What Does a Hydrogeologist Say About Well Development?
Not many people in the water supply industry can say they literally wrote the book on water wells. Thom Hanna can. In fact, he has several books under his belt, including working on the third edition of “Ground Water and Wells,” the “Guide for Using the Hydrogeologic Classification System for Water Well Boreholes” and “The Operational Stage of the Well.” As a hydrogeologist, he has worked for more than 35 years in well design and well hydraulics. Hanna has worked at Johnson Screens for almost 20 years, but he also has an extensive background as a consultant on well projects, including high-capacity, mine dewatering and remediation.
We ran into Hanna earlier this year at the 2019 Mountain States Ground Water Expo in Laughlin, Nevada. Our conversation here is edited for space and clarity.
Q. Tell me a little about yourself. Who are you, and why would readers want to hear what you have to say?
A. Well, I’m a hydrogeologist. I started out in the mining industry and that went to nowhere. I had an educational background in hydrogeology, which is the opposite of everybody else at that time in the early ’80s. So I knew mining and I knew hydrogeology, and all these gold mines started popping up in Nevada. There were huge, huge dewatering operations, and I’d worked on big well projects. So I got my first job in mining, but as [someone] overseeing core drilling. I’d been around drill rigs. So, I got a job designing and installing big Denver-based wells. Some of those walls are pretty deep, over 2,000 feet. Then mining came back, and I knew mining and I knew water, and it was kind of a unique combination. So I got into mine dewatering.
I worked for a number of different companies, and ended up being partner in a company (Hydrologic Consultants Inc.). Then, like a lot of small companies, things happen. I was getting burned out on consulting. I thought, I’ll try something different. So there’s Johnson Screens, a very technical company. I came to work at Johnson to work on the third edition of “Ground Water and Wells.” So that’s what got me to Johnson, was to work on that book. I always said, “Well, I’ll work at Johnson until we’re done with that.” Actually, the chief editor was a partner with me in Hydrologic Consultants Inc. That’s where he came from; he’s a friend of mine. But I’m still here at Johnson and I’ve written two other books since then. The last one was “The Operational Stage of the Well,” which came out a couple years ago. I really like the technical stuff.
Q. Your recent talk at Mountain States Ground Water Expo was about well loss. What causes well inefficiency?
A. If you want to create a more efficient well, you should know what causes it to be inefficient. ... You just have to have an understanding of that, and then you can design and construct it to be efficient.
Q. Obviously, a lot of the drillers out there aren’t scientists. Do you find that there’s a lack of understanding about some of these issues, or do they have kind of an intuitive sense?
A. I think they have an intuitive sense of what causes well loss and efficiency, right, wrong or indifferent, though it depends on the type of well. Obviously, if you’re drilling a domestic well that needs to make five gallons a minute and your aquifer is 300-feet thick, it’s not an issue. Where it gets to be an issue is high-capacity wells. It’s not that anybody couldn’t make any well better; but when you get into the more high-capacity wells, that’s where it becomes an issue. I think that’s where some of the people can separate themselves from others. Like Kyle Widdison (past president of the Utah Water Well Association). Kyle’s made a whole living out of — and he said it himself — developing and redeveloping wells because they’re never developed properly in the first place.
Q. You had talked about designing for development. Can you tell me a little bit about what you mean by that?
A. If you think about it, if I can’t get the water to flow to the well, what good is it? If I start with my concept when I design the well of how I’m going to be able to develop it out, I’ll be much more successful. ... Say you create a well that may have fines, but you don’t take the effort to collect a sample to get a good sieve analysis. You say, “I’m going to use very fine filter pack and a small slot.” Yeah, you may have stopped the sand from coming, but you’re going to have a very inefficient well. Start by saying, “How big can I make that filter pack? How big can I make that slot?” I can now make it more efficient. And, “How am I going to develop that out?” If I say, “Boy, I could develop out a well that’s got a bigger slot and bigger filter pack,” then I’m going to be better all the way around.
Q. What are some common errors you see out in the field as relate to well efficiency and how people are performing installations?
A. The biggest one is inadequate well development. That’s the biggest by far. ... I would say 80 to 90 percent of the time when there’s an inefficiency problem, it’s lack of well development. You say, “Why is that? It’s so important.” It’s interesting because you design the well, you buy the materials, you construct the well, then you’re down at the end of your budget and you’ve got to develop this well, right?
So when I was young and dumb and I was in charge of some of these projects, I was like, “You know, I can make back a lot of my budget if I just cut my development time by half.” But that’s the worst thing I could have done to the well. I left them with a well that was inefficient, and had more problems over the life of that well with biofouling and some other things associated with inefficient wells. That’s from the consultant’s chair. From a contractor’s chair, it’s the same maybe, but there’s more pressure. Again, if there were issues along the way and you get down to the end, it’s like, “Well, I can, you know, come in under contract.” It’s kind of more of a human nature thing of [thinking in terms of] today’s dollars. The hard thing is to go to the well owner and say, “Yeah, I might have messed up this, this and this, but the one thing we don’t want to sacrifice anything on is this part.”
Q. How do you advise contractors on making the case for development, especially when there are time constraints or budget constraints on a project? How do my readers make the case that development is critical?
A. I think at the end of the day, it’s always better to have people come to you and ask you to do the work. I think nothing says that more than good wells.
It’s not an easy thing to do, but as an industry professional you have to be able to go to the customer, and it needs to start from the discussion at day one. We’re going to do these things, this is why we do it, and well development is your best bang for your buck for the overall life of the well. That’s one thing — before we even start constructing the well — you should have the discussion about. The well owner at that point is on board with it. Yeah, if you go over budget someplace else, that’s not the place to cut it off. But you’ve already had that discussion before you even start the project. More often than not, I think any consumer would rather work with a professional — somebody who’s going to provide a product or service, I don’t care what it is — if they feel comfortable and they’re knowledgeable, and they have a reason for doing things. I think where it gets difficult is if you don’t educate the customer ahead of time, you get down to the end and now you have to have an awkward conversation.
Q. From a hydrogeologist’s perspective, what are some things you wish drillers would internalize more? What’s something that you wish drillers would do, or work with more, on projects that you see?
A. I think it’s being aware of how important well development is, and talking to their clients about that and the whole well design and construction process. I think everybody would benefit from that, the well owners and the contractors.
Q. Do you have any parting thoughts for readers?
A. I think, again, one of the most important things is well development. Here’s one of my mantras: The most important thing about well design and construction is development, the second most important thing is development, and the third most important thing is development. If you remember that, you’ll always have a good well.