French/land drain clogging up

[RogerS]

Am I alone in thinking that the design of these is fundamentally flawed? Dig a trench and even stick a perforated pipe in it and cover with small gravel, then cover with very expensive membrane ("to avoid the soil washing down and clogging up the gravel, Sir").

So the soil washes down and clogs up the membrane instead. Result. It stops working after a few months.

Any solutions other than an open ditch?

 

[Harbo]

We used to fill them up with 1" shingle then membrane, 6" topsoil and turf.
They lasted for years.
Some were filled with shingle to the top.

Rod

 

[RogerS]

Mine is less than two years old....membrane now covered with fine clay.....water just sits on top.

 

[Jonzjob]

I have no idea as to what ours is. It's been there since 1982 and still going well.

 

[RogerS]

I have no idea as to what ours is. It's been there since 1982 and still going well.

Ah but how do you know it's working?

 

[Harbo]

If you put the membrane near the top and getting problems it's easy to replace.

Rod

 

[dickm]

Not much help to the OP, but the son of an old friend got hiself a contract job cleaning the gravel on french drains alonside some of the motorways in the Midlands. He bought himself an old industrial carrot washer, water tank and excavator, and used this rig to take out the gravel, wash it and replace. Made quite a reasonable profit on the deal, apparently.

 

[Jonzjob]

How do I know it is working?

If I work on the principle that it hasn't needed to be emptied for the past 4 years or so and that there are no smells coming off of the fosse septique and there is a nice healthy grass growth about where it comes out.

Plus, the only problem we have had was when a couple of months back I had to get into, almost, one of the manholes and clear out a load or roots that had managed to block the outlet of the main loo. Everything is working very well.

There seems to be an odd situation here in that the fosse septiques here seem to be much mor delicate than the septic tank we had for 23 years in England. Everything was chucked down into that septic tank and it just carried on working. If we were to do the same thing here it would just go toes, or something, up and stop working!!

Believe me, ours is working 8) 8)

 

[RogerS]

John

Think we are talking at cross-purposes here. I am talking about a French/land drain that is used to take water into the pipe from the surrounding soil. Unless I am mistaken, you are talking about the pipe that comes out from the last stage of a septic tank and delivers the waste water back into the soil. Two different scenarios.

 

[Jonzjob]

Click! Correct Roger, I was thinking of the septic outlet. The water is going the other way init

 

[Harbo]

In the old days - Land Drains were generally small diam clay pipes butt-jointed together, covered with some gravel then back filled. Virtually abandoned and generally "lost"?
On highway schemes, FDs were generally filled to the top with gravel etc but where there was a danger of vehicle over-runs they were covered with shredded rubber tyres or sometimes sprayed with bitumen to stick the particles together?
It was only where a prettier appearance was required they are grassed over as they are more difficult to maintain long term.

Rod