In article , Sue da Nimm
.? writes
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, which is
why it can burst pipes)

Other way round - water expands when it freezes (which is why ice floats
- the same amount of water occupies a larger space when frozen, and so
is less dense), which is why it burst pipes.

But you don't usually realise the pipe has burst until the ice has
melted.


--
Kay
"Do not insult the crocodile until you have crossed the river"