Episode 65 | Phosphorus and streambanks: a battle for cleaner waterways

Todd Gleason 0:06
This is the Illinois Nutrient Loss Reduction Podcast episode 65. Phosphorus and Stream Banks A Battle for Cleaner Waterways. I'm University of Illinois Extension's Todd Gleason. Today, we'll explore the phosphorus load into the nation's waterways via stream bank erosion and how landowners can effectively set about stabilizing the banks and consequent the channel. We'll begin with a soil scientist leading a team of researchers and students here on the Urbana-Champaign campus of the University of Illinois.

Andrew Margenot 0:41
My name's Andrew Argonaut, the soil scientists at the U of I. I've been here since 2017 and my research team of 40 ish personnel, students and postdocs and techs. Our team works on soils from the perspective of nutrients and how to make their use more efficient for crops while also reducing the losses to surface waters. We also work on topics of soil health, on carbon sequestration, heavy metal pollution. But overall, we're trying to understand how can we better manage soils to keep doing what they do well, which is to help support food production?

Todd Gleason 1:25
Do you have any ongoing research that focuses on phosphorus loss from stream bank erosion?

Andrew Margenot 1:30
We sure do. That is one of our flagship projects. Currently, we are working with multiple funders. The first one to invest in this research was Illinois and REC, and now we have support from the National Corn Growers Association and the U.S. Soybean Board. So to give a bit of background here, stream banks, we know the soil that's on the edge of the stream or the river or the creek, these stream banks, they erode. That's a natural process. That process can accelerate with human actions in some cases. But the important point is that in very flat areas like Illinois, streams try to find the lowest point in the landscape. And they do that by meandering. So think of a snake riding back and forth, a similar approach. If you were to take a sky high view of the landscape and you were to accelerate the time scale. Fast forward things you would see over the course of decades, the streams across the state meandering back and forth, and as they meander, they slow off off the stream. Banks and sediment that is soil enters into the water body. That sediment contains nutrients, especially a lot of phosphorus, naturally. And so stream bank erosion is a relatively overlooked and under measured source of non-point phosphorus loading. And arguably, it's not really an agricultural source from the perspective that it's not fertilizer, phosphorus. There's ongoing research that we're also doing, which is how does the hydrology being modified by farming things like tiling, has that led to more bank erosion? And we have some evidence that actually it decreases bank erosion. So there's a lot there are still a lot of questions on the extent to which stream bank erosion is a non ag non-point source. The evidence suggests that is largely a non ag non-point source of phosphorus losses.

Todd Gleason 3:38
Is the reason that the stream banks are a larger load of phosphorus because they're deeper into the soil profile rather than just the top few inches.

Andrew Margenot 3:48
That's part of it. So it might help to think about some numbers here. So if we think about a typical application of phosphorus fertilizer as, say, die ammonium phosphate dump, well that's going to be roughly £200 of DAP per acre. That's what the State Agronomy Handbook suggests every two years, for example. So that's about

£92 of PE 205. And on an elemental phosphorus basis, because PE two or five is made up, it's just a designation. We're talking on the order of roughly a little bit fuzzy in the math here. We divide it by 2.26. I'm a social scientist, not a mathematician, for a good reason. Let me calculate that. It's on the order of about £30 of PE per acre. So that's what's going on. And when we harvest a very high yield and corn crop, say to 50 bushel about that amount is coming off in the grain itself. So these are just the magnitudes. And if we measure soil for phosphorus content by say, the BREY or the MELICK test, we're talking in, say, you know, 20 to 50 parts per million phosphorus of what's extractable Now soils in Illinois, if we go all the way down the profile, they have 15 to £25000 of PE per acre, so up to £25,000 of PE per acre. And that's because. Todd Yes. If you go all the way down the profile along that depth wise pathway, the total PE concentration is about 800 to 350 PM. So the magnitudes of the native phosphorus, as some call it, is orders of magnitude higher than what we're applying as fertilizer. This makes sense. We have the richest soils in the world because the parent material is plus l0. This is a fine silty powder that was blown in after these glaciers receded. And the less that we have in this part of the world is some of the highest fertility loss in the world, it's quite full. And phosphorus naturally, roughly 300 ish parts per million. So that's why we have a lot of phosphorus in the stream banks. And as you pointed out, Todd, we're eroding the entire bec. So there's a lot of material sediment falling in.

Todd Gleason 6:16
Why is it that farmers, landowners, the public might be concerned about this kind of sediment and nutrient loss?

