On 20 Aug, 14:03, Matty F wrote:
On Aug 20, 10:37 pm, Jim K wrote:

oh concrete will set, just keeping it where you want it whilst it does
if raining/water flowing at time - Bin liner - i.e. effectively make
"a bag of concrete"? will mould to contours around pipe and sides of
ditch and not get washed out whilst setting....

perforate the pipe with angle grinder for first couple if yards, lay
pipe on and surround with clean crushed rock, all sat on & wrapped
around in geotextile (to stop silts bunging up holes in pipe)?

That sounds like the plan thanks.
With the geotextile over the top I can cover the whole trench with
soil.

aye a "land drain" in effect...make sure the geotextile (I've used
black woven "weed control" stuff successfully) goes all around rather
than just on top,else it will probly bung up quicker, pipe in lower
half of rock.

Be careful too make your "collection zone" low enough for the slit
pipe to function as you wnat it to - i.e. so there is no other "way
out" for the water except your pipe...not through the stone layer
underneath the pipe for example. Your concrete "dam" should do the job
- placed around the pipe in the ditch "holding back" the crushed rock
wrapped in geotextile....


ASCII art section - viewed best in non-proportional font

////////
////////
=========
=rrrrrrr=
=rrrrrrr=
=rr(P)rr=
=rrrrrrr=
=========
SSSSSSSSS
SSSSSSSSS


//// soil
===== geotextile
rrrr clean crushed rock
P pipe
SSSSS - subsoil (whatever's under the ditch)

another - at 90degrees
///////////////
///////////////
=========CCCCCCC
=rrrrrrr=CCCCCCC
=rrrrrrr=CCCCCCC
ddd=rrrPPPPPPPPPPPPPPPPPPPP
SSS=rrrrrrr=CCCCCCC
SSS=========CCCCCCC
SSSSSSSSSSSSSSSSSSSSSSS
SSSSSSSSSSSSSSSSSSSSSSS


CCCC concrete
ddd bottom of ditch


Cheers
Jim K