[00:00:00] Bridget Scanlon: Welcome to the Water Resources Podcast. I am Bridget Scanlon. In this podcast, we discuss water challenges with leading experts, including topics on extreme climate events, over exploitation, and potential solutions towards more sustainable management. I'd like to welcome Robert Meese to the Water Resources Podcast.
Thank you so much, Robert, for joining me today. My pleasure. Robert is the Executive Director at the Meadows Center for Water and the Environment and is also a professor of practice in the Department of Geography and Environmental Studies at Texas State University. Robert has had this position since 2017, and prior to that, Robert worked at the Texas Water Development Board for 18 years as a Deputy Executive Administrator for Water Science and Conservation.
So your background is extremely interesting, Robert, because it bridges the gap between the science, the technical aspects and policy and really admire what you've been able to do to link those fields.
[00:01:13] Robert Mace: Well, thank you. And you did mention that we were colleagues, I guess, at the Bureau for I was there for about eight and a half years, which is where I got bitten by the science and policy bug. I worked on a study that was looking at natural attenuation of contaminants from gasoline spills underneath gasoline stations with natural attenuation being naturally occurring bacteria that were breaking down those constituents. And so it was very satisfying to do that study. And it was literally placed on every desk over at the state Capitol.
And then, and then led to some substantial changes in how the state was addressing those contamination issues. And so, so I was bit by the bug there. I haven't looked back since,
[00:02:03] Bridget Scanlon: well, we've known each other since the late nineties when you first came to Austin from New Mexico and
[00:02:09] Robert Mace: early, the early nineties.
Yes, 91
[00:02:16] Bridget Scanlon: So Robert recently published a book called Groundwater Sustainability: Conception, Development, and Application. And so it's available on Amazon. It came out in January in 2023. And I know what you were doing during COVID, Robert. And I would encourage listeners to read it because it is tremendous, a wealth of information.
And I love the historical context you provide for many of the concepts related to sustainability and all of the different examples that you show in the book. And it's difficult sometimes for people outside of groundwater resources to understand these fundamentals. And this is presented in a way that people can pick it up, I think, right with the illustrations and other descriptions.
[00:03:06] Robert Mace: And I'm glad you picked that up. I mean, one thing I. I gained from kind of being a scientist working in the interface policy and science is that communication is really important. A lot of scientists and engineers will complain that the policymakers don't consider their work, but if you're not speaking in a language that they can understand, for example, I do not use acronyms.
I'm very anti acronym and using acronyms, they're not going to get it. And if they don't understand it, it's not going to work into policy. And so that has turned into my writing style. And I was very fortunate that the editors at Paul Grave Macmillan, he allowed me to write the book I wanted to write, which is, it is an academic book, but it is written for practitioners, policymakers, just I would rather explain things clearly than try to impress people with my big words.
[00:04:06] Bridget Scanlon: And that's interesting that you bring that up, Robert, I mean, I'm serving on a NASA committee these days and every word, other word is an acronym and I have to to translate.
[00:04:19] Robert Mace: The Feds are the worst. I mean, we were all bad, but, but I've been in meetings. Sat there for two hours, had no idea what anybody was saying.
Yeah. And I get it. Yeah. It makes things easier for us to communicate within our own little scientific subcultures, but does create a major barrier to understanding even in a multidisciplinary world, let alone the public and policymakers. So, so one of these days I'm going to write a book that pretty much declares war on acronyms and probably when I retire,
[00:04:51] Bridget Scanlon: I think some people use it as a test to see if you belong? Yeah, yeah. And so to, to write this book, you had to submit it for review the concepts of the book early on. So maybe you were telling me some funny stories about that.
[00:05:06] Robert Mace: Yeah. Gary Schindel who's recently retired from the Edwards Aquifer Authority. I had a professor friend that reached out to him about writing a book on groundwater sustainability and, and Gary, Gary was like, no, not, not interested, but he said, Hey, I recommend Robert Mace. And so, so I got that call and, it has been a life goal of mine to write a book. And so, but at the same time, it's like the last thing I needed to do was write a book with everything else going on in my life, but I was like, yeah, why the hell not?
And so similar, well, maybe not similar. It's like, like, given it's an academic book, it has to go through peer review, which is similar to getting a peer reviewed paper published, but also had to have the proposal for the book undergo peer review. And so there were five peer reviews of the book outline, in the scientific world, we make jokes about reviewer number two, who's a real pain in the butt reviewer.
And so sure enough, reviewer two is pretty, it was a pretty intense review. In fact, my editors were like, don't worry about reviewer number two, you don't have to respond. And I read it and it was a real angry review and, but there was, t there was also some gems in there, gems of wisdom that I could take, but the funniest thing was the reviewer made a comment that, I'm not sure reviewer intended me to see this comment might've been just for the editor, but it was like, this book is too important to entrust to a Texan.
And, and I responded to that comment. I responded to all, all this person's comments, but responded to that comment because, when people think of Texas and groundwater, management, they think of mismanagements and they think specifically about the Ogallala Aquifer in the Southern High Plains, which is really world famous for not producing an aquifer sustainably.
