WHEN Margaret Simpson’s children grew up and moved out of her Killara home, her backyard pool fell into disuse. Faced with ongoing maintenance costs an electricity bills, Margaret took the plunge and converted her pool into a natural pond.
“Before embarking on this project, we had no idea how rewarding the process would be, nor how enjoyable the result,” she says. “It’s the best thing we’ve ever done to the house and garden. It’s given us years of enjoyment.”
Ku-ring-gai Council’s WildThings program assisted Margaret throughout the conversion by providing aquatic plants, native fish and technical advice. Within months, her pool had transformed into a self-sufficient ecosystem.
“The pond is wonderful for the environment and has been a mecca for dragonflies, frogs, bees, water boatmen, water dragons, skinks, and numerous visiting birds, including herons and ducks, who often sleep overnight on the floating wooden pontoon,” Margaret says. “Our pond is a wonderful retirement interest, a little like regular gardening, but much more interesting as it’s constantly changing and evolving.”
And no – mosquitos haven’t been an issue. Of the sixty mosquito species found in Sydney, the 3-4 species which bite humans prefer breeding in stagnant, shallow water sources. With a dislike for living in depths greater than 30cm, Margaret’s converted pool has not become a breeding ground for mosquitos.
Alongside saving more than $1,000 a year on electricity bills, the conversion requires no physical changes to the pool. The pond is easily reversible – simply take out the plants and fish.
Since WildThings’ Pool to Pond conversion program started in 2007, around 70-80 pools in Ku-ring-gai have been converted to ponds.
For standard chlorinated pools, the first step is to turn off the filter and stop adding chemicals. (For saltwater pools, the pool will need to be drained and refilled with freshwater.) As the chlorine gradually dissipates, the water will turn bright green as algae starts growing within the pool. This initial stage – regarded as the most daunting part of the conversion – typically lasts 3-6 months. Once aquatic plants and fish are added to the water, the pond will start balancing itself. The green will fade and the water will eventually turn clear.
To accommodate a diverse range of plant species, it is important to create varying levels within the pool. According to Dr Alexander Austin, Environmental Programs Officer at Ku-ring-gai Council, this construction phase is a crucial part of the conversion as most aquatic plants struggle with the severe depths of pools. However, he encourages people to not feel intimidated at the prospect of this task.
“Pool to pond conversions are very much a DIY concept,” he says. “You can go as little or as far as you like. Some people create levels with milk crates weighed down by bricks, [others use] old garden benches and garden tables…basically, anything you’ve got lying around.”
Although these levels will be visible in the early phase of the conversion, they will eventually be concealed as the aquatic plants grow and spread across the surface.
Over time, the pond becomes a magnet for native wildlife, attracting animals from both bush and urban spheres and providing them with a food and water source. Large water bodies are relatively uncommon within urban areas, so these ponds have become a haven for endangered species, including frogs and microbats.
“We like to think of these ponds as ‘habitat stepping stones’,” says Dr Austin. “In Ku-ring-gai, we have a number of disparate pieces of bushland and these ponds can make really great stop-offs for animals transitioning between those.”
Aside from helping the environment and being more water-sensitive, these natural havens offer a substantial health benefit for humans. Studies have proven that spending two hours a week in nature is linked to better health and wellbeing.
“It’s a very calming, relaxing place to be and the vast majority of our residents with mature ponds spend a huge amount of time there,” Dr Austin says. “It’s their little island of peace and tranquillity and they just watch nature be nature. Less and less of us are getting a connection with that as the urban sprawl grows.”
For more information about WildThing’s Pool to Pond program, go to https://www.krg.nsw.gov.au/Environment/Sustainable-living/WildThings/