 Today's webinar we will be talking about controlled drainage and management and design. The first section will be talking about experiences with controlled drainage. Here are a couple of pictures where we see controlled drainage in ditches. So I'm talking today about controlled drainage within the drainage system, but at the end of our presentation we'll also talk about sub-irrigation where it might be needed to also control the water level into the ditches. When we are looking at agriculture and we look here at the rainfall over the year, we see that most of our rainfall is falling in the spring towards June, July, and then it tapers off. However, if we look at the utilization of the crop, the utilization of course starts only once the crop is seeded and maximizes at the bloom period of the crop or the tasseling and filling of the grain in corn or other crops. So if we look at this graph, we see that there is a disconnect. In the beginning of the year we have more rainfall than that the crop can actually utilize, but at the second half of the year we see that there is more utilization by the crop than rainfall. So the question is can we utilize some of the moisture that we would otherwise lose in the spring and transfer that water into usable water for crop production in the second phase of our season, and that is when we are talking about controlled drainage. I have a research plot not too far from campus and on this graph you can see there are eight blocks and on each block I have one control structure. The control structure can manage the water level in each individual block. How I have set them up is I have some of them open and some of them closed and the closed one has to mimic a non-tiled condition. So here we see some of the installation and the boxes are just at the edges of the field. On the bottom slide you can see a control structure on the left and that one is the drained area. On the right we have a control structure and on purpose I completely close it off so that there is no drainage taking place and you can see the water standing there. Another graph that is kind of showing the difference is when we look here at the left is corn, the front end is kind of light gray and the background is what a little bit darker and that is exactly the line where we have drained versus non-drained. On the picture on the left looking towards the south you see a nicely drained area of the field where if we are looking to the north, I turned around, is where the box is closed and you can see that none of the water drained out and we see water actually standing in the field and reducing the crop production. You can see fire in the left corner of the bottom slide that there are two control structures and the northern part of the field was drained. If we look back to the south we can see there are also two control structures, the fire south end, the box is closed and you can see water standing in the field. So the control boxes do work and they can be closed to mimic in this case non-drain but of course that is not what we want. We want to have a controlled drainage situation. But over the years we have done a lot of research on drained versus non-drained and in this case we saw the picture. These were the yields obtained from that picture in that field. We see an increase in yields. Just recently in 2019 I was able to plant very early on a 12 inch row spacing in soybeans and we're comparing here tiled and non-tiled. So on the left two bars is tiled drained, on the right is non-tiled and I'm comparing two early planted soybean varieties and if you look at the difference that is 28% just due to tiled drainage. Over the last years since 2011 all the way to 2019 I combined all the combinations of no drainage and tiled drainage so where the boxes were open and where the boxes were closed and we see that there was a 7% increase in yield over that period which included some of the years that the tile didn't even run where we had actually very dry conditions. So therefore we have concluded over time there is a yield increase for tiled what we would expect. So the real issue is about water table and the management of it. So I'm going to run through a few scenarios. Here is a water table graph from 2019. The way it is in this graph is the zero is the soil surface. The next level is the red line here is where the tile is located at about 100 centimeters or about three feet. Then the next part of the graph is the undrained water level comparing that with the solid line which is the drain level. So as you can see here the water table large parts of the season in 2009 was below that tiled line except for early in the season and late in the season and that has to do with the rainfall. But what happens in that second half of the season is when the crop starts to utilize a lot of moisture actually draws all the moisture out of the soil and both the tiled and the non tiled the water table dropped very low below the tiled line due to that water utilization. So this is 2009. We're going to look at the next graph and that is in 2010. Basic same setup, soil surface, the tiled line, the tiled depth and then the rainfall. But as you look here you can see that there is quite a bit more rain in that June timeframe and the water table is staying a lot closer to the tiled line and on many occasions there is a need for the tile to actually run. Now when we talk about tile it doesn't mean that the water table stays at the tile level. Of course it comes up into the soil as the water is filled by the rain and then slowly it is reduced. So we have the two graphs, the undrained which is a lot closer to the surface compared to the drain. Now I want to pay attention to the undrained area. The red marker here shows that the top of that water table was 20 