Introduction: The Potential of Isotope Hydrology in Water Resource Management in Africa
Water scarcity and quality challenges have long affected Africa and have only increased as a result of climate change. Isotope hydrology, a technique that uses isotope tracers to assess water origins and interactions, is an essential tool in managing water resources. On October 15, 2024, the SDPU initiative, in partnership with Morocco’s National Centre for Nuclear Energy, Science, and Technology (CNESTEN), hosted an expert panel discussion with representatives from the International Atomic Energy Agency (IAEA), World Meteorological Organization (WMO), and the National Academy of Sciences and Techniques of Senegal (NAST-Senegal) followed by a fireside chat with Morocco’s Ministry of Equipment and Water at the 7th Annual Cairo Water Week to share insights on how isotope hydrology can support water resource management efforts across the African continent by improving water access and informing decision-making.
Understanding Isotope Hydrology
Dr. Moncef Benmansour, Director of Studies and Scientific Research at CNESTEN, opened the technical discussion by explaining the foundational principles of isotope hydrology, which analyzes isotopes in water molecules to track water sources, age, and the natural processes affecting it. Isotopes, whether stable like oxygen-18 or unstable like tritium, serve as natural markers that reveal detailed information about water cycles from rainfall infiltration to groundwater recharge. This data is especially valuable for regions where water scarcity is most pressing.
During his presentation, Dr. Benmansour highlighted how isotope hydrology enables a precise understanding of groundwater systems. He detailed how isotope analyses allow scientists to:
1. Identify recharge zones, which are crucial for replenishing aquifers;
2. Trace interactions between groundwater and surface water;
3. Assess the age of groundwater which can indicate sustainable withdrawal rates;
4. Determine the origin of pollutants in groundwater systems, supporting efforts to mitigate contamination.
Technical Applications Across Africa
The use of isotope hydrology has rapidly expanded across Africa, with significant impacts in countries like Morocco and Senegal. Dr. Mohamed Qurtobi from CNESTEN (Morocco) shared how the partnership between Morocco’s Ministry of Equipment and Water and the IAEA enables large-scale investigations of groundwater basins across the country. These efforts have led to important technical insights which can be translated into practical outcomes, allowing Morocco to map critical aquifers and better understand issues like salinity in coastal groundwater and overexploitation of strategically important water resources including the Tadla and Moulouya basins.
With isotope studies, Morocco has been able to develop detailed hydrologic flow models, which provide decision-makers and water managers with data-driven scenarios for resource allocation. For example, data from isotopic studies has previously revealed how artificial recharge could counteract depletion in certain aquifers, while in other regions, it demonstrated the critical role of surface water in recharging groundwater systems.
Dr. Dominique Berod from the WMO similarly stressed the need to improve understanding of the hydrological cycle, which relies on robust monitoring system of all components of the cycle at all space-time scales. However, many national hydrological monitoring networks lack the ability to provide a comprehensive picture of both surface and groundwater resources, demonstrating a need to use multiple data sources and developing innovative approaches, such as isotope hydrology, to complement traditional measurement techniques. Similarly, Senegal has integrated isotope hydrology into its water resource management framework, as highlighted by Prof. Cheikh Becaye Gaye from NAST-Senegal. Beginning in the late 1970s, isotopic studies have evolved over the past fifty years and play a central role in water management thanks to national support and IAEA programs. This is especially true in the Thiaroye aquifer, a key source of water for the city of Dakar, where isotopic studies were able to reveal the impacts of pollution and the influence of human activity on groundwater recharge rates. These studies were vital in developing policies aimed at protecting water resources and helping local communities adapt to seasonal variations in water availability, which are increasingly unpredictable due to climate change.
