By Stephanie Nestor, Assistant Editor, Council Magazine

After a decade of poor quality, the water of Terrigal beach has improved thanks to an investigation into coastal water pollution, earning the attention of Australia’s scientific community. Implementing innovative technology and partnering with scientists, Central Coast Council has contributed vital research to help understand what causes water contamination and possible remedies.

Partnering with the New South Wales Government and the University of Technology Sydney (UTS), Council’s Water and Sewer, Environmental Management and Roads, and Drainage teams have been investigating the causes of poor water quality at Terrigal Beach, the Haven and coastal lagoons.

Since 2019, the teams have undertaken comprehensive audits of the water and stormwater in the area, which have gained the attention of the scientific community. Central Coast Council’s initiative to improve beach water quality in its local government area was a finalist for the Applied Environmental Research category in the Australian Museum Eureka Prizes.

These awards recognise notable contributions to science, research, innovation and leadership across Australia. Collaborating with scientists, researchers, and operational workers, Council has been able to apply cutting-edge technology to help find solutions to solve poor water quality in a nationally-significant project.

Tackling Terrigal’s poor water quality

The investigation became a necessity after it was discovered that the water quality at several beaches in New South Wales was consistently poor, with the cause unknown. As part of the initiative, Council’s teams, and scientists, implemented cutting-edge molecular microbiology and DNA sequencing approaches to accurately diagnose the source of the contamination.

Director of Central Coast Council Water and Sewer, Jamie Loader, said that once the team identified the sources of beach pollution, Council could focus on sewer remediation. “The team demonstrated that sewage overflow into a specific stormwater drain had the biggest impact on water quality,” Mr Loader said.

“We inspected 115km of sewer mains and identified one third of these as in need of repair. We’ve since remediated 41km, which is 95 per cent of this problematic sewerage infrastructure.” Mr Loader said that since the remediation works, Terrigal Beach has received two ‘Good’ ratings in the Beachwatch Program after a decade of ‘Poor’ results.

Cutting-edge DNA testing

Bringing together scientists, technical experts and operational workers, the Council finally determined the impact of sewage contamination on water systems and what sewer remediation is needed. Other causes of contamination that were discovered include stormwater run-off, which enters coastal waters from streets, parks, buildings and other areas, often carrying contaminants such as dirt, oil, chemicals, waste and much more.

Sewer overflows and leaks can occur after heavy periods of rain that cause excess rainwater to enter pipes. This contaminated water overflows into coastal areas, such as beaches, and can go undetected if these recreational water systems are not monitored regularly.

The research teams used several methods to test where the microbial contamination was originating from, including water samples, smoke testing, dye testing and CCTV camera inspection.

Water sampling helped direct other testing to target certain areas and pipes for future testing. Smoke testing, which involves pumping artificial smoke into the sewer network, helped Council determine if houses or businesses had illegally connected gutters and drains.

Dye testing involves inserting non-toxic dye into the sewer network to test for breaks or leaks. If there is a break, the dye will leave the sewer network and be visible in the stormwater network.

CCTV camera inspection was mainly used to identify damage and defects in pipes. With innovative DNA markers, the research team and scientists from UTS could identify microbial contamination in the water samples, and determine that the pollution was caused by human sewage infiltrating stormwater after heavy rain.

Microbial testing is the most accurate method for detecting pathogens in water supplies and catchments, particularly for determining if faecal matter from sewage has polluted the water. By focusing on microbial contamination, Council can inform remediation works by targeting damaged sewer pipes and preventing overflows.

Informed solutions

Poor water quality in urban areas is a common problem for local governments in Australia. When residents use these recreational spots to swim, contamination from human waste can cause health problems, such as gastroenteritis. Central Coast Council manages 320 wastewater pumping stations and eight wastewater treatment plants, with over 80 million litres of wastewater passing through the Central Coast every day.

To combat poor water quality, Council will roll out significant upgrades and expansions across its sewer networks over the next four years. These works will include innovative solutions gained from this research and trial, such as a purpose-made liner to reinforce pipes and seal leaks.

Mr Loader said that despite the significant wet weather and flooding events in recent years, Beachwatch monitoring has shown improvements in water quality during dry weather, being suitable for swimming almost all of the time. “This is a direct indication of improved water quality.

As work continues, the improvements have already been widely appreciated by the local community, with implications for water quality initiatives both nationally and internationally,” Mr Loader said. Engaging the community has also been an important part of reinforcing Council’s wastewater assets, with blockages caused by the incorrect disposal of items down drains, such as wipes, sanitary items and rubbish, can lead to overflows and leaks.

To avoid this, Council has been educating residents about how they can help prevent overflows by ensuring only the right materials are flushed down the toilet.

Swimming ahead

Council Administrator, Rik Hart, said leading the partnership and community collaboration in the remediation phase of this project demonstrates Council’s dedication to improving water and sewer essential services, and placing our customers at the centre of everything Council does.

“The national recognition of Council’s work with industry leaders is fantastic, and an appreciated bonus to our partnership work,” Mr Hart said. By drawing on the expertise of scientists and engaging residents, Council has contributed valuable insights that will not only ensure Terrigal beach can continue to have good quality water, but also help inform how other councils keep swimming spots safe for public use.

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