What is a rain garden? (Courtesy of Melbourne Water)
A raingarden is a water saving garden that is similar to a regular garden bed, but is designed specifically to capture stormwater from hard surfaces such as driveways, patios and roofs via downpipes after it rains.
Raingardens are changing the way Australians think about gardening and are rapidly becoming an important part of garden design, particularly in Melbourne. They can even be positioned to capture overflow from a rainwater tank.
How do raingardens work?
Raingarden cross section depicting the layered construction Beneath the raingarden are layers of sandy soil which help to slow the rate of stormwater entering our rivers and creeks. These layers also assist in the removal of pollution, such as nitrogen and phosphorus, fertilisers, dust, leaves and animal droppings, which are washed off these hard surfaces.
The plants in your raingarden help to further filter out pollution that would otherwise end up in our rivers and creeks.
By capturing stormwater, raingardens are self watering and are therefore easier to maintain and use less drinking water than regular gardens.
Raingardens are rapidly becoming an essential addition to any sustainable garden design, thanks largely to the fact that they come with a serious benefit to the environment and the health of local rivers and creeks.
See raingardens in action
This video explains what raingardens do and how they work, and includes some backyard landscaping ideas.
What are the different types of raingardens?
There are many different types of raingardens you can choose to build at home.
This type of raingarden is positioned above the ground to collect stormwater from a diverted roof downpipe, allowing stormwater to filter through the raingarden before connecting to the stormwater system.
Inground (Geoline can supply liners for inground rain garden beds. Geoline can also weld liners around inlet/outlet pipes for your rain garden.
This type of raingarden is positioned in the ground to collect stormwater from hard surfaces or a diverted roof downpipe, allowing stormwater to filter through the raingarden before connecting to the stormwater system.
This type of raingarden is positioned in the ground to collect stormwater from hard surfaces or a diverted roof downpipe, allowing stormwater to filter through the raingarden and penetrate into the surrounding soil.
A slight depression in the landscape which can be either grassed or planted with other vegetation.
When the roof of a building is covered in vegetation and soil to assist with the filtration of stormwater.
When a roof downpipe diverts roof water through a hose via a d-shape mechanism, allowing water to soak into the garden and surrounding soil.
A permeable material, often brick like, that allows water to penetrate through into the surrounding soil.
Rainwater tank diversion
Similar to a downpipe diversion only the d-shape mechanism is fitted to the overflow of the rainwater tank.
A vegetable raingarden is sub-irrigated, which means that the water enters at the base of the garden. This helps to prevent the vegetables being submerged after heavy rain and water is used more efficiently as there is less evaporation from the surface.
You can be creative with how you utilise stormwater. You may have properly diverted a roof downpipe onto your garden, creating a frog bog or mini wetland for example.