The Common Swales

The Common’s swales were designed to capture and filter stormwater before channelling it into the underground stormwater system that eventually drains into the Darebin Creek. This helps reduce the risk of flooding in the local area and helps prevent pollutants from entering our creek environments.

The swales feature grassy channels, kerb inlets, rock beds, water retaining walls, and native gardens. These all help create an attractive, green streetscape while performing important stormwater improvement functions.

Inlets: stormwater running off hard surfaces in the surrounding area enters the swales through a number of inlets cut into the kerb channel surrounding the median strips. These inlets slope towards the swales, so water flows through them via gravity. Each inlet is contoured with a rock bed. The rocks trap large pieces of litter and debris as the water flows through them. They also help to slow the flow of water entering the swales, which helps prevent soil erosion.

Swales: water that has passed through the rocky inlets enters one of the swales. The northern swale is 120m long and the southern swale is 160m long. Each is lined with grasses, which traps smaller pollutants as the stormwater flows through it. The grasses also help to slow down the flow of the stormwater further; as does the gentle slope, wide channel and long length of the swales.

Rock retaining walls: these have been built to maintain the gentle slope of the swales and protect street trees and plants from erosion.

Outlet: Once water has travelled the length of the swale, it drains into the underground stormwater system that eventually drains into the Darebin Creek.
The swales at The Common form a simple system that is designed to provide an attractive, green streetscape as well as water sensitive drainage functions. Swales can be designed in a range of different ways to suit different landscapes and stormwater flows. Depending on the type of swale, some additional system components may include an overflow pipe, stormwater pipe adjustments, plant beds and mulch.

To find out more about building your own swale see Melbourne Water’s Building a swale.

The Common’s swales only require a small amount of regular maintenance. This includes removal of litter and weeds, and inspection of channels to ensure they remain free of obstructions (blockages).

The swales at The Common provide an attractive, green, water sensitive streetscape for residents and visitors to enjoy. They reduce the risk of flooding to local properties, and help to keep the grassy median strips healthy and green. The swales have been designed to blend in with the surrounding landscape so their stormwater management role is only obvious when they fill with water after heavy rain. The swales are an attractive alternative to open drains or gutters, with the added benefit of helping to protect our local waterways from pollution.

The Common’s swales help to collect stormwater that flows over the hard surfaces of Macleod and prevent it from entering the Darebin Creek untreated. This helps to improve water quality in the Darebin Creek, creating a cleaner and healthier environment for the plants and animals that live in and around the creek. It also promotes better water quality downstream in the Yarra River and Port Phillip Bay, benefiting ecological communities (plants and animals) in those environments.

The swales help to filter out a wide range of pollutants from stormwater. Rocks in the swale system trap large pollutants such as plastic bottles, plastic bags and cigarette butts; and large debris such as leaves and branches. Grasses and other plants in the system help to absorb excess nutrients from the water and filter out smaller pollutants such as micro-plastics, silt and chemicals. They also help to slow the flow of stormwater, reducing soil erosion and allowing sediments (small particles of silt and pollutants) to settle out of the water, which helps to improve water quality in the creek.

Many native animals call the creeks and lakes of Darebin home – such as platypus, rakali (native water rat), frogs, fish (such as the common galaxias) and birds (such as the sacred kingfisher). Waterways like the Darebin Creek provide food and habitat for these and other animals and plants, so it is important to prevent water pollution that may cause them harm.

Darebin City Council acknowledges the Wurundjeri people as the traditional owners and custodians of this land and pays respect to their Elders past and present.

Artwork infographics developed and supplied by City of Melbourne. For other examples of WSUD Urban stormwater treatment projects visit the City of Melbourne Urban Water interactive map here.

Funded by Darebin City Council.