Land drains - fill to top or not?

just do it

Here's one that seems to have divided opinion. What's yours?

Fill drain to top with stone showing, or fill within 4/6in and cover?

reilig

What depth of soil have you got?

Around here we have 2" to 4" max. We would always fill with stone to within an inch of the top.

I have seen drains on other land with up to a foot of soil and they would only be filled to within 4 inches of the top.

vanderbadger

to the top deffo

Harrier1980

simple really... must be to the top...

I do a lot of drainage design for the company i work for and in most cases where i am called to a site where there is complaints of recent drainage installed not working the issue is pipe drains have been installed backfilled with stone to 4 - 6 inch to the surface and covered with topsoil..

A modern drainage design would be to have the pipes installed in decent size trenches with stone covering and top soil on top.. Then gravel bands pulled at an angle to the pipe drains and also at the correct angle to catch overland flow.. These act as the connection from the surface to the drainage lines.. very efficient way to do it..

However cost is usually an issue when it comes to ag drainage so just fill to the top with gravel if you wand to banding..

Atilathehun

Harrier1980 wrote: »

simple really... must be to the top...

I do a lot of drainage design for the company i work for and in most cases where i am called to a site where there is complaints of recent drainage installed not working the issue is pipe drains have been installed backfilled with stone to 4 - 6 inch to the surface and covered with topsoil..

A modern drainage design would be to have the pipes installed in decent size trenches with stone covering and top soil on top.. Then gravel bands pulled at an angle to the pipe drains and also at the correct angle to catch overland flow.. These act as the connection from the surface to the drainage lines.. very efficient way to do it..

However cost is usually an issue when it comes to ag drainage so just fill to the top with gravel if you wand to banding..

I have it done with tile bucket and pipes covered with clean stone to the top of the drain. Working well after 12 years. Some have more water flowing from the stone at the exit points than from the pipe.
I have another area just tile bucket and stone to the top. No pipes. Done 10 years. Working equally as well as drains with pipes.
I dont believe pipes are worth the extra cost for ag purposes. Maybe others wouldn't agree

just do it

Atilathehun wrote: »

I dont believe pipes are worth the extra cost for ag purposes. Maybe others wouldn't agree

I've heard the same from a man that drives a track machine. He's no vested interest in how you fill the drain so he's a realiable source.

just do it

Harrier1980 wrote: »

simple really... must be to the top...

I do a lot of drainage design for the company i work for and in most cases where i am called to a site where there is complaints of recent drainage installed not working the issue is pipe drains have been installed backfilled with stone to 4 - 6 inch to the surface and covered with topsoil..

A modern drainage design would be to have the pipes installed in decent size trenches with stone covering and top soil on top.. Then gravel bands pulled at an angle to the pipe drains and also at the correct angle to catch overland flow.. These act as the connection from the surface to the drainage lines.. very efficient way to do it..

However cost is usually an issue when it comes to ag drainage so just fill to the top with gravel if you wand to banding..

So how much top soil on top of stone? 1 inch?

Harrier1980

just do it wrote: »

So how much top soil on top of stone? 1 inch?

Well.. that is exactly the concept behing banding to make a connection with the underlying drain.. The amount of topsoil you put on the drain is there for somewhat irrelevent.. usually in my line of work i would allow for 20 - 30cm on top. The banding there after carries the water from the surface and pipes take it from the field..

reilig

Harrier1980 wrote: »

usually in my line of work i would allow for 20 - 30cm on top.

That's almost a foot. I haven't seen any with that much soil on top.

What do you mean by banding? Is it Gravel Moleing???

Harrier1980

inches and feet.... common the metric system is here a while now..

And yes... a narrow trench filled with gravel is all it is..

grange mac

I also agree, last year had a large open drain (very wet field), then last summer put 6" of 4" stone in drain, 6"corrie pipe on it, more 4" stone covering pipe & 6"stone to within 6" of top of drain then straw in top of the 6"stone to stop earth from filtering down through and cover with earth.

Then put in channels filled with 6"stone to top that connect to the main drain. & covered them again with straw to protect the earth from seeping through the stones.

2 Years ago where I buried a 7ton hymac while making my open drain I put out bag manure with ease!!

Was costly & took time but for the first time ever the field is dry... now i just have to reseed it as grassseed failed last october.

Harrier1980

I guess this is where blinding layers is important and knowing bridging factors of different materials etc...

Although your field is dry now straw will degrade in time and migrate down through the large stone to pipe eventually blocking it.. god knows how long it will take to happen.

just do it

Harrier

Is this what you mean?

What distance would you leave between the banding drains as you call them?

Tefral

Drains ive installed have gone as follows

-Dig to required depth
-Back fill 50mm with 50mm washed stone
-Install land drain pipe in a central position
-Backfill with 50mm washed stone until 50mm near the top of trench
-Make up reminaing with soil.

