Living ponds or pools are good for your garden
WITH the cost of electricity and water rising, conventional swimming pools are becoming more resource-sapping than refreshing.
But landscape designer Phillip Johnson believes there are several smart ways to keep water bodies in our gardens – from natural pools to seasonal ponds and billabongs – if only we think a little differently.
“If you have water in your front or backyard, you’re bringing back habitat and biodiversity. And it helps cool down that space as well,” he says.
The first thing to do, he argues, is to think of stormwater as a valuable resource. Because of climate change, south-east Australia is expected to receive less rainfall overall, but more severe storms.
“Every property and road has been designed to drain water as fast as possible, and that contaminated water gets into our creeks and rivers,” Mr Johnson says. “If you can slow the stormwater, catch it and clean it, whatever leaves your place will be in much better condition.”
To help do that, he designs dry creek beds or swales running from rainwater tank overflows or downpipes. “When it rains, the dry creek bed comes alive and feeds into a billabong, water feature, or natural pool, which works as a reservoir for flood mitigation,” he says.
“In a natural system, billabongs exist on the edge of a creek. When it floods, it fills up this little wetland to the side. They’re really rich in biodiversity and create great habitats for frogs.”
Unlike conventional pools, Mr Johnson’s natural pools don’t rely on chlorine or salt to keep the water clean, but rather, use biological filters to aerate the water. An energy-efficient pump moves the water through a “regeneration” zone. “We learn from nature, where water often passes through river gravels and plants that absorb nutrients,” he explains.
Installing natural pools, and converting existing ones, has become a significant part of his business, but he maintains that you don’t have to spend big bucks or install a complex system. “You can do this yourself, but you’ve got to do your research.”
At her house in Northcote, permaculturalist Kat Lavers took the straightforward approach. She simply dug a hole and dropped in an old bathtub with the plughole blocked.
“We filled it with water from our tank and put rocks in there to create niches and different microclimates for plants that need a shallower depth,” she says.
“We also collected water from a nearby freshwater dam, which contained lots of critters like small shellfish, freshwater snails and maybe even dragonfly larvae. It added a diversity of life into our pond – and that means mosquito larvae don’t breed in large numbers.”
The plants in the pond also help inhibit mosquitoes by aerating the water and reducing the nutrient level. You can grow edible plants there, such as land cress and some kinds of mint. Water chestnuts will thrive in a boggy spot at the edge of a pond.
“The most obvious benefit of having a pond is beauty, but it goes beyond that,” Ms Lavers says. “It provides a reliable water source for lots of critters – some of them slugs and snails, but also really helpful ones like dragonflies, hoverflies, honeybees and lots of creatures that help to minimise the work you need to do in the vegie garden.”