Assessing Groundwater Drought Hazard in the Case of Groundwater Storage Trends caused by Human Water Use as well as Climate Variability and Change - Data set

Over the last decades, increasing groundwater abstractions, and to a lesser extent climate variability and change, have led to groundwater depletion (GWD), especially in major irrigation areas. Such negative trends in groundwater storage (GWS) are problematic in the context of groundwater drought detection since they can superimpose climate-induced drought signals including climate-induced groundwater pumping. As this is currently not considered in large-scale drought early warning systems (LDEWSs), we used time series of monthly GWS from the global hydrological model WaterGAP 2.2e to investigate how groundwater drought can best be quantified in an LDEWS covering GWD regions. Groundwater drought hazard indicators (GDHIs) based on three variants of GWS were analyzed: (1) GWS as impacted by human water use (GWS_ant), (2) naturalized GWS assuming no human water use (GWS_nat), and (3) GWS_ltc, in which the linear trend of GWS_ant is removed. Here, the reader can download 1) monthly time series of GWS_nat during 1980-2019, 2) GDHIs assessed in the study, 3) the R scripts for computing the indicators and other data (including required input data), and 4) WaterGAP-related data (e.g., landmask, big cities), and other meta data (e.g., GWD grid cells and LTC grid cells). WaterGAP 2.2e model output from an anthropogenic model run is available at https://doi.org/10.25716/GUDE.0TNY-KJPG.