Yes, you can build your very own garden pond. In 11 steps you’ll be able to invite a few pondonistas round for a pond-wetting party.
Words and Pictures: Andrea Abbott
Technical Advisor: John Abbott
I long wanted a pond in my garden but it took a clicking stream frog named Dart to galvanise my husband John and I into building one. So named for her dart-like diving action, Dart was always having to be rescued from the swimming pool despite a nifty ramp John had made to give drowning critters a lifeline.
Clearly, Dart needed a proper non-chlorinated pool of her own, one she could enter and exit with ease. And so John set about planning and building Dart Pond. The most important criterion was that it had to be leak-resistant. This required sourcing an appropriate pond liner and being ultra-cautious not to puncture it during the concreting phase.
There are many ways to build a pond but this method results in perhaps the most durable type. It’s turned out to be a much bigger pond than I’d imagined – you could swim in it. It’s robust, beautifully built, and already is attracting creatures such as dragonflies, water skaters and an entire troupe of clicking frogs, whose castanet-like calls make me half expect one to suddenly cry out, “Olé!”
The only one missing is the original Dart, who drowned in the swimming pool before her new home was completed. But, as a friend said, she didn’t die in vain. Because of Dart, there’s habitat for others.
- Cost: R10 000, excl labour and extras
- Difficulty: 5 out of 5
- Time: About 3 weeks
Take note before you start:
- Concrete mix by volume 2 parts 19mm stone: 2 parts river sand: 1 part cement, and just enough water to make it into a stiff porridge.
- Mortar mix by volume 4 parts sifted building sand: 1 part cement, and enough water for more stiff porridge. A squirt of washing-up liquid in the water makes the mortar a pleasure
to work with.
- Floor slab reinforcement: Since the bottom of our hole was like concrete itself, John felt safe in not having steel-mesh reinforcement in the slab. He was afraid it might puncture the all-important pond liner.
- Water pH: Alkali leaching from the cement used might affect the pH so you’ll have to wait for it to settle before adding plants and fish.
- Electrics: John is not a trained electrician but felt quite competent to do the elecrics. Readers might wish to hire an electrician for this. John attached a 15 amp male plug on one end of the electric cable – it plugs into one of the sockets in our garage – and a female socket on the other end was encased in a waterproof box and positioned within 5 metres of the pond edge. The fountain pump came with enough cable to reach this. We used armoured cable specially suitable for underground outdoor use and it was laid in a trench about 300mm deep going from the pond edge to the garage.
- Fountain: Although the plants should keep the water in good condition, we liked the idea of some water movement and aeration and opted for a centrally mounted submerged fountain pump.
We wanted it to be on 24/7 and, bearing in mind electricity costs, chose a low-powered one of 18 watts that has proved adequate.
- Plants: In addition to aesthetic appeal, habitat and diversity should be guiding factors if you want a living pond. This means using indigenous plants only. The more locally indigenous the lekkerer as this should attract endemic fauna in addition to more widespread species.
- Additional reading: The newly published Freshwater Life by Charles Griffiths, Jenny Day and Mike Picker (Struik Nature, 2015 ISBN 978 1 77584 102 9) is an immensely useful resource that no pondanista should be without.
You will need
This is just a guideline and applies to Dart Pond whose dimensions are 8m x 3.5m x 600mm deep. Time taken depends on time available. Dart Pond was a part-time project that was squeezed in between work commitments and thus took several months. Full-time, it would have taken about three weeks to complete. Employing a qualified brick layer would also shorten the period. And a cement mixer is great and saves a lot of time if you’re planning to build a largish pond.
- 6m x 10m 500micron pond liner
- 8 pockets cement
- 2m³ 19mm concrete stone
- 2m³ river sand
- 2m³ building sand
- 900 concrete bricks
- 1 x 18watt fountain pump, bought complete and ready to use
- 20m electric cable, 15 amp male plug, female socket, waterproof box
- 2 x 40mm overflow pipes (50mm in diameter)
- 0.5m³ broken bricks and tiles
- Plenty of compost and plants
- Stones of varying size to place over the bottom and to make caves for the fish
- Choose the best spot. Ideally, a sunny place where it will be easily seen. Not under trees. Set it out and put in lots of pegs to define the shape and move them about until you’re satisfied.
