David WE Roberts
wibbled on Wednesday 30 December 2009 18:50

I don't know if my rain water drainage is to a soakaway.
However......
Having just unblocked a rainwater down pipe at the top where it met the
guttering, and found it full of mud and moss (our North facing roof seems
to be almost a 'green roof' - there is moss growing around nearly every
tile) I was pondering on how much crap had gone down the pipe before it
became blocked.

Which led me to pondering about soak aways in general.

If you keep washing muck down into them they must silt up eventually.
So how do you deal with this?
Should there be a gulley and 'U' trap before the soakaway to catch rubbish
which can then be removed?

That would be the easiest to maintain way.

Or do you have to plan to dig the garden up every 20 years or so and clean
out the soakaway?

Once, I made a hollow chamber soakaway with a paving slab base, brick wall
with gaps between some bricks and paving slabs sitting on top. This was in a
lawn 4" under the surface, so if one remembered where it was, it was a
fairly simple matter to lift the sod and clean it. However, it would take a
lot of blocking up being a chamber type.

Can't do that here as there's clay 12-18" down so not much depth of soil to
drain into. I'm thinking of burying long lengths of perforated pipe 12" down
or just above the clay layer. In that case I will certainly be installing u-
traps with access lids as perforated tube will block relatively easiliy and
be nearly impossible to clear.

--
Tim Watts

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