Engaging Experts
After 25 years helping litigators find the right expert witnesses, Round Table Group’s network contains some of the world’s greatest experts. On this podcast, we talk to some of them about what’s new in their field of study and their experience as expert witnesses.
Engaging Experts
Engaging with Hydrogeologist Expert, Theresa Jehn-Dellaport
Want a masterclass in expert witnessing from someone who’s seen it all? Hydrogeologist Theresa Jehn-Dellaport joins us to unpack how technical experts can protect credibility, communicate complex science with clarity, and navigate high-pressure moments without losing the thread. From her first landfill siting testimony to water court battles and federal cases, Theresa shows how careful preparation and ethical backbone shape outcomes.
We dive into the first call playbook—what attorneys ask, what experts should ask in return, and the single red flag that ends an engagement: any request to ignore data. Theresa explains why credibility is a one-time currency and how to safeguard it across reports, social media, and public talks. She shares actionable deposition tactics, including pacing your answers, asking for breaks, and refusing to opine from flawed exhibits. Her approach centers on visual storytelling: GIS maps, groundwater animations, and simple demonstrations that bridge the gap between advanced modeling and lay understanding.
You’ll hear how venue differences—civil court, federal procedures, and Colorado’s water court with its referee process—change structure but not the essentials of good expert work. We also get into rebuttal strategy: how to evaluate opposing reports, concede valid points without losing your thesis, and frame disagreements in terms of data and methods. Underneath it all is a blueprint for strong attorney–expert relationships built on respect, clear roles, and independent judgment.
If you’re an expert curious about taking the stand, an attorney aiming to get the best from your experts, or a listener who loves the craft of clear communication, this conversation delivers practical, field-tested guidance. Subscribe, share with a colleague who needs it, and leave a review telling us your go-to tactic for keeping credibility front and center.
This episode is brought to you by Roundtable Grip, the experts on experts. We've been connecting attorneys with experts for over 30 years. Find out more at RoundtableGrip.com.
SPEAKER_00:Welcome to Engaging Experts. I'm your host, Noel Ballmer, and today I'm excited to welcome Teresa Jen Delaport to the show. Ms. Jen Delaport is a hydrogeologist and the owner of Quantum Water and Environment, an engineering firm specializing in water resources, environmental remediation, investigation, and cleanup. She is a published author and holds a master's in hydrogeology from Wright State University. Ms. Jen Delaport, thank you so much for joining me here today on Engaging Experts.
SPEAKER_02:Thank you. Happy to be here.
SPEAKER_00:Let's jump into it. You have several decades of experience in hydrogeology. How did you first become involved in expert witnessing?
SPEAKER_02:It was on my very first job as an entry-level junior staff member. I was um an expert witness at a hearing for a landfill sighting location in Lancaster, Pennsylvania. So I had like maybe a year or two experience, and they wanted me to do it, so I did it.
SPEAKER_00:What was that like? Were you even aware of expert witnessing as a career or as a job at that point?
SPEAKER_02:Yes, I was. In our graduate school, uh, there was uh an attorney that did teach a class about it and the legal aspects of water. And so she was able to teach us um various things about being an expert. So I wasn't completely unfamiliar with it.
SPEAKER_00:What were some of the things that uh she taught you, kind of showed you the ropes a little bit that you think other new expert witnesses should know when they receive that very first phone call out of the blue? Because a lot of experts don't have that opportunity. They haven't been coached at all. They just receive a call saying, Hey, I've got an action and I need somebody with your expertise. What are some of the things that uh that they should know?
SPEAKER_02:Well, first of all, don't be afraid of it. Um if they're calling you to be an expert, you're the expert. And you will know more than anybody else. Uh depending on the attorney, the attorney will coach you on how to be one if you've never done one before. And they will also um practice with you. Um, I've had one attorney, you know, was kind of very specific about what I should say and not say. And um, he was very good about saying, well, that's a good answer, but could you also just say it this way? And he would ask my opinion. And if I didn't agree, then he was fine with it. So, you know, work with your attorney, look at some of the podcasts, I guess, on or listen to some of the podcasts, um, and just be yourself. And the other really, really important thing is not to answer the question immediately. And that's one of the hardest things to learn as an expert because it's not you're trying to have a conversation with the attorney, don't do that. Take a breath and and stop before you respond. It's very hard to do, and it's very hard to be consistent. One of my techniques over the years was is that I would wait for the court reporter to finish typing in the question before I would respond. That was kind of my cue. But now it's not quite so clackety clack. And so you know, you can't really tell because they're using your computer. You can't sometimes you can't really tell if they're gone or not. So anyway, it's it's really, really difficult. And that to me is the biggest thing.
