In arid northern Kuwait, scientists lower a sampling tube deep into a dry well to reach the shallow pool of groundwater at its bottom. The water, which has been hidden underground for thousands of years, is being analysed as part of an IAEA research project on the country’s limited natural freshwater resources. The team is using isotopic analysis to study how carbon dioxide levels affect rainwater and groundwater and to better understand changes in water quality.

Groundwater is a scant resource in many parts of Africa and West Asia. Dwindling rainfall, rising temperatures and growing demand are increasing the pressure on the regions’ aquifers. Supported by the IAEA, countries are deploying isotope hydrology — a nuclear technique that traces the source, age and movement of water — to manage groundwater supplies more sustainably.

Isotope hydrology “gives us a fingerprint of the water molecule,” said Jodie Miller, Head of the IAEA’s Isotope Hydrology Section. “Using that fingerprint allows us to evaluate how long ago water in the ground fell as precipitation.”

As part of a recent IAEA coordinated research project, Kuwait, together with Algeria, Morocco and Tunisia, used noble gas isotopes such as helium-4 and krypton-81 to date deep fossil water — ancient groundwater that has remained underground for thousands of years with little to no current recharge — and assess potential contamination from nearby petroleum activity. The research helped determine whether the groundwater was safe for sustained use, a critical step in long term water planning.

“Studies using noble gases and radiocarbon have identified groundwater in Kuwait that is approximately 36 000 years old,” said Chidambaram Sabarathinam, a research scientist at the Kuwait Institute for Scientific Research (KISR). “This information helps us identify periods of intense recharge and supports long term planning to sustainably manage these non-renewable water sources.”

In the North-Western Sahara aquifer system — which extends over one million square kilometres and is shared by Algeria, Libya and Tunisia — the use of noble gases such as krypton-81 has revealed that much of the groundwater is over 150 000 years old. Countries are taking coordinated steps to protect one of the region’s most important shared water resources and ensure that the water is used carefully and preserved for generations to come.

In Kuwait, where almost all drinking water is produced through desalination, natural groundwater remains a vital reserve, especially during emergencies or supply interruption. Noble gases and stable isotopes have been used to test groundwater for fugitive gas contamination from the country’s oil fields. Since 2000, the IAEA has supported capacity building for isotope hydrology and water resource management through its technical cooperation programme, including by helping KISR establish a laboratory to conduct analysis on isotopes and carry out groundwater surveys.

In Tunisia, groundwater supports much of the country’s agriculture. Reduced rainfall and increased demand are stretching groundwater reserves. Tunisia is responding by managing aquifer recharge — the process of storing surplus surface water underground for use during dry periods. The IAEA is working with Tunisian scientists on the use of isotopes to trace how long recharged water remains underground and how far it travels from the recharge site.

“Environmental isotopes play a crucial role in Tunisian groundwater resource management,” said Kamel Zouari, Professor and Laboratory Head at the National Engineering School of Sfax, Tunisia. “These isotopic techniques are particularly effective for assessing complex multilayer aquifer systems, especially in hyper-arid areas.”

Integrating groundwater into water management strategies is critical in Djibouti, a country with little surface water and frequent drought. In 2023, with support from the IAEA technical cooperation programme, Djibouti opened its first national isotope hydrology laboratory. The facility has modernized the analysis of water samples, improving the country’s ability to protect water supplies and manage drought. The laboratory’s success is a model for other capacity-building efforts in the region.

Isotope hydrology is also helping countries assess the quality of their groundwater. In Morocco and Tunisia, isotope techniques are used to trace the sources and pathways of nitrate contamination in groundwater, particularly from agricultural runoff and urban wastewater. In Jordan, isotopes are used to determine natural radioactivity in deep groundwater and inform decision making about the safety of drinking water.

As water scarcity increases in Africa and West Asia, the call for science based water management grows more urgent. With IAEA support, countries across the region are establishing training programmes and laboratories, and accumulating the tools and expertise needed to make well informed decisions about how and when to use their water. These activities are part of IAEA regional technical cooperation projects to support sustainable water use in arid regions.

“The use of nuclear techniques in water resource management helps communities work towards more sustainable water resources, one drop at a time, which in turn can play a role in boosting economic development,” said Hua Liu, IAEA Deputy Director General and Head of the Department of Technical Cooperation.