satellite data including that generated by the us nasas gravity recovery and climate experiment grace have been able to provide overall monthly and yearly changes in groundwater stock in multiple regions it demonstrated for example the diminution of resources in california over time eg famiglietti et al smaller countries for which groundwater is a major source of freshwater and which have more homogeneous geological profiles of agricultural land and where data is collected and shared are able to properly track groundwater resources over time an example is denmarks national groundwater mapping and management program financed by private and public water consumers which uses new tools to track groundwater dwf