Pitch for innovative rain gardens to replace Wollongong stormwater drains - Illawarra Greens

Pitch for innovative rain gardens to replace Wollongong stormwater drains

Read the article by Kate McIlwain in The Illawarra Mercury, 4 February 2020.

Pitch for innovative rain gardens to replace Wollongong stormwater drains

Water catcher: A rain garden in an urban environment in Sydney. Picture: Supplied.
Water catcher: A rain garden in an urban environment in Sydney. Picture: Supplied.

On Monday, at the behest of Greens representative Mithra Cox, councillors agreed to develop guidelines to allow the swamp-style gardens - which other councils use to manage stormwater and capture water - to be built in Wollongong.

"Basically with a rain garden, instead of having a normal stormwater drain, you have a garden that is sunken to a lower level than the drain, so on the first instance the water will soak into the earth," she said.

Room for improvement: A existing stormwater drain at Murray Road, East Corrimal, which Cr Cox says could be vastly improved by a rain garden. Picture: Mithra Cox.

Room for improvement: A existing stormwater drain at Murray Road, East Corrimal, which Cr Cox says could be vastly improved by a rain garden. Picture: Mithra Cox.

"Only when there's a large amount of rain, and the garden floods, does the water go up and over into the drain. At the moment, our drains are concrete and all the water just goes down the drain."

As Wollongong works towards becoming more environmentally friendly, after declaring a climate emergency last year, Cr Cox said rain gardens would help protect against the effects of drought and floods.

"In terms of drought-proofing, you're capturing the water and putting it into the soil, rather than letting it flow into the ocean," she said.

"So where you have trees planted next to the cycleway or next to the road, instead of the council needing to use water from the Cordeaux Dam to water those trees, the rain garden catches the run off and soaks into the soil.

Diagram from Melbourne Water: melbournewater.com.au

Diagram from Melbourne Water: melbournewater.com.au

"In terms of floods, the garden can capture the first flush of rainwater and stops it from going down the stormwater system, so in a flood event there will be less water for the system to have to deal with because it's already been captured by the garden and allowed to sink into the soil."

She said gardens were used in Melbourne, Canberra and Sydney to collect and filter water for tanks that filled children's water play parks, for example, and to water vegetation in urban areas and near rivers.

"The guidelines include information on plants that can be used - reeds and rushes that you would see in a wetland - and these have the specific purpose of cleaning and sucking up the nutrients that can be in run-off," she said.

"They are ideal for around waterways, because the gardens can filter the water, so it flows into creeks and rivers as clean water, instead of dirty, polluted stormwater."

Councillors supported the motion, and also agreed to look into whether Wollongong's firefighting water supplies were adequate.