Ag pipe with geotextile sock

No, outback not at all, but as I mentioned previously - I have agpipe laid around my property with geotextile-sock and it works!!. You are yet to give any proof that it is not required.
I don't know what the soil conditions are where deathcock lives and if the sock is required, but what I do know is that I live around clay based soil and the sock is necessary to stop the sediment build up from reducing the effectiveness of my drainage system.
You offer no advice, or experience to contribute effectively, just meaningless "tit-for-tat" exchanges, so I don't see any need to continue this worthless discussion with you anymore.

Hi Farmboy, the pipe we used was slotted 100mm diameter ag pipe with geotextile sock. I dug my trenches around 1 metre deep (they were at least waist depth, and were , I think - from memory, around 60cm wide, up to 80cm wide, back filled with 10mm drainage gravel. I have my pipe sitting on 20-30cm of gravel. I filled the gravel to within 15cm of the surface and covered over with top soil. I also have it linked up to our downpipes.
We live on a sloping block, and water used to run off other properties through our backyard and flood under our house, when we first got there it was so bad everything was stored off the floor on palettes or shelving. After installing the ag pipe with geotextile sock, the ag-pipe solved all my problems with run off around our house.

thanks felix
i might invest in a trench digger from kennards for the day as i have about 40m or so to dig

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Originally Posted by Farm boy

thanks felix
i might invest in a trench digger from kennards for the day as i have about 40m or so to dig

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Good idea, I dug all mine by hand, or shovel:rolleyes: , took a while and I swear never again!

If you are on clay and waterlogging is the drama, then using a machine to create a slope system, running to a pit or a run off area might be a better idea. The backyard of a typical 1/4 acre block can be drained with one 90mm pipe this way, whereas 5 agpipe's may not.

The clay gets saturated and water sits on top of it. If the clay has wheel ruts or hollows in it (under the topsoil), then the water will sit in this and it will stay a mess.
Water doesn't move through clay well, so the agpipe will drain the trench and whatever runoff gets to the trench, only. Overtime the agpipe filter blocks up (either geotextile sock or felt) and the agpipe stops being as effective.
If you have access for a machine, then it might be cheaper (now and in the future) to get someone in to use a dumpy to set levels and then create a slope plan.

If its runoff thats the problem, then the trench you are planning can capture and divert the water and with the right fill mix, the agpipe becomes a bit redundant. Depends on surge volumes really.

Agpipe doesn't drain waterlogged clay, you've got to get all the water to run off.

Great thread! Love a bit of biffo.
Anyway my two bobs worth.
Water does not flow through the agdrain. rather it flow through and around the pipe through the gravel. It is perforated, it cant hold water hence logic then tells us a sock is useless, all filtration must happen at the gravel/soil interface. for a 65mm drain:-
250 wide and 250 deep acheiving falls on the base of the trench
Line with A14 geotextile so that you have enough overlap at the top to cover trench.
Fill with about 75mm of gravel and rake to falls. Place in drain, backfill and place over lap fabric over top of gravel ie you want this system fully enclosed. place soil over top and turf.
And remember it has to drain somewhere other wise it is just a retention pit.:)

I'm in the business of geotextiles, and this argument doesn't surprise me. I remember Don Burke of "Burke's Back Yard" running an argument against geotextile socks around ag pipes, saying, as Outback did, that it will eventually clog and render the process useless. On the other hand, while the sock is NOT clogged, it well help keep the drain holes and the inside of the pipe clean and therefore facilitate drainage.

My point is that it's a grey area, and as always these grey areas attract agro. It all depends on soil type. I guess the ideal scenario is to use geotextile fabric and hope that during the life of the ag. pipe the stuff doesn't cop enough silt to clog.

The pipe will probably clog up quicker without the felt or geotextile sock, hey?

The answer is in each individual problem that we may have. I live on clay soil, with the back yard sloped toward the house, which is timer-framed on stumps. The water erosion over fifty years took out my chimney, so I had to take drastic measures. Where there is a pooling of rainwater, I laid black plastic sheet and then covered that with crusher dust, burying the ag-pipe. I never used the net filter at all, as I want the water to have a place to go to quickly. In South Australia, after it rains, the sun comes out a begins to dry the place up again. The ag-pipes have all been laid sloping down and away from the house, and in the worst affected area, the water flows out into my banana trees. These trees literally take all the water you can give them.

The up-shot of all of this is, the ag-pipe should be buried in gravel not bare clay, and sloped to where the water will cause no problems, and if need be, it can be pulled out with ease, cleaned out and re-buried again.

The alternative to most of these problems is cementing a trough and grid which can be tricky getting the slope right, and it will fill up with everything imaginable, leaving the "gardener" with a weekly chore of cleaning it out, besides being very expensive to install. I went the cheapest way I could possibly go, and since we've had a drought from there onwards, I don't have an answer as yet. :D

What I meant to say was that it is the fines that will eventually clog geotextile fabric. If you add a tablespoon of soil to a glass of water, and stir it, it's the stuff that hasn't settled after a few hours (the cloudy water) that is caught. Clay soils have less of this than less organic or less reactive soils.

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Originally Posted by Rossluck

What I meant to say was that it is the fines that will eventually clog geotextile fabric. If you add a tablespoon of soil to a glass of water, and stir it, it's the stuff that hasn't settled after a few hours (the cloudy water) that is caught. Clay soils have less of this than less organic or less reactive soils.

