Latest / The Illinois Nutrient Loss Reduction Podcast / Episode 31 | WASCOB: Dry Dams for the 21st Century
Transcript
- Episode 31 | WASCOB: Dry Dams for the 21st Century 00:00:06:24 - 00:00:30:26 Todd Gleason This is the Illinois Nutrient Loss Reduction Podcast, episode 31: WASCOB, The Dry Dam of the 21st century. I'm Illinois Extension's Todd Gleason and Lauren Spaniol now joins us. She's with the Coles County Soil and Water Conservation District, where she serves as a resource conservationist. Lauren, thank you for being with us. I want to talk a little bit about WASCOBs with you today. 00:00:30:28 - 00:00:36:22 Todd Gleason First, I'd like to know what a water and sediment control basin might be. 00:00:36:24 - 00:00:54:02 Lauren Spaniol A water and sediment control basin. They're sometimes they're called catch basins. Or, as you said, WASCOBs, are an earthen embankment. That's used to manage runoff and reduce erosion. They're usually used across to drainage way. So at first glance, they look a lot like a terrace. 00:00:54:02 - 00:01:11:28 Lauren Spaniol But terraces are usually longer and follow the slope of the land, while WASCOBs tend to be short and straight, and are placed across the gully. So, sometimes they're also called gully plugs, or an older term is dry dam. And all of those terms are kind of used interchangeably. 00:01:12:06 - 00:01:15:15 Todd Gleason So how is it that one of these works to improve water quality? 00:01:15:15 - 00:01:24:24 Lauren Spaniol Well WASCOBs work by temporarily collecting and storing runoff water so it reduces the flow of runoff off a field, which also helps delay flood peaks. 00:01:24:25 - 00:01:41:05 Lauren Spaniol So once the water is collected, it is slowly released through an outlet pipe. And also to some degree through soil infiltration that can help reduce erosion. It can prevent gully formation or help heal gullies that have been there before. And it can also help remove sediment from the water. 00:01:41:08 - 00:01:43:05 Todd Gleason And how does that improve the water quality? 00:01:43:11 - 00:02:07:01 Lauren Spaniol When water enters the basin, it slows down and it's temporarily held there. That holding allows time for nutrients and sediments, like soil and crop residue to settle and fall out. The sediment then stays in that basin so that cleaner water can slowly enter, standpipe. From there, it's taken underground to a safe, stable outlet downstream so that it doesn't cause more erosion. 00:02:07:04 - 00:02:28:25 Lauren Spaniol And periodically, like, about once a year, maintenance is done to keep the washtub functioning properly. That usually includes removing some of that, collected sediment and spreading it back out on the field. So, for example, cleaning out would be taking a scraper or some kind, pulling that extra sediment that's settled out and putting it back up on the field where it's useful. 00:02:28:28 - 00:02:39:22 Lauren Spaniol Iowa State University shows, research that WASCOBs can reduce up to 80% of total solids and phosphorus by up to 85% that are leaving a field. 00:02:39:24 - 00:02:47:25 Todd Gleason So what's the typical cost to install one of these and are, more importantly, there cost share options that are available? 00:02:47:25 - 00:02:56:01 Lauren Spaniol The actual cost is going to vary a lot depending on the specifics of your specific, plan and the engineering design that goes with it. 00:02:56:03 - 00:03:13:04 Lauren Spaniol But as an example, a series of multiple WASCOBs might be needed to control, erosion on a specific field. For a single WASCOB within that, let's say 1800 feet long. 4500 to $5000 is about the average for our part of Illinois. 00:03:13:06 - 00:03:16:07 Todd Gleason And the cost share options that that might be available? 00:03:16:07 - 00:03:22:17 Lauren Spaniol There are several different cost share in grant programs that can potentially help offset the costs to install a WASCOB. 00:03:22:20 - 00:03:47:12 Lauren Spaniol One of the most popular ones is the Environmental Quality Initiatives program. Sometimes it's called EQIP. And that program is offered through the natural resource conservation service NRCS. That program accepts applications year round. But ranking and funding decisions are usually announced once or twice a year. It's a pretty competitive program, so your chances of getting funded tends to be better if you want to install multiple practices at the same time. 00:03:47:12 - 00:04:07:22 Lauren Spaniol But your local field office can give you more information and can help put together a plan so that you have the strongest chance of getting funded. The SWCDs also administer a program through the Illinois Department of Agriculture. That program is called the partners for Conservation Program, or PFC. The funding level for that program varies from county to county. 00:04:07:24 - 00:04:21:20 Lauren Spaniol And the money tends to run out fast, but it can be a good option for projects as well. Some areas have additional funding opportunities, and your local field office can give you more information about your county's specific programs. 00:04:21:22 - 00:04:32:13 Lauren Spaniol SCWD, of course, stands for Soil and Water Conservation District. What is the process like to install one of these earthen embankments or WASCOBs? 