Caves below Mopac a concern for expansion project

Added: 2026-05-07

[00:00:16][music] [music] [music] [music] [music] [music] >> Hi, welcome to Cakes and Plus. Thanks for joining us if you're watching on our socials, our website, or even our Cakes and Plus. Thanks for being here. I'm your host Asma Lassoued Mora, and today we have our What's Driving You Crazy episode where we talk traffic craziness, or sometimes just fun topics like the one we have today. And today with me to discuss this is our traffic expert Erica Brennes. Erica, thanks so much for joining me. How you doing? Good. It's been a busy few weeks as we prepared for this story that I'm about to talk about.

[00:02:19]A really unique one, but it was it was a lot of work, but I'm very proud of the work that I did, and it's only the beginning cuz there's even new news today. Wow. This is this was news to me.

[00:02:31]I was shocked when you first brought up the information behind it. And now that we have an inside look and more details, I'm excited to dive into it, and I'm sure our viewers are like, "What is going on?" What are you talking about?

[00:02:43]So, we're going to talk about caves below the streets of Austin. Caves in Central Texas. Caves in Central Texas.

[00:02:50]There's so many of them, and there is a lot in Austin, and I got the opportunity to go inside just one of the many many many caves. And this one was the one at Bowie High School. And I have some video of that, so. Yeah. And so, here's what spurred this. So, what you're looking at is a map of um the Mopac South area where the Central Texas Regional Mobility Authority is talking about expanding. And And this is video of the cave below Bowie High School. So, rewind earlier my Okay, we're we're in April. I think this meeting was in April.

[00:03:27]I don't remember. It was an earlier meeting at Bowie High School, a public meeting that CTRMA hosted in on an evening. Um and and I went to it, and I was also following along on Save Our Springs, which is a pretty known non well-known nonprofit here in Austin um that works to protect the environment, Edwards Aquifer, Barton Springs, and and some of these jewels of our city.

[00:03:50]And um I was watching on their social media, and they were like, "Oh, we went into the cave below Bowie High School."

[00:03:56]I said, "Excuse me? What? Cave below Bowie High School? Can I go?" And so, I reached out to them, and we went like on a day off. It was like the the teacher at Bowie High School that that um works on the life sciences program at Bowie, he was like, "You got to come on a day off." So, I went um and checked it out, and it was really it was the perfect amount of caving for my comfort level. Um there was no like spelunking or anything crazy like that. Um there I did get an opportunity to go spelunking at a different cave that was much closer to Mopac, but I said, "Absolutely not."

[00:04:34]>> What does that mean, spelunking?

[00:04:36]>> [laughter] >> Girl, it's So, this one uh it's basically where you're I mean, okay, I'm actually not even going to pretend because when I said spelunking to Enzo, who was the caver that joined us at Bowie, he was like, "It's actually really not called spelunking. Like, it's kind of an insult." I'm like, "Oh my god, I'm so sorry." But from what I always knew, it was like when you're crawling through a cave like on your stomach, and you're having to like crawl get your body in weird positions, and I've never been open to that. But there was this other cave that's closer to um to closer to Mopac near like Brush Country and and that area, and um they were like, "It's a crawly cave." And I was like, "Wait." And it was going to be like a 2 and 1/2 hour excursion of crawling on your hands and knees and scooting, and I said, "I'm out."

[00:05:26]Well, that's what you had to do initially to get into there, right? You had to >> have to scooch. I did have to scooch, but like you could stand, it was wide, you could like when we were doing our interviews with with SOS, we were there were four adults standing. So, like there was room. Now, by the end, we were down there for like pretty much an hour, and by the end I was like, "I need some oxygen. Like, I need to get out of here." Cuz there's no fresh air down there in the cave.

[00:05:50]Um but anyways, so long story short, >> [laughter] >> um I did this story because the CT Central Texas Regional Mobility Authority So, CTRMA wants to expand Mopac on the south side of downtown. So, from downtown to Circle C. And it's about 9 miles or so of roadway that they're talking about potentially adding up to two toll lanes plus an additional lane in both directions. And this stretch of Mopac is a little bit different than other than like the north side because you have Lady Bird Lake, and you have the Barton Creek Greenbelt, and it's all over the Edwards Aquifer Recharge Zone. And so um you know, in the past you may have heard Save Our Springs talk about like the salamander.