Prof. Jodie Miller from the IAEA shared the Agency’s appreciation for the work conducted in cooperation with the expert panel and reaffirmed isotope hydrology’s role in water resource management. As a way to empower countries to generate their own isotopic water data, Prof. Miller shared an overview of the IAEA’s Global Water Analysis Laboratory (GloWAL) Network. GloWAL was launched at the United Nations 2023 Water Conference to enable collaboration and communication amongst laboratories to share knowledge, foster capacity building, and support training so that laboratories can generate reliable data to meet United Nations Sustainable Development Goal (UN SDG) 6 (Clean Water and Sanitation) and deliver on the Water Action Agenda.
Morocco’s Experience Leveraging Isotopic Techniques
A fireside chat featuring Dr. Qurtobi and Dr. Moulay Driss Hasnaoui from Morocco’s Ministry of Equipment and Water provided a closer look into Morocco’s use of isotope hydrology to support its water security agenda. The discussion highlighted the country’s progress since the 1990s in integrating isotope techniques to map and monitor groundwater dynamics across Morocco’s water basins. Through these efforts and with the support from the IAEA, CNESTEN has advanced knowledge about the water cycle, groundwater recharge zones, and pollution sources, creating a foundation for evidence-based water resource management.
Dr. Qurtobi described CNESTEN’s work to increase awareness of isotope hydrology’s value among decision-makers and foster collaborative efforts with Morocco’s Ministry of Equipment and water. Dr. Hasnaoui explained that isotope hydrology provides data that is crucial to understanding water circulation and supporting sustainable water use strategies in Morocco. Dr. Hasnaoui further outlined priorities for future research in Morocco, including studying groundwater-surface water interactions, identifying recharge areas, dating deep water resources, tracing pollution sources and understanding marine intrusion effects. This proactive approach positions Morocco to meet its water security needs while responding effectively to environmental challenges. It further supports the wider MENA regional water security priorities and demonstrates how leading technical institutions like CNESTEN, which serves as an IAEA Collaborating Centre, are critical in leveraging nuclear and isotopic techniques for water resources management and environmental protection.
Progress and Challenges in Isotope Hydrology Use in Africa
Reflecting on advances over the past three decades, Prof. Gaye noted that isotope hydrology has enabled African countries to make considerable progress toward UN SDG 6. Despite these achievements, challenges remain. Data integration across regions, inconsistent funding, and limited access to isotope analysis facilities all pose barriers to broader implementation. These challenges serve as the key discussion points for a workshop the SDPU will be hosting in January 2025 in Rabat, Morocco, in partnership with CNESTEN, which aims to develop Pan-African collaborations to utilize isotope hydrology for the monitoring and management of water resources. The workshop will also explore data collection and analysis as well as best practices around sustainable laboratory management and equipment maintenance. To learn more about this workshop and register, please visit: https://www.sustaineddialogue.com/event/workshop-on-pan-african-water-resource-monitoring-and-data-sharing-with-nuclear-science-and-technology/.
Opportunities and Recommendations
As the discussion concluded, panelists shared their recommendations and opportunities to advance isotope hydrology in Africa. Among these were the importance of integrating nuclear techniques with traditional methods to enhance water management effectiveness and sustainability and the critical need for capacity development in both human resources and technology. Panelists underscored the need for opportunities like those provided through the IAEA’s GloWAL network for regional collaborations and shared laboratories that could further strengthen expertise by consolidating resources. The panel also welcomed support from other international organizations, such as the WMO, to support partners in developing standards on data formats, exchange procedures, and quality control to improve data sharing capabilities.
As African nations work to secure their water resources, increased awareness of and access to the peaceful uses of nuclear science and technology, such as isotope hydrology, remains critical to supporting sustainable development priorities and pursue the UN Sustainable Development Goals.
This report was composed by Ms. Carla Langenbucher, Project Lead, CRDF Global with review and contributions from Dr. Moncef Benmansour (CNESTEN), Dr. Mohamed Qurtobi (CNESTEN), Prof. Cheikh Becaye Gaye (NAST-Senegal), Prof. Jodie Miller (IAEA), and Dr. Dominique Berod (WMO). Please direct questions about this report, the event for which it was written, or the SDPU program to sdpu@crdfglobal.org.
