AGL Macquarie's Bayswater Power Station has been fined $15,000 for allegedly discharging saline water into a nearby waterway.
Saline seepage from the Lake Liddell dam wall is normally collected and pumped back into the lake.
However, a pump failure resulted in saline water, with concentrations in excess of that of Lake Liddell, to discharge from the collection system and into Bayswater Creek late last year.
"It's disappointing that over the past two years, we have seen several water pollution incidents at the Bayswater site, impacting the local environment and waterways," NSW Environment Protection Authority executive director Steve Beaman said.
"As a major operator in the Hunter region, we expect AGL Macquarie to be meeting its licence obligations while also doing what it can to protect the region's natural environment.
"With any ageing infrastructure it is critical that companies regularly check and maintain their equipment to reduce the risk of pollution incidents like we have seen here"
The EPA has indicated that it intends to vary Bayswater's Environment Protection Licence to require that it review the adequacy of the seepage collection system and investigate the source of the elevated salinity in the seepage water.
"Any sudden change in the conditions of a waterway can have a severe impact, with most aquatic organisms only able to tolerate a specific salinity range," Mr Beaman said.
"We are committed to working with NSW industries and communities to prevent water pollution and will always enforce regulatory action when obligations are not met."
An AGL Macquarie spokesman confirmed a penalty notice had been issued following a release of water from Lake Liddell dam wall seepage collection system into Bayswater Creek in late 2022.
"This was caused by a pumping system mechanical failure which has been repaired. We will work with the EPA to review the Lake Liddell seepage water collection and return system. At AGL, we take our environmental responsibilities and licence and regulatory obligations seriously," he said.
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