Water plans in pipeline
Outflow to go under surf break
NEW mapping shows a massive recycled water pipeline that crosses the Broadwater will be built through one of the world’s best surfing breaks at South Stradbroke Island.
The Gold Coast City Council has budgeted almost $32 million over the next 12 months for development of stage one of its long-term recycled water release plan, but until now little has been known about it.
Councillors discussed the financial contracts in closed session in late June, and a redacted version of an officer’s report now sheds some light on one of the city’s biggest ever infrastructure projects.
Despite earlier suggestions the pipeline might be built off The Spit sand pumping jetty or out through the Seaway, new mapping shows it going under the southern beach tip of South Stradbroke Island and extending 3km out to sea.
The report reveals two years of “investigations and negotiations” will see a revised construction method with tunnelling and boring used rather than dredging.
Construction powerhouse John Holland Queensland Pty Ltd, which built the Brisbane Airport link tunnel, won the contract after a review by council officers and independent technical consultants.
The council officer’s report confirmed the negotiated offer from the company would see a change to a “trenchless method” that “considerably reduces environmental and stakeholder risks”.
The benefits would include “an improved environmental outcome in that there will be no disturbance to the Broadwater and Nerang River from dredging activities”.
The report said negotiations had meant there would be “opportunities for a reconfiguration of South Stradbroke Island works and future offshore stages to be pursued”.
The pipe crossing of the Broadwater required a tunnel 1450m long and 2.4m wide, running about 20m deep. A 920m long polyethylene pipe, which would be 1.2m wide, would cross the Nerang River.
In an information sheet for residents, the council said up to 20 per cent of all recycled water from its four sewage treatment plants was reused for irrigation, dust suppression and the nonfood processing industry.
The rest was released using two underwater diffusers on each side of the Seaway wall.
But the Coast’s explosive northern population growth had put pressure on that system and the treated water, which could increase nutrients in the Broadwater, was only released on the outgoing tide.