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A Three-Part Series on Building
Ponds for Wildlife
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Build a Pond for Wildlife
How to Design the Pond
by Kathy Biggs, California USA
Click images to enlarge
In Part 1 of this three-part series, the philosophy and mindset
for building ponds for wildlife was covered. Revisit that article
here. This article,
Part 2 in the series, describes how to go about designing your
Choose the Site, the Size and Design the Perimeter
Contrary to what you might think, a wildlife pond is best
built NEAR your home. By placing the pond within sight, youll
not only get more enjoyment from it, but you will also be aware
immediately of anything that needs attention. The pond above
is just outside the kitchen window and deck.
One couple built their wildlife pond at the back of their
lot, with the idea of going to it as a meditative place. When
they failed to meditate for several consecutive days, an awful
sight greeted them: the raccoons had rearranged their waterfall,
and all the water had flowed out of the pond. It was dry, and
those critters that couldnt live without water to support
them were dead. They lost all their polliwogs, dragonfly and
damselfly nymph, countless larvae of underwater beetles, and
When your pond is near your house you can also use your windows
as observation posts and photography blinds. Having
a pond outside a kitchen window greatly increases the joy of
dish washing! A camera with a zoom lens is helpful for securing
good images of your wildlife visitors and dont forget to
keep binoculars handy.
Though most lilies and other pond plants found in nurseries
prefer sunny locations, you can site your pond under a tree!
On the other hand, if you place your pond where leaves can fall
into it, your workload will be increased. If your pond is under
a tree, stretch bird netting above the pond in the fall to catch
leaves (as in the photo to the left). If the netting is placed
at a sloping angle, it can be shaken and the leaves will tumble
down, perhaps into a strategically placed wheelbarrow.
Whatever size you are considering, you probably should increase
it. Build your pond as large as you can, as a larger pond is
more stable. It is best if you can reach into all areas of the
pond for maintenance, but that should be your only limiting factor.
The British Dragonfly Society did a study to determine the best
size for a pond designed for dragonflies. Their recommendation:
build a pond that is 15 x 20 feet (4.6 x 6.1 m). With a pond
that size you can reach from the edges to the center for debris
removal and the temperature of the water will remain fairly stable
due to its volume.
Youll want to provide both shallow and deep areas, including
a level planting shelf approximately 18 inches (45.7 cm) deep
for potted aquatic plants. A depth of three feet (91 cm) will
provide an area where the water temperature is more constant,
and where small creatures can hide from larger predators such
as herons and kingfishers.
Liner ponds will work best as they can be more naturally shaped.
Forty-five mm EPDM liner material is a good choice. Concrete
ponds might crack and split with age and need treatment to prevent
toxic chemicals from leaching into the water. Pre-formed polyethylene
molded ponds do not come with shallow edges or in large enough
sizes for a wildlife pond. Another option, especially when building
a large pond, is an earth-bottomed pond. This design requires
large equipment, however, so this type is not well suited for
a backyard pond.
Wildlife ponds should have a beach. This will provide
not only a way for wildlife to enter and exit your pond, but
also a way for YOU to get in and out. Your beach should be built
with steps leading into the deepest part of the pond.
You will need to enter your pond to do maintenance, a delightful
experience on a hot day. In fact, such days are the perfect time
to do upkeep! Construct steps by filling gunnysacks with soil
from your yard and place them between the liner and the pond
A path around the pond, as seen in these photos, allows
you to get close to the water. It also makes it easier to reach
into the pond to do maintenance. One artistic trick
is to make your path narrower as it moves away from your beach.
This creates the optical illusion that the pond is larger than
it really is.
Varying the edge treatments will not only make your pond look
more natural, but wildlife will be able to choose their entrance
and exit spots with an eye towards concealment and other safety
considerations. Please avoid the necklace effect
of using paver rocks as edging as much as possible. It will not
look natural and your smaller creatures will be vulnerable and
exposed as they cross it. Substitute more varied and natural
materials than just rocks and stones. A log can be used
as a part of your edge treatment. It also makes a nice bench
for friends to dabble their toes from on hot days!
One source for logs is the cull piles in our national forests
where timber companies have logged. Logs in these piles are destined
for burning, and, by using one, you help avoid contributing to
air pollution! The log we used, next to the path in the photo
above, is actually partially hollowed out and was placed over
cement bricks. The pond liner goes up and over the cement bricks
under the log. This log has become a favorite spot; it mimics
places Ive found and enjoyed in nature.
You probably will want to use some rock edging. Check
out what is available locally. Stones and boulders that naturally
occur in your area will look best. If rock collecting is legal
in your area, searching for your own stone can be a rewarding
experience. Otherwise, buy your rocks from local landscaping
and rock yard shops. Distribute rocks elsewhere in your yard
to tie the pond to your land and make it look as if it were always
Rocks can be secured in place with expanding spray foam insulation.