[00:06:38]And so, you're kind of like, "Well, why do we do all this stuff to protect the environment for a salamander?"

[00:06:42]>> And there's also like a species of grass, right, in the water that they're worried about as well?

[00:06:46]>> I don't know, but probably. I'm actually not sure. We talked about different types of like just bugs and the salamander, and I said, "Well, why?

[00:06:55]Like, what What does a salamander represent?" And basically it comes down to like if the salamander is happy and healthy, then the water is healthy. Like the the health of the salamander is a an an indicator of the quality of the water.

[00:07:10]So, if the salamander goes in extinct, then that means the water is not suitable for life down there. So, I was like, "Okay, well, that's a nice way to like simplify the thing." And I will say I have covered a lot of road expansion projects in Austin and and in my years covering, you know, traffic and and and whatnot in in Austin, this is by far getting the most attention. And when I first started at Cakes and in August of 2022, I said, "The one thing I want to talk about the Mopac South project because is it still on the table? What happened to it? Where do you know, are we whatever." And so, that was one of my first stories I did back in August of 2022 and and in the fall.

[00:07:48]And basically, yes, it was still on the table. However, it had been delayed for a couple of reasons. Number one was a lawsuit filed by the um the Save Our Springs Alliance back in 2016. So, it sort of just like brought that to a halt.

[00:08:02]But then, and they didn't win, but then you had the pandemic. So, it was like a couple of things just working against the Mopac South project. So, it was like this lawsuit and then the pandemic, and then it started getting speed again. And even then, it's still taken this many years. They've been doing a draft environmental survey, um studying the environmental impact of of this expansion project. And basically, the Save Our Springs Alliance wants more done. They want further deeper a full environmental impact statement, which is a more a more extensive study than a draft environmental statement. It's It's a little bit confusing. And whenever I try to explain it to like, you know, the Joe Schmo, it's like I see like twirly eyes. So, basically like And so, does like even the City of Austin Councilwoman Paige Ellis, she wants the the environmental impact statement. So, a further investigation into the environmental impact is basically like layman's terms of what they want. Yeah. They also want a smaller footprint. So, you know, like Paige Ellis was like, "Could we do one toll lane instead of two?" I mean, even up in North Austin, there's only one toll lane. Yeah.

[00:09:11]Could there be some interim fixes? Um there's a bottleneck point a choke point at Mopac and William Cannon in South Austin.

[00:09:20]So, could they just do some restriping there similar to how they did at Mopac and Barton Skyway?

[00:09:26]Those are some of the things that are being asked.

[00:09:28]>> The least amount of changes possible.

[00:09:31]>> And I think at the very least, the William Cannon at Mopac in both directions restriping should be done. Of course.

[00:09:38]>> Even if nothing else happens, Do that first.

[00:09:41]>> no-brainer. I drive that coming into work every single day, and girl, I have questioned before why it was ever striped the way that it was with an exit only lane on northbound Mopac [clears throat] at William Cannon. I'm like, "Oh my god." So like >> Traffic evolves as we move forward. So stripings, the way that they make those roads are going to have to change. Well, in years ago, so and this is getting like insider baseball, but Northbound Mopac at William Cannon, they did restripe it. And then they went back to the old way. And I'm like, "What?

[00:10:17]What are you doing?"

[00:10:17]>> Why? Why? And so it's just these stupid things that I'm like, hopefully at the very least we can get that figured out.

[00:10:23]>> Yeah.

[00:10:24]But we'll see. I mean, so okay, here is what's crazy. Today we found it SOS is going to the CTRMA board meeting today, when Wednesday, April 29th.

[00:10:36]Because they have now filed a new lawsuit.

[00:10:40]And so I mean, so this is like now the second lawsuit this that SOS has filed against CTRMA just for this Mopac South project.

[00:10:47]They also had a meeting last week at Austin High School where tons of people showed up. So there's so much interest and conversation around this project unlike anything I've seen when it comes to roadway expansions in the past.

