Posted: 1/23/2013 7:06:19 AM EDT
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Does anyone have any 1st hand experience with use of "drainage tile" to manage low lying areas with poor drainage?
First of all, I live in coastal North Carolina which is basically on the edges of a huge swamp. I have 10 acres that I have put a lot of time, effort, and money with deep drainage ditches on the edges of the cleared areas of my property and a lot of dozer work grading the cleared area. What I am left with are a couple of low areas that are habitually wet, the worst one being right where I put my round pen for training horses. I could spend a lot more money with dump truck loads of fill dirt and dozer time for more grading. That brings me back to my question about drainage tile. This seems to be a more economical method than a couple of days of earth moving/grading. Videos on you tube make it seem like a simple process, even though most of these videos show farmers using a drainage tile "plow" that breaks ground and feeds tile(actually flexible, perforated tube). It seems to me for a small scale project trenching for no more than a 100 foot or so for each drainage line, I could do the same thing renting a Ditch Witch and manually stretching out the tile lines. I guess my question relates to is it really that simple? I understand that in order to be effective the drainage tile line would have to be on a sloping grade towards my established drainage ditches. I may be able to accomplish this just "eye balling" it gradually increasing the angle of the trench to obtain a slope towards the drainage ditch. I may end up having to find a laser level, which I have never used before though. I am thinking that I would dig the trench starting at a 2 feet deep at the wettest spots increasing the grade gradually to 3 feet at the drainage ditch. I would then place the drainage tile in the trench and cover with rock and soil. I have about a dozen spots to trench and install drainage tile. I am calculating this would cost me about $1500.00 for materials and rental of the Ditch Witch. Below is a link to the drainage tile that I am thinking of installing. http://www.agrisupply.com/4-in-perforated-drain-pipe-black-sock-250-ft-long/p/11005/&sid=&eid=/ |
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Drainage is good and probably needed if you want to use round pen in spring and fall. If you put it around or through the round pen consider covering immediate length with pea rock and then raising the surface of the round pen area with a mixture of clay and sand anyway. The sand is nice to have in depth. I used to run a single row disk around my Dad's round pen just to soften it up after a rain. Wish I would have done it the day i landed like sack of taters and broke 3 ribs in 07.
These things happen when you put on a little too much weight and don't bounce and roll as well as you used to. I can still feel it when I sneeze. Check with your County Extension Office for information on how to do the tiling and what permits you may need in your area. Around here you have to have permit for anything and heaven help you if you drain into the road ditch. |
| We have had good luck with French drains which sounds like what you are talking about. As long as the water table is low enough it will work good for you. |
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Laser level isn't needed. Simple builders level will work just fine. You sight through your level to get the level elevation, then make sure the ditch you're digging is sloping down hill about 1/8" every 1-2'.
We need more info though to make a suggestion. Do you have a tractor with a bucket? How large are the areas? Ect. Honestly, If I were you, I would backfill with dirt to fill the low spots. |
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ditch witch may be enough may be real slow.
You can easily do it with a laser level. The soils are key... is it clay? depending on what the restrictive feature is ( old plow pan possibly?) deep tillage could help you do not need much slope at all. surface diversions uphill can help as well. Beware of the army core and local environmental enforcement when playing with wetlands. |
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Thanks for all the replies. I will try and sum up responses to all in this post.
Yes, what I am considering is in fact a French Drain. The soil here is a surface covering of loam about 4 inches in depth with hard clay under it, with pure clean sand at about the 5 foot point. If I go with the French Drain, I am looking at running 3 lines from the round out about a 100 feet to my drainage ditch. Regarding permits, I can't find anything that requires them on my county website. As far as I know my property isn't part of a named/defined wetland. If there is a permit requirement, the farmers around me are gross violators as they dig shallow trenches across huge stretches of farm land draining them directly into the state maintained ditch. From I what I see on youtube, the French Drain should filter the rain water as a natural process resulting in almost drinking quality water at the point of entry into the ditch. I do have a tractor with a front end loader (bucket) I have a yard rake and box blade as well. I could and have thought about just getting a couple of dump truck loads of sand and use the tractor to spread the sand in the round pen. Sand cost about $125.00 a load here so that's pretty economical. What I am worried about is that I would have to build the round pen surface up to a point that it would become dangerous to the tendons and ligaments of the horse during training sessions. Anything above 4 inches seems to significantly increase the risk of damage to the horse. The low areas are fairly large and irregularly shaped. Some are as long as 10 feet and range from 3 to 6 feet wide. |
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Lots of experience with it.
