Field drainage tubing

[OldMcDonald]

I think this seems to be the best thread for this.

I have drained quite a few acres in different countries over the last 40 years with plastic drainage tubing - mainly 3" or 4", running into 6 inch over some bigger acreages. I have always used tubes without a filter and then put small stone over the top to whatever depth seemed appropriate for the particular soil, then backfilled. I have never used tubing with a built in filter, but am considering it. The filters apparently avoid the need for the stone, as the filter keeps small grit away from the apertures in the tube that could eventually block the lot.

The built in filter tubing is almost twice the price of the unfiltered, but that cost could be saved if I do not have to place stone over it. I have a small area to drain, under 1000 yards run in total, but the time spent in collecting suitable stone and then placing it is going to be quite considerable. If I bought and had somebody else transport the stone to save time, it would become expensive, and it would still take a while to place.

Does anybody have experience of using the filtered tubing?

 

[paulharvey]

In a construction application, not ag, I've used soak pipe. It's perforated pipe with a fine nylon (I think) mess soak over the pipe to filter. Works great, quick to install (huge trencher), and no real maintenance over the life span of our project (15 months). The area we used it in had silt and sand, but no clay, so that may change things. It did have a cleaner discharge then other dewatering options (well points).

 

[fishheadbob]

I have used both methods when installing drainage. When I switched to using the pipe with the filter sock on it I still used stone around it, just not nearly as much. I think the costs worked out to be almost the same as the pipe with the filter does cost more but using less stone made up the difference. The filter sock pipe with stone definitely works better for me than the pipe without the filter.
Before I went with the filtered sock I asked 2 professionals what to do. They said the filter sock with stone would give better results, I agree.

 

[Fossil Farm]

For crop drainage, the sock tubing is used mostly for sandy soils, where soil fines are easily detached from the rest of the soil profile and can get into the tubing. For most soils around here (clay, silt loams), the sock tubing and any rock cover are not necessary. The soil will bridge across the slits in the tubing by itself. Just depends on your situation. Where the sock tubing is used around here, it is best to use washed bank run gravel instead of limestone. The limestone over time can create a seal and reduce the water flow rate into the drainage tubing if there are a lot of fines in the limestone backfill. Good luck.

 

[LD1]

The stuff with the sock is pretty uncommon around here, as is filling with gravel.

Most of the tile is laid with a trencher anyway, which makes it impossible to gravel over.

I have not used the sock stuff, and the only time I backfill with gravel is around perimeter drains along foundations or whatnot

 

[bigtiller]

Fossil Farm has the right stuff here. In 2 years, the company i worked for used a sock one time, for a 250' run through a brush overgrown sandbar surrounding a private pond that we wanted to dump our line into. We never did use rocks to cover it with.

 

[OldMcDonald]

Thanks for the quick responses. The area to be drained is a "basin" of coarse sand and very fine gravel (with some bigger stones) that is generally fine enough to get through the appertures on the drainage tube. It is part of an area of 5 acres of not quite flat land and the water cannot drain from it because of a bank of heavy clay on the downhill side. I assume there is an impervious layer underneath it too as it does not drain down. The basin is rock hard in summer and like a soft pudding in winter. I lose production from the basin land all year round.

At this stage, and taking account of your replies, I am favouring a filter. The water will drain through the sand/fine gravel to the drain without the need for stone over it. I am quite happy for anybody to tell me I am wrong.