And when I wrote this book, I could see that that was an example that popped up time and time again, across the world literature. A lot of people don't realize that there are a lot of interesting things that occur in Texas. And we do manage some of our aquifers sustainably. And so I think Texas has a lot to offer.
So in this book, it's intended for an international audience, do have international short case studies in one of the chapters, but, invariably I bring my Texas experience to this book and share Texas stories, which I think are useful for various places around the world, because I think the problems we face in Texas are faced across the planet.
[00:07:39] Bridget Scanlon: Right. Right. And I mean, I know from my own work, Texas, we go from semiarid to humid. Yes. Far west to east, subjected to a range of climate conditions, floods and droughts and a variety of different types of aquifers. And I know when I was doing work early on, a lot of the conditions and situations were similar to those in Australia.
So there was a lot of analogs over there. So today, I hope that we can discuss various concepts of sustainability from the book, and I really admire how you bring us through the history of these concepts and how they evolved over time, and then the challenges for managing groundwater resources in Texas and elsewhere and then end up with potential solutions at different scales from the city scale like Austin where we live or and more regional approaches. But so let's maybe start off, when you talk about sustainability in the book initially, you say some of the ideas of managing sustainably come from surface water and the concepts of safe yield and things like that.
And you are in San Marcos and San Marcos Springs, the Edwards Aquifer, which is sort of like a subsurface analog to surface water. And so it's kind of a hybrid between surface water issues and groundwater issues. It's so dynamic, it responds so quickly. And so maybe you can describe what you think the current conditions are like in the Edwards Aquifer and where Texas is at the moment in terms of droughts, conditions and stuff like that.
[00:09:13] Robert Mace: Sure. So we've just come out of three years in a row of La Nina conditions, which tends to mean and certainly has meant for the last three years, warmer than normal conditions and drier than normal conditions. And we've certainly seen that across the state with, with the droughts. It's, if you look at the drought monitor, it's, It's not been as bad as it was in 2011 to 2015, but each drought is different and each drought has a different kind of focus of where it really pounds the state and in the Hill Country and the kind of the catchment zone for the Edwards Aquifer and the recharge zone for the Edwards Aquifer has been particularly hit hard in this drought.
And so we've seen spring levels decline precipitously, J 17, the indicator well, go down also precipitously. For, on and off, depending on the day, for the last six months, we've been seeing the lowest flows in San Marcos Springs that we've seen since the end of the drought of the 1950s, since 1957.
So like right now, the flow is under 80 cubic feet per second. Normally, we would be about twice that for this time of year, and the only time it's been lower goes back to 57. I mean, that's been, pretty, pretty consistent. There's, things go up and down a little bit. If we get some, some rains that come through.
And that, that drought is continuing. at this point, I would call it probably a hydrologic drought, rather than a precipitation drought. If you look at the long-term rainfall amounts were still not normal, but we're not too far from normal. But what's happening is we get, we get a pretty decent rain, soil will suck it all up, evapotranspire it back out, and then, we'll have a big dry spell, and then we'll get another rain.
So we've been getting the rains, but we've not been getting kind of repeated rains that causes a great deal of recharge. And causes a great deal of runoff. So hydrologically, from the aquifer's perspective, we're still, still pretty low flow.
[00:11:20] Bridget Scanlon: I mean, oftentimes people say, we're getting this rain, why are the reservoirs not filling up or why are we not seeing this?
And oftentimes, those rains, you almost need a flood to end the drought. And that's what we've seen in California this year. They had atmospheric rivers in December and January. And that ended the three year drought that they were subjected to prior to that. 2017 was the same. So you almost need a big flood to end these long term droughts.
[00:11:50] Robert Mace: Right. And you need some rains to prime to pump basically kind of. Take, fill up that soil moisture and then have a big rain on top of that. If it was some, that last major statewide drought 2011, 2015 ended with some pretty flood, pretty huge floods here locally. And what was interesting about that was we'd had a bigger rainfall than the one that caused the Blanco river to flow over interstate 35 a week before.
But there was little to no runoff, but then another still sizable storm hit and then caused that flooding. So, so yeah, we, we need Was that the wind? Was that the Wimberley flood? It was, yeah. There was bigger rainfall event before that, but it just all got sucked up by the soil. And then when that second storm hit, it was, soil was satiated and phew, just all ran off.
[00:12:47] Bridget Scanlon: So yeah, a colleague of mine was doing a study on atmospheric rivers in Texas for the Texas Water Development Board, and that was an atmospheric river that came from the Atlantic, and Wimberley floods, so understanding these extremes is very important. So maybe we go back to the sustainability groundwater sustainably.
The safe yield concept has been around for a long time, and you can explain that a little bit, and , John Bredehoeft’s water budget myth, those concepts.
[00:13:20] Robert Mace: Yeah, so the concept of how to manage groundwater, they sourced from surface water management and many, if not most of early hydrogeologists were engineers and presumably they were trained in, how to tame rivers and create storage from rivers behind reservoirs and if you look at how they're managed, they're managed through a safe yield or a firm yield type approach.
One thing I hadn't appreciated till I wrote this book was that everybody uses those terms differently. So for folks that are outside of Texas or other parts of the world, just know that the definition of those terms is really important, but the concept for surface water is like you build a reservoir and the goal is to suck the reservoir out dry as soon as possible, you want to manage it over the long term, and so engineers will then typically make calculations based on the flow coming in over. What's a reliable supply that you can get from that reservoir system year after year without running out of water? That's typically looking backwards.
