Hi Jim,
Ponding disasters? Yeah, we've had a
bunch, over the years. Most were consequences of either
vandalism (a double-sized hide-a-bed sofa over the fence
and into the pond one Hallowe'en) or just poor design.
1) Our scariest moment was a water loss
issue, brought about by a fundamental misunderstanding of
the nature of water flow in a pipe. Our falls are significantly
higher than our filters and the pipe runs are all deeply
buried. As we were installing the pipe runs with 2-inch
flex-PVC, we forgot to check that the run was without dips
or bumps. We figured that as long as our big cloverleaf
filter was four or five feet higher than the top of the
falls, everything would be fine.
Two things did us in. First, our pipe
run had a slight rise-and-dip in the middle, and second,
we had a brand-new 1/4 horse Sequence that the pond guy
swore was perfect for the pond. You can guess the rest.
The combination of in-pipe resistance to flow, the intermittent
vapor-lock from the rise and the high flow generated by
the very competent pump dumped the majority of our pond
onto the garage floor. No safety cutoffs, either. Needless
to say, all of those defects have been eliminated over the
past ten years, and though our current system should not
work, it has done so flawlessly for the past seven years.
We now run two closed system bead filters on independent
pumps from the skimmer and the bottom drain, and boost the
input and output to and from the protein extractor/bioreactor
array with matched and balanced mag-drives.
2) Collapse and water loss occurs from
poor design, poor preparation, and poor construction techniques.
Wall collapse is most commonly caused by failure to compact
and cover the pond bed, or water leakage from holes in the
liner (careless rock handling) and seam failure. One of
our club members had a catastrophic collapse due to vandalism
by his certifiably insane neighbor. Nothing much you can
do about that.
3) You minimize the risks by doing your
homework; by knowing how ponds work and by finding a competent
contractor, or by learning how to do it yourself. Read read,
read!
4) If a pond is poorly enough designed
or constructed to fail catastrophically, there is little
to be done short of pulling it out of the ground and redigging,
or replacing the filter array and pipe with gear less likely
to fail.
5) The most ominous clue that something
bad is going to occur is a steady and untraceable leak.
This suggests that water is disappearing under the liner
or through an unreachable pipe run and the soil around your
pond is liquefying.
6) You need temporary holding facilities
big enough to handle your entire pond population, with filtration
enough to maintain them while repairs are under way. We
use a giant-sized inflatable swimming pool. You'll also
need dechlor, and Amquel.
7) The most common errors include
forgetting to add dechlor to the replacement water, failing
to take temperature differentials into account, forgetting
to filter or aerate your temporary facility, failure to
do water testing and water changes, and feeding your fish
while they are in temporary, cramped and under-filtered
quarters.
