Impacts App Table 1. Activities in CSG and LCM development that potentially impact on GDEs. These activities present risks to GDEs that include altering the number of native species and species composition within GDE communities; disrupting ecological processes that deliver ecosystem services; damage aquifer geologic structure; increasing risk of exotic species invasion; removing GDE habitat; altering groundwater quality; and changing timing, duration, pressure and flow conditions of groundwater Impacting activity Type of impact Type of GDE affected When does this impact need to be considered in EIA? Factors to consider during impact assessment Aquifer dewatering Watertable lowering; change timing and magnitude of groundwater level fluctuations All Aquifer connection to surface GDE; aquifer likely to have stygofauna (alluvial, karstic, calcrete) with dewatering at a magnitude and duration outside natural variability Magnitude, duration, frequency, and timing of dewatering; how these compare to pre-impact conditions Initial watertable depth; water level fluctuation range over annual and timescales, amplitude and rate of change Watertable lowering – will it convert gaining stream/wetlands to losing ones? Aquifer depressurisation Loss of artesian pressure Springs Depressurisation of an aquifer connected to a spring Lost pressure; alteration of discharge flow rate to spring Flow rate changes affect water level, permanence, and spring water quality Excavation of overburden Removal of upper aquifer All GDE types When overburden is an aquifer that supports GDEs Watertable in overburden; aquifer porosity Alteration of subsurface flow paths with excavation Surface topography changes Alter groundwater recharge patterns Vegetation; wetlands; river baseflow; aquifer GDEs Major landscape changes such as excavation of mine pit; subsidence of longwall panels Alteration to channelling of water to or from aquifer recharge zones; availability of groundwater modelling Potential flow changes considered in groundwater modelling If GDEs have some level of reliance on surface water diversion Disconnect river and aquifer River baseflow; aquifer GDEs If connection exists between channel and aquifer If the diverted reach is dependent on groundwater, either locally or upstream
Leaking of saline water from surface storage or through fractures between aquifers Increase in aquifer salinity; decline in quality All GDEs Pressurised, lower aquifer of poor water quality occurring beneath an aquifer with better quality water that supports GDEs If dilution of saline water will occur Overflow or leakage from storage dams and water infiltrates aquifers Rate of saline water dispersal When hydraulic fracturing is planned and there is potential for a confining layer to be ruptured. Chemistry of saline compared to receiving aquifer Construction and operation of surface infrastructure (buildings, rail, pipelines, stockpile areas) Permeable surface compaction; pollution from effluents, petrochemicals, explosives, other on-site chemicals All GDEs Location of infrastructure on upslope of aquifer recharge areas (including coal and rock stockpiling areas) Footprint of disturbance area Leachates from coal or rock stockpiles Potential groundwater pollution from saline or acid drainage Aquifer GDEs Potentially toxic stockpile leachate Geochemical characteristics of the stockpiled rock; process of stockpile draining Vegetation clearing Direct impact to vegetation; removal of organic matter source for aquifer communities Vegetation; aquifer GDEs Removal of vegetation areas considered Frequency of vegetation groundwater extraction Open pit lake Aquifer impact through poor quality Aquifers; river baseflow; wetlands When potential for pit lake to leak into aquifer supporting GDEs Potential to release water into the surrounding aquifer through seepage Geochemical rock characteristics; changes in pit water once mining ceases Flow rate and direction of groundwater drainage
T8 Water balance - vegetation Use of balance measurements and/or calculations to determine whether and to what extent plant water use is dependent on groundwater uptake GDE Toolbox T9 Stygofauna sampling Techniques available to collect groundwater fauna GDE Toolbox T10 Evaluation of surface water – groundwater interactions Analysis of the hydraulics of surface water – groundwater interactions. The processes by which groundwater discharge into surface water systems provides insight into the nature of groundwater dependency in wetlands and baseflow river ecosystems GDE Toolbox T11 Environmental tracers Environmental tracers are a naturally occurring physical or chemical property of water, or any substance dissolved in water, that can be used to trace its flowpath. Analysis and interpretation of these properties of surface water and groundwater can be used to identify groundwater contribution to dependent ecosystems GDE Toolbox T12 Introduced tracers Analysis of deliberately introduced hydrochemical tracers to identify sources and surface water – groundwater mixing relationships GDE Toolbox NT4 Genetic/DNA analysis Analysis of environmental DNA, or DNA collected from captured stygofauna, to identify species present in an aquifer NT5 Literature Review existing journal articles and reports. Look up conservation status and endemism of ecosystems T13 Long-term observation of ecosystem response to change Long-term observations of GDEs and the hydrologic environment they exist within to establish ecosystem responses to changes in water regime due to climatic and/or anthropogenic influences GDE Toolbox T14 Numerical groundwater modelling Construction of mathematical models to simulate groundwater flow systems GDE Toolbox NT5 Remote sensing Use of vegetation greenness, wetness, land surface temperature to discriminate GDEs. Use of wetness index to delineate water bodies.