Some of these issues pop up in the other Colorado River Basin. Did they have enough record? You can always have a drought worse than the drought of record. But that's how that's determined in Texas. We call that firm yield. Other places call that a safe yield. In Texas, safe field means something different. It's what you can rely on year after year with a built in safety factor.
So anyways, when USGS scientists were doing work in California and thinking about how to manage groundwater in one of their basins, they imported that safe yield concept from surface water over into groundwater. And then interestingly enough, also kind of brought in the mushiness of those definitions, the basically it's like how much you can produce indefinitely without causing dangerous depletions and dangerous air quotes is subjective.
What I think is dangerous, you may not think is dangerous, or a legislature might not think is dangerous, or the local stakeholders may not think is dangerous. So it's interesting that the elements of or current definitions of safe yield or sustainable yield, still build that into the concept. That's also, in the book, I read the literature forward in time. So like the first mention of the safe yield concept is 1915. And then I just found papers and reports so I could relive the experience of the development of it. And that was interesting to you because, people started thinking about different things that were important, back in those days, in the very earliest days of safe yield, it was about maximizing production for the benefit of people and the dangerous depletion related more to maybe creating saltwater intrusion that would wreck the supply.
But then with time, as society changed, the definition of safe yield changed, or what was considered dangerous changed to include impacts to other basins impacts to other uses in the seventies environment became important. And so then the environment got brought in as scientists and engineers.
We like things to be reproducible, it's like you can't, it's not good if you have a scientific process that if I do it, I come with one answer. And if you do it, Dr. Scanlon, you come up with a different one, but inherently “safe yield” or really any question of managing groundwater is a policy question.
And to me, it's policy informed by the science and policy is messy. it depends on the people around the table, the time that happens, the information out at that time, those decisions can change with time. And so, sustainable yield or safe field can change as people's policy preferences change.
And there's a lot of angst in scientific literature, hydrogeologic literature about that, which is unfortunate because that to me, that's the way the world works in the policy world. , we don't make a policy decision and, or hopefully maybe you don't make policies to live with it to the end of time because somebody made it.
, how we perceive the world, interact with the world, changes with time. So it was interesting to see that angst through time there. There's also talk in the literature about how sustainable yield is different than safe field. They're not, they're the same thing. It really depends. I think those differences come up when people look in the literature for the definition of safe yield to say yield has been developing over time and sustainable yield is kind of a term that became popular late 80s, early 90s. That's really the same same thing. There's arguments about you should use sustainable yield, not say safe yield because what is safe, which part of me agrees with that.
I think my preference is to talk about sustainable yield.
[00:18:33] Bridget Scanlon: Right. And yeah, I think, when you said that a lot of the concepts are brought from surface water. And so when you look at a reservoir, how much water is coming into the reservoir. And so with the groundwater, then people were fixated on what was the recharge rate, how much water was coming into the aquifer.
And if you pumped that, if the pumpage was less than the recharge rate, maybe you were okay. But John Bredehoeft you have to call this the water budget myth because, and that brings in a Where is the water coming from that you're pumping? Theis, I think, elaborated in the 40s on, so you're pumping water.
Where is it coming from? Is it coming from a reach? You're, you're changing the water balance before you start pumping. The input to the system is equal to the output. So the recharge is balanced by the discharge or the discharge is balanced by the recharge. Then you start pumping. So that water is coming from either increased recharge or decreased discharge.
And so I think those concepts are really important. Sometimes it's difficult for people to remember that, and that relates what is the impact of your pump. Mm-hmm. So if you decrease the discharge of groundwater, then you're going to impact the surface water that the groundwater was discharging towards the springs or other things. And so these fundamental concepts are very important, and the connection between groundwater and surface water is critical.
[00:19:56] Robert Mace: Yes. Yeah. And you mentioned I sit at San Marcos Springs, which is a great example of that, where historically people use the aquifer. And I would say, the state was fortunate that it's a big aquifer.
The San Antonio segment, the Edwards aquifer is a big aquifer. Very early on. The San Pedro and San Antonio Springs in San Antonio stopped flowing due to production there. And then as agriculture came in, and the population of San Antonio continued to grow and we saw severe droughts, then the question was, what do we want to do with Comal and San Marcos Springs?
Well, the locals up here want to keep the springs flowing, but from the perspective of San Antonio and the irrigators at that time, it's like, that's water is getting wasted because it's coming out of the aquifer and it's going down river. And because of the quirks in Texas water law, if you can capture that before it hits a state water course, it's private property.
And so there were serious engineering plans to build a, like a linear array of wells between San Antonio and San Marcos to intercept all that flow to keep it from coming out of the springs to maximize production for human use. Ultimately, it was the Endangered Species Act that saved these springs from drying up.
They, like this recent drought we're in now, if things had gone the way they were going. , back in the late seventies and eighties, they'd be dry right now. Maybe they would come back during really wet periods, but they'd be ephemeral. But it was Endangered Species Act that protected the springs.
