Build your own Garden Pond.

If you’ve always wanted a backyard pond, you’re not alone. Hundreds of thousands of homeowners already have them, and thousands more are installing them every year. Why all the fuss over a water-filled hole? Well, for one thing, gurgling waterfalls are inherently appealing. Also, with the growing popularity of “water gardening”, many people look at their ponds as an interesting, ongoing project.

But before you can start stocking aquatic plants and animals, such as fish, frogs, tadpoles and snails, you need the pond itself. It doesn’t have to be a huge project. A pond in a large garden may measure 3x4 metres (or bigger), but it can be built to virtually any size. In some designs, water trickles down a long, meandering stream before emptying into the pond. Many smaller ponds, like the 1,8x2,4 m kidney-shaped one shown here, don’t have streams; instead, water runs over a large flat rock and spills directly into the pond. This style is easier to build and can fit into the smallest yards. Basically, such a pond is just a hole lined with rubber, plus some tubing and a pump that’s powered by a cord from the house.

Build your own pond

Digging it

Once you’ve chosen a location for the pond, lay out the perimeter using rope or a garden hose. Next, mark the outline with ground limestone and start digging. Excavate to a depth of 40 cm, piling the soil at the rear of the pond, where the waterfall will be located. In the centre of the pond, dig down another 25 cm to form a pit where the pump will go.

Next, line the hole and the pit with builder’s sand (passed through a sieve) and rake it smooth. Place the geotextile fabric that protects the pond liner on top of the sand. Buy a piece big enough to cover the bottom of the hole, the pump pit and the walls. The sand and geotextile will cushion the flexible rubber liner, protecting it from punctures.

Laying rubber

Fold the rubber liner lengthwise, centre it over the hole, and unfold it. The liner should overlap equally on all sides. Using your hands and bare feet, carefully press the liner into the hole. Then, use a garden hose to fill the centre pit with water to hold the liner in place.

We built this pond out of stone that was relatively flat and easy to stack. When dealing with this much material, you want to handle it as little as possible, so be sure the supplier delivers the stone directly to the pond site.

Start stacking stones on the pond floor, also called the plant shelf (to differentiate it from the pump pit). Lay the stones in a 30 cm-wide layer along the wall. Overlap the stones between courses and use smaller stones to fill any sizable gaps. Next, set the pump’s hose in position so that it extends from the centre pit to the top of the hole. Carefully lay stone directly over the hose. Continue stacking stones until they’re even with the ground. Set a single layer of flat stones along the plant shelf, aligning them flush with the edge of the centre pit. Then, place one flat rock in the bottom of the pit to serve as a base for the pump.

Next, set large, flat rocks – called coping stones – around the perimeter. Stack stones at the rear of the hole to form the waterfall. A good rule of thumb is to build it to about 30 to 45 cm above the water level. Set the waterfall weir in place atop a large, flat rock (the spillway stone) that is tipped forward slightly, and connect the weir’s hose to the pump’s hose coming out of the pond.

Trim the rubber pond liner to match the waterfall opening at the front of the weir, then attach the liner to the weir using its screw-on faceplate. Backfill around the weir with soil and continue piling up rocks around the waterfall area. Conceal the weir by placing a rock on top of it.

Once all the stones around the weir are set, secure them with waterproof black foam sealant. Also apply a thin bead of the sealant under the lip of the waterfall weir to adhere it to the spillway.

Plugging in

Fill the spaces between the stones on the pond floor with river stones or suitable-sized pebbles, then take a hose and wash down the stonework around the entire pond. Pump or bail the dirty water from the pit.

Next, connect the pump to its hose and set the pump on a flat stone in the bottom of the pit. Check with an electrician to ensure a safe installation of your pump and power cord. Here, the pump’s power cord ran through openings between and under stones to an earth leakage-protected electrical outlet with a weatherproof cover that shields the plug while it’s connected. Be careful not to damage the cord under a stone. Finally, use a hose to fill the pond to within 10 cm of the coping stones. Once the pond is filled, plug in the pump. In a few seconds, water will spill gently out of the weir.

Pond safety

Ponds, especially those stocked with fish and frogs, are inviting to small children and can constitute a drowning hazard. Your local authority may require your pond to be fenced in, so check before you build. A pond that is adjacent to a path can also pose a tripping hazard, especially at night. In such an area, the path should be illuminated with low-voltage lights.

Construction costs

1. Buy the materials from your local garden centre or DIY store. Don’t be tempted to buy an inadequate or el cheapo pump; it will cost you more in the long run.
2. If you have a bakkie, pick up the sand and gravel yourself instead of having it delivered.
3. Got some nice rocks on your property? Use them.

This article was reproduced with permission from Popular Mechanics. For more DIY projects, visit the Popular Mechanics Web site at http://www.popularmechanics.co.za/content/home/main.asp