"Sue da Nimm" . wrote in message
...
Thanks. Wont that act as an overflow. I guess thats fine if you
leave
run for the water to run away but if you connect all the conduit
back
to the socket then you risk water running back to it during heavy
rain.

Just a few further thoughts.
We've always been told to install overflows beneath the edging slabs
or
stones. This is to kep the level constant and keep the water from
coming up
over the edging when the pond fills with rain.
This is not for aesthetic reasons, but because of the power of
melting ice.
The pond sides should always slope outwards so that any ice formed
cannot
exert sideways pressure when it melts. (Ice EXPANDS when it melts,

If that were true, ice would not float. The maximum density of the
ice-water system occurs at about 4 deg C at normal pressures.

which is
why it can burst pipes)

It bursts the pipe when it freeezes, but while it is solid, it seals
the crack. When it melts, the crack is able to leak.

[snip]

Franz