the river channels were somewhat different between the two layers. This made for an interesting view of the cave where you can see the old caves running at angles to each other. This area, being relatively close to the entrance has been historically inhabited by millions of bats. Due to the number of visitors, the bats no longer inhabit this part of the cave complex. However, the thousand of years of bats had built up a large amount of bat guano, which became important during the War of 1812 for the production of saltpeter, a necessary component for the production of gunpowder. The remains of the mining operation from this time are still in amazing condition begin stored in nature’s refrigerator, where the humidity and temperature are closely maintained at a very comfortable 65 degrees. The only change since that time is the construction of concrete walkways and stairs throughout the tour.
From the Rotunda the tour continues along Broadway and Gothic Avenues before descending into the third level of caves. At this point you cross over the Bottomless Pit, which used to be the end of the tour in the 1800s as this point was impassable. Today there is a metal grate over the pit, which means you can look straight down into the depths which they have lit with sufficient lights to see the bottom over a hundred feet below. Just so you don’t think the entire tour is along broad paved walkways, which it had been up to the descent into the third level, the path now snakes its way through a long narrow passage known as the Fat Man’s Misery. At points you also have to duck your head in order to get through. Then you descend again into the fourth level to the Great Relief Hall where they have benches to sit for a while. They do shine a light down a passage that leads down to the fifth level which is now the normal water level. This is not to say that the fourth level is always dry as it will flood during heavy rains. They also take advantage of everyone sitting down to turn off all the lights so you can see what total darkness is like. As this is the lowest point of the tour, the rest of the trip is climbing back up 400 feet. Most of the climb is up through Mammoth Dome which is a HUGE vertical shaft from the top levels to the current level of the river. They have constructed a metal tower to climb up through the dome and with the lights there are a number of spectacular views!! In my opinion, this was the highlight of the tour as I have never seen such a large underground area. The final quarter mile of the tour is along Audubon Avenue, which is the other river meeting at the Rotunda and the exit from the cave. This was truly an amazing experience which I will always remember and if I forget, Kal got some terrific pictures with her camera.
Due to the spring weather and storms we did not get another chance to visit Mammoth Cave this week, which was really unfortunate as there was a lot more to see and do there. The weather on Thursday wasn’t too bad, so we were able to explore the 1 mile loop trail at the campgrounds. While a nice walk, I was disappointed we could not go back to Mammoth Cave.