Andrew Margenot 6:23
Oh, there's at least four reasons that I can think of here. So the first one is that if we think about what states like Illinois have done in terms of our nutrient loss reduction plans or strategies is, the first step is to understand apportionment. So where is the PE coming from? Same for nitrogen, of course. And broadly speaking, we've got two divisions. We've got point sources. There is a pipe and you can measure the emissions. So a wastewater treatment plant in Chicago is a great example of a point source. Then we've got things that we can't measure. They're diffuse, they're not in one location, and we just call all those other sources non-point source. And when we think about carving up the sources of apportionment, the state plan talks about reductions in point and non-point source. The problem is because we measure non-point source by difference, not quantifying the within non-point source contributions means that we don't have the finesse to understand what is ag versus not ag. So when we measure point source, we have a good number and what is being given out for PE and we know what is exiting the state because we have gauges on the rivers that drain into the Mississippi or the Ohio. So when you subtract from the total the point source by difference, you get the non-point sources. And I'm saying sources plural, because AG is certainly a contribution to phosphorus losses from fertilizer, from erosion of soil, from fields. But there's other non-agricultural sources within the non point source sector. So in Vermont, for example, they include agriculture but also forested lands, they include wetlands, they include stream banked erosion. So if we aren't able to distinguish what is ag versus the stream bank erosion, we just have it all as non-point source. And in many states like ours, we incorrectly think of non-point source as synonymous with agriculture, and that's wrong. That means that we're counting stream bank erosion as an agricultural source when it's not.

Todd Gleason 8:36
As we began our conversation, you told us that streams, creeks, rivers meander much like a snake. What on the ground over a long period of time, are there conservation practices? Do you think that farmers or landowners can adopt that would reduce, I suppose, this meandering? And is that something that they should do for stream bank erosion control and nutrient loss?

Andrew Margenot 9:02
I'll begin with the second question, which is a really good one. Is that so if this is a natural process, should we really think much about trying to mitigate it? Let's talk about why it might make sense to just attempt that evidence suggests from work, from our group funded by Enric and USP and CGA, that stream bank erosion is roughly 30% of phosphorus Loading. That's quite a bit right. That's almost a third. And that's based on data from Iowa. It's based on meta analysis where we look at every peer reviewed scientific article ever published in the world and in the US. And so all of these data converge on an average of 30%. In some places it's as low as 4% of the peers from stream banks. In some places it's 80%. So that's an average water wide distribution. So that's a reason for why we might want to ask the questions that you're asking. So it is a natural process, but that doesn't mean that humans can't exacerbate it. And we've just finished the study finding that in some places if you tile drain the watershed, you can increase the flashiness of the stream, meaning that when it rains there's a surge of water. The stream has more power and more power of a stream. More flashiness tends to entail more bank erosion. So there's a question of by tilling and by trying to think about how we manage tile effluent at the watershed. Might that be a way to mitigate bank erosion? And what we have found is that on a global scale, if you look at all of the cities ever published, we find that tiling decreases stream flashiness and thus presumably bank erosion. If you have low infiltration soils, think of flat land with a lot of clay content. The water can't get through the soil and it runs off the surface by tiling. In those systems you help absorb the rainfall and you decrease the flashiness and thus you presumably decrease the bank erosion. So tiling could be a way in some places to help mitigate this. Now in some locations we find that the opposite happens, that if falls already infiltrate well tiling that increases subsurface drainage and thus there's more flashiness. But on average, globally speaking, there's no effect of tiling on more stream flashiness and higher infiltration of soil, watersheds. So that's the first thing that has just emerged as of a month ago from our research. Now, I think that of course averages are nice, but context matters. So what could farmers or land owners do is what you asked. Todd There's I think two things. One, that we know works but is very expensive is to shield or armor stream banks. This makes sense if you have a stream band where there is massive erosion and shielding or armoring, there's different ways of doing it. One that's very common is to rip wrap. This could be, as nurses did back in the sixties, old car holds used cars on the bank. Now we use concrete or even trees and dead trees like Christmas trees. And these buffer the power of the stream water hitting the bank. But this is quite expensive. It's really not scalable. The other approach is to think about how we manage water with, say, wetlands, where if there's a drainage ditch with a lot of stream velocity and this power cannot go into a buffer wetland that effectively slows down the water. The name of the game here is to slow the water down. Now that is not been studied, but I think it's a promising avenue and the third approach is we might want to rethink about how we channelized ditches. So ditches help collect all the water from the main tiles that drain and a lot of times they've been channelized, they've been straightened by the US Army Corps of Engineers. The problem is that if you have a straight ditch, the water picks up velocity and it sloughed off a lot of erosion. So I think that's a low hanging fruit opportunity to try to rethink how we manage the ditches. And a lot of that is the Army Corps of Engineers jurisdiction.

