Groundwater hydrochemical characterisation of the Surat Region and Laura Basin, Queensland

Project completed 2015

Background

A windmill near a paddock, with a background of lined trees and a cloudy sky

Windmill accessing shallow
groundwater, Surat Basin

The increase in coal seam gas (CSG) developments across many parts of eastern Australia since the early 2000s led to widespread community concern about potential environmental and human health issues associated with the CSG industry. Of primary concern to many people are the potential impacts to water resources caused by CSG and large coal mining developments. Fundamental to better understanding these impacts is an improved understanding of groundwater systems and processes within the regions where development may occur.

Geoscience Australia completed a desktop study to investigate the potential for hydrochemical analyses to discriminate groundwater in coal seams from adjacent aquifers in Queensland's Surat Region and Laura Basin. This study collated and analysed existing groundwater chemistry data in the two areas. Analyses of the compiled hydrochemistry data involved a variety of methods to characterise groundwater chemistry within specific hydrogeological units.

This project was commissioned by the (then) Department of the Environment’s Office of Water Science.

Objectives

This project characterised the hydrogeochemistry of groundwater associated with coal seams and surrounding aquifers in Queensland’s Surat Region and Laura Basin. The project objectives were to:

  1. Hydrochemically characterise (ionic, organic, gaseous, radiogenic and stable isotopes) groundwater within coal seams and adjacent aquifers to determine baseline conditions and distinguish between coal seam water and that of surrounding aquifers
  2. Identify knowledge and data gaps relevant to CSG hydrogeochemistry
  3. Compare groundwater quality data with relevant water quality guidelines (ANZECC/ARMCANZ 2000; NHMRC/NRMMC 2011) to identify environmental values of groundwater relevant to ecological and human use.
Two men standing near a paddock and a water tank with groundwater gas sampling equipment

Groundwater gas sampling in the Surat Basin

Outcomes

This project has informed the Independent Expert Scientific Committee on Coal Seam Gas and Large Coal Mining Development (IESC) about:

  1. the environmental values of groundwater and groundwater composition in coal seams and adjacent aquifers assessed for this study
  2. the key data and knowledge gaps that limit current understanding
  3. targeting future investments (where appropriate) that will address the most critical knowledge gaps that exist in the Surat Region and Laura Basin.

This preliminary assessment identified areas for further targeted research. This included collection of additional baseline hydrochemical and geochemical data for specific aquifers and coal-bearing units, as well as other information to assess the potential for inter-aquifer connectivity.

Outputs

The following reports are available:

Final technical report: Groundwater Hydrochemical Characterisation of the Surat Region and Laura Basin - Queensland

Summary report: Groundwater Hydrochemical Characterisation - Surat Region and Laura Basin, Queensland