City trials world-leading technology in raingardens to keep waterways clean

24 Nov 2021

City of Newcastle is leading the trial and implementation of a new sustainable technology that improves cleanliness of stormwater runoff through an innovative filtration system used in garden beds along our city streets.

Filter soils have been installed at test sites in Newcastle suburbs using compost soil and specially processed recycled materials like glass and green waste.

Raingardens are small garden beds located along the street featuring soil and plants that slow down and filter pollution in stormwater, so it doesn’t harm waterways and beaches.

The raingardens are usually found on street corners where cars can’t park and have more grass-like shrubbery than usual roadside plantings and are set in lowered beds over drains.

Recycled glass and green waste is now being used as a filter material that creates a healthy environment for plants increasing biodiversity in the suburbs. In addition to filtering the water, the raingardens also create a habitat for flora and fauna and absorb heat, meaning our streets are cooler in summer.

Data collected from these test sites will be verified by University of Newcastle as part of a Memorandum of Understanding (MoU) between the Centre for Organic Research and Education (CORE) and City of Newcastle.

City of Newcastle is the first council to use the biofilter material that contains recycled products within the soil mix, such as crushed recycled glass instead of virgin sand, and organic composted waste products instead of artificial fertiliser and clay.

The unique material can remove pollutants such as sediment and heavy metals that come from our tyres and brake pads as they wear down; grease, oil, petrol and air conditioner coolant that drips from motor vehicles; and excess nutrients from parks and gardens that can cause algal blooms.

The water is carried away through drains, pipes and channels to local creeks, wetlands, estuaries and finally to the ocean, which is a great outcome for the environment.

Biofilter raingardens have now been installed at sites in Cooks Hill, Merewether, Mayfield West, Stockton, The Junction and Wallsend. Existing systems in Beresfield and Fletcher will soon be renewed with biofilter material.

Costa Georgiadis, Chair Centre for Organic Research and Education Eric Love, City of Newcastle Asset Services Manager Peter McMurray and City of Newcastle Asset Engineer Luke Jaszczyk at a biofilter raingarden in Wallsend.