inches below the surface. Now that is the liquid water table so that means that above that area we had saturated conditions. That is not good for our crop production and that is where we need that tile to be working. Now I'm going to explain here how the water structure might help. So on the middle section we see a control structure and we see a line there where the control box is set with two blocks. So actually it is raising the water on the field side and if the water is going above that block it can still go over and out of the tiled line. Now in this particular graph I have extended the bar to where the control box was set in the field and as you can see the tiled line in the picture we go to the left that is the three feet where the tiled line was located. So in other words we have here the tiled line and how the control box was set not at the level of the tiled line with one block higher. So if you look at this picture you see that there is a yellow area that is where the blue line which is the drained average is now set at that blocked level and that is the water that we are conserving instead of that water just draining out quickly that is what we keep by the control structure and that is what now can be utilized by the crop and as the control setting is deep enough we can still work the ground and the crop has still enough area where the roots can grow and obtain all the nutrients in a good soil condition. So here we're talking about transferring that water keeping that water for the next crop. We did this experiment on a wheat study and what I did here is I have limited management and best management and what it means that in the best management we closed under the drier conditions in 2009 we closed that box with a block so we raised that water table slightly whereas under the wet conditions in 2010 there was a lot of rainfall so I opened the box so that the water table could go down and there was no interference of the access moisture in crop production. The letter behind the two wheat yields is indicating that there was significantly higher yield with the best management compared to the limited management. In other words you have to manage the water table on a year-by-year basis one out of those years I was able to keep water back the other years there was access moisture and I let the water out so it is a management factor but in this case I had an increase of 3.5 percent in yield due to the management. The next graph is indicating five state manage where we compare an open tile versus a managed tile and you see here various states and on average there they found under those conditions a 1.3 percent increase in yield. Every experiment will be different and as every crop will have a different utilization of the crop for instance wheat is more sensitive to water starts early in the season as we have an early season crop so when we look over averages yes we can see that there is a yield decrease the other big benefit of a controlled drainage is that because we keep in the tile line a little bit more water we let less water go into the streams we also see a nitrate reduction into the outlets and here on average we see that there is a 34 percent reduction in the nitrate load going into the streams that is very beneficial from an environmental point of view and it keeps that nitrate also available for the crops to grow better. The last thing I would like to talk about today is that control structures are also critical if we are thinking about sub-irrigation so in this particular field you see here on the left there is a ditch there are three outlet points and those are each outletting one third of the fields. The farmer has a big tank he pumps the water from the stream into the tank to get some head pressure and again when we look at this stream it will be important to also manage the water table in that stream in order to obtain enough moisture to pump into the tank. The next picture is showing the field of the grower on the left top is where the control structures are on the right top there will be the tank with water all the black lines in this field are the tile so the water goes from the right to the left so if we are looking here at the system you see the blue lines is the water going for drainage now the yellow lines is the water coming from the tank and going into the tile line if the tile control boxes are open of course the water would just disappear but if we can close them and set them on the level that we want that water that comes out of the tank in yellow will be backing up and then it can go out of the tile line into the field and we can have sub-irrigation however sub-irrigation typically we talk about narrower row spacing or spacing between the tile lines compared with drainage so it is not completely the most efficient way for sub-irrigation but for drainage it is the right dimensions so this is some of the aspects of the agronomy now we were looking more at the design factors of the tile boxes. So I want to talk about the actual water control structures that you saw on Hans's presentation and I'm going to look at some of the commercial water control structures that are out there a little bit of the installation requirements and then some other configurations that you may or may not want to pursue so we'll start off with you've seen this picture probably many times the basic water level control structure is a usually PVC or PE plastic structure located at the outlet of the tile drainage main or sub-main and it's that they refer to these as movable baffles or some people call them stop logs in the agro-jane which I'll talk about here in a minute you can put in these water-tight baffles either five, six or seven is tall so that you can adjust it to whatever elevation you want based on the depth