Water quality

Taking a deep dive

Improving the quality of the State’s beaches and waterways was one of our very early successes. Keeping NSW water fit for drinking, cooking, washing, agriculture and recreation is still one of our priorities today.

Water pollution has a range of causes. Chemical spills and contamination, treated sewage discharges and stormwater run-off are common ones, and led to some major water pollution events in 2021–22. The stories in this section show some of what we’ve been doing to ensure water quality, our third focus area.

Dead in the water

A mass of dead fish in a river is distressing to see. Why does it happen?

Dead fish washing onshore in February.

Many people are quick to identify pollution. But disease, poor water quality and lack of dissolved oxygen are also common causes. Fish kills can result from entirely natural processes, such as flooding or high temperatures, or be linked to human activity, such as chemical releases or excess nutrients degrading water quality.

What happened on the Parramatta River?

On 3 February 2022, a fish kill was reported at Haslams Creek, a tributary of Parramatta River. Over the next few days more dead fish washed up on the riverbank from Rydalmere to Homebush Bay. In total, some 4,000 fish may have died. Community concern was high, both for the river and for any potential risk to people nearby.

The EPA and Department of Planning and Environment (DPE) worked together to find out what had happened. They took samples from the water and the fish, and set out instruments for continuous monitoring. They didn’t find any sign of pesticides in the fish, and the pattern of fish deaths was not consistent with a release of chemicals from an industrial site. Instead, the monitoring showed that oxygen levels were critically low, especially near the bottom of the river – too low for fish to survive. Once reoxygenated, the water was not toxic to organisms.

Why did it happen?

The low oxygen levels were caused by a combination of natural processes. Intense storms swept organic material such as leaves into the river. Tidal currents mixed sediment with organic material far up into the water. As this organic material decomposed it used up oxygen. In addition, fresh rainwater on the river surface slowed the diffusion of oxygen back into the water. Years of improving the health of Parramatta River has increased the number and diversity of fish in the river, meaning more fish died when oxygen levels fell.

Estimates put the number of dead fish at up to 4,000

Following up

City of Parramatta Council and Sydney Olympic Park Authority acted swiftly to remove the rotting fish from the shore. DPE scientists left monitors in place to track oxygen levels in Parramatta River and Haslams Creek. To reassure the community, a public webpage was set up to release the results of the investigations and the additional monitoring.

Marine Litter Campaign 2022

Litter harms our environment, wildlife and waterways. Over 80% of marine litter comes from land-based sources. Sea creatures suffer when they swallow litter or get tangled up in it.

In April and May 2022 we held several Marine Litter Campaign roadshows as part of our Don’t be a Tosser! campaign, to explain ‘why litter matters’ and strengthen the reasons to ‘Put our rubbish in the bin’.

Our roadshows ran at high-profile NSW locations including the Sydney Royal Easter Show, the Hawkesbury Show, the Overseas Passenger Terminal in Sydney and Manly Beach. They reached over 30,000 people.

To educate the community, we displayed sculptures of the most harmful litter items found in the marine environment and of animals injured by litter.

Visitors spent a good amount of time interacting with the displays and said that they found the content engaging and confronting, and that it delivered a powerful message.

Learn more about what you can do to reduce litter at Don’t be a Tosser!

Safe for swimming

The Parramatta River runs through the heart of Sydney. Thousands of people could easily pop down to it for a dip on a hotday.

However, decades of pollution have meant the river is used less for recreation than it could be. Fishing has been restricted and many swimming sites closed. The EPA is a member of the Parramatta River Catchment Group, which is working to make more parts of the river swimmable again by 2025. ‘This is a great example of agencies collaborating for public and environmental benefit,’ says EPA’s Director Regulatory Operations, James Goodwin.

Four sites – Cabarita Park beach, Chiswick Baths, Dawn Fraser Baths and Lake Parramatta – are already open for swimming and four more – McIlwaine Park, Bayview Park, Putney Park and Bedlam Bay – are being assessed for both swimming and recreation. Assessment has several steps, including determining both the water quality and the potential for contamination, and developing a framework under which councils will manage the sites. As of mid-2022 Bayview Park was on track to open in September 2022.

‘This is a great example of agencies collaborating for public and environmental benefit’

Monitoring the swim sites

Rivers are at their most dangerous after floods and other major wet-weather events. Strong currents can stir up potentially contaminated sediments, stormwater can wash in pollution and sewage systems can overflow into the river. The Riverwatch program monitors the safety of the swimming sites along the Parramatta River and advises on their current and predicted state. ‘The general advice is to avoid swimming in rivers and waterways three days after any major wet weather events,’ says James Goodwin. n

Sights on the sites

In May 2022, after much of the State had seen months of heavy rain, we joined the month-long Get the Site Right campaign.

Launched by the Parramatta River Catchment Group, it’s a joint initiative of catchment groups, local councils and government agencies that targets erosion and sediment run-off at construction sites.

‘Sediment leaving building sites can pollute water and may damage the health of our urban waterways,’ says one of our officers in Regulatory Operations, Nathan Hale. ‘This is an issue that became front of mind for many people after the large-scale death of fish in the Parramatta River.’

Compliance blitz

Get the Site Right ran a compliance blitz on 19 May. Our focus was supporting local councils, which regulate most small construction sites.

‘Several councils – including Blue Mountains, Fairfield, Goulburn, Lithgow, Shellharbour and Wollongong – joined the campaign for the first time this year,’ Nathan Hale said. ‘Council staff and EPA officers reviewed erosion and sediment controls at more than 140 building sites.’ In addition, EPA and DPE officers inspected several large infrastructure projects across Sydney.

‘Council staff and EPA officers reviewed erosion and sediment controls at more than 140 building sites’

A compliance blitz helps make sure large and small construction sites are meeting their legal obligations to control erosion and sediment. It’s also a great opportunity to work with other regulators on shared issues. Spending a day with colleagues from other agencies lets our officers share their knowledge, learn from others, and better understand the regulatory challenges and approaches of each agency.