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Rossluck dont you mean clay soil has more of it. :confused:
The IT being the clay content of the soil itself. From memory its the kaolinite content in the clay that is highly dispersive (dissolves in water) and the bentonite does not.
A simple test to determine what type of clay you have it add a small lump of clay to a clean glass of water after 5 minutes give the glass a small tap and if the piece of clay slumps down and causes the water to go cloudy you have a dispersive clay ...if it dont... you have a non dispersive clay (good for making dams etc). Its all to do with the cation exchange capacity of the minerals:eek: :p
Dispersive clays cause filter fabrics to block. That is why you need as big as possible surface area so the filter will last longer ie a big trench as I described previously.
People have mentioned the use of gypsum before, what that does is make the dispersed clay particle cling together and form lumps (flockulate) and then they act more like an aggragate and so you get better drainage. I must admit everytime I have tried it it never has made a pinch difference, I know the theory is sound but....:rolleyes:

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Originally Posted by Bleedin Thumb

Rossluck dont you mean clay soil has more of it. :confused:
The IT being the clay content of the soil itself. From memory its the kaolinite content in the clay that is highly dispersive (dissolves in water) and the bentonite does not.
A simple test to determine what type of clay you have it add a small lump of clay to a clean glass of water after 5 minutes give the glass a small tap and if the piece of clay slumps down and causes the water to go cloudy you have a dispersive clay ...if it dont... you have a non dispersive clay (good for making dams etc). Its all to do with the cation exchange capacity of the minerals:eek: :p
Dispersive clays cause filter fabrics to block. That is why you need as big as possible surface area so the filter will last longer ie a big trench as I described previously.
People have mentioned the use of gypsum before, what that does is make the dispersed clay particle cling together and form lumps (flockulate) and then they act more like an aggragate and so you get better drainage. I must admit everytime I have tried it it never has made a pinch difference, I know the theory is sound but....:rolleyes:

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You're right. I mucked up. When I posted that I instantly realised that what I said was incorrect. But in my experience with sediment and erosion control, the first step is to deal with two categories: Clay and dry, before moving into the distinction between dispersive and low-dispersion clays. In general, it's harder to release the fines from clay than from drier, dustier, less fertile soils. In QLD especially, with the quick summer storms with a lot of water flow in a short period, the water tends to run over clay and find conduits through it rather than disolve it, while the drier soils will mix more easily with the water and run.

Please understand that I'm not talking from a scientific viewpoint (qualificatoins = 0%), but rather from experience in dealing with sediment runoff from construction sites. What you've said about surface area of filtration in relation to soil type clearly hits the nail right on the head. But what home owner trying to drain his yard would bother with that, so the question still remains, should you use geotextile fabric over the drainage pipes? I dunno. Your post was informative, thanks.

:D The point being missed here is that ag-pipe is not to be buried in clay soil, but in a trench of drainage gravel - therefore the discussion on clay sediment clogging ag-pipe is irrelevant. I am discussing backyards, not building sites, so sediment being carried by runoff is not a big issue, after all this "sediment" has to travel through the garden and across grass ( a natural filter) before it can filter through gravel to ag-pipe.
I am sure drainage gravel has some sediment, but in 5 years is has not had enough sediment to reduce the effectiveness of the ag-pipe on my property.:)
Also, my original posts were in relation to reducing runoff on my property - not draining clay so I don't know where this came from.:confused:
The post about drainage gravel draining more water than ag-pipe is an interesting point of view, but I can stand at the front of my property and watch the water POUR out of my outlet drain, so the pipe is effective.
I have no doubt the drainage gravel in trenches traps, retains and dissipates a percentage of runoff itself, but I still maintain the effectiveness of the ag-pipe.
At the end of the day it is all trial and error for each application for DIY situations.:D

And.....No matter what you say, and how much geology, science or mumbo jumbo you bring to the discussion, my pipe continues to be effective in QLD in summer, so nah nah nah nah!:D
(Must run away NOW!)

Sorry Felixe, my comments were for threads originator.... :eek: ... next time I'll do better! :) ;)
Thought I'd bring up the issue of draining water out of an area in case thats what the intent of the activity was.

Dear Felixe,

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The point being missed here is that ag-pipe is not to be buried in clay soil, but in a trench of drainage gravel - therefore the discussion on clay sediment clogging ag-pipe is irrelevant

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I think you have missed the point. Just because the agline is encased in gravel doesn't mean that it can not get clogged.:(

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The post about drainage gravel draining more water than ag-pipe is an interesting point of view, but I can stand at the front of my property and watch the water POUR out of my outlet drain, so the pipe is effective

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Tell me what sort of outlet are we talling about. if its your standard curb outlet then your 600 x 800mm gravel filled trench ends there leaving the pipes end exposed and surrounded by concrete. At this point the water that has so far travelled through the gravel not the pipe is forced back into the pipe where it discarched into the gutter where you can sit and watch and marvel at your own brilliance. :D For all you know the sock around your agdrain is already clogged.:eek:

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I have no doubt the drainage gravel in trenches traps, retains and dissipates a percentage of runoff itself, but I still maintain the effectiveness of the ag-pipe.

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We are talking sub-surface not surface runoff and there are many ways of acheiving effective subsoil drainage but if you are using agpipe for this purpose you have to use gravel. Once more for the hard of hearing the water travels along the gravel not the pipe. Go do an experiment go pour a bucket of water down a length of agpipe and see how much comes out the end.:D

As far as the DIY thing goes that may be true in many arenas but there are also many when the DIYer can benefit from the knowledge gained by others who have experience in their particular field.

Nah Nah to you too mate.

Too much agro, I'm outa here :eek: .