SPEAKER_00:Let's talk about some of those uh initial phone calls. So you get a phone call from an attorney. What are the sorts of questions that attorneys ask expert witnesses for a new engagement? And what are the sorts of questions that expert witnesses should be asking the attorneys as well? Because it is a two-way vetting process.
SPEAKER_02:Yeah. Um, so the attorneys will ask you about your qualifications, whether or not you've done something similar, whether or not you have the expertise, and you just have to be honest enough front, completely. Don't over-emphasize any of your qualifications. Just say, yes, I've done something similar, and this is what I've done. And they will ask you, do you feel comfortable with it? And if you don't, say you don't and just decline it.
SPEAKER_00:Um, absolutely.
SPEAKER_02:Yeah. And then you also have to be comfortable with the attorney. If there's an attorney that you don't feel like you have a rapport with, um, and that does happen, you can decline that as well. Just don't take on anything just because you've been flattered or you feel like you can do it. You have to be super comfortable because if you're not, that's going to come out in your testimony.
SPEAKER_00:Are there any red flags that you look for that let you know, gee, maybe I shouldn't take this engagement?
SPEAKER_02:Yes. I and it's never happened to me, but it's happened to a colleague where they've asked uh expert to not talk about a piece of data. Can you just ignore that piece of data in your testimony? No, you can't. Your credibility can only be lost once. Once it's lost, it's out there.
SPEAKER_00:Absolutely. Speaking of having uh your credibility is out there, everything that we write these days is on the internet. And a lot of expert witnesses are well published or have an active social media presence. What are the sorts of things that experts can do to make sure that they stay consistent with what they're saying in their regular daily life? Because uh, you know, they can be impeached during depositions or cross-examination or rebuttal reports on anything that they've ever said. How do you keep track of everything? And how do you respond when uh somebody tries to impeach you on something that you've said before?
SPEAKER_02:Well, that's a really good question. And I've seen that happen to other experts. Well, in this case, you said X, and now you're saying Y. And why does that happen? That's never happened to me. It's just try and be consistent and technically, scientifically engineering accurate on everything you do, and then you will be able to come up with an answer if something was different. And technically, uh, it is a challenge. In in my case, a lot of these cases are decided by a judge. There is no jury. And I have found that in the really highly technical cases, the judge doesn't understand. And they would split the baby. That that's happened to me more than once.
SPEAKER_00:Tell tell me a little bit more about that. How do you handle those sorts of situations?
SPEAKER_02:Well, it's, you know, the judge decides, and then the attorney can decide whether or not they want to appeal it or not. And I I've had that more than once where they just divide and give everybody half.
SPEAKER_00:Uh let's talk a little bit about preparation. So, expert witnesses find themselves in all different high-pressure situations. There's report writing, there's depositions, there's cross-examination if you make it to a jury trial. How do you like to prepare for a potentially contentious action?
SPEAKER_02:Yeah, you mentioned um report writing and um deposition and so forth. So, what one of the other things that's very important in my field is exhibits. So, exhibits um tell a story. Most people are visual learners, and if you can prepare exhibits that describe the very technical details to a lay person well, then you've done your job. So that's how I like to prepare is I start with the visuals first and then go down from there and prepare the, and then once you have the visuals, then you the report writes itself. And preparing for depositions, just read every piece of information that's available. If a lawyer has sent you 5,000 pages, read every single page because it's in the record and you're gonna be asked about it.
SPEAKER_00:Sure. Let's dig a little bit more into those demonstratives and exhibits. Do you prepare those to your yourself or does your attorney prepare those? How do you how do you go about that?
SPEAKER_02:I have an excellent staff behind me, and as an expert, I direct them to do things. So I have an outstanding um GIS individual, so geographic information systems, which is mapping, which is so important in my field. Show a map and show how and then the data behind the map and how the day it works. So we often use animations of data so that uh people can understand what it is. Okay, well, there's a there's a groundwater model. Well, what is that? And so you can show like the surface, and then you can tilt it in an animation and say, well, here's where the groundwater exists, here's how it flows, here's where the creek is, that kind of thing. And that's been super helpful um in a lot of my work.
SPEAKER_00:Is that something that has been there from the time that you've started expert witnessing?
SPEAKER_02:Yeah, well, well, I started, we were using pen and paper.
SPEAKER_00:Sure.
SPEAKER_02:And it changes constantly. And as far as the way we look at it here is that we have to keep on top of all that emerging technology to see how it helps us.
SPEAKER_00:Have have you been through a lot of depositions?
SPEAKER_02:Yes, I've been through many, many, many. I mean, I probably dozen more. I I lost track along the way.
SPEAKER_00:Why don't you walk me through a deposition as a first-time expert witnesses step by step? What are the sorts of things that uh you come into contact with and what are the sorts of questions they ask? And just give me uh an A-Z walkthrough of a typical deposition in your experience.