They were for garden drains I did, been working for years now...

grange mac

Mr Harrier I'm 2 years wiser than you going by your name!!! Bit everyone have their own way, the purpose of the stray is to slow the effects of the earth wasging directly down into the pipe, however once it goes through the stray, it then has to go through the 6 inch stone & then the 4 inch stone b4 it blocks my pipes!!

Only good thing is that cost on my new dry 10 acre field caused a huge loss on farm so can offset against paye for next few years.

Bodacious

just do it wrote: »

Harrier

Is this what you mean?

What distance would you leave between the banding drains as you call them?

I like your diagram. I've some draining to do and will do this i think, should i cut into the plastic pipe wher it meets this banding bit? Plus this crack do you cover soil over the 3" stone over the pipe/trench or leave it showing?

Harrier1980

The type of design you have there would be the traditional herringbone type design. That would have a main drain down the centre and the others as laterals usually a smaller diameter pipe.. depending on the intended flow rate.
So what you have there is the pipe design without the banding as far as i can see.

Its difficult to descrbe so the attached might explain it better. Pipe drains in the subsoil with gravel bands connecting to them.. And no you do not cut the pipe, you just have to ensure a good clean connection between the gravel ontop of the pipe drain and the gravel band. As you can see in this design there is course sand over the gravel bands but you can just run the gravel to the top to save time and money. The course sand over the pipe drains is to prevent the soil from migrating through the gravel and blocking the pipes over time.. It is essential that bridging factors are correct to make sure the sand doesnt migrate through the gravel...

As i said earlier this is too expensive for mosr agricultural settings but had been done before, especially on some UK ag land.

The pipes should run with the natural fall on the ground and the bands at a an angle to the natural fall, thats how you catch overland flow and drain it.

And Mr Grange your actually 4 years wiser if thats how you want to put it.. all i am saying is from an engineering perspective your design is fundimentally flawed. Saying that it may work for years and i hope it does for you.

Harrier1980

forgot the image

funny man

just do it wrote: »

Here's one that seems to have divided opinion. What's yours?

Fill drain to top with stone showing, or fill within 4/6in and cover?

I don't see any advantage in filling stone up to the top of the drain as in wet ground top soil will go through the top layer of stone and block it anyway, i'd be of the opinion that a drain should be dug in dry weather with a v bucket, pipped to allow water to drain faster and then no bigger than 2" stone filled within 6" from the top and then plough the field across the drains where possible. if the ground gets wet run a mole plough across the drains and this will open up the route for the water to get away.

follett

I only ever use 4 inch stone and only use about 3 feet of a pipe at the mouth of the drain, I always notice its the mouth of the drain that gets blocked

crackcrack30

I have a 12 acre field that is gradually being taken over by rushes,
There is a source spring in the neighbouring field, A natural almost flat low (170meter)then go's thru the centre of the field (that is wet almost year round) with rush climbing out both sides of it at 30 yards both sides in places. The natural low gradually makes its way down to a bog which I also intend to open drain.

Should I use a v bucket and how deep should I go......was thinking of leaving the drain open and fencing both sides for cost reasons and grazing purposes (possibly fill in my own time if ever)

Any suggestions recommendations.....

Figerty

Go on Bing maps, find the field and take a screenshot. Post that with an arrow point in the direction of the fall to give better image.

There may have been in a drain in the low part of the drain that might have collapsed, especially if the rushes are only starting to take off.

Open a drain. fence in off, come back and close it one section at a time as finance allows. Make crossing points for cattle over pipe sections.

The choice of stone and piping will depend on soil type and fall. If you do fill it with stone then fill it to the top. If this is a low point, you will want water to flow to the stone and filter down quickly. Filling with soil on top of stone is only useful if the problem if water is coming up ( like a spring).

crackcrack30

<div><iframe width="500" height="400" frameborder="0" src="http://www.bing.com/maps/embed/viewer.aspx?v=3&cp=52.744000~-8.476410&lvl=17&w=500&h=400&sty=h&typ=s&pp=&ps=55&dir=0&mkt=en-us&src=SHELL&form=BMEMJS"></iframe></div>

That picture is a couple of years old and dosen't do justice to the rush on the ground today....

mikefoxo

Does drainage not work by lowering the water table? I.e. water table rises to level of drain; stone around drain sucks it into pipe and takes it away, lowering the table. Or am I hilariously wrong:o

Conmaicne Mara

crackcrack30 wrote: »

<div><iframe width="500" height="400" frameborder="0" src="http://www.bing.com/maps/embed/viewer.aspx?v=3&cp=52.744000~-8.476410&lvl=17&w=500&h=400&sty=h&typ=s&pp=&ps=55&dir=0&mkt=en-us&src=SHELL&form=BMEMJS"></iframe></div>

That picture is a couple of years old and dosen't do justice to the rush on the ground today....

Some detail on them maps, looked at my own place and the neighbour was busy burning furze lol.

Figerty

mikefoxo wrote: »

Does drainage not work by lowering the water table? I.e. water table rises to level of drain; stone around drain sucks it into pipe and takes it away, lowering the table. Or am I hilariously wrong:o

Ya, Mike...but you lost me there as to why you are asking it?
Normally you put a drain in to lower the water table i.e. to get below the natural water table level where it is a problem.

