Credits

Created by Alli Kenlan, Explore Natural Communities Intern Summer 2017, NatureServe.

Sounds: Civil War Drummer, recorded by DrumM8 (soundbible.com). Soldiers Marching, recorded by Mike Koenig (soundbible.com). Licensed under Creative Commons: Attribution 3.0. Water Music from the Handel Show, recorded by The United States Army Old Guard Fife and Drum Corps (freemusicarchive.org). Public Domain.

Music: Adventure Darling, by Gillicuddy (freemusicarchive.org). Licensed under Creative Commons: Attribution-NonCommercial 3.0.

Photo: Explore Natural Communities Interns 2017, NatureServe. Licensed under Creative Commons: Attribution 4.0.

References:
Cave / Karst Systems at Antietam
Karst Topography
Killiansburg Cave

Transcript

Podcast time: 2:50 minutes

[civil war drummer fades in] Let's journey back to 1862 at the Battle of Antietam, which would become the bloodiest single day in the entire Civil War! Imagine you're a soldier making your way through the landscape. [footsteps marching] The rough terrain is difficult to hike, but it can also provide military advantages. Rocky outcroppings, hollows, and shallow pockets of wetland all provide cover from the eyes of your enemy.

[music starts] The soldiers in the Civil War might not have known this at the time, but they were navigating through what we call the Ridge and Valley Province of the eastern United States. This indicates the presence of hills of shale and sandstone and valleys of limestone bedrock. Usually, when we hear the word “bedrock,” we think about rocks located deep below the earth's surface. But in many spots around the park, the bedrock is much closer to the surface, and in some cases it's even exposed as rock outcroppings.

When rain water begins to seep through the porous limestone bedrock, it eats away at the soft rock. The more acidic the water, the more rock it dissolves. Over time, this creates open cavities underneath the ground’s surface. In other words, it forms caves! Beneath your feet there could be vast cave systems and even underground streams! We call this kind of “swiss cheese” terrain “Karst Topography,” and it's commonly found throughout the Ridge and Valley Province.

In addition to caves, sinkholes and springs are also common where there's karst. Many of the farm houses that once stood on this land had their own springs, and some of them can still be seen today.

In regions with karst topography, pollution can easily contaminate well water and streams.

And here's why: rain water naturally seeps through the soil. Normally as it sinks down, the soil filters out pollutants that the water might have picked up on the surface. By the time it finds its way to the closest stream or becomes part of an aquifer, it's nice and clean. But, where there's limestone, the soil layer on top is thin and the bedrock has holes; remember that “swiss cheese" terrain? Think about how quickly water that seeps into the ground would travel through all those holes. There's basically no soil to filter out pollutants before the water reaches a stream or an aquifer. That's bad news for the locals who rely on well water!

Karst features need to be protected not only for natural reasons but also for cultural values. [music ends] Not far from the park a natural karst cave sits along the nearby Chesapeake and Ohio Canal. This is the Killiansburg Cave, where the people of Sharpsburg, Maryland ran and hid when they sensed the impending battle. By protecting natural karst resources like this cave, we're also preserving pieces of our nation's history! [military music begins]

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