Texas Parks & Wildlife Magazine   


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State Park Underground

Spelunkers wriggle, crawl and shimmy through caves and crevices to document karst features at three parks.

At Government Canyon State Natural Area in San Antonio, we gather around to receive our assignments for the day.

One team will explore a cave-like feature called 9-H-1.

Another team will head to Lost Pothole, a cave that requires a rappel to access, says Marvin Miller, who leads caving expeditions for the Government Canyon Karst Project. It harbors the kind of mystery that cave explorers love.

“At the bottom there’s a crack that blows air,” Miller tells me. “That means there’s another entrance somewhere, or more cave beyond. They’ll be working on that lead.”

Our team is next.

“You’ll be going to San Geronimo Creek,” Miller tells our group of six. “It’s an area with tall cliffs and lots of caves.”

We’ll take it.  

What is karst?

GIVEN OUR marching orders, we spread out across the state natural area to explore, survey and inventory the cave and karst features at Government Canyon, an area rich in such resources. The Texas Speleological Association has been doing work here for 30 years, discovering and exploring several dozen caves.

The group has the ambitious goal of documenting all the karst features — limestone landforms such as sinkholes, fissures, ridges and caves — in three state properties: Colorado Bend State Park and Government Canyon and Hill Country state natural areas. Monthly outings occur at Colorado Bend; Miller leads groups each month at either Government Canyon or Hill Country, rotating between the two.

Found mostly in Central Texas, karst terrain contains important economic, scientific and recreational resources. The porous limestone plays a crucial role in groundwater by filtering and funneling rain as it goes underground. It’s home to special cave-adapted species, some found nowhere else in the world.

The cavers and the parks both benefit from the relationship: The cavers feed their desire for adventure and discovery while adding to the body of scientific knowledge, and state parks learn more about their natural resources.

“The work that Marvin and his crew started here in the ’90s is absolutely essential to the ‘why’ of Government Canyon — it’s all about water,” says Nic Maloukis, Government Canyon superintendent. “Their work contributes to a better understanding of our karst environments and improves our ability to protect these sensitive environments and the unique and rare critters that call karst home.” 


 Sonja Sommerfeld | TPWD


AT GOVERNMENT CANYON we hike through the rocky bed of San Geronimo Creek, noting interesting rocks and animal bones, on the way to the caves.

“You can start to see some cave features on the right. Yep, we’re in cave land!” says Jessica Gordon, chairman of the Texas Speleological Association and an educator for the City of Austin’s Watershed Protection Department.

Like a limestone hunk of Swiss cheese, the cliffs ahead of us are pockmarked with cave openings. Our map indicates that some of the caves have been surveyed, while others remain unexplored.

“That’s unexplored right there — unexplored, unexplored,” says Ethan Kuhlken, a 16-year-old volunteer, as he points to caves on the color-coded map, excited by the prospect of discovery.

Gordon explains why we’re here and spells out our goals for the day.

“These karst environments are fragile,” she says. “Water flows through them and feeds our aquifers. It’s important to protect them. In order to protect something, you need to understand it.”  


 Mark Ross

The abundance of karst and caves is the main reason Government Canyon, in northern San Antonio, gained protection as a state natural area in 1993. It sits in the Edwards Aquifer recharge zone, where rainfall gurgles through karst into the aquifer.

San Antonio depends primarily on the Edwards Aquifer for its drinking water. Citizen concerns about development over the aquifer led to creation of Government Canyon State Natural Area, which opened to the public in 2005 and protects 12,224 acres of mostly aquifer recharge areas.  


WE HAVE TWO tasks for the day: Locate and survey an unnamed cave just above creek level, and survey a cave called Crawl, Hop and Fly. The first assignment is a little more involved; we are to mark the cave with flagging tape and an aluminum tag, take the GPS coordinates, photograph it, sketch it, survey it and, most exciting to us, give it a name.

We find the cave and gear up with helmets, headlamps, kneepads and elbow pads.

“To be considered a cave, it needs to go back 5 meters,” Gordon says. “And the entrance needs to be smaller than the inside of the cave.”

Kuhlken crawls in on hands and knees.

“It’s definitely bigger inside,” he says.


And it appears to be deeper than 15 feet.


Gordon takes a GPS reading at the entrance to the cave and records the coordinates. She creates an aluminum tag with the number 28-33 and attaches it and some flagging tape near the entrance. She aims a red laser beam into the cave, and she and Kuhlken take a series of measurements to assess its dimensions.

With protractor and pencil, Gordon uses those measurements to create a sketch of the cave’s interior in her notebook. This will become part of the scientific record for the cave and for the state natural area.

The other members of our group — Heather Kuhlken, Sawyer Kuhlken, 11, and Geo Reynolds, 8 — and I climb up and crawl in the cave to join Gordon and Kuhlken. The six of us fit comfortably. If you were going to pile people in here the way people used to cram themselves into old Volkswagen Beetles, you might fit 15-20.

And now comes the naming.

The two openings of the cave — one round and one more horizontal — prompt Heather Kuhlken to suggest the name Old Man’s Eyes.

It sticks.  