Make certain that you choose a nontoxic brand that will be inert
once it dries. Handfuls of your local dirt can be thrown on the
foam as it is drying. It will adhere and make the area look natural,
thereby disguising the foams appearance. Spray foam must
be used on a dry, not wet, surface. Therefore it may be necessary
to drain the pond down a foot (.3 m) or more after testing that
the edges are indeed level.
Even when using a pond liner, it can be difficult to create
variations in the edging contours without forming wrinkles.
Yet these contour changes make the pond appear more interesting
and natural. They also create microclimates.
One way to counteract the problem of wrinkling, once your pond
is filled, is to create plant pockets. Do
this by adding a ring of stones inside and adjacent to the pond
edge. Place a piece of pond liner within this ring; fill the
pocket with clay soil and then add plants. Here a
plant pocket was created next to the log and beach area (photo
to the right) and filled with Pt. Reyes checkerbloom (Sidalcea
spp.), which loves damp soil. The checkerblooms flowers
are especially sweet.
If you have areas of lawn in your yard, allow one section
of the lawn to abut the pond edges to help tie the two areas
together. But a pond ringed only by lawn will look out of place
One or more bog areas next to your pond will provide ideal
entry and exit points for many creatures. The foliage provides
cover, shade and dampness while serving to tie the pond in with
the rest of your yard.
To create a bog: Dig the bog area 18 inches (45.7 cm) deep and
then line the area with pond liner, or less expensive black plastic
sheeting. Add drainage holes to the lining. Fill the bog area
with one-half peat soil and one-half garden soil. Then plant
it with moisture-loving plants. Click here for a list of native North American
bog and pond plants.
Bogs can be placed in both sunny and shady areas. The sunny
bog in the picture above is situated between the path and an
edging boulder. Yellow seep monkey flowers (Mimulus guttatus)
are blooming in this May photograph.
When deciding on the placement of your pond, its wise
to consider the natural runoff on your land. It is a mistake
to put your pond in the lowest area of the yard. This is NOT
a good idea because the water that flows through your yard may
have originated across the street, or farther away. It may contain
pollutants such as herbicides, pesticides and/or oil that would
be very harmful if they entered your pond.
Build berms around your pond so that runoff cannot
enter. Waterfalls, bogs and logs are all good ways to create
berms that appear natural.
When it is raining cats and dogs, youll need
to make certain that the rising water in your pond has an escape
route. Your ponds runoff wont exceed what would fall
on that area if it were a patio, so it is only necessary to vent
the water towards a lower area or drainage ditch. Some people
build sumps for their overflow, but whether youll need
to do this will be determined by the lay of your land and where
your neighbors homes are, for example.
A very simple way to build an overflow outlet is to provide
a slight indentation at one place on the exterior edge. Place
a piece of plastic ABS drainpipe there (black is best as it will
show least). Position a rock or other heavy object on top of
the PVC pipe to keep it in place, and hidden from view. The water
that falls into the pond will escape through this pipe. Situate
the pipe so that the runoff is directed towards the lowest area
of your yard. This will function much like the downspouts on
Another way to provide overflow drainage is to create a creek
bed, lined with pond liner material and covered with rocks. In
the photo above, a deer drinks from the pond at the overflow
To some extent, bog areas next to the pond will also allow
A wildlife pond does not have to have recirculating water,
but there are many benefits to using a pump. Stagnant water is
more likely to develop algae and host mosquitoes. Aquatic creatures
need oxygen and recirculating water has more of it. This is true
partly because the waterfall creates ripples on the water and
oxygen diffusion occurs there. Think of it this way: the surface
of still water is flat, so a string going across the pond would
measure the surface diameter. But a waterfall creates ripples,
so a string going across the pond would have to go up and down
with each little ripple. Thereby the measurement of the diameter
is increased allowing for greater oxygen absorption.
A waterfall makes a wonderful addition to any pond,
and it can serve as one of your edge treatments. Waterfalls,
besides being aesthetically pleasing, also discourage mosquitoes,
which prefer still water. The pleasing sound of a waterfall helps
mask other noises in your neighborhood, and many people find
the sound of falling water restful, helping to ease the tensions
from a stressful day. Birds are attracted to the sound of moving
water that a waterfall produces and will often choose this site
for their drinking and bathing.