and they are made out of plastic and as you can see in this picture depending on how you set them you can control what the water level would be held in the root zone of the crop so I'm going to start off with advanced drainage systems or ADS as they go by just they had a system that looked like this and they were using stop logs but a couple of years ago but they have changed their design I think because of the round barrel they had trouble keeping the stop logs water tight so they went to this system on the left you can see it's made of a plastic called nylaplast it's got a plastic cover that's lockable it's got bell joints with gaskets so you can slide the pipe into it and the center is a drawing showing a riser the water's coming in from the right side goes up and that PVC riser pipe that's inserted into this sets the water level in the control structure and then it over tops and goes down and goes out to the left now when you want to drain this and you can reach down and grab that slide gate there and pull it up and it would drain the system out for a quick release I don't know what size they put these out they said they go up to 14 inches in diameter and they could end up quite deep so reaching that slide gate you would probably have to have a special tool the agra drain which you saw in Hans's presentation which is a lot of people put in is made out of a high density PVC and they have several configurations you'll notice in the middle there that's the typical one that Hans has been using it will have and showing the insulations and these have been used in a number of other insulations in small dams and so forth but in agricultural structures we have been using them to they this company also makes an automated one the solar powered on the right hand side up a right hand side you can see where you could probably if you want to pay for this service you can act that with your smartphone and actually change the water level it will raise and lower based on your recommendations just a close-up of the agra drain structure just to give you some idea of this comes it's got a metal top it's lockable you can see at the top there's a hinge there where you can put a lock on there so people the device on the lower left is the comes with it that allows you to raise and lower the baffles and if you you can see what the baffles look like they're gasketed on both sides they got those hooks there for that tool to grab onto either pull up or push down as you can see here you can see in the middle that there's a baffle in there but it's raised up so this was it being free drainage mode and of course if you push it down with that tool now you set the water level so that the water coming in has to go up and over the top to go out if you want to raise it higher you stick in that second baffle and it would raise the water level and this is a blurry picture but it shows the installation and one of the things I want to point out first you got to have bring in and out and where that gentleman is standing that is a anti-piping anti-seat collar we've had some people put these in did not tamp the soil tight enough and water always likes to they call it piping it likes to fall along the edge of the pipe and and work its way out especially if the soil is loose so to keep that water from following along the pipe and then washing out part of the bottom of it you put an anti-seat collar in there usually upstream and downstream and you got solid pipe because there's pressure here and you're holding water back typically the first 30 feet going into the structure is solid PVC to handle the pressure and just in front of that gentleman you can see where it's connected into the main from this tile system this system we found that over time it becomes those baffles if they're set in place and not exercised every year they can sometimes be very difficult especially in a tall structure like this you may actually have to have a jack sometimes to help pull them up it gets it can be quite difficult just one of the things that we've learned so the recommendation is to pull those baffles out and grease them up every year just to make sure you can move them up and down by hand so just to kind of recap the structure inlet and outlet connections need to be watertight and preferably pressure rated these commercial structures already set that but the pipes going in also have to have a certain amount of pressure or rating in a pipe the structure should be non-perforated either PVC or dual wall drain tile anti-seep collars are recommended to be at least 10 to 15 feet in structure on the inlet and outlet pipes and the soil must be solid under the structure and tamp down these can have experience some settling and sometimes some twisting which might make it a little bit difficult to move the baffles that's why we had the recommendation of about greasing them to give you a different perspective on there I know of two farmers that have built their own where as you can see the water flow comes in they put in a riser pipe some use dual wall depending on the size and some use PVC and it got a concrete section in the bottom with PVC on the bottom and what they do is they have a section of PVC that will slide into that elbow joint at the bottom and the length is cut to set the water level in the field to what they want and some farmers on smaller ones they have a couple of these and so they would slide them down when they want to control the water level and the water comes in and goes over the top and goes out in the Red River Valley and the northern parts of the U.S. this is a recommended design because you can pull that up in the fall and let it drain you don't have any standing water in the main an alternative to this design is one where the water flow comes in from the