Soakaway q

[Rick]

I have crap soil ... basically a base of a valley filled with a mix of slag from steel works & stone from when they built a dual carriageway nearby.

It was used as railway sidings for 30 yrs .. then left abandoned for another 20.

Anyway it is where the house is ... and about 25' up from valley floor.

I had dug out around 6 cu M to create a small pond ... but it just keeps filling with water, even to overflow ...
I pump it out .. it fills back up.

As garden is level, bottom of the hole is lowest point so rest of site drains into it, can't create an overflow to anywhere.
Only fully empties when water table lowers in dry weather.
Creating this big hole has just given water somewhere to collect.

So given up on idea of a pond ... before I just fill the hole back in .... thought that it might be worth putting in 2 standard Geotex wrapped soakaway crates. (picked up 2 Polystorm ones cheap)

I know this won't work as ideal soakaway but would it help keep soil area above less clogged?

(I did this other end of site and after 3 years ground still stays dry)

So first Q is ... is this a good idea - or will it make things worse.

Secondly if good idea - on the existing install I laid crates on 100mm sand and surrounded top & sides with 40mm clean stone ... in the soakaway section on this site it shows for domestic use that coarse sand is used not stone?

Which is best ... (only occasional garden foot traffic above) I have to buy in one or other so ... might as well get what is better.

I have plenty of non woven Geotex to wrap crates.

[Tony McC]

If the ground as it is effectively floods, then replacing some of that ground with a crate will achieve nowt. The water will just sit in the crate wher it used to sit in the ground.

[Rick]

However it did solve the bog problem at other end of site ... put in 2 x polystorm crates, Geotex wrapped.
On a 100mm bed of sand, and then surrounded by 150mm of clean stone.

I'm assuming water collects in it .. and it then drains - albeit very slowly, but enough that ground above is no longer boggy.

As I have free crates & geotex to do this, and hole already dug ... would seem sensible even if less than optimal.

The question still applies ... do I cover crate with stone or coarse sand ?

[seanandruby]

If you must then gravel will do.

[Rick]

Thanks.. I have no coarse sand or gravel .. so wanted to get in the most suitable.