How to calculate volume of water in
your garden fish pond
The volume of water in your garden fish pond
plays an important role in deciding upon correct size of pond pump, pond
filter and pond ultra violet light. Sometimes you need to convert from
different units
Know your pond’s volume ... ie the volume of water it holds including
the waterfall
Ideally a pond’s volume should be measured accurately at the time of
filling the first time. If not then the slide rule or something more
modern must come out. Many countries allow the house owner to read the
water meter. This is the ideal way to measure your pond’s volume. Just
don’t let the kids use the bathroom while you are doing it.
Conversion factors come in handy when working out volumes in and
around ponds... In the table below you can see what the equivalent volumes are for
different units … To use this table read across the rows.
For example 1.0 US gallons is the same as 0.83 Imp.gallon or 0.13 cu
feet or 3.79 litres and so on.
You will also notice that 1 cu metre is 1,000 litres or 35.3 cu
feet etc
Volumes of Irregular Shaped Ponds
 If
your pond is not a simple rectangle or square the calculation of pond
volume can become a little tricky. Here's the way to do it ...
If your are not totally accurate do not be too concerned
because we are looking for an approximate volume. However you should aim
to be within say 15% accuracy. In making approximations the simplest way
to do this is to assume the pond is surrounded by a rectangle and then
ask yourself what proportion of the rectangle is covered by water (shown
in the sketch as blue). See the sketch here to assist in understanding this measurement technique.
Iy you want to make a quick guess here's the formula ...
Lets say the proportion is 50% and the depth of the pond is constant at
0.5 metres and the rectangle around the pond is 3 metres long x 2.8
metres wide. The volume is calculated as follows:
3.0 x 2.8 x 0.5 x 50/100 = 2,1 cu.metres = 2.1 x 1,000 = 2,100 litres
NOTE: If the depth is not uniform then use the average depth to calculate
the volume.
Another more accurate approximation can be made by counting the small
squares into which the pond has been divided as in the diagram above.
This is the method explained in detail:
You can download a calculator have created to do this for you
if you have Microsoft Excel on your computer. Here's the link to
download the irregular pond volume calculator and then save to your
computer.
-
The pond was first drawn to scale using graph paper or something
similar like a spreadsheet (this sketch was done on a spreadsheet):
-
Each square in the sketch has a constant size. As you can see the
total squares covered in the total rectangular area is 11 x 12 = 132
squares.
-
The total yellow squares must now be estimated. I estimate about 21
full squares are covered by the yellow bits. If you get a bit different
it does not matter much.
-
Now count the white squares ... I get 56.
-
This means you can now calculate the number of squares covered by the
blue pond as follows:
-
132 – 21 – 56 = 53 squares
-
If each square is 0.2 x 0.2 metres then area covered by pond is as
follows:
-
53 x 0.2 x 0.2 = 2.12 sq metres
-
If average depth of pond is 0.5 metres then pond volume is
-
2.12 x 0.5 x 1,000 = 1,060 litres
Knowing the volume of your pond is important if you want to specify
other equipment correctly. Once again if you are not sure seek help.
While considering pond volume 1,000 litres of water is a good volume
to hold about 1 kg of fish.
Choose low cost reliable supplier on-line
I suggest you look a both suppliers and compare prices and shipping
costs ... take note that both suppliers offer specials at times and these
often appear in right hand border of this website.
These suppliers do sell other makes of pumps also of high quality and
performance which you might want to investigate and you can search the
websites for the model you want ...
Florida based
supplier specializing in very wide range of garden fish pond equipment
including pond pumps filters and UV lights ... just click the link
This article by Tony Roocroft, "The Pond Professor" first published
on his water gardens
and water features website |
