Council officers rule out The Spit for $400 million wastewater discharge system

THE Gold Coast’s most expensive planned piece of infrastructure, a $400-million recycled water pipeline, will be built at least 2kms offshore from South Stradbroke Island.

The sand pumping jetty at The Spit was ruled out by the State Government as an option for a future cruise ship terminal. Photo: Kit Wise

THE Gold Coast’s most expensive planned piece of infrastructure, a $400 million recycled water pipeline, will be built at least 2kms out to sea from South Stradbroke Island.

As part of the $75 million first stage of the project, barges will tomorrow be stationed in the Nerang River and the Broadwater for the next month to enable drilling of the sea bed for future piping across to the island.

Mayor Tom Tate two months ago wanted the council to explore the existing sand pumping jetty at The Spit being used for both his planned cruise ship terminal jetty and the waste water pipe.

But council officers, after a two-year investigation, have narrowed down the options for discharge from the city’s sewage treatment plants, ruling out The Spit.

The Gold Coast Bulletin has obtained the Long Term Recycled Water Release Plan which shows officers rejected the northern end of the Spit, the Main Beach area and a proposal to use the existing outfall from the desalination plant at Tugun..

They found the depth of discharge must been 20m which could only be reached 2kms offshore.

Other critical factors included the currents at the Seaway, along with the northern longshore flow and the how close the discharge would be to residential and recreational areas.

“These features combine to suggest the best location for the ocean release is off South Stradbroke Island,” the report said.

If the offshore ocean release was built south of the Seaway, there was a possibility the northerly flow would cause the nutrients to be sucked back inside the Broadwater.

Under the plan put forward by engineers, land could be accessed on the island’s southern tip which was not listed as national park. The council and the State Government are joint trustees.

The system operating since 1984 relies on secondary-treated water being pumped across the Broadwater from Labrador to an outfall at the western tip South Stradbroke Island on the northern side of the Seaway.

A second underground pipe from the Nerang River through Main Beach connects to the southern side of the Seaway.

Both only operate on outgoing tides to control the nutrient load in the Broadwater.

Officers had considered a first option of “doing nothing”.

“The first option (do nothing) would result in a breach of regulatory requirements, have increasing unacceptable impacts on the environment and result in a failure to protect the community,” the report said.

Another option was to reduce nitrogen levels in treated water from the city’s four sewage plants but this was too costly.

The first stage works, which start this week, involve engineers drilling 10m holes in the seabed to help determine the location of a second pipeline across the Broadwater to South Stradbroke Island.

Work will begin in the Nerang River on a pipeline near Winchester Street and later at Lands End at Biggera Waters.

Council will advise Broadwater users of any restrictions as work progresses.

Once the geotechnical studies are done, construction work will begin and be completed by latek next year, clearing the Broadwater of crews before the 2018 Commonwealth Games.

The second stage through to 2021 includes the South Stradbroke pipeline, leading to an estimated capital expenditure of between $300million-$400 million, the report said.

The ultimate solution would be “constructed in several stages rather than one”, allowing the council to invest in improved drilling technology.

Mayor Tom Tate said residents could expect to see barges with geotechnical equipment operating in the Nerang River and Broadwater from now until July.

“This equipment is used to investigate conditions and material below the surface and this will allow us to gain an understanding of the soil, rock and bedrock properties,” he said.

“While the works may temporarily stir up sediment and create a change to water visibility, there will be no effect on the surf break, long-term diving conditions or impact on marine life.”

Land-based investigations will happen at Quota Park (Biggera Waters), Doug Jennings Park (The Spit), JH Davies Park (Southport), Pelican Beach (Main Beach) and South Stradbroke Island.

Cr Tate two months ago proposed his offshore cruise ship terminal could be built on an upgraded sand-pumping jetty at The Spit, with a wastewater outfall underneath it, under a “three-in-one solution”.

Gold Coast Mayor Tom Tate’s plans for his latest cruise ship terminal plan.

The State Government later confirmed it opposed development on the northern end of The Spit, forcing the mayor to explore his first option at Philip Park opposite Sea World.

Councillors on the major economic development committee met in closed session last week to discuss the project to which council has committed $800,000 in 2016-17 Budget.

The Bulletin understands the mayor is expected to discuss the outcome of those discussions and his latest plans for his pet project at a full council meeting today.