If you have lots of clay, you are going need a really big ditch and lots of clean stone to make it work. In most other soils though it is a straightforward process. Most of the time you start at a point and try to go to daylight with it, meaning you keep running the tile until you pop out of the side of a hill or ditch or something. When I worked for a landscaping company standard procedure was to use the ditching machine to make a ditch, or the excavator with a small bucket if it was with another crew. Then throw some clean stone in the bottom of the ditch, we would grade the stone with a 6' level to run downhill to daylight, doesnt take much pitch, just the bubble touching the line on the high side. Before the pipe went in we would roll out this fabric from Dupont, like a giant syntetic coffee filter, and put it down in the ditch folded like a hotdog bun. After that was done we would roll out the line, any connections we had to make we glued and then duct taped to ensure they wouldn't break. Then we covered the pipe with clean stone until we had just enough of the fabric to fold over itself, then cover the rest with clean stone, then another strip of fabric, a layer of 1A's and then topsoil to finish it off, topsoil was seeded and we were done. The fabric acts as a silt filter, to keep fines out of the line and to make sure the stone can keep moving water into the pipe. Not sure how long the system would last until it needed a flushing, probably years and years that way. |
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Lots of experience with it. If you have lots of clay, you are going need a really big ditch and lots of clean stone to make it work. I hope I am not coming across as stupid here, but what do you mean by a big ditch? Do you mean the trench for the tile needs to be wider or deeper than with other types of soils? |
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Lots of experience with it. If you have lots of clay, you are going need a really big ditch and lots of clean stone to make it work. I hope I am not coming across as stupid here, but what do you mean by a big ditch? Do you mean the trench for the tile needs to be wider or deeper than with other types of soils? Yeah, with the clay you have lots of silt to deal with, and the water tends to just sit in the stuff, so you might need a triple wide trench. It will help move off rain water faster. |
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My dad does this for a living (installing drainage tile for farmers).
While it is possible to do this with a normal level, it's also much more likely that the grade can be screwed up with a normal level. On a short run it's not a big deal, but on a long run it can mean the difference between draining and not draining. As far as drying things out, as mentioned, clay is much tighter than loam and it's harder for the water to penetrate. The part the wasn't mentioned though is that the process of trenching breaks that clay barrier and mixes the clay with the loam and sand layers. As long as you have sand as you said you did you should have enough sand in the mix to allow good penetration of the water down to the tile. If you don't think you do it might be worth-while to get a load of sand delivered and mix it with the clay before you back-fill your trench. A wider trench will help as already mentioned. One important thing to remember is that drainage tile isn't a miracle cure. It still takes time for things to dry out. It just helps them to dry out a bit faster. If you have problems with actual water holes filling up and holding standing water for a period of days or even weeks then you will be better served by a surface drain. These are relatively common for farm use because they stick above the ground and can be seen so you don't destroy your surface drain when plowing etc. There are also surface drain systems that will sit flush or below ground level if that is the route you want to go. A few tips for you: #1 be careful that dirt doesn't fall back into the trench before the tile goes in. There is a reason most tile applications feed the tile in as they go and it's not just because it's easier to feed it that way, it's because any lump of dirt that falls in the bottom of the trench will create a "hump" in the tile and slow the water flow. That may not be a huge issue for you as long as they are small and you have steep grade, but try to keep it to a minimum. Commercial operations feed the tile directly after the "digging" is done and then they intentionally push dirt in behind that to help hold the tile flat in the bottom of the trench. #2 If you aren't using a real grade system to keep your grade consistent you can check the ground with water. Once the trench is cut dump a bunch of water in and watch it flow. You will quickly see any high spots that are prevent the water from flowing. The exact way that water flows in the open trench is how its going to flow in the tile. If it's not flowing at all it probably won't flow through the tile at all. #3 If you are running through areas with plants that have roots that extend deep (trees, large bushes etc) use solid tile in that area or a root-preventer fabric on the tile. Otherwise tree roots will find that tile and pentrate it to get at the water during dry-spells, blocking it off during wet-spells. |
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SigOwner_P229