SPEAKER_02:Well, I I don't think any of them are typical. I think they're all different. Um, it could be one attorney, it could be several attorneys, they could have exhibits that you they want you to look at and draw on. Um, I've been in basements, I've been online. I had one here recently in my office, and they were the attorneys were remote. So it's it's you prepare for anything. And I had one where an attorney wanted me to draw lines on a map, yeah, about a particular thing. And I said, well, first of all, I don't know who created those maps. I don't, you know, there was no information there, you know, in the technical details, there was no scale, there's nothing. So I just said, no, I can't do it. So don't be afraid to do that. Um if you don't know the answer to a question or you need a few more minutes, um, you know, take your time. Ask to take a break. Um, you're you're allowed to take a break and use the restroom and um confer with your attorney. Um sometimes I will take a drink of water to give myself another minute to to think. Um, so have water, have um like cough drops or throat lozengers because sometimes you're talking a lot, then you get hoarse and you're you know, whatever. So always have that available. Um, I learned that the hard way. Like, oh my gosh, you know, talking so much that I have to have something to soothe my throat. So those are two really good things: water and throat lozengers. Just have them available.
SPEAKER_00:Sure, sure. Excellent advice. Do you have any any stories, any tent pull cases that either change the way that you go about expert witnessing or uh reinforce something that you were already doing as an expert witness?
SPEAKER_02:Well, you know, there's many stories. Um but one recent one I did, it was a case about who owns which part of the river. It it had to do with the the thread of the stream. So where was the deepest part of the roof? Uh and a very flat line stream. And so we had used lidar data. So LIDAR data is a type of laser that's that that you could collect data from an airplane.
SPEAKER_00:Sure.
SPEAKER_02:And so I um um was trying to illustrate how a laser goes through water, and so I thought, well, use a laser pointer and point it through a glass, right? And so I had purposely packed a laser pointer and everything, and I got to the courtroom and I couldn't find it where I don't know what I did. The opposing counsel as I was going up, he says, Oh, Teresa, do you need a laser pointer? So I said, sure. And the judge had a glass of water on his desk, so I was able to demonstrate that very easily. So that was kind of a fun coincidence there.
SPEAKER_00:Quick thinking, huh?
SPEAKER_02:Yeah, and then that particular day, you know, I was not feeling a hundred percent either. Uh I had a little stomach bug or something, so that the opposing counsel was a little grumpy at me and because I wasn't responding quickly enough. And I just I used I because I'd already told them that I wasn't feeling well. And I said, I apologize, Judge. I'm feeling a little under the water, just give me a minute, you know, and uh so just to get the sympathy for me. So that was one thing I get. Yeah, you have to be you have to be quick on your feet. And don't let up jud don't let an opposing counsel bully you. If they are if they are just after you rapid fire questions, don't answer right away. Take a minute and don't let them roll over you. And hopefully your counsel will object to the bullying.
SPEAKER_00:How important is your demeanor in these in these actions if you are in a deposition or if you're in court? And when you're on something like a remote telepresence deposition, does that change anything?
SPEAKER_02:Yeah, all good questions. Um, be yourself, don't be hostile. Uh, some of the best experts I've watched, they're friendly. They want to be your friend, they want to explain it to you carefully. And those are the best kinds because it's disarming. And so don't don't be hostile. You know, the opposing counsel is just doing their job and they're asking questions. They're gonna try and chip you up, and they they do, but you know more than anybody else. Just know your stuff.
SPEAKER_00:Uh have you written rebuttal reports before?
SPEAKER_02:Yes.
SPEAKER_00:Tell me a little tell me a little bit about the differences between writing an initial report and writing a rebuttal report.
SPEAKER_02:Good question. Well, the initial report is your opinions. It's this is this is what I found, this is what I'm doing. And then a rebuttal report is can be a couple different things. So a rebuttal report, you could be looking at your opposition's expert and reviewing their report and say, well, yeah, but you didn't look at this or you didn't look at that, and we don't agree with this kind of thing. This the other kind of rebuttal report is a rebuttal of your of the rebuttal. So if another expert writes something to you, then you can respond to their comments. So um rebuttal of a rebuttal kind of thing. So it's looking at, you know, maybe they have look seen something that you piece of piece of evidence that you didn't know existed that you weren't aware of, and then you could look at as in a rebuttal, and you could say, okay, well, I do agree with that, and or you don't agree with it.
SPEAKER_00:There's a variety of venues out there, and they range from subject matter, things like working in torts, class actions, IP, etc. And then there's also uh look locations. You might work in a state or local government, a new state, a new country, or a new type of court. Um, have you worked in different venues? And if so, as an expert witness, how are some of the how does some of these differences affect the way that you go about expert witnessing or preparing?
