Thirlmere Lakes is a group of waterways in the Greater Blue Mountains World Heritage Area that includes Lake Gandangarra, Lake Werri Berri, Lake Couridjah, Lake Baraba and Lake Nerrigorang. The lakes are thought to be about 15 million years old.
Water levels in Thirlmere Lakes have fluctuated over time. A decline in water levels over the last decade caused significant local community concern that has led to the development of the Thirlmere Lakes Research Program.
Thirlmere Lakes Research Program
The former Office of Environment and Heritage (OEH) committed $1.9 million over 4 years for the Thirlmere Lakes Research Program to help understand the fluctuating water levels in the lakes.
The research program aims to provide a more detailed understanding of the dynamics of water sources and water flow paths in Thirlmere Lakes by investigating the geology, geomorphology, hydrogeology and hydrology of the system.
Work began in 2017 and Department of Planning, Industry and Environment (former OEH) is collaborating with research partners at the University of NSW, University of Wollongong and Australian Nuclear Science and Technology Organisation (ANSTO). As well as looking at the internal dynamics of the system, researchers are investigating the sensitivity of these wetland systems to external influences, including the potential effects of mining activity and groundwater extraction.
Five research themes are being addressed:
- Geological mapping and geophysical surveys of the Thirlmere Lakes area (UNSW Lead Researcher Dr Martin Andersen)
- Environmental isotope investigations into periodic and recent water losses from Thirlmere Lakes (ANSTO Lead Researcher Dr Dioni Cendon)
- Geomorphology, sub-surface characteristics and long-term perspectives on filling and drying of Thirlmere Lakes (UoW Lead Researcher Dr Tim Cohen)
- Surface water–groundwater interactions (UNSW Lead Researcher Dr Martin Andersen)
- Developing an understanding of the flow of water into and out of the lakes (UNSW Lead Researcher Associate Professor Will Glamore).
Inquiry and outcomes
An inquiry was conducted in 2012 in response to community concerns about the low water levels in Thirlmere Lakes and potential impacts from mining and groundwater extraction in the region. The NSW Government appointed 4 independent scientists and a community representative to evaluate possible causes for the low water levels in the lakes.
The inquiry identified knowledge gaps and recommended more research was needed to better understand how the lake system worked and what was causing or affecting water level changes, including surface water loss. The findings of the inquiry were published in 2012 in the Thirlmere Lakes Inquiry: Final Report of the Independent Committee.
The NSW Chief Scientist and Engineer also reviewed the findings and agreed that more research was needed. More information is available in the Chief Scientist and Engineer's review of the final report of the independent committee, which was published in 2013.
A water monitoring system was installed at Thirlmere Lakes in 2013.
A workshop held in 2016 discussed potential research methods that could be used to address the knowledge gaps identified by the inquiry. The content from this workshop was captured in the report The Mysterious Hydrology of Thirlmere Lakes.