Assessment of groundwater resources yields knowledge necessary for their informed management and governance. Assessment means more than hydrogeological characterisation alone: it includes all other aspects (e.g. social, economic or environmental) that are needed for understanding of the resource and its state, in accordance with purpose of the assessment.
At IGRAC, we distinguish country-wide, transboundary and thematic assessments. Since groundwater resources are subjected to change, possible changes and their impact need to be assessed on regular basis. Already in 2003, IGRAC put together the first country-based global overview of groundwater resources, containing a set of aggregated groundwater-related indicators. The reason for a country-based (and not aquifer-based) overview was simple: the most groundwater data were available at the country level. In meantime, more and more information is becoming available at the aquifer level and IGRAC is compiling it, concentrating at transboundary aquifers firstly. Nevertheless, the country level remains an often used entry-level for global and regional analysis. Therefore IGRAC maintains and updates the country-based global overview. Thematic assessments, dedicated to selected groundwater issues, are conducted on regional/global scale; occurrence of arsenic and fluoride worldwide is an example of thematic assessment.
Groundwater is connected to many goods and services people depend upon, including food and energy production. Over the years, groundwater situations have changed rapidly in many places around the world due to intensive use of the resource, particularly for irrigation and domestic water supply, coupled with climate change.