SPEAKER_02:Well, yeah, sure. Um, I uh work in civil cases. I was an expert for a federal case. A lot of my work is in water court in Colorado as an expert. So, yes, there are different venues, different rules, different types of ways that the attorney wants you to respond. Civil cases um are a little different than a water court case. Water court case is also decided by a judge. Um, you can in a water court, you can go to a what's called a referee first.
SPEAKER_00:What's a referee?
SPEAKER_02:So a water court referee is below the judge. So the referee, what they try and do is bring the opposing parties together to come to an agreement before going to trial. So the referee can say, well, you know, uh City X, if you if you do this, um, will you will they get out of the case, that kind of thing? And so you come up with called a consent decree. Um and if you if that fails, then you set it for trial, and then you have all the trial dates and all that all that stuff.
SPEAKER_00:Sounds a little bit like a uh like an arbitration or something.
SPEAKER_02:Kind of, yeah. Kind of. And then the referee can sign a ruling. So there's that, and then of course there's civil cases, and then um at the federal case, I get federal judge. When you've worked for I've never been in front of a jury.
SPEAKER_00:What when you've okay, well, when you've worked for a federal case, for instance, are there differences that your attorney makes you aware of saying, hey, I know this is the first time you've been in this venue. These are some of the changes, these are some of the things that you need to do differently.
SPEAKER_02:Yeah, good question. Yeah. Um, it was a while ago, and I'm trying to remember exactly, but yeah, he did coach me very well on what to do, um, how the report needed to be formatted, uh, those kinds of things. And it was I it uh that one settled before it went to trial, so it was only deposition, but um similar, similar. But the the attorney coached me pretty well.
SPEAKER_00:Let's talk a little bit about a couple general topics. What makes for a positive expert attorney relationship? Or put another way, how do you get off on the right foot and maintain that momentum and have a just a good productive relationship throughout the engagement?
SPEAKER_02:Yeah, big question. So I work with many, many attorneys. Um, I work very well with attorneys that respect my opinion, um, ask me very detailed questions, uh, learn about the topic. Um, I had one attorney who was completely new to it, it was a water trespass case, and he came to my office and we just went through everything step by step by step so he could learn it well. And um, so those are those are the best, those are great. You get a really good report, they're very respectful, they trust you as an expert, and they ask your opinion, they make sure everything. Um, they don't try and do your job.
SPEAKER_00:Well, as somebody who's worked with so many attorneys, are there any behaviors that uh are off-putting or that you wish that other that attorneys knew about and things that they shouldn't be doing?
SPEAKER_02:Yeah, tell me what my opinion is. I I've had one or two of those, and I told them, you know, I've had them say, Well, your opinion is going to be this. And I I have I have said, I can't work for you, I'm sorry. I just can't do it. As I said, or your reputation can only be lost once. Yeah. And so I had to tell the client, I'm sorry, I really, unless you change attorneys, I can't be your expert.
SPEAKER_00:You've mentioned your reputation and credibility uh several times. What are the things that what makes a credible expert witness? Is it being current in your field? Is it being well published? Is it your demeanor? What what are the the most important aspects of credibility?
SPEAKER_02:Yeah, a very good question. Yeah, in my case, it's always being upfront and honest. Uh with if you don't know the answer, don't make it up. You know that you could be relied on to give give scientifically accurate information.
SPEAKER_01:Sure.
SPEAKER_02:And um, yes, and all those things. So being published, public speaking, being well respected by the regulatory agencies, so working well with regulatory agencies is is another thing in my field that I've no I've seen so many people just be extremely hostile to regulators when they represent a client. And I I, you know, these folks are just trying to do the job. And so you have to be respectful of them and what they're asking for, which maybe you know seems silly to you, but that's what they need to do. And so getting that rapport with regulators, so then you have that reputation all the way down the line, and with contractors and anybody that you work with. So uh respectful.
SPEAKER_00:Absolutely. Before we wrap up, do you have any last advice for expert witnesses or attorneys who work with experts?
SPEAKER_02:Yeah, sure. I I worked with several very well respected consultants who have never done it. And they they say, Well, I just I don't know if I can do it. You can. Uh maybe you have a you have to have a certain mindset to do it. I I work with a lot of introverts and it's okay. I just it's not for everybody, I guess. And if you if you don't feel comfortable, then don't do it. Because it'll come out in your testimony.
SPEAKER_00:Sage advice. Ms. Jen Delaport, thank you so much for joining me here today.
SPEAKER_02:Well, thank you. I appreciate it. My pleasure.
SPEAKER_00:And thank you as always to our listeners for joining us for another edition of Engaging Experts. Cheers.
SPEAKER_01:Thank you for listening to our podcast, Engaging Experts. Our show notes are available on our website, roundhable group.com.