Resources required for identifying GDEs, including national data availability App 3. Landscape and ecosystem data sets that are useful to help identify GDEs. National-scale dataset sources are shown Ancillary data Likely source National dataset/Source Landscape datasets DEM/surface elevation Aerial photograph, satellite imagery 9-second DEM (GA) Groundwater depth Maps, reports, observation bore records National groundwater information system (BOM) ; Groundwater flow systems and elevations; hydrogeology Maps, reports, observation bore records, DEM Surface water level Maps, reports, observation bore records, river gauge data (BOM) Surface (rivers, wetlands, springs) mapping Aerial photographs, satellite imagery, Google Earth Geofabric (BOM); Flow direction grid (GA); Water Observations from Space (GA); Surface water (GA) Groundwater quality (including temperature and salt) River connectivity/classification map GW-SW connectivity Geological and geomorphological mapping Underlying geology and geological structure (e.g. fractured rock aquifer); geophysics Maps, reports, ground survey, geophysical survey (GA) River flow data River gauge data (BOM) State sources of data River regime gauge data State sources of data Consumption infrastructure (bores) (BOM)
Climate data Bureau of Meteorology Soil mapping Maps, ground surveys, geological survey, site assessment National soil database Hydrogeology (watertable salinity; aquifer boundaries; principal hydrogeology) Maps, ground surveys, geological survey, site assessment National groundwater information system (BOM) Recharge/discharge areas Remote sensing, geological mapping information CSIRO Tool to calculate recharge/discharge Landuse Aerial imagery, remote sensing Ecosystem datasets Vegetation (classification and composition) mapping Maps, ground surveys, aerial photographs, satellite imagery Known GDEs (subsurface especially), potential GDEs Reports, ground surveys, satellite imagery IDE layer (data on IDE likelihood) GDE Atlas Wetland classification mapping National Wetland Inventory EPBC listing (flora and fauna, Threatened Ecological Communities) Department of Environment and Energy State protected/vulnerable flora and fauna Department of Environment and Energy Threatened Ecological Community Leaf Area Index MODIS - NASA Root depth Reports, site assessments Vegetation condition Reports, maps, site assessments, satellite imagery Derive from Landsat mosaic;
Monitoring and periodic assessment of mitigation Mitigation action F Moderate Value/High Risk Protection of hotspots Protection of hotspots Adaptive management; Continue monitoring Baseline risk monitoring; Mitigation action Monitoring and annual assessment of mitigation G Low value/Low risk Protect hotspots (if any) Protect hotspots (if any) Adaptive management; Continue monitoring Baseline risk monitoring Baseline risk monitoring H Low Value/Moderate Risk Protect hotspots (if any) Protect hotspots (if any) Adaptive management; Continue monitoring Baseline risk monitoring; Mitigation action Monitoring and periodic assessment of mitigation I Low Value/High Risk Protect hotspots (if any) Protect hotspots (if any) Adaptive management; Continue monitoring Baseline risk monitoring; Mitigation action. Monitoring and annual assessment of mitigation