bottom and goes out and for the southern states farther south where you don't have frost penetration is deep this might be an alternative you can reduce the amount of PVC and again it works on the same way you slide a piece of PVC into the elbow and set your water level and the water comes in and goes out the top those are two different configurations that farmers have built themselves they work good for if you're talking that barrel and you know up to in some places they've had them on sub mains with eight inch diameter or a 10 inch diameter and they work very good you can put them on and out pretty easily and pull them out this is that same field that Hans talked about but this was the earlier version of the farmer installed control structure which he replaced later with the AgraJane and this is looking down into it you can see he used a corrugated pipe you can on the lower right hand side you can see where the pipe's coming in and then you can see the top of the PVC elbow there and that pink material is just a sealer to make sure you seal the pipe coming into the another version of this used for sub irrigation by a company called Agrum this is a demo of their riser comes in and this is for sub irrigation so they pump water into the riser it's got that same type of design as the farmer made one looking down you would see you see on the right is what sets the water and of course the valve control there putting water in there to feed the the tile system another end of just a few years ago one of the problems with control structures on fields is you could end up with a series of them and they may interfere with field operations so they created this water gate that would allow you to control the water up to a foot deep along a field and this will be explained in more detail in our following presentation by Gary Sands but it's designed so that the floats you have a control structure at the outlet and then this would be buried one foot elevation upstream from it in the main the water you'd set the water level in the main control structure and then it raises the water backs it up lifts up the floats and you can see at the top the there's a plastic gate that would that's open and not one but when you lift the floats you can see it's closed so it prevents water from coming down and you would have a series of them as shown in the inset pictures we do not have a lot of research information on these at the present time I know they've been in installations but I haven't seen any any research papers on how they perform or if they have any problems with them but this is an option they can like as you can see they're buried in the main line they don't interfere with field operations and yet still to do the same job they probably work best in installations where you would tile on the contour as shown in the lower page there so that it can do its job and control about each foot elevation the last thing I want to talk about is in the Red River Valley in other areas we have a lot of lift stations where the outlet is at a higher elevation than the tile and you can use this as a pump control structure and many people do they you can always turn it off and there's you can check the water level it'll rise to a certain level within that sump that barrel and if you feel it's getting too high you can turn the pump on for a little while and lower it but you can always shut these off and and do the same thing as those other control structures so the management recommendations that we have in areas where frost penetration is can be three feet up over three feet we found that after harvest and late fall you shut off the pumps and you raise the baffles and the control structures to allow free drainage the reason we want to do that is that we've had some situations where people left the baffles in the frost penetrated and froze the water in in the control structure and then it took almost until June to thaw out so that they could use it in the spring after frost is out and flood danger has passed you can turn on the pumps and where we get our most benefit from nitrates as hounds showed is after the crop has emerged and you got most of this spring done you set the baffles and the control structures to the elevation you want to hold them to and then you can turn off your pumps and then adjust them one of the things what pumps some of the newer configurations you can actually control the water level in the pumps in the sump by a smartphone again that would be a service that you would pay for so that's my presentation on water control structures and pumped outlets to get more details about the design of control drainage systems I would encourage you go to the transformingdrainage.org website as you can see in the upper left hand corner of this slide and they have created a series of videos you can see them here on the right hand side it's got drainage water management training videos so if I click on that you'll see that there's a series of eight of them and you can view any of these at your own leisure but the one I'd really want to point out to is number six by our colleague Dr. Gary Sands at the University of Minnesota the first 24 minutes of this his presentation goes over basic design and layout for control drainage systems and some of the design considerations you would have to do with different field configurations taken into account topography and so forth so go to this one and watch that and if you want to see how to retrofit an existing system that's the follow-up at the end of that presentation this is the end of our presentation we are more than happy to answer some of your questions our email addresses are on this last slide feel free to contact us by email and we will try to reply to your questions as soon as we can thank you for attending