Pond design is an important factor that should be
considered before building any pond. It
will have an impact on the actual workings of the pond, the work required to
maintain the pond and even the health of the pond life. Achieving a balanced ecosystem is the key to
healthy pond design.
Some of the pond design aspects to consider are:-
size is determined by the area that you have available. This may be a small bowl or tub for a
courtyard or balcony to a large in ground pond with a waterfall.
shape depends on your personal taste.
However, it is important to have the correct pond depth for a healthy
pond profile or cross section does have an influence on the growth of plants,
control of algae and the water temperature.
A shallow saucer shaped pond has a large surface area to volume
ratio. This allows more sunlight to
shine on the surface and heat the water.
However, at night this heat is also lost faster. This creates an environment which has greater
changes in water temperature which is not so pleasant for fish or other aquatic
life. It also stimulates greater algal
growth. A pond design
with the same surface area but steeper sides, holds more water and therefore has
a lower surface area to volume ratio.
The larger volume takes longer to heat up in the sunlight and is slower
to drop in water temperature at night.
This creates a more stable environment which is much better for plants
and other aquatic life.
In ground or above ground
A pond design that is set into the ground is preferable
as the ground around the pond helps to stabilise the water temperature. That is not to say that you cannot have a
smaller bowl or tub as a water feature.
But it must be realised that this type of water feature may require a
little more care or maintenance.
Pond plant depths
plants have different needs in relation to water depth. Oz Watergardens have developed a system for
classifying plants according to their optimum water levels. To simplify plant selection we have divided
the pond into FIVE Pond Plant Zones.
This can be a useful guide to plant selection and basic pond design.
Ideally ponds should be at least 45cm deep but
can be more than a metre.
aquatic plants such as Waterlilies are self adjusting to water depth. Most plants supplied to Nursery Garden
Centres have been grown in shallow water in order to make them easier to
transport. However, if your pond is
deeper and all the leaves are below the water surface, you have two options
available. Firstly, you can leave as
is. The plant will produce new leaves
which will grow up to the water surface, while the older ones die off
(resulting in no harm being done to the plant).
Secondly you can place bricks / pavers (being careful not to damage your
pond liner) under the pot to raise the plant.
Waterfalls and fountains
and fountains can add charm to a water feature and the sound of splashing water
can be a soothing distraction to our often hectic lives. Moving or splashing water also improves the
health of the pond by increasing aeration and therefore improving the oxygen
levels. Most plants with floating leaves
do not like water splashing continuously on them as the leaves suffocate,
yellow and can die. We recommend placing
these plants in areas clear of splashing.
in a good pond design, should not be necessary,
provided that there is the right balance of sunlight, water depth, water volume
and plants. However, the extremes of
temperature, light levels, high fish populations and/or low plant numbers can
affect the water balance. Thereby creating
an environment where algae can flourish and cloud the water. In instances such as these there may be
simple remedies such as introducing more plants. However, if high fish numbers are to be
maintained, then biological filtration should be installed.
needs and types can vary greatly.
Mechanical filters trap particles.
Skimmers can help save a lot of work in pond maintenance, as a well
designed and maintained skimmer system, can potentially collect more than 75%
of the debris before it sinks to the bottom of the pond.
filters provide a medium for beneficial bacteria to grow. The bacteria feed on the toxic ammonia
produced from fish waste and decomposed plant matter. As a byproduct, the bacteria produce nitrates
and nitrites which are then a food source for the plants.
filters are designed to sterilise the water passing through them and may be
appropriate for some pond systems. They
are often used in conjunction with other filtration methods, as the water
passing through, must be relatively clear of particles for the light to effectively
Capturing the rainwater
Why only have water storage tanks to
capture and store the rainfall? When you
can develop a pond design that naturally
captures run off of roof tops and channels the water into your own billabong. Care should be taken not to divert all the
garden run off into the pond. This water
often contains a lot of organic matter and increases the nutrient levels in the pond
water, resulting in increased algal problems.
We live in the driest continent in the
world and yet we landscape in a way that results in the little rainfall that we
do have, to run off down the drains and out to sea. This precious resource should be harvested
and retained on site for the benefit of the local environment. Once our urban billabong is filled, excess
runoff would then be able to continue to support other areas of the garden. Replenishing natural ground water has also been
overlooked in many garden designs.
A pond built from concrete, limestone, or marble
will also tend to have a high pH, which can contribute to greater algae growth. Ponds
constructed from these materials can be treated with sealants to prevent the
lime leaching out and affecting the pH levels.
Plastic liners, though cheap, should be
avoided. The cost and effort of
repairing damage and leaks tends to outweigh the initial investment.
Preformed fibreglass or plastic pond are an easy
solution to pond construction, however they do limit the potential size and
shape and are often difficult to add to or extend.
EPDM and Butyl rubber liners are recommended for
most ponds as they offer flexibility in the pond design. They are durable and allow for easier and
more natural pond designs. These
materials can also be joined to create much larger ponds.
Ask yourself why you want the pond?
What is your dream pond?
What do you like to do outside?
What kind of lifestyle do you live and what
would you like it to be?
The answers to these questions will help you
decide the style of pond. This is a
great place to begin.
For some further ideas, check out the Pond
Themes-Styles section in our website.