On Thu, 6 Feb 2003 17:37:59 +0100, "Pierre de Ponthiere"
wrote:

What happens when some pond water evaporates?

It will evaporate and I top off the pond to the level I want it once a
week.
Is it correct that the level of the pond will be maintained at the rim of
the first vessel connected to the bottom drain until the level of the pump
vessel is at the level of the pump itself?

My priorities are fish then pump. I suggest putting the pump in a
bucket so the water will not flow into the bucket until the pond is
drained and fish die, but stop the pond depth at the top of the bucket
waterline. Waterline meaning a level plane (imaginary) from the top
of the bucket extending through the walls of the pond and across the
surface.
The water buffer to compensate evaporation (until external water addition)
is only the volume of the vessel containing the pump.
As this volume is not so huge, we run the risk the pump has no more water to
pump.

Not sure I understand, but try this. Lets say we dig a pond 2' deep
and use a 1' deep bucket weighted to the bottom of a 2' deep cavity on
the same plane as the pond, containing the pump. A gravity flow line
connects the two, bottom to bottom. The top of these bodies of
water, the pump cavity and the pond will also be on the same
waterline. That way water flows continually until the water level
drops below the rim of the bucket and the pump runs dry. If the pump
runs dry we can find a dead pump, but live fish in 1 foot of water
waiting to be rescued.

Regards,

Hal

Regards,

Pierre.

"Hal" wrote in message
.. .
Not an issue in my pond. The bottom drain empties into the side of a
55 gallon barrel and the pump sits in the third barrel.
If this is a concern you could put the pump in a bucket. Allow the
water to flow over the rim of the bucket and be picked up at the
bottom by the pump.

Regards,

Hal

On Tue, 4 Feb 2003 11:28:01 -0500, "BenignVanilla"
wrote:

For those of you with a bottom drain...how do you protect yourself
against
emptying your pond if there is a failure somewhere upstream from your
bottom
drain?