One way to construct a waterfall is to pile the soil you excavate
to the far side of the pond. Use pond liner and rocks to create
a stream-like waterfall (photo above left). Or, if the slope
of your yard is downhill, then you can bring in large boulders
and have them artistically piled on top of each other (photo
above right). This waterfall was built with four boulders. Two
of the boulders create the base of the waterfall and a cup-shaped
boulder serves as the top. The fourth boulder was placed to the
left of the waterfall, to give continuity to the design. The
recirculating pump was positioned in the deep area, as far as
possible from the waterfall itself. Flexible piping (dark colored
is best) runs from the pump to between the two boulders at the
base, and then comes up to the top of the cup-shaped boulder
from behind. A splitter at the end of the tubing is concealed
under a few flat rocks and the frog sprinkler.
Soil was added behind the boulders and a skirt
of soil, held in place by black plastic within a mesh of wire
(bird netting also works), surrounds the cup-shaped boulder and
is planted with polypodiums and five-finger ferns (Adiantum
Having water falling from an overhang increases the sound
effect and is pleasing to the eye. It apparently is pleasing
to frogs too, as our native frogs have found that it naturally
amplifies their chorus!
Your waterfall rocks and recirculating pump will be your main
expenses, other than the pond liner itself. Research these expenses
on-line. Be certain to choose a magnetic pump, rather than one
that uses oil: a pump that uses oil can create problems. If roots
get into the pump and it burns out, the oil will be released
into the pond. Luckily, oil floats. If such a disaster should
occur, contain the oil spill with a hose
and then overflow your pond by adding water at the opposite end
from where you want it to overflow. At the overflow site, place
newspapers. The oil will float off and be absorbed by the newspapers
while the water flows through.
It can be beneficial, especially with a larger-sized pond,
to add one or more smaller water features such as a frog
spitter or some other type of ornamental water display
in a different area (photo at right).
Design the Interior of the Pond
One of the main ways a wildlife pond differs from a koi or
tropical lily pond is the edge treatment. A wildlife pond should
have shallow edges. Unlike tropical ponds where the sides are
purposely built with a steep edge to prevent raccoons and other
creatures from entering, a wildlife pond embraces and encourages
entry by wildlife and humans as well.
Your wildlife needs the gently sloping sides to get in and
out. We once visited an owner whose pond for wildlife was on
their mountain property. But it was built with steep edges. One
day when they returned from a trip, they found a dead fawn in
the pond. It had stepped in and had been unable to get out!
The diagram below shows the varying depths of the Bigsnest wildlife
pond. The outside edges are shallow, only a few inches deep.
Think about those ponds youve visited in nature, and youll
recall seeing the polliwogs and many other creatures at the shallow
edges where the water is warmer on a sunny day. This is what
we are trying to mimic. The shallow area is blue-green in the
The next area in the diagram, shown in lighter green, is a planting
shelf, about 18 inches (45.7 cm) deep. This is designed as a
level area where plants in squat pots can be placed. (Information
on how to pot plants for ponds can be found in other articles
on the WGI web site.)
The area beyond the planting shelf in the diagram is shown
in dark green; this deep area is needed to give stability to
the ponds water temperature. It also provides a place for
creatures to hide from predators, and a place for them to overwinter,
when deep water will be the warmest. Remember that steps into
the pond for your own use increase safety. Gently sloping pond
liner material, especially with a layer of natural pond slime
on it, can be very slippery!
It is wise to provide an escape route. A log or some branches
that transcend the pond edges (extending from inside the pond
to several inches or even several feet outside the pond) offer
any small creatures that fall in an escape route. An object that
bisects the edging also is an artistic trick that anchors
the pond to the surrounding terrain.
An old gnarled branch works well. When we were filling our pond,
we put in a manzanita (Arctostaphylos) branch (left).
As the pond continued to fill, we noted that the branch was floating
out in the middle and needed to be repositioned. When we waded
out to move it, there was a lizard on the branch! He was most
grateful when the branch was brought back and he could run to
Designing the interior planting of your pond will follow basic
landscaping guidelines. Plant in clumps. The photo to the right
shows pickerel weed (Pontederia cordata) and blue flag
iris (Iris versicolor). Plant something for each season
(the pickerel weed flowers later than the blue flag iris). Vary
foliage shapes, textures and colors.
Add some element of drama to the pond to make it
more appealing, esthetically. The Indian rhubarb (Darmera
peltata) in the photo to the left serves that purpose, growing
in our shady bog area at Bigsnest Wildlife Pond. It is a plant
that could be grown in a sunny bog, also. Its leaves reach almost
a yard (1 m) across!
In the fall, golden hues rule! In the photo at the left, Japanese
maples (Acer palmatum) provide some striking fall color.
Their size is in a good proportion to the ponds size.
In the winter, especially if you live where there are frosts
and/or snow, most of your plants will die back, but they will
grow again in the spring. If you live where winter is a season
of constant snow, your ponds beauty may be hidden, or have
its own stark beauty.
