Inge de Graaf , PhD student in our group has published a paper about a global 6-arcminute one-layer groundwater model. The model is made in MODFLOW and is forced with recharge and surface water levels from our global hydrological model. In this publication a steady state global groundwater depth map has been made, but in subsequent work Inge will provide an updated 5-arcminute two-layer version and transient runs, including the effects of groundwater abstractions.
The paper was highlighted at the EGU website:
A nice picture of the global groundwater table: