The Water Table

#114 | Crumbling Ag Drainage Infrastructure = Unique Upgrade Opportunities

• Jamie Duininck • Episode 114

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Trey Allis takes over hosting duties to talk with Iowa State PhD student researcher, Eric Henning about the work he’s doing to assess Iowa’s opportunities as the state replaces its outdated water mains. From reducing ponding, increasing yields and addressing water quality issues, the benefits could be significant to agriculture in the Midwest.

Chapters & Episode Topics:
00:00   Today on the Water Table Podcast
00:25   Welcome Eric Henning
01:00   Drainage District improvements in Iowa
03:00   Crop production impact
04:00   Thinking differently
05:29   Keeping yields private…
06:00   Utilizing satellite images
07:30   Comparing sister districts
09:00   Upgrading the main
10:30   Isolating the corn and soybean fields
13:10   Seeing the damage firsthand
14:19   ET – evaporation and transpiration
16:30   How do you measure that?
18:30   Drainage water recycling
20:30   Digging the storage ponds
23:30   A lot of moving parts
25:00   Where’d you matriculate from?
26:45   Nebraska to ISU
27:40   What’s next?

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Trey Allis (00:12):

Welcome to the Water Table. I'm joined here today by Eric Henning, a PhD student at Iowa State University, working on getting that Dr. ahead of his name. So Eric, thanks a lot for coming on. Want to dive into some of the research, some of the stuff that you've been working on. But first off, welcome to the water table and thanks for hopping on.

Eric Henning (00:35):

Yeah, thanks for having me, Trey. It's great to be here.

Trey Allis (00:36):

Yeah. Yeah. I got your name from Matt Helmers in a previous conversation that we had, and he said, hey, you'd be a good candidate for coming on on the Water Table talking about some of the research that you're doing, and then actually had a chance to bump into you at a conference previously and get a little preface for some of that. But maybe we can just dive into it. You're doing some research on drainage district improvements in Iowa. Talk a little bit about that. What's the overview of the project and what are y'all looking at?

Eric Henning (01:08):

Sure. So to start out, as you may know, and maybe some of the listeners know the drainage infrastructure in North Central Iowa and up there in Minnesota is aging. A lot of it went in a hundred plus years ago by hand with a lot less technology. So a lot of these systems maybe are undersized by today's standards. We have a lot more row crops and a lot more demands out of that land. Or they're failing and need repair.

(01:44):

So there was a project that Matt told me about, so I'm one of his grad students where a little over a decade ago, 10, 15 years ago, they had this idea of, okay, when we go and improve these drainage districts, we need to make these repairs for them to be functional. Let's upgrade the capacity and then pair a wetland at the outlet. And so we can get like a crop production and water quality win-win situation where you address two needs at once. And so there was five districts that they looked at in Pocahontas, Palo Alto, Clay County's, up North Central, Northwest Iowa. There's another group of researchers at Iowa State that have been looking at the water quality, the performance of the wetlands, and have shown that these wetlands are on par with other treatment wetlands as far as nitrate removal, even with the increased drainage capacity. But then nobody really looked at some of the other factors like crop production impacts. So that's where I've stepped in a little bit here in the past year.

Trey Allis (02:54):

Yeah. And I want to jump off a little bit on that, talking about the infrastructure and the situation at hand, essentially that we're dealing with. And that was a previous guest that we had on of Chuck Brandel. He mentioned the similar situation in Minnesota. It's infrastructure that's degrading, like you said, it's been around for a hundred years, probably longer than that. In some cases, installed by hand, old concrete and clay pipes, they're starting to break down. They've functioned for the last hundred years and definitely paid for themselves on that. But at this point, essentially it's a liability in some cases where when that clay does crack or that concrete does break down, it's sucking soil with it. It's moving all that sediment and all that soil and stuff right downstream anyway. So that's the opportunity that we're leading into with what was looked at down in Iowa on how can we do some of this stuff differently, put in these wetlands, put in some water storage on these sites, because essentially, we're only going to get this chance to upgrade this infrastructure and do it the right way.

(04:03):

We have to start doing it a little bit differently, thinking about it a little bit differently, and definitely pairing in that water quality aspect of it too. So that's the other thing with these drainage districts or county mains or whatever that they are, is it's an opportunity to have that water in one location where you can route it through a wetland or through some of these treatment practices too. So just wanted to make that point a little bit and set that stage a little more. And I think that's something that maybe isn't discussed a whole lot or thought about too much where it's just an old pipe in the ground. Yep. But it's been there for a long time, and when we do start looking at updating some of this, the infrastructure, it's we have to be doing it and thinking about it a little bit differently.

Eric Henning (04:52):

I mean, what an opportunity it is, right? The pipe is already in the ground, it's already there. Let's just make it better on both fronts, water quality and for crops. But just to continue on looking at the crop production impacts.

Trey Allis (05:13):

Yeah.

Eric Henning (05:13):

So a couple of things we thought, so it's hard to look across the whole district and compare yields because those farmers are entitled to keep those yields private. But another way to think about it is like, okay, how much crop flooding are we reducing by upgrading the outlets and the district mains and all that? So you can do that by just looking at satellite images. And so that's what I've been working on in the past six months here is looking for satellite images of these districts in May and June before and after they had the improvements. And then comparing them to similar districts around close proximity, similar soil, similar depressional landscape, and saying, okay, before any improvements went in, were they any different? And I found, no, they weren't.

(06:19):

And then afterwards, the reduction is just staggering. We found about 75% or higher reduction in surface ponding, which I should also mention, I'm mapping the ponding on clear days, so it's after the storm's already blown through. I'm looking at the ponding two plus days after the storm's through, so that water's been there for... It's drowned out the crops pretty good. You might lose that whole portion of the field. And then also you have delaying planting and all that. Really, the way I looked at it is pretty much super-conservative looking at ponding two plus days after a storm.

Trey Allis (07:07):

After the rain event. Right. Just to look at what you mentioned with comparing the different districts and just to make sure I am understanding this right, and I have it right. You're essentially looking at sister districts in the similar watershed, same watershed?

Eric Henning (07:25):

Yeah. Yeah. Yeah. So for instance, in Palo Alto, we have the north portion of the district that got the improvements, the capacity improvements, and then the south portion of the district that did not.

Trey Allis (07:36):

Yep. And you mentioned similar landscapes, similar cropping systems, and that was from that previous look at what you did as saying, hey, these have similar, essentially like you said, sister areas that you can make those comparisons. One of these districts is getting the improvements, is getting essentially the upgrade to that drainage main, the other one isn't, and then that's how you're comparing the differences. Am I tracking that right?

Eric Henning (08:01):

Exactly. Exactly. Yeah.

Trey Allis (08:03):

Gotcha.

Eric Henning (08:04):

Yep.

Trey Allis (08:06):

And then with those improvements, and maybe it's different for each of the sites that you were looking at, is it essentially just the mainline improvement or was there also other, I guess, pattern tile or whatever going in those watersheds too? Or is it more so just, hey, we're looking at when you do put in that new main or upgrade that old clay or whatever it is to a new pipe, that's the difference? Or do you have the extent of essentially acres drained or is it just a new mainline?

Eric Henning (08:35):

To my knowledge, it's just new mainline, but adding capacity certainly adds the ability to put in new pattern tile in your fields. And one thing that I think is also important to note is that really, because we were getting so much ponding before any improvements and then upgrading the main just resulted in such a dramatic decrease. It goes to show if you put new pattern tile in that district without enough outlet, it might not do too much.

Trey Allis (09:19):

Exactly.

Eric Henning (09:20):

So it really shows that improving those outlets could really, really make a big difference.

Trey Allis (09:27):

Yep. And that's getting that right size in your whole watershed, whether that watershed is the field that you're designing a drainage system for, or like you said, a county or district watershed with that main too is you, if you have all the, whatever, all the laterals in the world, it isn't going to matter if your mainline is undersized and vice versa too. Yeah. No, and that's interesting. That's what I was just wanted to maybe hit that point or ask that question for how undersized that these mains are. If you just relieve that pressure that's on them, and then that allows the rest of the water upstream to get relieved and keep moving.

(10:11):

The other question or other point that I want to ask too is on, when you're talking about ponded area, ponded land, this is cropland that's, it's been worked, it's been fertilizer put on, it's been planted. This isn't just the cattails and some wetland or whatever that you're analyzing. This is just water sitting on cropland that's already being farmed. Correct?

Eric Henning (10:37):

Yes. Yes. Thanks for pointing that out. So yeah, I'm isolating corn and soybean fields. I'm not looking at anything else. So because yeah, it'd be pretty unfair if I was comparing ponding with one district that has a bunch of wetlands and CRP to one that doesn't. But yeah, I'm isolating out just straight corn and soybean and then taking a percentage of that cropped area in the district that's been ponded in May or June when I'm looking at, that I can find a satellite image for it.

Trey Allis (11:07):

And essentially that's what you're finding pretty consistently is after those improvements, that it reduces that ponding by 70 plus percent?

Eric Henning (11:14):

Yep. Yep. And again, to put that into perspective, let's say you have a 2000 acre district. So for instance, one that I was looking at in about half of the years in the past 20 years, 10 out of 20 years, there's an average of 5% of the cropland that was ponded at some point in May and June. So that would be a hundred acres that might be completely lost. If you reduce that by 75%, you go down to 25 acres. So 75 acres isn't anything to sneeze at when you're talking about complete crop failure potentially.

Trey Allis (11:59):

Yeah. And you can make the argument, and I have in the past of, like I said, those are also acres that you're paying rent on or you're paying your taxes on. You're already applying fertilizer there, you're applying your chemical. This is stuff that you already invested in many times. And then all you need to do is have the weather work out. And in those years that don't, then you're seeing those losses. And that's also leading to the other issues of that fertilizer, those nutrients have to go somewhere as well. They're usually going downstream with the water too. So there's an argument on the environmental side of being able to utilize everything that you put down for that fertilizer and stuff like that. So growing healthy crops has that benefit of consistent yields across the board. And also being able to have all that ground cover too, and not sitting and drowning out, sitting in weeds and having to go back in there and replant or do a whole bunch of other stuff with it too.

(13:06):

So maybe it's just hitting a tough spot right now. That's what we had to deal with here pretty much this last summer down in southern Minnesota too.

Eric Henning (13:14):

Oh yeah.

Trey Allis (13:14):

Fresh memories.

Eric Henning (13:15):

Yeah. Yeah. Well shoot. So I started working on this project in 2018, 2019 were my big year that I was looking for stuff. And then I went up to Okoboji 4th of July and was able to see some of the damage in that neck of the woods. And then it was bittersweet where I'm like, ooh, more data for me to look at to get my point across. But man, it was devastated up here.

Trey Allis (13:45):

Right. Awesome. Yeah. Well, and sorry, I keep sidetracking us on going through this research, but anything else with what you've been looking at for those drainage district improvements?

Eric Henning (14:00):

Yeah, so like I said, with the ponding, and I think just mapping ponding, it's like a conservative estimate of potential economic loss. Another thing that we were looking at was ET, so evaporation and transpiration throughout the year in the improved districts. And so our hypothesis was maybe that you'd see more evaporation without improvements, because you'd have more surface water, and it's just wetter conditions because it's not being not to drain earlier in the year. And then potentially you might see higher transpiration in the districts with improvements later on in the year. Those roots were able to go down deeper, be a more vigorous crop. Unfortunately, like I said, we didn't have very many wet years in our data set, so we didn't see those differences too much. There was a little bit of an indicator that there's more evaporation without good drainage, and that's really just saying that it's verifying that surface water ponding mapping was correct.

Trey Allis (15:26):

Gotcha.

Eric Henning (15:27):

It goes hand in hand. Yeah.

Trey Allis (15:28):

Yep. And like you said, that ET that's evaporation. So that's essentially your ponded areas releasing water through regular evaporation. Then transpiration, that's the crops breathing out water, is that correct?

Eric Henning (15:41):

Yep. Yep. So they like put them together hard because it's hard to measure them two separate things.

Trey Allis (15:48):

Gotcha.

Eric Henning (15:49):

But yeah, it's just water going into the atmosphere.

Trey Allis (15:51):

Yep. And then, yeah, with that transpiration you said, I mean, you obviously see, or you'd hope that you would see more of that with essentially more crops. Less ponding, more transpiration.

Eric Henning (16:02):

Yeah. Yeah. So yeah, like I said, the idea was maybe we would see in areas with better drainage, they could transpire more water in the hot months when they need it, that means they have more water available because the roots are going down deeper and it's just a healthier crop. Like I said, we didn't really see those results yet, right now.

Trey Allis (16:32):

How are you measuring that?

Eric Henning (16:34):

Yeah, so that's a good question. We use this satellite based data set called OpenET. So there's a group, it's really big out west because they really care about measuring how much water they're losing to the atmosphere, where they put together this free data set where they basically measure cooling of the atmosphere and translate that into ET. So the temperature would be lower on the surface if it's evaporating, like how you sweat, how it cools you down on. And so it's a good tool, I think, to be able to estimate some of that stuff for free. Maybe it's not completely accurate, but especially when you're looking at trends or comparing things side by side, it gives you a good idea.

Trey Allis (17:39):

Sure.

Eric Henning (17:39):

Yeah.

Trey Allis (17:40):

Yeah, yeah, exactly. It's good to have those tools available to use in a lot different application like you said out west. Yeah, that's what we're seeing with a lot of the irrigated lands and all the water issues that are out there. A lot of what we're seeing in the Midwest and have seen for a long time is, hey, we have too much water. We don't know what to do with it. Trying to put it all downstream. And out west, they're looking for ways to hold more and to hang on to more. So it's water issues just a little bit differently. And that's something interesting that we're starting to looking at a little bit more as an industry and hopefully talking with some other experts on some of that. And maybe that leads into a little bit of what you mentioned coming up here with some other research that you're looking at with drainage water recycling.

Eric Henning (18:28):

Yeah, so me and Matt and Chris Hay, another drainage scientist, and others, we've been looking at drainage water recycling systems. So there's three farmers in central Iowa who we work with who have installed these drainage water recycling systems. And the way that Matt likes to describe it is it's like a rain barrel on steroids.

(18:59):

So you're routing tile into a big pond that you build in the spring, so you're holding onto water, keeping it, rather than just letting it go downstream, getting it off, but still draining so you can get in and plant and everything. But then holding onto that water so that in July and August when you might need a little bit, you pump it back through a pivot or a sub irrigation system. And then you can, again, it's like a win-win type situation where since we're holding our drainage, preventing all those nutrients from going downstream, and then we're putting them back on the field when we need to put it back on the field, it could be beneficial. So a water quality crop production win-win potentially.

Trey Allis (19:46):

And yeah, and those basins, like you mentioned, having some treatment with nitrogen, phosphorus and [inaudible 00:19:53] and sediment settle out and some of that stuff too, and looking at some other documents, it's only maybe one to 5% essentially of your drained areas that you need to have for that basin or for that settling pond. So the percentage of land that you're essentially taking out of production for that base, and it's usually low land anyway, it is fairly minimal compared to the benefits that you get with essentially all it is is putting on irrigation or essentially irrigated benefit. But like I said, you get those environmental benefits of storing that water, slowing everything down and treating some of that and being able to put that back on later in the year when you dry.

Eric Henning (20:38):

Yeah. Yeah. And really, as far as digging these storage ponds of the three sites that we have monitoring, one of them, they wanted an outlet for the pattern tile that they were going to put in. They didn't have a good outlet, so they dug a pond and it was a low-lying spot in the field that didn't produce very well anyway. Another similar story, they had a corner that just was always wet, always a problem, and they're interested in routing tile to that and then pumping it back. And then another was just actually, it was a pasture tucked between a cattle lot and a crop field. I mean, it was just perfect. It was right at the end of a county main. They had some clay there on site, too, that they could line the whole thing with. So yeah, you can get creative with where you put these ponds. It's not like you're taking out your best land to put it in.

Trey Allis (21:46):

Yeah. And that's what there's no great cookie cutter approach on that. And I know talking with a few other folks too of what's the average cost or what's the estimated input and all this other stuff. They're like, "Well, it depends on everything. What you have available for your water source. If you already have a pivot, do you want to do a sub-irrigation system? Do you have stuff on site to build berms or have that clay and line everything? Or where are you putting your pond? How much water you have coming in? How much do you need?" So a lot of those questions that are hopefully going to be able to get sorted out here in the near future to get better estimates to be able to invest in some of this infrastructure a little bit differently, more above ground infrastructure with some of these pivots. But definitely something that's interesting too, like we talked about earlier, is do something a little bit different.

(22:38):

We've coming out of a handful of years of drought down southern Minnesota and Iowa, and I know the spring was really wet and then now it's dry again here as we're recording this in late September and has been for a little while. So how can we be looking at water use differently? If not just getting rid of it all the time, how can we hang onto it, have a little bit of that treatment for those nutrients, be able to use that water later on in the year? And I think that's something that seems to be gaining some steam with this drainage water recycling. And that's a tip of the hat to folks down in Iowa and a lot of yourself and the researchers that you're working with on some of this stuff too. So it always seems to be the up and coming practice that's out there, and it's just a little bit expensive to get rolling with it.

Eric Henning (23:29):

Well, and yeah, there's a lot of moving parts. There's a lot going on. But another thing that we talked about before we started, but having this water allows you to be creative in other ways, where we work with a farmer, so the one that has the cattle lot, he puts on cover crops in the fall, and then he can give the cover crops water if they need it, because right now we're dry. He's probably going to put on water onto his rye to get it started. And so it just gives him more use for that land. He puts nitrogen through his pivot to be a little bit more efficient with his fertilization. It's just like there's a lot of possibilities out there for putting this infrastructure in and maybe intensifying the water management to really be efficient in all aspects in crop production and water quality.

Trey Allis (24:32):

Right. Just gives you more flexibility with everything that you're doing, be able to really dial in your use of water and fertilizer and whatever else for some of these applications that are likely going to also be up and coming. So yeah, it gives you a lot of flexibility and a lot of ways to adapt and make sure that you have what you need on site all the time. Well, awesome. Wrapping up here a little bit, I forgot to ask you, where did you do your undergrad and where are you from?

Eric Henning (25:03):

Sure. Yeah. So I'm actually from West Des Moines. So grew up in the suburbs, but I've had family always involved in agriculture. Grandparents lived on farms and parents custom farms to lend outside town. So-

Trey Allis (25:04):

Sure.

Eric Henning (25:21):

I was always interested in agriculture, always interested in the environment, hunting and fishing and just enjoying the outdoors. Went to University of Nebraska-Lincoln for my undergrad. So I should mention, my dad's side of the family is all from Nebraska and I'm a huge Husker fan.

Trey Allis (25:41):

Sure.

Eric Henning (25:42):

So yeah, I wanted to go to Lincoln. Ended up getting involved in biosystems engineering, ag engineering, worked in a manure lab for a while doing some soil health stuff with manure application. But yeah, just also took some irrigation courses over there, which has paid off now in my current role.

Trey Allis (26:11):

Right.

Eric Henning (26:12):

But then towards the end of undergrad, was able to connect with Matt Helmers and he had an opening and it really excited me. So I've been over here in Ames for four years now.

Trey Allis (26:27):

Nice. Right on. Yeah, that's what I was curious on coming from Lincoln, coming from Nebraska and how that transition back to Iowa State was like.

Eric Henning (26:39):

Yeah. Yeah. It's funny. So I took an Irrigation and Drainage Engineering class in Lincoln and we get a big textbook, says Irrigation and Drainage Engineering, and then first week the professor says, "Okay, we might do a week of drainage, but probably not because 80% of the state is..." So much of the state is irrigated. So didn't get my drainage education until I came back here.

Trey Allis (27:10):

Right on. And I guess, like you said, you've been involved on ag and some of this research and stuff here for your career and most of your life. What gets you excited about looking forward into the future of water and agriculture and some of that stuff that you're getting involved with? Other than the stuff that we already discussed, already mentioned, but what else? Where do you see the industry going that way?

Eric Henning (27:39):

Well, I would say, I mean it relates to the stuff we talked about earlier today, but just that ability to really be precise and maximize every acre. Precision ag has been a term that's been used for a while, but I think we can do precision ag with water too, where, okay, maybe this wet spot, we can either drain it better or we can turn it back to a wetland and get some water quality benefits. And really we can, with technology and everybody just being more knowledgeable and having more access to information, I think we can really maximize everything. We don't have to have just crop production at the expense of water quality or water quality at the expense of crop production. I think there's definitely an avenue for both, which that's what excites me and gets me going as a young person in this field.

Trey Allis (28:47):

Yeah. Awesome. Hey, that's me and you both. That's well said. That it gets a lot of opportunities out there to keep dialing and everything and make better decisions with more information that we're getting. Awesome. Well, again, appreciate having you on taking the time out of your day to sit down and talk through some of this stuff and maybe promote your research a little bit and some of the cool things that you're working on. So thanks a lot for coming on and being on the Water Table here.

Eric Henning (29:14):

Yeah, thanks so much for having me. It was a lot of fun.

Trey Allis (29:16):

Awesome. Appreciate it. Thanks, Eric.

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