Build Your Pond Slowly and Dont Be Afraid
to Let It Evolve
There is no reason to rush the development of your pond. Take
your time and enjoy the stages. Youll find that some plants
may migrate to where their individual needs are better
met. If you let this occur naturally, your plants will be healthier
as they know where they will grow best!
To control algae: cover two-thirds of the ponds surface
with floating and/or emergent plants. These plants will not only
provide shade, which lowers your water temperature (warm water
encourages algae), but they will also use some of the nutrients
in the water, thus starving the algae which would otherwise flourish
on these same nutrients.
Then, plant an area equal to one-third of the ponds surface
with underwater plants, such as Elodea. These plants will
absorb nutrients through their foliage, further starving the
algae. The use of tall plants on the west side of your pond will
provide shade in the afternoon, the time when the ponds
water can become the warmest. The photo to the left shows a tree
on the west side of Bigsnest pond. It provides afternoon shade.
In the photo above, the Elodea (underwater plant) was
allowed to grow to the surface where it formed a mat and bloomed
with tiny white flowers. If the mat is unsightly or accumulates
debris, it can be trimmed back periodically with hedge trimmers:
the perfect task for a hot day!
Another method to control algae by starving it is to use a
filter, preferably a biological filter.
Be aware that although algae may be unsightly, it is a natural
occurrence. Every pond will have an algae bloom its first year
as the plants have not yet had time to grow large enough to provide
the balance needed to starve the algae. Dont despair or
quickly rush to use chemicals in your pond. Be patient. The second
year the spring algae bloom will be much less intense, the third
year even less.
A recirculating pump will benefit most ponds, but you can
build a pond without one, using only the plants in the pond to
filter the water and using a net to remove debris. Dragonfly
Roost pond, to the left, is an off-the-grid, totally unfiltered
pond. It does have low inflow and outflow though, with the inflow
arriving in the bog area where the plants provide some filtration
(bog area in photo is to the back right).
A mechanical filter simply removes suspended solids in the
pond water. A biological filter, which is more complex, can operate
much like the under gravel filters in fish tanks.
The biological filter can be designed as part of the pond itself
or be housed in a separate tank. Read about filters here.
Control Mosquitoes in a Wildlife Pond
Although moving water, such as a waterfall, helps discourage
mosquitoes, sometimes a more direct approach is necessary. Besides
being pesky, mosquitoes can carry disease, so although
they are a part of our natural environment they are NOT something
you want to have breeding in your back yard (or front yard either!).
In many areas, mosquito abatement agencies distribute free
mosquito fish (Gambusia affinis) to pond owners
to help keep the number of mosquitoes down. However, these fish
are not native to all regions in the USA; they occur naturally
only in the Gulf of Mexico watershed. In the western USA, in
particular, our native Pacific tree frogs (Pseudacris regilla)
have evolved in ephemeral ponds and their polliwogs have not
developed the habit of evading fish as predators. Ephemeral waters
do not persist year-round, evaporating as the season progresses,
and are, therefore, fishless. Frogs worldwide are in trouble;
they are not breeding successfully and they are dying out. We
need our ponds to be a refuge for them, not a death trap.
You can learn more about mosquito fish and to which areas
they are native at this Wikipedia link.
What works well in all backyard ponds for mosquito control
is a natural product that harms ONLY members of the Diptera
family. The Diptera family includes mosquitoes, black
flies, and crane flies. By floating donuts impregnated
with the bacillus Bti (Bacillus thuringiensis israelensis)
in your pond, you kill the larval stage of all members of this
family, but NOT the members of other insect families, nor any
mammals, amphibians, reptiles, or fish.
Use of Bti will reduce the total amount of critters in your
pond. However, it will also reduce the amount of food
for some of the residents, such as dragonfly and beetle nymph.
Dosage charts on the packaging describe how much to use and how
often to replenish the dunks. In a pond the size of Bigsnest
Wildlife Pond, one dunk weekly keeps the level of Bti constant.
We recommend using a Bti product as your first line of defense
against mosquitoes. It is available at most nurseries and at
Should the Bti not work, or if they are not economically feasible,
we recommend you use a NATIVE FISH species. You will need to
research what fish are native in your area. In many areas of
the world stickleback fish are native. They are about the same
size as mosquito fish but are surface feeders, while mosquito
fish feed at all levels. This means that sticklebacks are much
less likely to feed on the polliwogs and dragonfly nymph, though
they still may to a small extent.
Now youre ready to build your wildlife pond! Next issues
Part 3 of this series will cover how to maintain your pond.
to learn more about Bigsnest Wildlife Pond, 15 years old in 2010
and Dragonfly Roost Pond, five years old in 2010.
1: Why Build a Pond for Wildlife? (WGI Online Journal, November
Part 3: Maintaining a Wildlife Pond
and Other Pointers (WGI Online, May 2010)