Development of a spring typology to inform the assessment of risks and to guide management arrangements in the Surat Cumulative Management Area, Queensland

Full text: The Office of Groundwater Impact Assessment (OGIA) has developed 17 conceptual models and a typology for springs (wetlands) in the Surat Basin, an area of intensive coal seam gas development in Queensland. Since 2013, there has been a significant investment in monitoring and research at wetlands by the CSG companies and OGIA. Data collected has included time series wetland discharge, extent, chemistry, flora, macroinvertebrate assemblages and local hydrogeology. A critical and often overlooked component of wetland risk assessments is identifying the ecological components of an ecosystem that are directly linked to groundwater. These "ecological endpoints" are the backbone for the development of monitoring and mitigation arrangements. Data is analysed in relation to local hydrogeology, hydrochemistry and wetland dynamics with relationships between these elements and ecology determined. Pictorial and text based conceptual models describing the major components of the wetland system at a landscape and wetland scales are developed. Following conceptualisation, a wetland typology is established which informs OGIA's key management requirement which is to understand: how would wetlands respond to a change in the groundwater regime, what are the implications of this change and what are suitable indicators? Four groupings of wetlands were identified for the Surat Basin. The types are based on the following wetland attributes: landscape setting; geomorphology; groundwater flow systems; regolith; water regime; and ecology (macroinvertebrates and flora). For each wetland type, the wetland water requirements and suitable monitoring indicators are identified. A critical assessment of the implications of a change in the groundwater regime is also developed. The established wetland typology allows for a more structured approach to consider impacts and monitoring requirements for wetlands. Wetlands that respond and function in a similar manner can be evaluated collectively. The approach and framework has broad applicability, particular across other parts of the Great Artesian Basin. (author)