Hydrologic reference stations to monitor climate-driven streamflow variability and trends

The Australian network of Hydrologic Reference Stations (HRS) embraces 221 well-maintained river gauges with high quality, long periods of streamflow records managed by Commonwealth, State and Territory water agencies. The HRS attempts to monitor and assess the streamflow variability and trends in 221 catchments reflecting the diversity of Australian flow regimes. Detecting the streamflow changes in the HRS network focuses on unregulated catchments with minimal effects of water resource development and land use change, which enables observed trends to be distinguished from direct anthropogenic impacts. Trend analysis identifies inter-annual, seasonal, decadal variability, long-term linear trends and step change in streamflow. Trends are characterised for annual total flow, base flow, seasonal flows and four daily flow quantiles. The results suggest a varying pattern of spatial and temporal variation in streamflow across different hydroclimatic regions in Australia. Most of the stations in New South Wales and Victoria show a significant decreasing trend in annual streamflow, while increasing trends are observed in Northern Territory and the northern parts of Western Australia and Queensland, and no significant trend visible for stations in the central regions of Australia. The findings in trend analysis of annual total streamflow show evidence of hydrological response resonating with observed climate changes over past decades. Overall, the HRS stations serve as 'living gauges' for streamflow monitoring and climate change detection. A wealth of freely downloadable hydrologic data are provided in the HRS web portal including annual, seasonal, monthly, daily streamflow data, trend analysis products, and relevant site data.