[00:11:00]>> And how long has it been since they announced that this project was going to start and oh these conversations have happened?

[00:11:06]>> Over 10 years. Wow.

[00:11:08]>> Yeah, I mean, it's been I mean, the idea even like going back to when they did this with the Mopac North project like the the expressway. Mhm. Um so it's always been a possibility.

[00:11:20]>> Yeah.

[00:11:20]What will come of this? I really don't know because CTRMA is playing the balance, right? Like they don't want to do something that's going to completely make people mad.

[00:11:31]But they also have been tasked with helping the flow of traffic. Yeah. So it's like you know, it'll be >> slope.

[00:11:39]>> It'll be very interesting to see what comes and and in in my many years covering Austin traffic, I'm like, I don't know. I don't know what they're going to do. In your many years covering Austin traffic, have you thought that you would discover caves? Did I This is crazy. No, this is my hometown. I moved to Austin in '96 and I knew, you know, the green belt and the trails and and I knew there were like salamanders, all the things.

[00:12:02]>> All the things, but I'm like, oh, there's literally caves beneath all of these roadways. So take my map my traffic maps for a second so [snorts] I can show you. This is our TxDOT camera.

[00:12:15]It's at Gaines Ranch Loop. Give me a second.

[00:12:18]>> No, you're fine. I know where you It's okay. So basically um one other thing that when Whenever I moved to Austin Here we go. I would drive this part of Mopac, right? Like and I would see this like a sea, I would call it like this blanket of green and it's the trees along the Barton Creek green belt and I always was like, that is beautiful.

[00:12:40]And this is an area that would get expanded. And so you know, it's >> We're going to miss all this green.

[00:12:47]>> it wouldn't take down all the trees by any means. They would build in the center area of that.

[00:12:54]>> much expanding these two roads. Yeah, towards the middle. Like go cuz cuz what's interesting is that they're not going to the reason that they're saying the draft environmental statement is sufficient is because it's within the right of way. So they wouldn't need to expand beyond the footprint that they already like own in a way. Like they wouldn't have to acquire any new land.

[00:13:19]Which it's it's like I hate to unpack that can of worms in a way because it's very it's it goes really deep. However that is what the law potentially states, right? Like they're they don't really have to.

[00:13:35]Could they potentially? I think it's I think it's a possibility.

[00:13:39]Um but we'll see. I mean, when the city council person who represents this area saying, "Please do this that this that."

[00:13:45]Like you know, you would think that they would eventually like listen. But we'll see. Um so let me move to this map. This is a map of the project again from downtown to Slaughter Lane. Which Slaughter Lane is right there. Um there's like the Slaughter Alamo Drafthouse. Mhm. It's by Circle C. On the east side is Bowie High School, which is where I went. And then on the west side is is um is where like Okay. Yeah. Oak Hill and that area. So all of that is um environmentally sensitive along that that green line that you see. That is a big stretch. This is a photo taken um below Bowie High School. And if you see on the left side of that photo, do you see that like pipe? Yeah. So that's a um Oh my god, I'm blanking on it. So whenever they were building Bowie High School in the '80s, they hit this cave.

[00:14:32]They didn't know it was there.

[00:14:34]And so that's a support beam that literally goes through the cave. Wow.

[00:14:39]And so [clears throat] you know, that's what like things like SOS, like that's what they're worried about is that you know, could this potentially could could a cave be discovered that we didn't already know was there? And that did happen for the Mopac expressway on the north side of of Lady Bird Lake.

[00:14:58]Yeah. Um closer to like Enfield and and Cesar Chavez. So it happened. I mean, just recently when Mopac when the Mopac expressway was being built. So it's a it's a real possibility.

[00:15:08]Um this is interesting, Esme. Okay, this is called the Midnight Cave. Wow, that looks crazy. Right? So um I couldn't find the photo off the top from the after. But um this is Okay, so one thing that SOS talked to me about was like the evolution of caves from like a knowledge standpoint, okay? So hundreds of years ago like farmers and ranchers did not like the caves for a couple of reasons.

[00:15:40]Number one, could their livestock or animals fall into them?