00:04:32:15 - 00:05:00:27 Lauren Spaniol There are five basic steps. Planning, clearing the site, installing the plumbing, doing the earthwork, and then future maintenance. So the process starts with planning. That includes a site visit from a SWCD or NRCS staff. Then an engineering survey. And once the conservation plan is made and that engineering design is finalized, there will be a pre-construction meeting which is, representative from NRCs, the landowner and the contractor. 00:05:00:29 - 00:05:23:13 Lauren Spaniol So they can go over that plan together. Construction usually starts with clearing away surface vegetation and debris. So old riprap, for example. From the construction area and then the plumbing is installed. That usually includes an outlet pipe and a riser or risers. Sometimes that's done a full season before construction of the earthwork. 00:05:23:15 - 00:05:47:22 Lauren Spaniol Having that extra time allows the dirt to settle around, before the construction of the berm begins and makes the final product more stable. Once that outlet pipe and risers are installed, the slope and the elevation of the pipe is checked. The trench can be backfilled and compacted. And then the earthwork can begin. So material for the berm, comes in from the channel at the toe of the berm. 00:05:47:25 - 00:06:10:12 Lauren Spaniol And from the basin area upstream. Potentially adjacent areas could be identified in the design as well, if they don't think that there will be enough from those areas. The materials moved in and it's compacted layer by layer to construct that berm. So that, that can, settle in and withstand future heavy rain events like we've been getting so many of lately. 00:06:10:14 - 00:06:20:19 Lauren Spaniol Even though the berm is compacted during the construction and it will still shift over time. So they're usually built a little bit higher than the final finished desired height. 00:06:20:21 - 00:06:24:07 Todd Gleason Are there any site considerations farmers need to know about? 00:06:24:07 - 00:06:46:09 Lauren Spaniol Yes. WASCOBs usually work better than terraces on land with irregular and inconsistent slopes. The WASCOBs spacing and placement is going to depend on your specific fields, so it'll depend on your land slope, on your specific cropping and tillage patterns, your equipment width and your kind of overall general management system. 00:06:46:12 - 00:07:09:14 Lauren Spaniol Also, just like a pond, they should be designed and located so that if the berm happens to fail, it won't result in damage to things like roads or public utilities or buildings. And there are also some limitations as well. The uncontrolled area drain into the basin, is usually relatively small. At most it'll be 50 acres, but it's usually way less than that. 00:07:09:16 - 00:07:27:06 Lauren Spaniol Also, sometimes the site is too steep for a WASCOB to be feasible. A stable outlet is also required. Sometimes, if there's not an adequate, stable outlet nearby, it would require really long run to the outlet pipes that also can make them not always economically feasible. 00:07:27:11 - 00:07:29:22 Todd Gleason Any advice for farmers before I let you go? 00:07:29:23 - 00:07:30:15 Lauren Spaniol Yes. 00:07:30:17 - 00:07:49:26 Lauren Spaniol Contact your local SWCD or NRCS field office if you are interested in putting one in. They'll talk to you about your field, your concerns, and they'll help you figure out what practices could address that problem. They are also a good stop if you need financial assistance to help with the project. They can help you apply for cost share programs right there in the office. 00:07:49:29 - 00:08:13:22 Todd Gleason Hey, thanks Lauren. Lauren Spaniol with the Coles County Soil and Water Conservation District, where she serves as the resource conservationist. Now we're joined by John Pike. He's an agronomist, a consultant, and the farmer with Pike AG, LLC, near Marion, Illinois. Hey, John. Thanks for being with us. Can you tell me a little bit about yourself and what you do? 00:08:13:25 - 00:08:45:26 John Pike I am a private, agronomist involved in, research and consulting here in southern Illinois. I live in Marion. I'm involved in projects all across the state. I was a former, research agronomist for University of Illinois, and was in charge of, agronomy research at the Dixon Springs Ag Center before that center was closed. And I do similar work in fertility and water quality research and other, types of, agronomic work across the state and throughout the Midwest now. 00:08:45:29 - 00:08:51:12 Todd Gleason So as an a farmer and an agronomist, do you like how the WASCOB performs? 00:08:51:18 - 00:09:12:23 John Pike Yes. I think it's a good, sound conservation practice that has a fit in a number of areas. I think it's a lot like, other practices that we have. It, it is at its best when it's used in combination with other conservation, projects and processes. 00:09:12:25 - 00:09:26:25 John Pike But, I, I think that in a number of places where we have, those pretty extensively across the, the bigger part of, southern Illinois, they tend to work very, very well when they're managed and maintained correctly. 00:09:26:27 - 00:09:31:03 Todd Gleason What are your suggestions for farmers considering these? 