That was an awesome response. I have a question regarding your comments below: If you have problems with actual water holes filling up and holding standing water for a period of days or even weeks then you will be better served by a surface drain. These are relatively common for farm use because they stick above the ground and can be seen so you don't destroy your surface drain when plowing etc. There are also surface drain systems that will sit flush or below ground level if that is the route you want to go. I went to the link you provided. Am I correct that these "risers" are intended to work in conjunction with a "T" junction that is connected to the drainage tile to direct standing water underground? |
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SigOwner_P229 That was an awesome response. I have a question regarding your comments below: If you have problems with actual water holes filling up and holding standing water for a period of days or even weeks then you will be better served by a surface drain. These are relatively common for farm use because they stick above the ground and can be seen so you don't destroy your surface drain when plowing etc. There are also surface drain systems that will sit flush or below ground level if that is the route you want to go. I went to the link you provided. Am I correct that these "risers" are intended to work in conjunction with a "T" junction that is connected to the drainage tile to direct standing water underground? Yes, they work with an underground T and rather than waiting for the water to "seep" through the earth to the underground tile, they skip right past all that and allow the water to go straight down the tile. Typically they don't get installed except in extreme circumstances where water normally gathers anywhere from 6" to 2-3' deep during heavy rains. If you're only getting small puddles and stuff that just won't dry out then these won't do much good. The water has to get high enough to actually flow down into the pipe. Another alternative that just occurred to me is that if your drainage tile is terminating at the water hole you can bring the end up out of the ground and put a perforated plug in the end (you need to cap/plug the end no matter what to keep foreign objects from obstructing the tile). This is the plug I'm referring to. It would also be wise to consider "critters" at the drainage ditch. Often times tile is terminated with a pipe that feeds into the ditch (10' of that green plastic sewer pipe) and an animal guard is bolted onto the pipe. This is sort of like a "one-way" valve for animals and critters. If one gets in somehow it can push it's way back out because this will swing up and out of the way but it can't be pushed in if an animal is trying to push it's way in. Now you may be wondering, "what animal is dumb enough to go up a field tile?" Well, they don't quite understand the purpose of said tile so it's entirely likely they just go up there looking for a meal etc and along comes a rain and within a short matter of time they drown and clog it, or they suffucate, or get trapped etc and then your tile is clogged. I'll keep posting as I think of things. I'll be honest, i don't do the field drainage work with my dad anymore but I spent many summer days as a child helping him in the fields. It's hard, back-breaking work and I never did like it. |
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Unless you have sand soil the tiles will likely plug up after a few to several years of use.
Trench, line trench with filter fabric, install tile and 6" pea stone, then depending on how bad the surface drainage is, backfill with original soil or pea stone. Cap pea stone with filter fabric or 6" straw. Posted Via AR15.Com Mobile |
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Unless you have sand soil the tiles will likely plug up after a few to several years of use. Trench, line trench with filter fabric, install tile and 6" pea stone, then depending on how bad the surface drainage is, backfill with original soil or pea stone. Cap pea stone with filter fabric or 6" straw. Posted Via AR15.Com Mobile Millions of feet of drainage tile laid down by my dad over the last 2 decades without the use of filter fabric and not a single problem yet. Typical useable life of drainage tile before filling up with sediment is a LONG time, like many decades type of long time. As a matter of fact, the number 1 cause of a tile filling up is not infiltration through the perforations, it's "broken down tile". A broken down tile can happen for any number of reasons but most often happens with old clay tile that actually breaks and allows dirt/water to flow straight into the tile or a bad connection on modern corrugated plastic tile that comes apart and lets the dirt/water flow in. What you get after a year or more of that "open" hole in the tile is a "suck hole" where all the dirt has been washed away and you have a large hole in the field. Guess where all that dirt went. Right into the tile. Under normal conditions and normal soil, the perforations are corrugated tile are small enough that the dirt does not infiltrate the tile. The water just seeps in through the perforations. The filter fabrics are for extreme conditions and are most often use in expensive landscaping projects because the cost to dig up and redo landscaping is high and the added cost seems "worth it" to the home-owner. For longer runs, it gets very expensive and it isn't used because in 50-70 years you will be able to afford to replace it. |
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SigOwner_P229, others, my research seems to indicate that large scale agricultural installation of drainage tile foregoes the use of contractor cloth in the trench bottom, but french drain installation in yards etc seem to go with the contractor cloth, covered with rock, overlaid with the perforated pipe (drainage tile), then covered with rock.