[00:15:43]>> [laughter] >> Like, yeah. Okay, great.

[00:15:45]>> That is a great concern.

[00:15:46]>> Fair point. Number two when it would rain, the water would go down into the cave and they wanted the water. So they would do things like close them off. They would put rocks inside the cave. They would So there has been efforts in the past to pull rocks out of caves to get them back open.

[00:16:04]The other thing that caves have been used to used for is to dump trash. So like the this Midnight Cave, this photo that you're looking at is full of trash and it was cleaned out over years. It took years to clean out this cave. And this is actually one that I actually really wanted to go into. If you pull up my um I think if you pull up my web article >> Yes. And you play the video, you'll see um I do have a video of the after of that cave cuz it looks amazing. We might have to wait a little. I know, we might have to wait a little. You can keep scrolling until that loads and see what else we have um to look at, but or you can take back my maps or whatever whatever works for you. But um they've cleaned out the cave. So it's been a big transition, right? Of like how people feel about caves and what do caves represent and what are their purpose? And it's just really interesting that, you know, once upon a time it was like, oh, we can't have that cave cuz we want to keep the water up here for our ponds, for our livestock and that sort of thing and and um anyways, but now, you know, we know what the caves represent and how important of a resource water is.

[00:17:13]Um but this cave was so pretty to see um in photos. I actually What's funny is that I told the people I was like, I would rather go into a cave where y'all have to lower me down like the Midnight Cave.

[00:17:27]Yeah. Then which is close to Bowie, which is very near where I was. I was at Bowie. And you had to get strapped in.

[00:17:33]>> Oh, yeah. So and I got like what's cool is that that little device is one of those like if you've done any rock climbing recently, it like helps you so you don't like plummet to the ground and it also is like I think like 40 lb of resistance.

[00:17:48]Did you have to use it?

[00:17:50]Um no.

[00:17:53]No, but it's it makes you feel a little safer. Yeah. But I'm like, I would rather be lowered down into one of these really big caves than have to spelunk and crawl on my stomach.

[00:18:05]Um but maybe that's for a future time.

[00:18:07]I would go. I mean, I think it's really fascinating um that this lies beneath the footprint of Austin. And so I thought it was just great to be able to like you know, educate some people who may not even realize that this is there. And what was really cool when I was down in that cave was it was completely silent. It was also obviously like pitch black, but we had headlamps and different flashlights and stuff, but except the entire time we were down there, there was dripping water. The entire time. Just But it was silent otherwise. And so it makes you think like, oh wow, you know, when they talk about groundwater and this recharge zone, like that's what they're talking about.

[00:18:52]And it's interesting because when you do look up at the footprint of highway expansion in South and Southwest Austin, we are in a way behind. And that is because of efforts from organizations like Save Our Springs because they work and fight tooth and nail to protect these environmental elements that aren't as prominent on like the north or northwest side. They're there, but they're it's not quite like it is down in in South and Southwest Austin. Yeah, and I think it's easy for us as residents to constantly be pointing out, "Hey, this I-35 project never got finished." But you also have to keep in mind that there's things like this that slow down those projects, right?

[00:19:33]>> And they did file a lawsuit against I-35, but that didn't work. So they do they do their See, there's the the where I'm talking about the water dripping. So at this point in this cave, I'm 50 ft below Bowie High School.

[00:19:46]And so yeah, we we basically it was basically a vertical climb down to where we were. Yeah. But I'm standing on literally a gate. A platform. That's look look at this. I point down and that goes a hundred more feet down.

[00:20:00]>> Oh hell no. I don't know how you did that. I would be terrified.

[00:20:04]>> It was It was very cool. I mean, I definitely would like Now this this video which was taken decades ago. Look at that guy crawling absolute like you could not catch me there.

[00:20:16]>> But this is this cave right here is below Slaughter Alamo. Wow. And Nico Howard who is a hydrogeologist who has studied caves and and done work with the city for decades and decades, he was saying when you're in that cave below the Alamo Slaughter, you can actually hear um the movie theater up above. Can you hear if you're under a road, can you hear the those cars coming in and out?

