Oral Presentation NCGRT/IAH Australasian Groundwater Conference 2019

Investigating the source waters of the Doongmabulla Spring Complex (484)

Robin K. Keegan-Treloar 1 , Adrian D. Werner 1 , Eddie W. Banks 1 , Dylan J. Irvine 1
  1. Flinders University, Bedford Park, SA, Australia

The Doongmabulla Springs Complex (DSC) is a collection of permanent freshwater springs that provide water to approximately 160 wetlands, which are ecologically significant and provide niche habitat for several threatened species (Fensham et al. 2016). Currently, the source of water to the DSC is uncertain, and with proposed developments within the vicinity of the springs, it is essential that the source waters of the DSC are properly examined. Alternative conceptual models have been presented for the source of the springs, and there is conjecture as to the contributions from the Triassic Clematis Formation and deeper Permian sediments; these being separated by the Triassic Rewan Formation, a regional aquitard that represents the base of the Great Artesian Basin (Habermehl and Lau 1997; CSIRO and Geoscience Australia 2019). This presentation describes efforts to collate available hydrochemical data and supplement this with additional measurements from a field sampling campaign to address knowledge gaps in the existing hydrochemistry dataset for the DSC and nearby sedimentary units. Statistical analyses, including Principal Components Analysis (PCA) and K-Nearest Neighbours Clustering (KNN), were applied to hydrochemical data for the DSC and the aquifers of the region. PCA suggested an overlap between the hydrochemical signatures of the water types of the region's aquifers and the DSC. Hydrochemical overlap can be indicative of inter-aquifer mixing, which may suggest connectivity between the Triassic and Permian aquifers. KNN, a supervised classification technique, provided an insight into the most likely source aquifer of individual springs of the DSC. These preliminary results shine new light on the statistical association between individual DSC springs and groundwater in Triassic and Permian aquifers. These findings highlight the importance of continued investigation of alternative conceptual models for the source of discharge to the DSC. 

  1. CSIRO and Geoscience Australia (2019) Advice on Groundwater Management and Monitoring and Groundwater Dependent Ecosystem Management plans to the Department of the Environment and Energy. February, 2019, 63pp. http://www.environment.gov.au/system/files/pages/cb8a9e41-eba5-47a4-8b72-154d0a5a6956/files/csiro-geoscience-australia-final-advice.pdf
  2. Fensham, R.J., Silcock, J.L., Laffineur, B., MacDermott, H.J. (2016) Lake Eyre Basin Springs Assessment Project: Hydrogeology, cultural history and biological values of springs in the Barcaldine, Springvale and Flinders River supergroups, Galilee Basin springs and Tertiary springs of western Queensland. Report to Office of Water Science, Department of Science, Information Technology and Innovation, Brisbane. https://publications.qld.gov.au/dataset/11c1af89-93b9-497a-b99f-2ec6c7a8d339/resource/c5d1813b-73a4-4e05-aa86-39a8ed3045fb/download/lebsa-hchb-report-springs-wst-qld.pdf
  3. Habermehl, M. A. and Lau, J. E. (1997) Hydrogeology of the Great Artesian Basin, Australia (map at scale 1: 2,500,000), Australian Geological Survey Organisation, Canberra.