, people will be like, well, endangered species act protect spring flow. It really doesn't. It protects the endangered species. And there's assumptions in there. The management of this system is based on a repeat of the drought record, which for this part of the state is the 50s.
But again, we could have a drought worse than the drought record. Setting aside climate change, we could have a drought worse than the drought record. You look at tree ring data, climate change makes it more likely that we're gonna see a drought or something worse than the drought record. So there's still a chance that, the springs go by despite best management techniques, which is why Endangered Species Act provides for these refugias.
So if the springs go dry and everything gets extirpated and killed off in those springs, the species can be reintroduced.
[00:22:28] Bridget Scanlon: Right, right. I mean, the Edwards is a great example because it's dynamic. It responds quickly. You have a drought, it responds quickly. You can see it, . Some other aquifers that are porous media for sandstone aquifers or whatever it may take, years to see the response and stuff. So it's a really nice example for lay people to understand the linkages between rainfall, droughts, floods, and the response of the aquifer system. I think one of the aspects of your book that I really enjoyed was your description of unconfined and confined aquifers. And I think that is really important and very difficult to parlay to lay people.
And in, in Texas, the Ogallala Aquifer is a great example of a large unconfined aquifer, but the Carrizo groundwater is confined maybe. But we're okay with overexploiting an aquifer of water. The impacts, we've talked about the connection with surface water, which happens in unconfined aquifers, but then other aspects could be subsidence or seawater intrusion or things like that.
So maybe you can describe a little bit about, the concepts of unconfined and confined aquifers and those.
[00:23:43] Robert Mace: Sure. So, an unconfined aquifer is, is like, if you have a glass of water with ice cubes in it and a straw, and if you pump your little aquifer, sucking that straw out of your glass of water, you'll see the water level on your glass go down.
And so where's that water coming from? Well, it's, it's coming from the, the drainage of water between the pores. Of your aquifer, between the ice cubes. And so that's an unconfined aquifer. And that's how the Ogallala operates. sand instead of ice cubes and wells instead of straws. There's a water table, which is specific to a unconfined aquifer that goes down.
And, maybe there's a lot of recharge that happens one day. Maybe it comes up. Mostly in the Ogallala, though, it's going down.
Confined aquifer, on the other hand. Is, the aquifer is capped to where it's under pressure. And so in that case, you can still drill a well down into that aquifer.
And, and it's kind of like, I forget what analogy I use in the books. I tried different analogies, but one analogy I like to use is like letting air out of your tire. Like your tire is under pressure. And so if you go over and kind of press on the valve, you can let some air out of your tire. The tire is still full of air.
It's just at a lower pressure now. And, and there's a little bit of compression. Probably you can't measure it depending on how much, if you let a lot of air out of your tire, you'll see it come down. But you get some, you get some compression from the overburden of the car, the weight of the car pressing down.
somewhat analogous to a confined aquifer where you poke a well into it, the water level will rise above the top of the aquifer. If it's, if there's enough pressure in the aquifer, it'll rise above the land surface, be an artesian flowing well. And then if you start pumping that well, you'll, you'll lower the water level but the aquifer will still be full of water. So it sounds a little weird, where it's like you pull all this water out of the aquifer, but yet it's still full of water. , it sounds like some Yoda would say in Star Wars or what the hell does that mean? But it's bleeding off the pressure and in these confined aquifers, it's that pressure that's extremely valuable because in getting water to go to a well, one of the factors is, is the head difference or the pressure difference between the background and the aquifer and the pumping level in your well.
And so the bigger that difference is, the more water you can push to your well, I mean, in some of our aquifers, it's over a thousand feet of pressure above the top of the aquifer and the aquifer may be very, very thin if it was an unconfined aquifer. , maybe you have to put in 10, 20 wells to get the same amount of production from the one well in the confined aquifer.
[00:26:44] Bridget Scanlon: And so in an unconfined aquifer, then, you're draining the water directly from the pore space. And so the cone of depression that they talk about in a well when you start pumping it is usually fairly local. But in a confined aquifer, then that pressure can expand. And so the water that you're pumping in a confined aquifer is coming from compression of the aquifer and compression of the water, and those compressibilities are almost zero, but there's still enough to release water.
[00:27:12] Robert Mace: Now, that's a great point. , the Ogallala is a fabulous groundwater resource and it's a big part of what makes it so fabulous is it is unconfined, which allows all those thousands of farmers to, to do their thing, but like the Carrizo Wilcox, which is mostly confined, the cone of depression around Bryan College Station is like a hundred miles wide, so it stretches across three counties.
Yeah, sometimes there's talk in the legislature about assigning like, if you pump a well and you pull water from someone else's property, you owe them a check because you've, you've taken their water and, there's a certain logic to that, I guess, but then I'm like, what the hell does Bryan College Station do when there's probably tens of thousands of property owners that have been affected by their pumping and, how do you calculate that?
That could be an administrative , nightmare in a confined aquifer.
[00:28:11] Bridget Scanlon: And I love the aspects of your book where you're talking about historical development, when they drilled those first wells into the confined aquifer, they had artesian flowing wells. I mean, and they were just gob smacked, this is a limitless supply and, and can go on forever.
And of course they left those artesian wells flowing and everything. And I liked that you presented your book in a reading forward mode, because oftentimes we just think after the fact, well, we knew everything, but it's much more difficult to present the story, like trying to put yourself in the position that they were in or what they knew and what they didn't know.