 Heather Kuhlken

In her trip report, Gordon noted that before leaving the cave, she and Ethan Kuhlken “peered out the old man’s eyes in search of wisdom across the horizon.”

Gordon’s been involved in cave education for a couple of decades, but her first cave expedition was in 2015 as a volunteer to haul scuba tanks for some cave divers who were exploring Honey Creek Cave, the longest known cave system in Texas.

“It was transformative,” she says.

She had spent years teaching how groundwater works at her Austin watershed job. Underground in Honey Creek Cave, she saw it for herself. She developed and deepened interests in cave exploration and biology. Along the way, she discovered a welcoming caving community with old cavers, young cavers, caving families, crusty characters and dedicated scientists.  


AT GOVERNMENT CANYON, we turn our attention to that world and to our next task: surveying Crawl, Hop and Fly.

We try to puzzle out the name. To access the cave, you have to hop down into a pit, then crawl up into the cave on the other side. But fly? We don’t know.

Ethan Kuhlken volunteers to go first.

“Oh no,” he says after entering. “There are moths swarming all over in here. Every time I move one of these little rocks on the floor, more moths fly out. There’s one in my underwear! This is going to be a traumatic experience.”

Enduring the moths, Kuhlken and Gordon take laser measurements, and Gordon makes her sketch.

When I ask Miller about the name later, he says, “It was named Crawl, Hop and Fly because everything in the cave either crawls, hops or flies.”

Now we understand.

While the Underwear Moth might not be a species worth noting, Government Canyon’s specialized cave habitats contain several species listed as endangered.

“By finding these caves and documenting them, it lets the park know what natural resources they have here,” Miller says. “We’ve found a number of caves with endangered species,” especially karst invertebrates, or cave bugs.

Cavers started documenting the cave systems in the 1990s, when the Texas Parks and Wildlife Department started purchasing land here. Miller keeps coming back because he finds satisfaction and rewards in discovery.

“I like the freedom to find cool things,” he says.

One of the coolest things he’s found over the years is Dancing Rattler Cave. After discovering a small, promising sinkhole, he dug in. The cave and passageway didn’t seem like much.

“I found myself looking down into a pit,” he says. “I went feet-first, and all of a sudden I was looking into this space filled with all kinds of formations on the ceiling and floor. We called it the Dance Hall. Around a boulder was a room we called the Pool Hall, with beautiful formations and water filling these rimstone pools.”

The Pool Hall’s centerpiece is a formation called the Frozen Cascade, a white flowstone surrounded by crystalline pools of water.

“Knowing you’re the first person to stand in a certain place is a pretty amazing feeling,” he says.  


 Sonja Sommerfeld | TPWD


A FEW MONTHS LATER I make the trek to Colorado Bend, where more than 400 caves have been discovered. The park’s topography reveals a landscape of hills, canyons, caves and springs, including notable features such as Gorman Falls and Gorman Cave.

Texas Speleological Association cavers are conducting work similar to that being done at Government Canyon — looking for new caves, exploring caves, trying to push further into known caves.

One team this weekend will be exploring a connection between Horseshoe Crevice and Gorman Crevice.

Our team’s tasks? To find Corazon Cave (to make sure the GPS points are correct and to see if it’s worth surveying) and to visit Gorman Sink and Copperhead Cave (mainly to have fun).

Led by Liz Herren, we head cross -country through brush and trees and up and down ravines. Herren thinks we’re getting close to Corazon Cave.

We finally find it — a rocky hole in the ground — in a grove of trees.

“I don’t know if this cave is passable,” Herren says, “but I’m going to try.”

“It’s a bit of a squeeze,” agrees volunteer caver Joel Ashman.

Herren tries to contort her body around the rocks at the entrance but has little luck.

“Joel, do you want to try?” she asks.

Ashman wriggles down, feet-first, as far as he can.

“My chest is bigger than my behind, and my behind is having a hard time,” he says.

After marking the correct GPS location, Herren makes a note for future explorers: It’s a “skinny-only” cave.

We hike to Gorman Sink, where Herren points out a tricolored bat in torpor and we crawl through a few passageways.

Ashman tells me why he spends his time volunteering for the project.

“I like exploring,” he says. “I like crawling into places where not many people have visited.”

At Copperhead Cave, we slide down a dirt hill to gain the entrance, then crawl through a narrow passage to find a bigger chamber. The chamber is basically a large tube going through the earth at a 45-degree angle.

Herren, like Gordon, works for Austin’s Watershed Protection Department, and here inside the cave she traces the flow of water.

“You can see where the water flows down and goes through this hole at the bottom of the cave. There’s a whirlpool effect where the water swirls before leaving the hole,” she says, pointing to markings on the wall.

That’s exactly the reason this cave is important to know about. The water going through here recharges the aquifer below.

“I do this partly for conservation because I like protecting natural resources,” Herren says. “I also do it for exploration. Each cave is different — different passages, different animals. There’s something new to see in each one.” 


 Chase Fountain | TPWD


The caves at Colorado Bend, Government Canyon and Hill Country are not open to the public (except Colorado Bend’s guided tours). If you’d like to experience cave exploration and learn more about caves and karst, consider volunteering with the Texas Speleological Association

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