On our recent family trip to Sydney, Hannah co-taught a permaculture design course for Milkwood and little Frida Maria and I (Anton) visited a hundred different playgrounds and parks. The most impressive of these was Sydney Park in St Peters just south-west of the city. Why is it awesome? Well the place is a stormwater re-use wonderland.
Stormwater (ie run-off from streets and parks) often looks like the shot below. Here, there are thousands of plastic bottles and wrappers and water that doesn’t look so great for public health and the environment.
Instead, Sydney Park uses a variety of biological methods to clean water for reuse and provides a lush and inviting play space. So where does the water come from? Curbs like these below. The Sydney Council says that 78% of the catchment has hard surfaces, i.e. paving or roofs – that’s a massive catchment area…
After passing through pipes under the street they enter the Munni Street Channel. Apparently around 43 tonnes of gross pollutants run through this channel. When the water levels are high, water is drawn from the channel into the Sydney park Wetlands. Before they enter the park they go through a gross pollutant trap (“gross” means big, but its probably pretty ugly as well). This filter removes the bottles, chip packets, cigarette butts, etc etc – that we like to leave on the street. Perhaps fortunately Frida and I didn’t manage to find this part of the park.
In permaculture, we talk about managing water in a landscape by the following principles – “slow, sink, spread, store”. This system shows all these elements.
The water is diverted into large bio-retention ponds, here the water is filtered through a living system that removes a lot of the heavy nutrient loads in the water. This park has an incredible amount of dog walking action, so I’d say there’s a good portion of dog poo (with is rich nutrient) making its way into the water.
As you can see the water is diverted through several stages of retention beds.
Here you can see the overflow from the retention ponds to the storage ponds.
In total there are four main ponds, each filling each other as they move downhill through the site. The park now features thriving water life and ever-improving water quality.
The park also features just about every design element out of a “water sensitive urban design” book. Here instead of guttering beside a pathway, water runoff infiltrates through a rock channel and is planted out with reeds.
Casuarina trees (a classic native riverside trees in Australia) line a drainage line.
The park also has some great interpretive signage, so you can learn about what’s happening as you frolic though the parklands.
If you’re thinking Sydney park is over the top and too expensive to implement, here’s a nearby raingarden. These are a bio remediation technique on a much smaller scale, slowing, sinking and cleaning road runoff before entering the stormwater drain.