- Dig the hole about 700mm deep with a flat, level bottom.
- Lay the pond liner over the hole and weigh it down with lots of bricks both around the perimeter and in the hole. It must extend beyond the sides of the hole by about 500mm.
- Mix and then lay the concrete floor slab directly on top of the pond liner, taking great care not to cause any punctures in the liner.
- Make the concrete at least 75mm thick and as flat and level as you can.
- The next day, cover with 20mm water and leave for three days to cure the concrete. This will make it stronger and prevent shrinkage and cracking.
- Lay bricks around the inside perimeter, leaving a gap of about 100mm between the brickwork and the sides of the hole. Lay the first course in soldier fashion (i.e. side by side instead of end to end thus forming a 220mm wide base). This will spread the load more evenly on the floor slab. The second and subsequent courses can be laid centrally over the first course to form a 110mm perimeter wall.
- Force the pond liner sides against the outer face of the brickwork by completely filling the void with concrete. Dart Pond extends above natural ground level so we devised formwork by stacking bricks around the perimeter in order to contain the wet concrete above ground level to the height required.
- Trim off surplus pond-liner level with the top course of bricks. Lay a final coping course of bricks in soldier
fashion to seal the top of the bricks and backing concrete and to provide a neat 220mm-wide finish.
- To allow overflow drainage, build 2 x 50mm pipes into this course. These can be directed into an artificial wetland area.
- Form a beach at one end of the pond to allow shorties easy access and exit. This is done by closing off this end
with a 110mm brick wall the top of which is 200mm below final water level.
- The closed-off area is filled with broken bricks/tile etc. and a sloping concrete slab is poured forming a gentle ramp right up to the top of the copings. Very handy for frogs to get in and out and for birds wanting to paddle.
- Make a planting shelf by building a 110mm brick wall around the inner perimeter leaving a 250mm gap between it and the pond sides. This wall should end about 300mm below the final water surface.
- Fill the gap between the inner low wall and the outer pond wall with 19mm stone or washed river sand on which aquatic potted plants can be placed. Unfortunately we used unwashed river sand which, once saturated became like quicksand. Not wanting to remove it all we pushed bricks down into its surface to provide a firm base for the plants.
- A fountain is worth having to maintain water movement and help with aeration. Build a brick column in the centre of the pond for it to sit on just high enough for the fountain nozzle to clear the water’s surface. Our fountain pump has rubber suckers as feet so we glued a ceramic tile on top of the brick column for them to adhere to.
- Provide a nearby waterproof plug point for the fountain pump. Arrange some natural rocks on the bottom slab to provide extra protective cover for aquatic critters.
- Time to fill it up. (Using harvested rainwater if possible.)
- Take the opportunity of creating a marshy area under the overflow pipes. Dig a hole 500mm deep close to the side of the pond – not too close in case you encounter some unprotected pond liner.
- Line the hole with more pond liner (just as if you are constructing another pond) and fill with top soil and compost. If this gets too waterlogged it is a simple matter to drive down a steel rod to puncture the liner and allow some drainage.
- Put good soil and compost all around the perimeter of the pond and establish plenty of suitable indigenous plants (see Step 11). Once they’re established you’ll see only the natural beauty of water and plants.
- Throw a Pond-wetting Party. Lay on the bubbly and snacks, and invite fellow pondonistas to BYOP (Bring Your Own Plants).
For further queries contact the architect/builder at [email protected]
Ramsar World Wetlands Day
- World Wetlands Day falls annually on 2 February. It marks the day in 1971 that the Ramsar Convention on Wetlands was ratified.
- The importance of wetlands cannot be overstated: they’re fundamental to all life on Earth. The Ramsar Convention’s definition of wetlands encompasses almost every type of naturally watery site you can think of and, gratifyingly, human-made sites such as Dart Pond.