An underground stormwater drain built by the City of Sydney in partnership with Sydney Water is expected to reduce risk of flooding, improve water quality and save drinking water.
The two kilometre-long stormwater drain runs underneath the bustling Green Square town centre. Located on a floodplain that used to be a network of wetlands and creeks between the city centre and Sydney Airport, Green Square is prone to flooding during heavy rain and severe storms. However, when Green Square was hit by a ‘once in a hundred years’ storm last year, the stormwater drain infrastructure, which was already in place, prevented flooding.
Designed to carry up to 30,000 litres of stormwater per second from Epsom Road to Alexandra Canal, the stormwater drain significantly reduces potential flooding across the area.
Key stakeholders in the Green Square stormwater drain project include the Drying Green Alliance, the City of Sydney and Sydney Water with UGL, Seymour Whyte Construction, WSP and RPS.
Announcing the completion of the award-winning $140-million engineering project, Lord Mayor Clover Moore says it marks a huge milestone for one of Sydney’s fastest-growing urban areas.
“This project demonstrates how water resources can be used and managed to reduce demand on drinking water, minimise flood risk, improve water quality and enable development in a highly urbanised area.
“Together with our new stormwater harvesting plant, this is a key component of the City’s $540-million transformation plan for new infrastructure and community facilities at Green Square that will ensure this is a sustainable neighbourhood and a great place to live, work and enjoy.”
Paul Plowman, the general manager for Liveable City Solutions at Sydney Water, has spoken about the collaboration with the City of Sydney.
“By working together we have delivered innovative solutions that will greatly reduce the risk of flooding for residents and improve liveability for the local area. This is part of Sydney Water’s commitment to providing stormwater services to support growth and development in the Green Square area, to ensure Sydney remains a fantastic place to live and work in the future.”
The stormwater drain was designed to run through areas mostly owned by the City to minimise impact on residents, businesses and the environment. Several challenges faced during the execution of the project were addressed through engineering innovations.
Solutions included micro-tunnelling that enabled tunnel boring machines to install huge 1.8m diameter pipes up to 12 metres underground with minimal disruption; largest gross pollutant traps available in Australia to treat stormwater runoff and improve water quality in the Cooks River; and a new harvesting system to divert stormwater from the drainage system to a water recycling plant in Green Square, delivering up to 320 million litres of stormwater annually to new buildings and open spaces.
Lord Mayor Clover Moore and Paul Plowman from Sydney Water will officially open the Green Square stormwater drain at a public open day on Saturday 9 November at Matron Ruby Grant Park.