Sydney’s Green Square stormwater drain project has won a prestigious silver medal at the International Water Association’s Project Innovation Awards held in Copenhagen, Denmark.

The project — delivered in an alliance with Seymour Whyte — has reduced the threat of floods, provided millions of litres of recycled water to communities and cleaned up the water that ends up in Sydney’s Cooks River.

The problem

Green Square was once a network of wetlands and creeks – essentially a floodplain. When it became an industrial heartland, paved areas increased and natural drainage drastically decreased.

With a growing population, Green Square couldn’t be fully redeveloped without finding a solution.

The solution and the team

Stretching for more than 2km, the Green Square stormwater drain runs from Zetland to the Alexandra Canal.

Made possible by forming the Drying Green Alliance – a partnership with City of Sydney, Sydney Water, UGL Infrastructure, Seymour Whyte, Rob Carr, WSP and RPS Group.

The $140 million project also raised and lengthened Huntley Street Bridge and made the area around Sheas Creek open channel an attractive and usable public space.

The benefits

The drain has drastically reduced the threat of high-level floods in the area and some of the features of this huge piece of infrastructure are having great outcomes downstream.

We put in 2 of the country’s largest gross pollutant traps to treat stormwater. This means that up to 320 million litres of non-potable water is sent to new buildings and open spaces every year, effectively recycling rainwater closer to where it falls.

These traps also filter the stormwater meaning that what does flow into the Cooks River is cleaner and better for its ecosystem.

Stormwater drains may well be out of sight and out of mind, but with another La Niña declared this summer, reducing the risk of rising waters has never been more important.

“It’s wonderful to see this project achieve the recognition it deserves. Although it can’t be seen or accessed like our libraries or pools, it is as important as any infrastructure the City of Sydney has delivered,” Lord Mayor Clover Moore said.

“Not only does the trunk drain limit flooding and keep Green Square safe during downpours, it helps us capture and re-use water to increase our resilience during times of drought. This prestigious award is further proof that we are delivering a world-class precinct in Green Square, making it a wonderful place to live, work and visit.”

The international award is further recognition of this project, which won the Infrastructure Project Innovation Award for NSW at the 2019 NSW Water Awards.