Todd Gleason 13:19
That's Andrew Morgan out. He's a soil scientist at the University of Illinois, located in champagne on the eastern side of the state. We'll turn now to Trevor Tolland, who lives in McComb Township in McDonough County in western Illinois, where he raises beef cattle on permanent pasture, has cropland and some hardwood forest. Now, Trevor admits he's a little older now and has a lessee who manages the cattle and the crops. Though he's still in charge of mending fences and monitoring the water supply, the LeMoyne River snakes through his farm and as you'll hear, he had it rip wrapped to hold the river and the stream banks in place. Trevor says he's always been conservation minded.

Trevor Toland 14:03
I think so. I've done several things over the years. We have a very large diversion terrace that goes completely across the one one corner of the farm. It's rather extensive, keeps water flow coming down off of the off of the hillsides here, off of lower crop ground, and diverts that to a safe exit to the east for to the LeMoyne River.

Todd Gleason 14:35
To tell me some more about the East Fork of the LeMoyne River that runs through the farm and what you've done over the years to stabilize it and the stream banks.

Trevor Toland 14:45
To the east or the LeMoyne River that's right through the center of our property. So it's a signature, the part of part of our our whole landscape here, and we have quite a bit of floodplain.

It's the LeMoyne River is, I think, the seventh largest tributary in this stage to the Illinois River. So it's drains thousands of acres. So the amount of water that comes down the river is significant.

We have a couple curves in the river here. We see it on our property and the river because it's silted down so much. Over the years, doesn't have very much volume. And when we get heavy rains, therefore the flooding happens pretty easily. And what the river was starting to do was on those curves instead of following the curve with high water, it was hitting straight off the curb, right out into the land and cutting a new channel. So we needed to do something quickly to alleviate that problem. And that's the reason we went to the Stream Bank stabilization plan.

Todd Gleason 16:17
What does that look like? What did you put in place?

Trevor Toland 16:20
Yeah, it was rather extensive. We had to we had three, three places, actually two curves. Those were 250 feet each. Those required a half a ton of a five rip wrap

per sludge. So the change was significant

and there was a third side near a cement bridge, an old cement bridge that we have. And it was trying to the river was attempting to cut it across the end of the bridge and make that unusable. So we had about 175 turns for each of those 250 foot sections, and then another 75 tons for the bridge part.

And then that to get that rock close to those sites where a truckload could put it in place was it was another issue. It was difficult to get that located because of the terrain and the floodplain as it was.

Todd Gleason 17:40
This was in August of 2007. Were you able to cost share any of the expenses?

Trevor Toland 17:47
Yes, we were. This was a at the time when we started the process in

2006, this was ac2 thousand project. So that was a 75% funding. The project ended up being about 13,500, and the funding that we were able to obtain was about

9500 out of that. So it was a it was a big, big help to get that project done that way.

Todd Gleason 18:23
Was there anything you learned as the farmer landowner that you think others might be interested to know as they approach a stream bank stabilization project?

Trevor Toland 18:34
Well, yes, this I would say that maybe it was the engineer that was able to design this, but this really worked. Really well. It's been tremendous. I just never would have believed how significant it But the change it has made, there's quite a process. There's a number of steps to get through to do a stream bank stabilization, not only maybe applying for funding under one of the government programs, but you've got to work with a number of agencies to get approval for it, including the Corps of Engineers. So they have to that all has to be approved those several steps to take several months. So if someone wants to do one of these project, I don't think it's going to happen in just a couple months. They need a lot of time to get the whole thing in place.

Todd Gleason 19:36
Now, Trevor Tolan had the rip wrap project completed in the portion of 125 mile long LeMoyne River, part of which flows through his western Illinois farm in 2006 and seven. As he mentioned, it does take some time to get such a project started and some expertise maybe like that from North Water Consulting in Springfield, Illinois, with offices in North Carolina and Michigan and staff in Saint Louis and even some in Haiti. Jeff Beckler is one of the co-owners there. I asked him just exactly what stream bank stabilization might entail.

Jeff Boeckler 20:13
Okay, good question. So there's, I guess, two types. The natural solution or hard, hard rock stabilization. And if we're talking about a stream, I typically and this is not the same for everybody, but I typically lean toward the more hard solution just because based on my limited experience, it lasts longer.

But natural solutions such as will or post method, other types of natural vegetation, bank trapping, that kind of thing, they are they do work and people do them. I just haven't gotten involved in a lot of those work. When it comes to rock, there are two main things that we typically do. Number one, what are called grade control or rock riffles, and those are rock structures placed in the stream itself,

and they are designed to prevent what's called down cutting or deepening of the stream channel. And then the second thing that we do a lot of is what's called stone toe protection. That's rock placed along the bank of an eroding the eroding bank with a little gap between the bank and the rock to allow for the bank to kind of naturally fluff into that void and reach equilibrium and become stabilized. A lot of times those two practices are done together because a lot of the bank erosion problems we see are triggered or started from the deepening of the channel itself. So you first have to stop that because the deeper the channel gets, the steeper the banks get and then they fall in. So those are the two main ones are other things then way weirs

or barbs, all sorts of other techniques for stabilizing stream banks.