[00:20:39]>> I'm sure. I mean, I never went under a cave that was directly below MoPac.

[00:20:44]So [laughter] I'm like Maybe stay away from the road.

[00:20:47]>> I know. I know, but it is It's very interesting and so the deal is through and part of the lawsuit that SOS this new one that they are filing um has to do with public comment and making that public comment available for all like publicly public law Make the public comments public like Make the public comments public. Right.

[00:21:12]Which actually they do when you look at some of these highway projects like you'll download a PDF and it'll be like this is 375 five pages long. The first 25 are like the actual nuts and bolts and then the rest are like public comments. I've seen that before. CTRMA says they're going to release the public comments. We'll see I'm This is literally happening right now this meeting. Um so we're we'll learn more about it.

[00:21:34]Um but you can you can leave a comment till May 3rd is when the public comments um time frame ends for this project.

[00:21:42]It's May 3rd and on kxan.com you just have to look up these Austin caves.

[00:21:46]You'll find my story. You'll find the link to um to be able to leave your public comment.

[00:21:51]>> Yeah, it's titled KXAN's Erica Brennes explores cave below Bowie High School to learn about aquifers and the video we played if you want to watch that in full with the audio, it's in the article as well plus those links you were talking about.

[00:22:05]>> It was a real treat, you know, to be able to bring this story to the public, to bring it to our KXAN viewers and hopefully shed some light on, you know, what what lies beneath our feet which is most of the time out of sight out of mind. Um and just to be thinking about our impact on the environment and um CTRMA has said that it it that during the construction phase it could have some impact on the environment, but that long-term it would have minimal impacts. That's another part of like them not necessarily having to do a full environmental statement is that it would have minimal impacts, whereas if the draft environmental statement had found significant impact, they would have to move forward with this full statement.

[00:22:49]Again twirly eyes you're like what are you talking about?

[00:22:53]They would have to do a deeper study if it was going to have a significant impact. Interesting. You have also SOS who says we absolutely don't believe that. Yeah.

[00:23:03]>> So it's two sides of every story, right?

[00:23:05]Like I mean but when you see those caves, you think huh.

[00:23:10]That is right below our footprint.

[00:23:11]>> How is a construction project not affecting these [snorts] caves? They're right underneath us. They're right underneath us. And you we got to we got to be, you know, protecting our resources especially when it comes to water. I mean, my goodness.

[00:23:25]Um you know, we we need a lot of water.

[00:23:28]>> Yeah, Texas is in a crisis right now. We do need all that water.

[00:23:32]>> I know.

[00:23:32]>> to share with you when you first mentioned to me about finding these caves, I spoke with my mom about it and she's a retired science high school science teacher and the first thing that she mentioned was oh my gosh under a high school do the science teachers know about it?

[00:23:47]>> Yes.

[00:23:48]You need to tell her it's the I'm like also I'm going to get my hair done tomorrow and I'm like oh you really need some help. Um the tell her it's the life sciences teacher at Bowie High School and what's so cool is that when I did this story, I had so many people messaging me saying I didn't even I went to Bowie or my kid went to Bowie or Yeah. I had no idea there was a cave there. There sure is. So science classes need to get in there.

[00:24:09]>> It's the life So if you want to if you have a kid that goes to Bowie, you got to tell them to take the life sciences classes and that will get them into that cave.

[00:24:19]That is awesome and it's such a great tool to have right in our backyards. I think it's I again, I feel enlightened and I know the kids will too.

[00:24:28]>> [laughter] >> Well, this was a fun topic to learn about and we'll get back into traffic later, but this was we needed to talk about it. We needed to unravel >> you my caving experience. Our caveman era. Yes.

[00:24:41]>> Cavewoman era. Cavewoman era. Bam bam.

[00:24:44]Bam bam. Well, thank you for joining me Erica and we'll talk to you next week.

[00:24:49]>> All right, bye. For anyone who is interested in hearing more about this weather that we're expecting today, we will be talking about it later today. If you're live watching us live, stick with us. Kristen Curry will be with us soon and we will chat more about this severe weather we're expecting. Thank you.

[00:25:18]>> [music]