Evolution of knowledge on springs in the surat and southern bowen basins: Survey, conceptualisation and wetland dynamics

Abstract

Permanent wetlands supported by discharge from the Great Artesian Basin (GAB) are of global significance due to their unique ecological assemblages and cultural values. Since 2005, rapid growth in coal seam gas (CSG)a development has occurred in the Surat Basin, a sub-basin of the GAB. In parallel with this expansion, there has been substantial investment by government and industry to identify spring wetlands and their source aquifers, understand natural variability in groundwater discharge and to manage predicted impacts resulting from groundwater draw-down. The assessment of consequences to the springs from groundwater drawdown relies upon sound hydrogeological conceptualisation including: the mechanisms through which springs occur; understanding of the wetland water balance; knowledge of historical spatio-temporal changes in wetland extent; and an ability to distinguish between the effects of groundwater drawdown from natural variability in the wetland water balance and other non-hydrogeological influences. In parallel with changes to groundwater pressure, key factors that influence wetland dynamics include the soils surrounding the wetlands, landscape setting, the type of groundwater flow system (local and/or regional), adjacent land use and climate. Integrating multiple lines of evidence and knowledge is pivotal to understanding the influences of a change in ground-water pressure on the abundance and resilience of biota that are dependent on the groundwater discharge. This paper provides a synthesis of the research and monitoring undertaken in the Surat and southern Bowen basins since 2011. Detailed surveys and hydrogeological concep-tualisation have led to new insights on the occurrence and distribution of springs and the key influences on the spring wetland water balance. This knowledge has provided the scientific basis for the management and monitoring of predicted impacts. The approach of evolving the under-pinning science to inform a specific management and monitoring requirement is more broadly applicable to groundwater-dependent ecosystems.