And so those artesian wells early on, and same in California, they had these flowing artesian wells, not a limitless supply, and there's no end to this.
[00:28:58] Robert Mace: Well, I don't know about you, but I mean, I'll drive a hundred miles to go see a flowing artesian well and have, but yeah, back in the day, the artesian well drilling boom in western society started with the Grenelle well in Paris that captured the imagination of the world.
And it was like a well that took something like seven, eight years to do, they did a cable tool chipping rather than drilling, but to drill, and it came in flowing an amazing amount of water and it was world famous. And so that prompted folks to start wildcatting water wells. And so in Fort Worth in Texas, the first big one was in Fort Worth that then kicked off a bunch of wildcatting of wells across the state.
, and early on RT Hill, who's like the godfather of geology in Texas, with the best information he had at the time said some unfortunate things, which was one of them was it's a. He did limit it, but practically limitless supply, I mean, made some estimates of the recharge rates, which, which were ridiculously high, I'm remembering 50% of rainfall.
And in reality, it's much less than that, maybe 4%. And then what actually goes down dip to the confined zones, 1% of rainfall. And so people just drill these wells in and just let them flow down the streets. I mean, it was like like having a model S Tesla in your front yard. , if you had a flowing well, make the neighbors jealous.
So they drilled hundreds. Dallas was jealous and they drilled their first one at Big Red, the old courthouse, that well is still there. You can go look at it and then they're still using it, believe it or not. And the Trinity Aquifer. And it came in and just gushed really, really good. And people just came from miles around.
There's a guy quoted in the Dallas morning news. He's like, I’d soon come see this than a hanging, this is a lot of fun. but , and then, then the USGS scientists started realizing, well, they saw the pressures declining. I mean, they were just like, Hmm, this isn't good realize that. The estimates that they had made about recharge were not correct and started encouraging people.
Hey, you need to shut these wells off, don't, open them when you use the water, shut them down when you're not to preserve the pressure, but people believe what they want to believe. There's a lot of kind of classic human psychology in this and in respect to how we relate to the natural environment, natural resources, and, within 20 years, all those wells had stopped flowing, right?
[00:31:36] Bridget Scanlon: Yeah. And I think, in, in the book you talk about, I mean, most people are familiar with the Ogallala Aquifer and the fate of the water there, and many people are familiar with the Edwards Aquifer. But I don't think people are as familiar with it than the Trinity aquifer in the Dallas Fort Worth region.
And you described it very nicely in the book, where you see up to a thousand feet of drawdown in the Trinity aquifer for municipal purposes and not just irrigation, and that happened in the early 1900s, right?
[00:32:09] Robert Mace: Right, I kind of point to, so I worked on the Superconducting Super Collider site when I worked for the Bureau and was working on putting together a numerical groundwater flow model because the Department of Energy was considering pumping from the Trinity to cool the particle accelerator for the super collider.
And, and one of the things we develop a model is try to get pre development water levels. So you kind of see how the system was before there was any pumping calibrate to that and then move forward. And so I was surprised like digging back in time that, found this 1901 RT Hill report with all these kind of shut in pressures for these wells.
And it was just amazed at, that was out there and nobody had really dug that far back, which that gave me the history bug. But yeah, people put in all those wells. You see, you saw a cone of depression or water level declines from 1885 to like 1915 and then things leveled off until pump downhole pump technology became affordable.
And then you saw levels drop again, and pretty much they dropped those levels down to the top of the aquifer more than a thousand feet below land surface. And then what we've seen there is like, your productivity of the well, because you don't have high enough background pressures to push the water to your well, went way down, and so I think less than 1% of water for Dallas Fort Worth is groundwater.
it was a lot higher in the day. It's still an important source of supply. I often describe groundwater in Texas as the gateway drug to development, so people will tap groundwater and then people will over pump and then have problems with their wells, and then transfer to, more centralized surface water supplies.
[00:34:04] Bridget Scanlon: And the nice thing that you described about that example, it's mostly confined, right? And so the narrow unconfined portion, then, where there's surface water and groundwater interacting in the unconfined portion is not really impacted that much by all the pumping and the decline and the confined aquifer because only less than 1% of it is coming from that outcrop zone.
[00:34:26] Robert Mace: Yeah, that was the other fascinating thing back, back in my Bureau days, was looking at those huge water level declines and they hinged off the outcrop, the water levels just hinged off the outcrop and, and, and then that prompted me to go look, have there been base flow declines?
No, there hadn't been. It's a permeability limited system is what it boils down to. So there's a lot of recharge coming in and then coming out in the recharge zone, but only a very small amount of it goes down dip. And so even though that thousand-foot water level decline, we've increased the hydraulic gradient, or the volume of flow going deep into the aquifer three to four times.
There's not been a measurable impact, up in the outcrop that's starting to change, not because of the pumping down deep, but because development is now moved over the outcrop. And so now you've got all these household wells out there and they're starting to see some water level issues, similar to what we see in our backyard here in the Hill Country.