The other side of the coin is what is causing the water table to rise. Flooding from outside sources on to the surface or is it from a spring coming up.. point is to get rid of the water anyway.

Figerty

crackcrack30 wrote: »

<div><iframe width="500" height="400" frameborder="0" src="http://www.bing.com/maps/embed/viewer.aspx?v=3&cp=52.744000~-8.476410&lvl=17&w=500&h=400&sty=h&typ=s&pp=&ps=55&dir=0&mkt=en-us&src=SHELL&form=BMEMJS"></iframe></div>

That picture is a couple of years old and dosen't do justice to the rush on the ground today....

Bing maps are more up to date than Google for my area. Looks like bog to the right hand side and water moving downward as you said.

Looks like you need a cut off drain along the wall between your neighbour and yourself to stop the flow. Probably why there was a wall there originally.

Last year put so much water into the ground that it has to come up somewhere so it may well appear up through your field even with a cut off drain. A drain down through the rushes is still a good bet.

follett

I think v bucket is too narrow I like the bottom of my drain at least a 12 inch wide, if you don't close your drain all the mud will scale into it so you be cleaning it with a shovel every day, could you devine the field, its the cheapest part of the job

reilig

follett wrote: »

I think v bucket is too narrow I like the bottom of my drain at least a 12 inch wide,

You'd want to be getting your stone for free!!

just do it

Dig now while the land is still dry. No problem leaving the drains open for a few weeks particularly if the base is clay. I've left drains open in my place like this and have only had to shovel out a few odd bits here and there.

just do it

mikefoxo wrote: »

Does drainage not work by lowering the water table? I.e. water table rises to level of drain; stone around drain sucks it into pipe and takes it away, lowering the table. Or am I hilariously wrong:o

Your right but they also catch rain and, if there is a slope to them, run off from the ground around them. This carries the rain away before it gets a chance to soak in. You'd imagine this must also help prevent poaching.

follett

land drainage is not cheap. you need room in the bottom of the drain for water to circulate, you need a serious track machine driver too, does any use the gravel mole plough that's your 1s to eat your money, it is brilliant job do

vanderbadger

use cuts off from a flag quarry for the first time in the last few weeks for fillings drains, alot cheaper than clean stone

crackcrack30

Figerty wrote: »

Bing maps are more up to date than Google for my area. Looks like bog to the right hand side and water moving downward as you said.

Looks like you need a cut off drain along the wall between your neighbour and yourself to stop the flow. Probably why there was a wall there originally.

Last year put so much water into the ground that it has to come up somewhere so it may well appear up through your field even with a cut off drain. A drain down through the rushes is still a good bet.

That's my field also........and i'd say its causing a lot of the problems, looks like a spring that can be a small pond in the winter.....

Figerty

http://maps.osi.ie/publicviewer/#V1,591271,743300,0,10

Have a look at the old maps and see where old walls or drains might have been. It could tell you a lot about how the water was dealt with in the past. You can do an overlay on the current maps.
You would be surprised what you will find out. It's likely a 12 acre field was a set of small fields. That could tell a lot about your current problems.

orchardfarmer

there are too many stones to mole plough round our way, only option is to stone the drains and shores right to the top.
drained my first field 3 years ago, filled drains with washed 2" stone to 4 inches from top, then topsoil. when the rain came the water sat right on top.
broke my heart looking at over the winter so the next year i stripped the topsoil back off, filled to the top with stone and the field is perfect since. the field is at the bottom of a valley and there is serious water flowing down into it, would do your heart good watching the water disappear now!!

so my advice would be fill to the top if you cant mole plough!!

just do it

Figerty wrote: »

Bing maps are more up to date than Google for my area. Looks like bog to the right hand side and water moving downward as you said.

Looks like you need a cut off drain along the wall between your neighbour and yourself to stop the flow. Probably why there was a wall there originally.

Last year put so much water into the ground that it has to come up somewhere so it may well appear up through your field even with a cut off drain. A drain down through the rushes is still a good bet.

What's the url for bing maps?

Username John

just do it wrote: »

What's the url for bing maps?

http://www.bing.com/maps/

just do it

Username John wrote: »

http://www.bing.com/maps/

Funny thing. I tried that earlier on the phone and it wouldn't budge from Seattle. Working fine on the PC now!

Conmaicne Mara

If they could combine the quality of the Bing maps with the tools of the Geological Survey Ireland, the scribbly bits off Google Earth, and the other bits and bobs of the OSI map it'd make one very useful mapping site.

follett

orchard I think your right fill to the top, have you got good soil, where as i don't I have loads of spings

just do it

follett wrote: »

orchard I think your right fill to the top, have you got good soil, where as i don't I have loads of spings

With springs you could use stone and perforated pipe at the start and then sewer pipe to the trench.

Pat the lad

Try daft logic.com in search engine. It has distance and area measurement tools . It's handy for checking field size etc