Coal Mining Impacts on Baseflow Detected Using Paired Catchments

Large-scale coal mining not only disturbs natural landscapes but also alters catchment hydrological processes. Although investigating how mining activities such as open cut and/or underground mining change catchment baseflow is critical for understanding mining-related hydrological mechanisms and for helping water resource management, published data on these changes have not been well documented. This study uses data-driven approaches to examine how baseflow changes in four sets of paired catchments in the Hunter River Basin in Australia, which is one of the most intensive mining regions across the globe. The difference of cumulative anomaly percentage and double mass curves are used to detect the changes in baseflow and to identify the potential mining impacts. Our results show that underground mining has led to a decline in baseflow, while open cut mining has tended to increase baseflow, and significantly changed the baseflow trend for catchments where underground and open cut mining coexist. The mining impact signal, however, is on the top of regional climate change impacts that dominate baseflow annual variability. The data-driven investigation cannot separate impacts due to multiple and overlapping disturbances of mining activities but provides insight and guidance for hydrological modeling to simulate mining impacts on hydrological regimes.