[00:35:30] Bridget Scanlon: And, and it's nice, when you say, they deplete, I mean, it's not nice that they depleted the Trinity aquifer, but then they shifted to surface water and they've all these reservoirs there now. And many of the reservoirs at different times are full. And so they could push water back into the aquifer using managed aquifer recharge or aquifer storage and recovery.
And I think maybe we've seen similar thing in Houston, they. pumped a lot of groundwater early on, then they had subsidence, but we didn't see subsidence in the Dallas Fort Worth region, maybe we weren't monitoring it as much, but you had a lot of subsidence in Houston and then that caused them to shift from groundwater, to surface water.
[00:36:10] Robert Mace: Yeah, I did the calculations back in the day up in Dallas/Fort Worth, the rocks are pretty competent, the compressibility is low that you wouldn't have expected to see, even with a thousand feet of water level decline, you wouldn't have expected to see land subsidence.
Houston, of course, is a different story. Those are relatively new sediments, been a great deal of groundwater pumped out down there. And historically, Houston was 100% reliant on groundwater. And, some lawsuits popped up, of one landowner accusing another landowner of pumping groundwater and sinking their property into the Gulf of Mexico.
San Jacinto Monument, which is of course a holy spot for Texans. That's where Sam Houston rushed Santa Ana and defeated the Mexican army in Texas, earned its independence and was literally, literally sinking into the Gulf of Mexico. One of the main roads actually went completely underwater. And so, so there was a lawsuit and then, and then legislation that created kind of a special district, a land subsidence control district down there to basically get people off of groundwater onto surface water to, to minimize land subsidence. And so they manage, similar when I describe groundwater, the gateway drug, they'll let people on the fringes use groundwater and then they reach a certain point where they then, force them over to use surface water.
To control land subsidence down there, that's particularly an issue in Houston because it's so close to the sea level and the massive floods. And we saw some interesting things when Harvey came through, for example, I was still with the state and watching that flood pretty closely and yeah. And we're trying to figure out like when different flood control reservoirs would spill, but nobody had gone out and cited them in a while. And so they'd actually sunk. And so it was hard, hard to figure out what was going on because of the land subsidence.
[00:38:09] Bridget Scanlon: But I mean, oftentimes people think one size fits all. And if you think about California, they've had a lot of subsidence and stuff, but then they think anywhere you have a lot of groundwater depletion, then you're going to have subsidence.
But I think as you say, the Trinity the rocks are not that compressible, maybe the Carrizo Wilcox also winter garden area. There's been a lot of depletion, but I don't think we've seen subsidence, but I'm not sure that we monitored it,
[00:38:37] Robert Mace: but yeah, I would say stay tuned because, there was a paper that came out that was looking at using interferometer satellite data, and it was focused on the Houston area. But, but it happened to like get part of the Carrizo Wilcox and the Bryan College Station, and it showed land subsidence up there. Right. Appreciable.
[00:39:02] Bridget Scanlon: Right, but not to the extent that we've seen in Houston, where you see at the center. Right, so I guess, we've talked about a lot of the challenges, the, the initial overexploitation, and then the adaptation may be more where you can move from groundwater to surface water, but in the Ogallala, dried up a lot of the springs along the edges of the Ogallala and surface water declines, but there, you don't have much surface water that you can use. So you're kind of stuck and the recharge rates are extremely low in the Ogallala. And, it always cracks me up when people say, well, under irrigating areas, you have higher recharge, but they're pulling the water from the aquifer. So yeah, it's going through the soil a bit faster, but it's ultimately coming from the groundwater. And so it's not increasing the groundwater storage, because as you're pulling out as much greater than once going back in.
[00:39:57] Robert Mace: it's interesting too, like the numbers I see for total recharge for the Ogallala in Texas, they're bigger than the average recharge to the Edwards aquifer, but we're pumping it at six times the rate that's coming back in. So that's how I operated my checking account in college. And it didn't have a happy ending.
[00:40:17] Bridget Scanlon: Yeah. I know we did work way back in Amarillo area, involved that they were pumping maybe over 10 times what was recharging and stuff. So you can't do that for very long anyway. But so to get back then to potential solutions, and you've been discussing some already, shifting from groundwater to surface water where they could, but maybe let's look at Austin as an example. I think maybe you participated in the future planning for Austin, the water forward. And I normally think of solutions, and think of a bank account, input minus output = change in your balance, so you to manage it, then you could increase how much you're depositing or reduce your withdrawals and hopefully stabilize. Your bank balance. So can you describe some of the aspects that they're considering in Austin Water Forward (100 yr water plan), this integrated water resources planning efforts? Sure.
[00:41:17] Robert Mace: So, so Austin and in response to Austin, the drought was 2009 to 2015. That became a new drought of record for the Colorado River there, as well as the Highland lakes.
It was disturbing. I know you live in Austin. I lived in Austin. It was disturbing to see how quickly those reservoirs went down, part of that is agreements at the lower Colorado River Authority and how how they manage. And, and for the most part, they're looking backwards at the drought of record.
Austin got concerned where climate change is not considered in regional and state water planning. So they wanted to look at climate change and, and because they're looking at climate change, they also wanted to look out a hundred years rather than the 50 years that State and regional water planning is under.