00:09:31:05 - 00:10:01:00 John Pike Well, I think the first off is to, consider what your, problems, might be as far as, soil erosion and soil conservation on your farm or on a particular field, and evaluate what the best solution to that, that might be. In a lot of cases, WASCOBs or as they're commonly referred to in, in many areas, terraces or dry dams. 00:10:01:03 - 00:10:38:06 John Pike They, they have a good fit. The whole, idea behind that is the, the erosion process is, is a combination of the ability of the soil, the steepness of the slope and the length of the run and what the WASCOB system does is it breaks up the run of the slope, to slow down the velocity of, of water and then the, the WASCOB or the earthen structure that's involved in that, backs up water and allows the sediment to settle out of that and clean, clean or cleaner water is discharged. 00:10:38:06 - 00:11:03:11 John Pike Then at the end of the, of the, of the pipe. So while it's a it's a good sound conservation. Process that that works very well. It doesn't completely eliminate erosion. It's just a matter that it slows it down. Now, if it's paired with with other, other practices such as no till or cover crops, the, the benefit of that can be magnified quite a bit. 00:11:03:11 - 00:11:27:08 John Pike But I think in the big picture is that what we see in, in southern Illinois and, in any part of the, of the state or the country where you would have sloping fields where waterways are common in the waterway would be a remedy for, preventative, gully erosion. In a lot of cases, it allows us to farm fields across the slope on the contour. 00:11:27:11 - 00:11:46:27 John Pike That might have to be, more practically farmed up and down the slope with the modern day equipment if a waterway was used. But the WASCOB system can be designed to fit equipment in the field area available to farm on a on a contour and, and be able to work very well. 00:11:47:01 - 00:11:48:16 Todd Gleason Hey, John, thank you for your insight. 00:11:48:23 - 00:11:49:04 John Pike Sure. 00:11:49:10 - 00:12:14:02 Todd Gleason That's John Pike, he's a farmer and agronomist, a consultant at Pike LLC located near Marion, Illinois, not very far from him as Carbondale and Southern Illinois University, where Dr. Jon Schoonover is, and he serves as a professor. Dr Schoonover, thanks for being here today. I take it things have changed just a little bit in your college since the last time we talked. 00:12:14:06 - 00:12:28:06 Jon Schoonover I'm was a professor in the College of Sciences. Now I'm in the College of Agriculture. Life and Physical Sciences has been here for 14 years. I teach a couple classes in, watershed management and two classes in, in soils. 00:12:28:10 - 00:12:34:07 Todd Gleason What research are you doing related to WASCOBs? And can you share your preliminary findings there? 00:12:34:08 - 00:12:34:19 Jon Schoonover Yeah. 00:12:34:19 - 00:12:57:01 Jon Schoonover So this project started out with the Illinois Farm Bureau, actually contacted me and put me in contact with a landowner up in Menard County who just recently installed a series of WASCOBs, or was in the preliminary stages of doing the installation. And we got together and I decided to write a proposal with Illinois NREC, which got funded. 00:12:57:01 - 00:13:20:21 Jon Schoonover So we've got this project going on up in Menard County now where we're looking at, two WASCOB watersheds, each have a series of two WASCOBS within that watershed. One of those two watersheds has cover crops planted and another one has no cover crop planted. And then we also for a control can, compared that back to just two ephemeral drains that go through the field. 00:13:20:21 - 00:13:49:02 Jon Schoonover One of those we planted a cover crop and one without. So we kind of have this, four treatments going on. We've got two cover crop treatments and two WASCOB versus no WASCOB treatments. Some of the preliminary findings we've found so far. Overall, for dissolved reactive phosphorus, this is like the overall WASCOB. So just comparing the four treatments, the DRP is about half in the WASCOB watersheds compared to the. 00:13:49:02 - 00:14:11:24 Jon Schoonover No, no WASCOB. As one might expect, you know, these these have been researched for a while as sediments, total suspended solids. And those numbers are quite a bit lower in those WASCOB watersheds as well. And then nitrate is also lower. So that's looking at the overall systems within a system within like the WASCOB drain itself. 00:14:11:24 - 00:14:33:12 Jon Schoonover So we have each one of these are equipped with control structure where we can monitor the discharge. And and and we can also monitor the stage within each one of those basins, the ones without, WASCOB have partial flumes at the end. So we can also do a comparison of that, water coming out of the outlet. 00:14:33:12 - 00:14:58:09 Jon Schoonover So how much drainage we're getting through these basins? The basins are retaining water. About 12 hours on average, I'd say. So they're they're holding water back for a little while, and that's allowing for some, processing going on. So we're seeing DRP concentrations or dissolved reactive phosphorus concentrations, about half of what we're seeing in the non WASCOB watershed. 