IGRAC launches new Transboundary Aquifers of the World Map 2021


IGRAC has published the new Transboundary Aquifers of the World Map (TBA Map) 2021. The TBA Map 2021 shows 468 identified transboundary aquifers/aquifer systems underlying almost every nation. The new map will be launched at the opening ceremony of the ISARM 2021 Conference.

TBA Map 2021

The Transboundary Aquifers of the World Map (TBA Map) shows the state of information presently available on the occurrence and extent of Transboundary Aquifers worldwide. The map is based on the most recent inventory results of many projects carried out around the world. There are now 468 identified transboundary aquifers and aquifer systems identified, underlying almost every nation, increased from 366 in 2015. The number of transboundary aquifers has been increasing steadily since the first ‘Transboundary Aquifers of the World Map; was released in 2009. It is likely that new transboundary aquifers will still be identified in the future and that the delineation of existing transboundary aquifers may be refined once further studies are conducted.
A significant source of information for the 2015 map, and now the 2021 map, was data collected as part of the Global Environment Facility Transboundary Waters Assessment Programme (TWAP). Other significant inputs to the 2021 map include contributions from the Transboundary Aquifer Assessment Program (TAAP), SADC Groundwater Management Institute (SADC-GMI), the Scottish Government Climate Justice Fund Water Futures Programme (CJF) and the EU:WATERRES Project.

For countries in the EU, Switzerland and Norway, previous editions of the global transboundary aquifer map have also displayed transboundary groundwater bodies as adopted by the EU WFD alongside or instead of transboundary aquifers. Transboundary groundwater bodies are not necessarily hydrologic units, but rather management units. In many cases, aquifers are subdivided into groundwater bodies while occasionally groundwater bodies may contain multiple aquifers. This causes confusion when describing the number and extent of transboundary aquifers and aquifer systems across Europe. Therefore, IGRAC have decided to remove transboundary groundwater bodies from the 2021 map update in order to more accurately reflect the true number of transboundary aquifers globally. For those interested in the number, extent, and location of transboundary groundwater bodies in the EU, Switzerland and Norway, more information can be found in the WISE Water Framework Directive database

The TBA Map will be also available online at IGRAC’s Global Groundwater Information System: https://ggis.un-igrac.org/view/tba.

Raising Awareness

Groundwater is the most abundant source of freshwater on earth, accounting for approximately 97% of non-frozen freshwater. It is an important natural resource that greatly contributes to human development. Groundwater sustains ecosystems, maintains base flow of rivers, and stabilizes land in areas with easily compressed soils. Aquifers can also buffer impacts resulting from seasonal variability and climate change. However, groundwater does not stop flowing at political borders and huge resources are stored in transboundary aquifers. Therefore, the identification, mapping, assessment and development of governance mechanisms for transboundary aquifers (TBAs) are important tasks for ensuring the sustainability of these resources and peaceful cooperation between countries. 40% of the worlds available water is transboundary.