Four million litres a day of untreated sewage continues to be released into the sea from cliffs between Bondi Beach and South Head. Credit:Christopher Pearce Over the years, locals groups have fought against the prospect of everything from damaged house foundations due to tunnelling, closed streets, sludge trucks and odour if a waste treatment solution is used in the area. There has also been concern that an upgraded sewerage system could trigger a demand for denser development in those exclusive suburbs. Three detailed reports into the Vaucluse and Diamond Bay outfalls – two by private sector consultants – have been commissioned by Sydney Water since 2003 when it shelved plans, first announced in 1996, to build a 3.5 kilometre diversion tunnel to the Bondi deep ocean outfall system. The tunnel, which could have cleaned up the Sydney coastline of sewage pollution for good, was announced with a budget of $32 million in 2000.

The sewer outlet at Diamond Bay. The century-old sewerage system of the eastern suburbs is the last in NSW to allow human waste to flow directly into the sea. Credit:Nick Moir By the time a "strategic planning report" by Sydney Water was circulated internally in 2011, the cost of the Bondi tunnel option began at $150 million, while a cheaper strategy of directing sewage to the Rose Bay "submain" was costed at $65 million. The Rose Bay solution would reduce discharge from the cliff by 85 per cent, with the Bondi tunnel option described as "economically unjustifiable" by 2011. While the sewerage fix remains on long-term hold, the NSW government last year took $745 million in cash dividends and other payments out of the profit-making Sydney Water monopoly.

The 2011 report notes that the continuation of untreated discharges conflicts with the authority's corporate goals to ensure "clean beaches, oceans, rivers and harbours" for the public. The report states that the water quality impact has "no measurable impact beyond the mixing zone" off cliffs used by rock fisherman, despite being just three kilometres from Bondi to the south and the entrance to Sydney Harbour to the north. "The water quality in the localised area around the outfalls will exceed the guidelines for primary contact recreation (swimming). However, swimming is not a regular activity near the outfalls because the high cliff and rocky shore make the area relatively inaccessible," the report states. But it also notes aspects that threaten Sydney's reputation as a clean water city for locals and tourists. "The outfall plumes can be seen from the top of the cliff on a very calm day. Gross litter is visible from the water in the area close to the outfalls," according to the 2011 internal report.

Fairfax Media has visited the Diamond Bay south outfall where raw sewage drops from the cliff on to a rock shelf where a community of seagulls picks at the discharge and what appeared to be wet wipes. The minutes of a Sydney Water meeting in an appendix to a report raised the prospect that pollution from the "mixing zone" carried to the northern beaches, including NSW Premier Mike Baird's Manly electorate. "Visible pollution (nappies and other plastic items) near Long Reef (Dee Why) during northern current in the ocean – could that be due to Vaucluse and Diamond Bay face-cliff outfalls?" the minutes record as one discussion topic in 2011. In a summary document, Sydney Water notes: "In October 1996, the State Government made a commitment to the community that a tunnel would be built by December 2000 in accordance with the timetable set by the Environmental Protection Authority (EPA)." NSW Water Minister Niall Blair would not commit to action.

"Sydney Water is working on a pollution reduction program and will issue a report to the EPA by early 2017. We'll wait for the results of that study before considering the next steps," he said in a statement. Water quality expert Stuart Khan, an associate professor in engineering at UNSW, said Sydney Water was right in insisting that the public health risk was minimal due to the inaccessible nature of the area to anyone but fisherman and divers. "The real issue is the gross pollutants, things like nappies and wet wipes that will be in the water there," he said. "No one really wants to see raw sewage coming off the cliff but it really comes down to cost-benefit questions and whether the public will accept the situation. Public perception is one of the things that shapes Sydney Water's priorities, which is why coverage and debate about these issues should be welcomed," he said. Persistent problems with stormwater run-off at beaches in the Royal National Park and Coogee should also be part of public discussion, he said.

A Sydney Water spokesman insisted that despite the timeframe, the authority was still working on a solution, with another report expected in 2017. "Sydney Water is working closely with the EPA, experts and community representatives to identify the best solution to manage releases from the outfalls," he said. "It is a complex issue that is a legacy from our early sewage network. There is no silver bullet to fix it without high costs and significant disruption to the community. However, we remain committed. We're currently undertaking a pollution reduction program, which includes a study to further assess any environmental impacts." Do you know more? Contact haston@fairfaxmedia.com.au DECREPIT SYSTEM

In December 1990, The Sydney Morning Herald carried a story about a public meeting at Diamond Bay Bowling Club in Vaucluse. "Will the state government introduce medium-density housing in the eastern suburbs when the Water Board has improved the sewage system?" was one of the main questions 200 residents who turned up to discuss a proposed upgrade to the area's 100 year-old pipes wanted answered. If the decrepit system was plugged into Bondi's deep ocean outfall, the theory went, Woollahra and Waverley councils could be ordered to allow higher, denser development in suburbs where most houses still had gardens and a backyard. In other words, the discharge of four million litres of raw effluent from a cliff in their neighbourhood had a silver lining for those residents not wanting to see change. To this day, the suburbs of Vaucluse, Dover Heights, Rose Bay and Watsons Bay have hardly changed compared to the rapid infill that has taken place in other parts of Sydney.

The recent district plans by the Lucy Turnbull-led Greater Sydney Commission spared the area again. Michael Yabsley​, the then Vaucluse MP and corrective services minister, was reported as assuring locals in 1990 that "it doesn't stack up to abandon the existing [medium-density housing] policy." He said the Liberals would maintain the medium-density plan for the area but warned the do nothing option on fixing the sewer outfalls was "unacceptable". This week, Mr Yabsley told Fairfax Media that his memory of that meeting was hazy but he does not recall local opposition being centred on development policy or real estate prices. He said he was surprised the untreated Vaucluse and Diamond Bay outfalls had still not been upgraded 30 years on.

"I recall there was so much emphasis on the Bondi outfall where the real volume was coming from and where the visual problem was. The water went from brown to blue and everyone was patting themselves on the back about fixing the problem," he said. An internal "submissions report" written by consultants Manidis Roberts found significant opposition persisted in 2003 when Sydney Water shelved the first proposed upgrade. "Property impacts; negative impacts on property prices" was one of the top three concerns when the company asked residents to explain opposition to strategies outlined in a brochure and "minimise property value loss" was raised as a suggested priority not covered in the brochure. Peter Poland, a longtime Vaucluse resident was a member of a group that called itself CROSRS (Concerned Residents Opposed to Sewers on Residential Streets) said the main gripe was the prospect of building a tunnel through local roads. "Some of the streets they wanted to go down were about two and a half cars wide, there would have been absolute chaos," he said.