The message
from "Gerry" contains these words:

I am looking for a group that might be appropriate or advice on layout. I am
considering digging two trenches down the length of the tunnel to minimise
bending and to get better use of the edges of the tunnel as it slopes to the
ground.

I did that with a tunnel, shoring the sides with corrugated iron, and it
was well worth the work.

I dug a sump at one end which had water in it most of the time, and
after heavy or prolonged rain I sometimes had to wear wellies.

The work isn't quite as much as you'd think, because in digging the
trench you will be raising the bed with the spoil. (Even if you have to
remove topsoil first and then replace it on top.)

--
Rusty Hinge http://www.users.zetnet.co.uk/hi-fi/tqt.htm

Dark thoughts about the Wumpus concerto played with piano,
iron bar and two sledge hammers. (Wumpus, 15/11/03)