00:14:58:09 - 00:15:12:02 Jon Schoonover So there is some microbial processing going on T-S is settling out. We have some deep nitrification probably occurring in those watersheds as well because we're seeing lower nitrate concentrations in those outlets compared to the upper basins. 00:15:12:04 - 00:15:14:16 Todd Gleason Explain what these look like to me. 00:15:14:16 - 00:15:19:28 Jon Schoonover So you'll have a berm that cuts across a small valley. So you need some topography. 00:15:19:28 - 00:15:37:20 Jon Schoonover You'll have a little berm, and then you have a riser pipe that comes up at the bottom of that basin. So it's a kind of a combination of a dry dam and a basin. That's the the water and sediment control basin. So there's an outlet pipe. So water will rise up in that basin. Like I said, it's staying about 12 hours in our system. 00:15:37:22 - 00:15:54:29 Jon Schoonover And that's going to be dependent on, the size of the the tile, the riser outlet. So you can, you know, if you have an eight inch tile versus a six inch tile, you're going to get quicker drainage. And some folks are even putting in 12 inch tiles, which gets that water out of there even faster. So it's a lot of it has to do with residence time. 00:15:54:29 - 00:16:16:00 Jon Schoonover And I think a good, good time would be about 12 to 18 hours. So you can have some of that microbial processing going on and you have more settling of sediment and things like that. So, yeah, it's it's the tile size is driving a lot of it. And then you got the amount of soil you have to move. 00:16:16:00 - 00:16:36:13 Jon Schoonover So there's kind of this economic balance between tile diameter and the amount of soil. So do, do I put more soil in to raise the water higher and put a smaller pipe in to let it drain slower, or do I put a lower move less soil and put a bigger pipe in so it doesn't over bank the the berm? 00:16:36:13 - 00:17:01:24 Todd Gleason So there's kind of an economic balance of tile size and the amount of soil you got to move. So yeah, it's just another alternative for you know, if you got an ephemeral drain coming off a field, you've got two choices. You can either put, well, you got three, you could do nothing and fill it in every year because you know, you're going to get erosion and then it's going to knock you out of your tractor seat every time you go through or through the combine. 00:17:01:27 - 00:17:20:09 Jon Schoonover So you're going to have to fill it in with a dirt pan. So that's kind of like the Band-Aid approach. Fill it in, let it blow back out. Fill it and let it blow back out. So the other option is either a grass waterway or one of these dry dams with a WASCOB, to kind of stair step that water down that ephemeral gullies to prevent erosion. 00:17:20:09 - 00:17:38:19 Jon Schoonover And it keeps your soil on site so it prevents it from getting washed down to the neighbors or down into a pond or lake or wherever it may go. So it's kind of this stair step down and, you know, between those two options, you got a grassed waterway. So you're taking out, you know, 25ft on each side of that ephemeral gully. 00:17:38:19 - 00:18:03:16 Jon Schoonover If it's a 55 or 50ft buffer, and then you're taking that out the length of that gully or, or you can put this WASCOB in and take out less land, you know, of production, because you don't have the grass strip out there occupying your farmland, and you can farm through it or farm around it, and it just cost maybe a little more to install because you got the tile cost and then moving in the dirt. 00:18:03:16 - 00:18:06:15 Jon Schoonover But in the long run, you're not losing all that topsoil. 00:18:06:17 - 00:18:12:06 Todd Gleason Right. And so and, and because you're tiling the rest of the way out from the loss cob. 00:18:12:08 - 00:18:23:28 Jon Schoonover Oh yeah. Right. So that's, that's how you're slowing the water down with the dam and then allowing it to, to slowly go down that pipe. And it doesn't erode when it's inside of a pipe. 00:18:24:00 - 00:18:28:16 Todd Gleason Depending on the topography you can get rid of a waterway even. 00:18:28:18 - 00:18:44:23 Jon Schoonover Yeah. The grass waterway. Yeah. You can eliminate that so that, you know, it's going to save you. There's it's it all comes down to economics with the farmer because it's going to cost to install the tile. It's going to cost to move the dirt. It's going to cost a lot less to plant a grass strip. 00:18:44:29 - 00:19:00:21 Jon Schoonover But if you do the calculations 50ft wide times, how many other hundred feet long, that could be an acre. Two of of production that you're losing. So you could be losing those crop yields. And over ten years that's going to add up to maybe the cost of a WASCOB. 00:19:00:24 - 00:19:05:14 Todd Gleason Thanks, John. John Schoonoven is with the College of Agriculture, Life and Physical Sciences. 00:19:05:14 - 00:19:31:29 Todd Gleason He joined us from the Southern Illinois University campus in Carbondale for this episode. 31 of the Illinois Nutrient Loss Reduction Podcast. The program was produced in conjunction with the Illinois Extension Watershed Outreach Associate Jennifer Woodyard Jones. As described in the State of Illinois Nutrient Loss Reduction Strategy, Woodyard Jones works in phosphorus priority watersheds. I'm Illinois Extension's Todd Gleason.