How much drainage stone in a trench please?

Steevo · Feb 13, 2023

I'm thinking of putting in a 6" twinwall pipe approx 160m in length across a field. Assuming the trench is dug with a 12" excavator bucket.....how much stone would I likely be needing to use please?

Depth clearly makes a big difference - I'd be grateful for advice on this please.

Kevtherev · Feb 13, 2023

Dig with narrower bucket chief

Grassman · Feb 13, 2023

Some heavy land we stone up near the surface. Ideally you need a narrower bucket.

shumungus · Feb 13, 2023

Kevtherev said:
Dig with narrower bucket chief

He can't really as a 6 inch twinwall is nearly 9 inches wide.
@Steevo your not going to like my advice but we have put in thousands of metres of this stuff, Stone needs to be within 4 to 6 inches off the top for field land or right to the top for wet spots or wet land.

Vincent · Feb 13, 2023

We fill up to where the plough would just hit the stone fill.

Tarw Coch · Feb 13, 2023

Vincent said:
We fill up to where the plough would just hit the stone fill.

I can’t see any point filling any higher on land that is regularly ploughed.

Kevtherev · Feb 13, 2023

Stone to within ploughing depth and I’m quite aware of the width of twinwall pipe.

Derrick Hughes · Feb 13, 2023

shumungus said:
He can't really as a 6 inch twinwall is nearly 9 inches wide.
@Steevo your not going to like my advice but we have put in thousands of metres of this stuff, Stone needs to be within 4 to 6 inches off the top for field land or right to the top for wet spots or wet land.

Thus 100 % ,but does help if you have your own stone
Not googled

Goweresque · Feb 13, 2023

6" twinwall is heavy on the stone even when put in by trencher, so if its a 12" bucket, that means even more, not least because the trench will be over 12" wide by the time its dug. My drainage guy tells me to allow 6m/tonne for 6" and 8m/tonne for 4", so I'm guessing you'll be lucky to get 4m/tonne. Thats putting drains in at minimum 30" deep, usually 36", maybe more at times. Obviously the size of stone will affect the amount you use, bigger stone = more gaps. I've been using 63-10 stone and we've probably done a bit better than the above figures using that.

My guess would be you'll need 3 x 20 tonne loads, and you should have some left over, but probably less that you think!

Derrick Hughes · Feb 13, 2023

Steevo said:
I'm thinking of putting in a 6" twinwall pipe approx 160m in length across a field. Assuming the trench is dug with a 12" excavator bucket.....how much stone would I likely be needing to use please?

Depth clearly makes a big difference - I'd be grateful for advice on this please.

Why u using twinwall though?

quattro · Feb 13, 2023

Derrick Hughes said:
Why u using twinwall though?

Wouldn’t use anything else than twin wall up here where there’s stoney ground

Derrick Hughes · Feb 13, 2023

quattro said:
Wouldn’t use anything else than twin wall up here where there’s stoney ground

OK, thousands of miles been put in on farms around here with diggers and trenchless machines over the years many grant aided , never seen anyone use twin wall apart from gateways , but all would have drainage stone protection

ploughman1963 · Feb 13, 2023

Depending on how much you have to do, £800-900 for a vee tile drain bucket would quickly pay for itself in stone saved

Boohoo · Feb 13, 2023

Is it just carrying water, is it to take away surface water or is it to take away rising water?

Steevo · Feb 13, 2023

Goweresque said:
6" twinwall is heavy on the stone even when put in by trencher, so if its a 12" bucket, that means even more, not least because the trench will be over 12" wide by the time its dug. My drainage guy tells me to allow 6m/tonne for 6" and 8m/tonne for 4", so I'm guessing you'll be lucky to get 4m/tonne. Thats putting drains in at minimum 30" deep, usually 36", maybe more at times. Obviously the size of stone will affect the amount you use, bigger stone = more gaps. I've been using 63-10 stone and we've probably done a bit better than the above figures using that.

My guess would be you'll need 3 x 20 tonne loads, and you should have some left over, but probably less that you think!

Thank you very much - just the sort of fag packet figures I was hoping for.

I think everyone above telling me to use a narrower bucket is right, and I'm probably better to use a smaller pipe and smaller machine.

Boohoo said:
Is it just carrying water, is it to take away surface water or is it to take away rising water?

It's currently a silted up ditch alongside a track - the field alongside but downhill from it has suffered badly with the wet over winter with water from the fields above. I wasn't keen to dig the ditch out too deep and leave it as the track is narrow and I didn't fancy losing a vehicle down into it. Hence considering piping the ditch.

I think I'll dig the ditch out for now, and then perhaps after harvest put a proper drainage pipe in a narrow trench filled to plough depth with stone a few more yards out into the field parallel with the track and it'll be done and dusted good and proper at the most reasonable cost I can manage.

fudge · Feb 13, 2023

If the existing ditch is reformed with an adequate way out for the water why do anything else? I don’t understand the benefit of a parallel drain if there’s no adequate way out for the water, the downhill fields will still suffer from excessive rainfall. More generally we backfill to 15 inches from the surface than mole across but that doesn’t seem appropriate in the above circumstance. Perhaps I am missing something?

Lincs Lass · Feb 13, 2023

How deep ,youve got length and width

Steevo · Feb 13, 2023

fudge said:
If the existing ditch is reformed with an adequate way out for the water why do anything else? I don’t understand the benefit of a parallel drain if there’s no adequate way out for the water, the downhill fields will still suffer from excessive rainfall. More generally we backfill to 15 inches from the surface than mole across but that doesn’t seem appropriate in the above circumstance. Perhaps I am missing something?

The idea of the parallel drain would allow for the ditch against the track to be filled, but providing for a pipe (like an underground ditch) in the field to take the water away instead of the ditch. The pipe would terminate at the field headland into the ditch there. This is where the existing ditch also terminates.

Steevo · Feb 13, 2023

Lincs Lass said:
How deep ,youve got length and width

Ditch depth!

@Goweresque was probably right with somewhere about 750-900mm.

Lincs Lass · Feb 13, 2023

Steevo said:
Ditch depth!

@Goweresque was probably right with somewhere about 750-900mm.

70 tn ish or there abouts

How much drainage stone in a trench please?

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0 %

Up to 25%

25-50%

50-75%

75-100%

100% I’ve had enough of farming!

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