I am probably going to go with trenching, then putting the pipe down, and finish with covering with crush and run vice pea gravel. I need to save money where I can. I am probably going to expand this project out and put drainage tile around 2 sides of my gardent to try and reduce some of the flooding in lower areas. My garden floods in a couple of spots and takes forever to dry out. It makes a significant section almost unuseable. Sig, what depth should I trench? I am reading some places on the internet that it should be as deep as 36 inches. That seems awfully deep to me, except that using it at that depth in my horse round pen, it would preclude the horse hooves from uncovering/tripping over the pipe. |
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Sig, what depth should I trench? I am reading some places on the internet that it should be as deep as 36 inches. That seems awfully deep to me, except that using it at that depth in my horse round pen, it would preclude the horse hooves from uncovering/tripping over the pipe. Trenching depth is figured by many factors, the most prevalent being grade. Normally you nead 1/10 grade minimum for good water flow (1/10 foot fall for every foot of tile). From this point you can then balance the other factors. This is where it helps to have surveying equipment. You can measure the height where you want to terminate the tile into the ditch and the ground height along the way to determine how much ground cover you will have. Factors that determine your minimum trenching depth are what the land will be used for and/or how easily you want the water to drain. If you expect heavy traffic over the land (large tractors, concrete trucks etc) then 3 feet is your minimum depth to prevent the tile from being crushed. If its just your yard and you occasionally drive a medium size utility tractor over it you should be fine at 20" or so minimum depth. At 20" it may even tolerate occasional (once a year or so) heavy traffic withiout significant damage. I wouldn't go anymore shallow than 20" though otherwise you risk crushing, cutting, collapsing etc by way of different tillage practices or just plain old "driving over it". Of course, if it does get crusedh you can also dig up and replace just a small section of it by using connectors and a new section of tile. Factors that determine your maximum depth is where the water will discharge. You want it to discharge well above the water level in the ditch, and if possible above the "high-water" mark in the ditch. Other factors that determine it will be the presense of any hills etc on the property that you must trench through and the maximum digging depth you desire or are capable of. For example, lets say the point at which you desire to terminate the tile into the ditch is at 0' relative elevation. Your tile run is 500 feet long, so the lowest your starting height can be is 50" higher than the terminating point. So just over 4' of rise over a 500 foot run of tile. If the ground level at the starting point is 6' above the termination point you're all fine, until you see that you have to go through a hill that rises 20 feet higher than the termination point. In order to keep your tile on grade you will have to dig the trench 20' deep through the middle of that hill. If your max dig depth is 6 feet (common for the trenching industry without specialized equipment) you can only dig 6 feet deep in that hole. Which means on the other side of that hill, at the starting point for your tile you're going to have to have a minimum elevation of 16' above your termination point plus your grade. Hopefully that doesn't confuse you. If so I'll try to clear it up. If you can tell me a bit more about the lay of the land (elevation changes etc) I can help you lay it out. On a side-note, the technology surrounding the layout work on trenching has advanced incredibly in the last couple decades. My dad and brother recently started using GPS guidance system that controls everything from the path that their trenching machine takes to the depth it is digging to yield perfect grade on the tile. That's nothing that spectacular, it's how they program that path and grade that is pretty cool. When they get a job the first thing my brother does is put the GPS receiver on the Polaris ranger. He then drives the field in paths every 20-50 feet. Flat fields can be driven at wider intervals but hilly fields need to be driven more closely to get the best "lay of the land" measurements. He then takes the thumb drive out of the GPS on the ranger and puts it in the computer. He plugs in the maximum digging depth of the trencher, minimum ground cover, minimum grade of the tile, and desired spacing of each string of tile and the computer program will "draw" a map with the strings all spaced properly for the most efficient water drainage. The grade of the tile will perfectly match the most ideal conditions to get the tile installed. So, for example: if the lay of the land is a gently rising hill that drops off on the other side of the hill, the grade of the tile will follow the minimum ground cover (less digging, less cover, and more fall means lower costs and better drainage) until it gets to the point that the projected grade line following the minimum grade happens to coincide with the maximum digging depth right at the peak of the hill and it will shoot the minimum grade line as far as it can until it reaches the minimum cover depth again. Somewhat hard to explain, I'll try to find a picture which will also help you understand. |
Here is somewhat an opposite example of what I described above. You can see that on the right the depth is controlled by the "minimum" depth they have set which is shown by the red line. The green line is the mapped tile depth. The small discrpancy shown is the difference between the bottom of the trench (dig depth) and the minimum amount of cover (measure from the top of the tile). However, on the left, you can see that the lay of the land rises back up some and the green line goes further below the red-line. This is because the lay of the tile is now being controlled by the minimum grade, and must go deeper to maintain the minimum cover on the right portion of the tile and keep the water flowing to the left as it should. The blue line on that chart is the maximum digging depth of their equipment and it's clear that doesn't come into play here. That typically only comes into play when cutting through hills that have a pretty high rise.
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Another shot. Here you can see on the left, starting at the outlet, the tile follows the "optimum" depth, but as it nears the hill it is now mastered by the minimum slope and the minimum depth in the low spot in the middle and the tile must go deeper through the hill to maintain the minimum depth in the hole. But after the hole the minimum slope continues until the tile hits the optimum depth then goes back to being mastered by the optimum depth.
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