An autumn environmental flow is being delivered through the lower Lachlan to sustain critical wetland habitat for the endangered southern bell frog.
This follows strong breeding results recorded for the species over summer in the Greater Cumbung Region.
The 30-day watering event (managed by the NSW Department of Climate Change, Energy, the Environment and Water (DCCEEW) in partnership with the Commonwealth Environmental Water Holder) began on 15 March. The event will deliver around 300 megalitres per day.
The flow builds on a successful spring-summer watering program that triggered southern bell frog breeding across Greater Cumbung Region wetlands. Follow-up monitoring surveys have since confirmed recruitment, highlighting the need to maintain wetland habitat as conditions dry.
Senior Scientist Amelia Walcott said monitoring showed clear evidence of breeding in response to wetland inundation.
'Male southern bell frogs were heard calling at six sites across the Greater Cumbung Region during our September and November 2025 surveys,' Amelia said.
'In February 2026, we observed young bell frogs at two sites, confirming successful breeding and metamorphosis.'
Lachlan Environmental Water Management Officer Paul Doyle said the autumn flow aims to protect those gains by keeping habitat available long enough for juvenile frogs to survive.
'This flow is about giving those young frogs the best chance to make it through winter and become next season's breeders,' Paul said.
'After a series of heatwaves, some wetlands had dried, so maintaining key refuge habitat is critical. Building off recent good rainfall, this flow will help refill these areas and keep them wet for longer.'
The timing aligns with an existing water quality allowance flow of around 150 megalitres per day currently moving through the system, allowing ecological outcomes to be achieved with a lower total volume of environmental water.
'Because the system is already primed, we can extend habitat without delivering a full stand-alone event,' Paul said.
The delivery will focus on channels and adjacent wetlands, where the water will provide the greatest ecological benefit.
The flow is also expected to support wetland vegetation (particularly reeds, sedges and rushes) and will enable bathymetry mapping to improve future water delivery planning.
Monitoring will continue in collaboration with the NSW DCCEEW Saving our Species (SoS) southern bell frog program, including analysis of acoustic data collected across multiple wetlands during the core breeding season.
'This monitoring helps us better understand how frogs respond to flows and improve future conservation outcomes,' Amelia said.