I joined halfway through the first round and with them now through the second round, but I'm part of a citizen's advisory panel to Austin water and developing this plan and identifying strategies. One takeaway with the current plan, we're currently revising it, but the current plan projects the population of Austin proper, not greater Austin, Austin proper from 1 million today to 4 million people in a hundred years, which was a shock.
It's I'm just like, is that New York city? But that's more density like Los Angeles. I'm like, okay. Maybe, and then, and then the other shock was that looking at climate change in a hundred years, the Colorado River and the Highland Lakes, it's probably going to produce, half of what it produces today. It's, it's, so in other words, it's gonna become a lot less reliable, you can argue about the assumptions. I think a lot about those assumptions. It is, I hesitate to call it a worst case scenario cause it can always be worse, but things kind of lean towards the bad direction in terms of the assumptions of looking at climate change and it's up for debate and how realistic those are, but I'm becoming more, more convinced that that's a good thing to do since there's a great deal of uncertainty.
So in terms of like how Austin's going to deal with that, the biggest is aquifer storage and recovery. Okay. They're going to take excess treated Colorado river water during the good years and inject it into a local aquifer and they haven't chosen. They're in the process of doing studies now. They haven't chosen one, but my guess is going to be Carrizo Wilcox, has a really good track record with San Antonio who does that with the, taking excess Edwards water, storing it in the Carrizo.
They've had close to 200,000 acre feet of water stored underground, which would be equivalent to four years of Austin's annual use of water. So great deal of storage potential there after that it's, it's a lot of kind of using water more efficiently. So kind of like you talked about with your budget, it's like you kind of decrease your use of the resource while also looking for other supplies.
So some interesting things that Austin is looking to do is continue to promote rainwater harvesting and condensate harvesting, amplify their water reuse program. Austin has a new main library down on the lake that uses rainwater harvesting and condensate harvesting to meet all indoor and outdoor non potable uses and by doing that, they've been able to lower their use of the Colorado River by 90%.
Also, I'm recently opened up a new permitting center in north central Austin that collects condensate from air conditioning rainwater, but then also has an onsite black water, basically wastewater treatment plants and the output from that plant goes back in the flush toilets and urinals again, and they've been been able to lower their use of their source supply by 95%. I went to that opening is, is I encourage you to go see it. It's, it's pretty much, it's like kind of out in the open. There's interpretive signage. It's the cutest damn wastewater treatment plant you have ever seen. I've never cried at a wastewater treatment plant opening, but I did it. This one is just so adorable.
[00:45:39] Bridget Scanlon: Right, right. So, so you, you did a report many years ago with Sam Hermitte, about per capita water use in the urban areas in Texas. And so that report, it was tied to the grass is always greener. And it made me think of Irma Bombeck's book, the grass is always greener under the septic tank.
But, so at that point, time and I'm not sure the numbers were about 200 and almost 270 gallons per capita per day or, per household. I dunno, was it per capita?
[00:46:09] Robert Mace: Per, probably, per, that's a, sounds like a 200 gpcd per capita. Gallons per capita per day. So, so it would be probably the total. Yeah, indoor and outdoor.
Yes. Yes. Well, this is probably, for Austin total. And then divided by the population. Right.
[00:46:26] Bridget Scanlon: Right. And 2019, City of Austin was saying it's down to 120 gallons per capita per day. So I think the incentives for the indoor fixtures and maybe people converting to different lawn systems. Systems and all of these things are reducing that demand and they have to do reduce it a lot if you're considering the population growth so many factors to consider.
And when you mentioned with climate change, reducing reservoir volume in the Highland lakes, I guess maybe a lot of that would be increased evaporation related to the temperature, projected temperature increases also.
[00:47:06] Robert Mace: Yeah, that's part of it. And then also just decreased runoff.
[00:47:12] Bridget Scanlon: So a lot of challenges, but you're always trying to adapt to these and, and to managing, you mentioned wastewater reuse, and I guess Big Springs is one of the few areas where there's direct potable reuse globally, I think, or in the U.S.
[00:47:26] Robert Mace: Maybe. Yeah. Yeah. It's the first place in the U. S. to do direct potable reuse, and if your listeners aren't familiar, that's treating wastewater without an environmental buffer that goes back into the drinking water system. Indirect would be, you put it in the river, flow it down the river, pull it out, and treat it, which happens a lot. Direct is like, it's not touching the lake, it's not touching the river, it's not touching an aquifer. It’s direct potable reuse, but that's the first plant in the United States. And the second in the world, the first being in Namibia, Africa, that started in like the mid eighties, El Paso is currently building a big direct potable reuse plants that they call it direct to distribution.
So, so Big Springs project, they treat the wastewater and then it goes into a raw water pipeline that gets mixed with raw water from the reservoir and then goes to a conventional surface water treatment plant. So it's direct potable reuse, but it gets mixed with raw water and goes through additional treatment.
El Paso is going to do direct to distribution, so they're not going to mix it with raw water. It's going to get treated and then stuck directly into the distribution to their community. So that's an exciting project. And there's there's gosh, a dozen. We have a couple dozen projects in the water plan, including several in central Texas to employ direct potable reuse.