Todd Gleason 22:10
Interesting. I'm wondering, however, if the legalities, relatively speaking, because we're talking about access to these stream banks might be as big a barrier and that could be government based. I'm thinking army Corps of Engineers and or just who happens to own the properties.

Jeff Boeckler 22:31
That can be a challenge. Land ownership, if it's a privately landowner and it's a costly project, it's challenging to get buy in and left. That particular landowner has a immediate need for the project and is willing to put up some dollars, even with grant money. So that can be a big challenge if you're trying to do severe eroding stream banks and some private property, probably a little bit easier actually, if it's a municipality owned by a municipality or park district or something, because they would have direct access to grant funds. And sometimes just working with them is a little bit easier. I don't find that permitting is a huge challenge until you get to very into very large projects that take you outside of what's called a nation wide permit and in doing an individual permit. So when you're doing permitting and if you're if you're doing a nationwide very simple permit, you also have to consult with the Illinois EPA and Illinois and also Illinois Department of Natural Resources and the Office of Water Resources. I do I would say for the small projects that we work on, cost and access are the biggest barriers way left. So the permitting part of things.

Todd Gleason 24:00
So it's about finding the grant money then I assume have that.

Jeff Boeckler 24:04
I mean, and that's the challenge. There's just there's not a lot of programs out there that fund this kind of work, even though there is a huge need for it. There are key programs. The Illinois Environmental Protection Agency, Section 319 program. There's another one that is ran through the Illinois Department of AG called the Stream Bank Restoration and Protection Program. I think the problem with that one is they cap it at, I believe, $10,000 a site. They have limited amounts of money each year. And for most projects, $10,000 is spent very easily. You really cannot get much done for $10,000. So if you're capped at that and you have a medium to somewhat large project, the cost is just well beyond what that particular landowner would be willing to do to cover the difference. And then really the only other game in town is that Illinois EPA program that gives you a lot more flexibility. But again, that one is limited as well. So that's a huge challenge, is finding that grant money, like I said, gets back to cost.

Todd Gleason 25:18
The last question I have for you, I want to I want to try a couple of different tacks at which is any advice you might have for a farmer or a landowner pursuing Springbank stabilization as a project. First, how do they know what looks like it needs to have stream bank stabilization? What? What is it that you you look at at a site that says, okay, this is a project, it needs to be done.

Jeff Boeckler 25:45
If I would take the perspective of a landowner, it's they would say, okay, it's a problem if it's causing if I'm losing land or it's causing issues with some of my my home or my property, either losing a big chunk of farm farm ground to acres because a bank is cutting into their farm field or a bank is encroaching on their house or garage or barn or whatever it is, then it becomes an issue. If it's kind of out of sight and out of mind. I mean, aside from just visually seeing it and it knowing it's a Bear bank and it's a problem, it's not really a big issue because it's not impacting anything. From my perspective as somebody that works with public water supplies to keep that sediment out of the reservoir. I just look at the banks and the stream channels in terms of how much sediment are they producing, kind of regardless of whether or not they're having some sort of impact on infrastructure. And I look for what are the sites that are contributing the highest rates and are most easily accessible to fix.

And if I had some advice for a landowner that did have a section of stream that they're interested in or concerned about, probably just start with their local solar water district for technical assistance, that's probably the best place to go to start. And if they can't get any traction there, they can. Engineering firms are available, they're quite a few of them in the state. Just simply doing a web search, you'll find somebody you can talk to you that would take a look and give you some ideas. I would suggest not trying to do it alone because there are some design considerations that go into these things. Proper rock size, for example, proper placement of rock. And just if you don't know what you're doing, you can cause more problems than you started with if you just go at it alone. So starting with this whole water district lease to get some technical assistance and then possibly some assistance with funding also, if you're in a watershed and you can figure out if that watershed has an active watershed group and an approved watershed plan, you could potentially approach that group with your issue and work with them to submit a competitive grant application to the Illinois EPA. For example. That would be my advice. I don't think there's really other any other places you can you can start aside from just going at it alone. And I would not recommend them.

Todd Gleason 28:41
Jeff Batchelor is a co-owner of North Water Consulting. He's in Springfield, Illinois, and joined us on this episode 65 of the Illinois Nutrient Loss Reduction podcast Phosphorus and Stream Banks. The Battle for Cleaner Waterways, along with McDonough County Farmer in western Illinois, Trevor Toland and University of Illinois soil scientist Andrew Argonaut. This program is produced in conjunction with Illinois Extension's Rachel Curry. Nicole have her back, and Emma Eldridge. I'm University of Illinois Extension's Todd Gleason.