Analysis of the spatio-temporal variability of terrestrial water storage in the Great Artesian Basin, Australia

The Great Artesian Basin (GAB) in Australia, the largest artesian basin in the world, is rich in groundwater resources. This study analyzed the spatio-temporal characteristics of terrestrial water storage (TWS) in the GAB for 2003–2014 using satellite (Gravity Recovery and Climate Experiment, GRACE) data, hydrological models’ outputs, and in situ data. A slight increase in TWS was observed for the study period. However, there was a rapid increase in TWS in 2010 and 2011 due to two strong La Nina events. Long-term mean monthly TWS changes showed remarkable agreements with net precipitation. Both GRACE derived and in situ groundwater disclosed similar trend patterns. Groundwater estimated from the PCR-GLOBWB model contributes 26.8% (26.4% from GRACE) to the total TWS variation in the entire basin and even more than 50% in the northern regions. Surface water contributes only 3% to the whole basin but more than 60% to Lake Eyre and the Cooper River. Groundwater, especially deeper than 50 meters, was insensitive to climate factors (i.e., rainfall). Similarly, the groundwater in the northern Cape York Peninsula was influenced by some other factors rather than precipitation. The time-lagged correlation analysis between sea surface height and groundwater storage indicated certain correlations between groundwater and sea level changes.