[00:48:49] Bridget Scanlon: And with the advances in treatment technology, I think that makes that feasible, tertiary treated wastewater and other things. So I think those advantages have helped. So Robert, you're a glutton for punishment and you weren't satisfied with what you had to endure to produce your first book. Now you're looking at another book and maybe you can describe that a little bit for the listeners.
[00:49:12] Robert Mace: I didn't learn my lesson the first time, so I thought I'll write another book. This one is, it's called Beyond a Reasonable Drought, and it's focused on climate change impacts on on water resources. So similar to this groundwater sustainability book, I'm writing it in hopefully an accessible way and following the water cycle.
All the way around to talk about how a warming planet affects every part of the water cycle, and then what impacts it may have on our water resources again across the entire planet. But I'm Texan. I can't help but bring my Texan experience to the table. So there'll certainly be a lot of Texas stories in there to boot.
[00:49:55] Bridget Scanlon: Well, I mean, Texas is a great field lab for many of these examples.
[00:49:59] Robert Mace: It is. Yeah, it is. It has everything.
[00:49:55] Bridget Scanlon:So you mentioned oftentimes that people don't get your puns, but I guess beyond a reasonable doubt or beyond a seasonal drought. Just to be explicit, so it can be very subtle.
[00:50:18] Robert Mace: I have been warned by editors that, that title may not stay, but I'm going to fight for it. Right.
[00:50:23] Bridget Scanlon: I'm so, so considering all the work you've been doing and your involvement with the states and now at Texas State University and stuff, how do you see the future of water resources in Texas? Are you optimistic?
[00:50:40] Robert Mace: on, on balance, I'm, I'm optimistic. I'm quoted in Seamus McGraw's book about water in Texas is saying that Gulf of Mexico helps me sleep at night and, and it does.
We're fortunate that we have easy access to desalinated seawater. I feel, feel like that is going to bea big answer for us going forward. We'll just, we'll just see when that happens. Corpus Christi has several projects that hopefully one of those will get realized there's, there's legitimate concerns about seawater desalination there's the, the power it's very power intensive, but I also feel confident that renewables and, and energy can be used that doesn't contribute to global warming.
can be found and then the, the disposal of the brine concentrates and the projects that have been proposed that are under consideration now are pretty much discharging into kind of the bays and estuaries. And so that's caused a great deal of concern, but, but I feel like that can be engineered in a way to minimize impacts.
And Texas does have an incentive for folks to go offshore. However, that's, that's expensive. And then people will also say, well. Seawater desalination is too expensive, but, but when you start bringing in these more esoteric reuse approaches, even, even some of the more advanced water conservation techniques, seawater desalination is either competitive or far less expensive. So, so I feel like that that's going to get there. What causes me concern is that the state does not consider climate change in its water planning. And, that's troubling because I think it does put a number of Texans industry, the environment at risk for water supplies.
I also feel confident at some point where maybe we're a little slow in the uptake, but at some point we'll get there, unfortunately, I think in Texas, it's going to. It's going to be something scary that's going to have to happen before things get considered. One of the things I'm working on at the Meadows Center is to provide that information to planners, so at least they have it when they're evaluating their plans, so if they want to, they can then build that in there is an increasing drumbeat of concern about climate change and demand for information on climate change in the regional water plan. So for political reasons the state agencies can't address it, but, but it's academics, we can, it also allows me to leverage kind of my practical experience with working for the state to kind of provide information that the planners can use.
[00:53:32] Bridget Scanlon: Well, I think that's a really good summary because we generally adapt. I mean, you can see with the drought in 2011, extreme drought and a couple of years afterwards, and you could see people maybe changing their lawns and doing different things. It's kind of like quitting smoking. It takes a long time, which but it's a penetration for people to change behavior. And I was just talking to a colleague from Israel yesterday, and they now get 80% of their potable water from seawater desal. And he explained to me that the discharge concentrate, they mix it with seawater. So when they discharge it, it's only slightly elevated and they have these long mile long pipelines where they diffuse it out into the Mediterranean.
So there are things that people are doing. And you're right. It's good that we live, we're next to the Gulf of Mexico.
[00:54:20] Robert Mace: Well, I look at Australia, they built emergency seawater desal plants, and that nasty drought from what, 20 years ago. And they, they've engineered things in a way that minimizes impact to the environment. I also think there's a benefit, seawater desal the environment because even, even tree hugging Austin, if there's a choice between putting water in the river for environmental flows versus keeping water in the system for people, what's Austin going to do? I mean, it's going to be for the people and so if there's a true drought proof supply of water, in my mind that actually increases, the likelihood that they'll, they'll be water in our rivers for the environment.
[00:55:04] Bridget Scanlon: Right, right. And the wastewater reuse, that's also kind of drought proof and increases with population growth. So.
[00:55:11] Robert Mace: yeah, I would argue with you on that, though. It's only as good as the source supply, like, for example, Austin's wastewater, you gotta have water to have wastewater. And so if the river dries up, there ain't no wastewater.
[00:55:04] Bridget Scanlon:Yeah. Yeah. Well, our guest today is Robert Mace, and he's the executive director at the Meadow Center for Water and the Environment, and I would encourage you to read his book. Groundwater Sustainability: Conception, Development and Application. It's available on Amazon. Thank you so much, Robert.
[00:55:43] Robert Mace: Thank you for having me, Bridget.
