By: Charles E Lewis
California has earthquakes; we in the south and
east coast have hurricanes. One thing we all share is
power outages. Ours are usually caused by storms.
Most power outages last only a few hours and only
happen a few times a year. A hurricane is always a
threat that hopefully will never happen or have only a
minimal consequence. Flooding may be more common
then a power interruption and both can happen at
the same time.
A well built well thought out well designed pond
will survive a big storm with a long power outage, lots
of rain and flooding. This pond also will be less
worrisome during the numerous smaller but strong
storms. The most obvious and the most popular is the
garden pond. It has few fish so it does not need
extra filter or aeration. There is enough surface area
for oxygen levels to be sufficient. The surfaces of the
pond and plants handle the filtration. A koi pond
should be able to stand-alone for hours without
danger of quick suffocation or toxic waste build up.
The key is in the number of fish. Conditions in an over
stocked over fed pond will quickly deteriorate. A
lesser or under stocked pond will always be healthier,
have less maintenance, and survive periods of no
Heavy rain can make a pond quickly overflow or
be flooded out. Heavy rains can cause a rapid change
in the pH and the temperature of your pond water.
Check your inventory of chemicals such as pH
adjustors, Amquel or Ammo Lock. Heavy rains can
cause a change in the pH and the temperature of
your pond water. Water with higher alkalinity will
have a stable pH. Buffers can be used like baking
soda will help keep ph stable. If it is possible use a
tarpaulin a few feet above the surface to permit
airflow yet keep rains out.
A pond should be built with the top above grade. Six
inches is minimum and twelve inches is better. This
can be a raised wall or lip. It also can be graded out
and still have an in ground look. This will make
rainwater drain away from the pond instead of into it.
Choosing a spot that is not the low spot that always
floods should be avoided or built higher. ? If at
ground level consider surrounding the perimeter with
a wall of sand bags 1 or 2 bags high. Drastic, but it
has been done. This may protect your fish from being
washed away and never to be seen again. Is it
possible to set up a portable show tank, maybe in a
garage or other protected area? We know that with
changes to their environment, Koi will often jump.
Murphy says that they will land in the worst possible
location. A net surrounding the edge or covering the
pond is therefore advisable.
An overflow drain is easy to build and may be the
most used and important design of a pond. Without
an overflow the water level will never be constant,
be hard to maintain and get too high during a storm
flowing over the top. An overflow drain should be
large enough to handle large amounts of water I like
four inch pipe. It can be above the waterline or
stubbed up from below. It needs to drain to an area
that can handle a lot of water. A storm drain, a dry
well or a drain field, which is a large hole with gravel
in it, then covered work well. Making a bog area
where the overflow water goes also works. Just take
care that it does not flood someone else. Having the
waterline above grade makes any overflow drain
Lower stocking and overflow drains are simple ways
of making a pond storm proof but there is more we
can do. Most of us like to be heavily stocked with
more fish then we should have. We may not want our
fish not to have periods of low oxygen or risk an
ammonia build up. One solution is to have an
emergency generator that can be started
automatically when the power goes out. They may
not be too expensive for the piece of mind and
convenience they provide. A portable generator can
be used for some or all your equipment but will have
to be started and switched usually during a storm.
Both of these solutions work but will need fuel on
hand and tested regularly for events that may only
happen once or twice a year or a big event that may
Lets say we are in a hurricane watch or a tropical
storm warning and we have five days to get ready.
There are a few simple things you can do and a few
simple items you should have on hand that could
save your fish until power comes back on in a few
1: STOP FEEDING!
Koi will be fine for a week with no food. With no
food the amount of ammonia produced will be
dramatically reduced. This is a common practice
when taking koi to a show to prevent ammonia build
up in holding tanks. Koi excrete the most ammonia
right after they eat so if bad weather is approaching
you may want to skip a meal. The longer the better.
3-5 days of no food will make a huge difference.
2: WATER TREATMENTS.
Products like Amquel or Ammo Lock are products
that bind ammonia and prevent it from harming fish.
These products should be on hand normally. You can
test your water for ammonia and use these products
to control it. Make sure your test is a salicylate type
as opposed to a Nessler rent base kit that will give
false readings with ammonia control chemicals. Mydor
is one brand of test kit that will work.
Storms happen during the summer when it is
sunny and hot. A tarp on PVC legs or rope over the
pond will help keep the temperature down. This will
help keep the dissolved oxygen up and make the fish
more comfortable. With no power or air conditioning it
may also be a nice place to be. I have seen some
inexpensive quick garden shade canopies that could
4: EMERGENCY POWER.
A car battery and a power inverter can run an air
pump and air stone for hours. The battery can be
kept charged with a charger on low and a timer so it
is not charging all the time. When the power goes out
you plug your air pump into the inverter. Aeration
using this method is very efficient, low in cost and
easy to do. You may have these items already. For
longer periods of time you can recharge the battery
with a car, self start lawnmower, motorcycle or small
emergency generator. You also can find complete
units like the XP600 for $279.95 from Aquatic eco-
systems. Small emergency generators are good on
fuel and can provide many hours of aeration.
5: HYDROGEN PEROXIDE.
This is another item that should be on hand. It
can be added to the pond and add huge amounts of
dissolved oxygen to a system. Simply use ½ to 1 cup
per 100 gallons. Apply with a squirt bottle forcefully
under the surface of the water. 60 squirts is good for
Bacteria in a filter will go anaerobic without
oxygen. It will start going bad and producing toxic
wastes like hydrogen sulfide. A few hours may be ok
but if the power is out for more than a few hours you
should not pump right back into the pond. You should
back wash your filter first. If it is an open filter you
can have air stones on your emergency power to help
keep the filter aerobic and living.
Make sure that all equipment is grounded with
heavy wire and GFI protected. This will lessen them
being damaged by lightning, storm surges and shorts
from wet weather.
This is only intended to be a brief guide and in no
way details all steps that can or should be taken in
In summary plan for flooding and power outages. Do
not to over stock unless you have the equipment to
support a livable condition. Plan for ammonia build up
with no filtration by chemical treatments and halting
of food. Emergency power works most efficiently with
aeration. Most storms are short or do little real
damage. Having a plan to handle them will make life
less stressful for you and your fish.
* Re-printed with permission of Charles Lewis,
President of the South Florida Tropical KOI Club