Part I - Free Form Pond with 45 mil Firestone EPMD Liner
Free form ponds give you the greatest opportunity to custom design an enclosure to meet the
specific needs of your turtles. However the landscape and local conditions will play a part in
the final design of the pond. For myself, prior to the turtle pond this area was the home of
two eighty foot spruce trees that were cut down two years prior to digging. The amount of
work it took to remove all of the roots with diameters ranging from less than 1 cm to more
than 20 cm nearly convinced me of what a bad idea this was.
Choose an area that recieves the amount of
sunlight appropriate for your species. If you choose
an area that receives full sun don't forget to
include adequate vegetation for creating shade
and the microclimates your species desires.
Once the site has been choosen and you've
worked up a rough layout for the pond & enclosure
begin by digging the footer for the retaining wall.
Clear away all large roots and stones.
The footer needs to be deep enough to get below the frostline to avoid upheaving by
frost & ice, leading to cracks and eventual repair. After the area has been dug out,
leveled, and tamped down (or gravel laid) pour the cement and allow it to cure following
the recommendations of the manufacturer.
Now that the footer is set you have a solid smooth surface to build the wall on. As
mentioned before follow the manufacturer's recommendations for mixing and cure time of
the mortar. Because I live in the Northeastern U.S. I included extra drains at each end of
the retaining wall to avoid accidental flooding of the area near the wall after the snow
melts or heavy down pours that can cause the pond to overflow.
After the retaining wall is set you can get a better idea of the lay of the land within the enclosure. Because my enclosure is boardered by
a wood fence I laid boards horizontal to the base of the fence and faced it with 5 mil plastic sheeting to reduce the amount of soil lost to
the neighboring yard.
Measure out the length, width, and depth for the size pond you want and begin digging the hole. Keep in mind that all of the dirt you dig
out of the hole has to end up somewhere; I used it to build up around the water fall, back side of the pond, and the nesting area. Natural
barriers offer the opportunity to make the pond more unique and naturalistic by forcing you to carve out a shape around it. For example,
the large root I ran into lended itself to building a shallow emergent zone with a reinforced edge. Make sure to include shallow water rest
areas for your turtles to use for sleeping, foraging, and mating. These areas also help to produce a natural thermal gradient. Deep zones
should have a sloped end or submerged structure for the turtles to climb should they become fatigued or become less bouyant as a result
of a small breath and a hasty dive into the water.
The underlayment is important to help avoid accidental punctures by rocks, roots, or sticks once the water's weight settles the soil under
the liner. The underlayment can be as simple as a thick layer of newspaper, carpet fragments, or a special pond underlayment material.
You are now ready to add the pond liner. I went with 45 mil for the added durability against larger turtles digging into it. The actual laying
of the liner will take some adjusting taking into account that a little extra slack in the liner will reduce stretching as the ground settles
under the weight.
Begin filling the pond slowly, this is the fun part, climb in and work the liner into place using large rocks to help hold it where you want it
until the water pressure keeps it in place. Keep filling right up to the highest point, this will help you to identify low areas to build up before
you backfill the soil against the liner. Looking at my pond you will see a that the liner forms a small mound around the pond, this is to
prevent the rain from washing soil into the pond. The ground is graded around the pond to allow the surface water to flow around it.
Building up the rock features is where the project starts to really take shape. If you want the water to flow naturally the key is variety.
Variety in the shape and size of the rock used will keep the larger rocks locked safely into place. A good standard is if you can walk over
the rocks without them shifting under your weight then they are set correctly. I personally don't wish to find one of my turtles or a
hatchling pinned under a rock that was carelessly placed (this includes rocks falling into the pond).
At this point you can start the pump and filter. Overkill is not bad thing with filtration: my pond is around 550 gallons, the pump moves
3900 gph, and the biofilter can handle a 1000 gallon pond. After the pump and filter have been running without problems you can add plants
and fish. Allow the filter, plants, and fish to establish themselves before entertaining the idea of adding turtles. This time frame will be
determined by your climatic zone and size of the pond. Should something go wrong with the pond the fish and plants serve as the canary in
the mine and you can remedy the problem before throwing the turtles into the mix.
Landscaping will bring new life to the pond habitat and a sense of completion to the project. Part II will cover the landscaping and plants.
Overwintering the pond is important. Unless you plan on moving the fish and plants
indoors make sure to dig the pond deep enough for fish to last the winter, you will need
to check the requirements for your local climate. During the fall months I allow the leaves
that blow into the pond to stay at the bottom until spring as the fish will hide among
them. Once the temperature falls below 4° C (40 °F) I disconnect & remove the pump and
filter then add the floating pond heater to prevent the gases from building up under the
**Because of the depth this pond ultimately housed Pelusios castaneus during the summer months.
DIY Project - Free Form Pond
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