Modelling and isotope-based age for assessment of fossil GW resources

Open for proposals

Project Type

Coordinated Research Project

Project Code




Approved Date

6 September 2023


Active - Ongoing

Start Date

25 March 2024

Expected End Date

31 March 2028

Participating Countries



Environmental tracer data rarely directly address the ultimate questions related to sustainable groundwater use or dealing with contamination issues. Instead, they contribute to these issues indirectly by improving conceptual models and quantifying parameters or providing calibration data for numerical groundwater models. In many of these cases, groundwater models are the mediator between isotope hydrology and the ultimate goals. In other cases, modelling can help better interpret environmental tracer data. Therefore, to maximise the usefulness of environmental tracer data, a tighter integration between isotope hydrological studies and numerical groundwater modelling is highly desirable.One significant obstacle for a tighter integration is a lack of a common understanding between isotope specialists and modelling specialists. Many of the isotope specialists in the previous CRP didn’t have the necessary knowledge and experience to progress lumped parameter modelling beyond calculating piston-flow tracer ages. And they often also don’t have all the expertise required to build or modify numerical groundwater models efficiently. Groundwater modellers on the other hand often don’t have enough knowledge on environmental tracers, their assets and their limitations, to know how to integrate these data into models directly or of what isotopic tracers can or can’t do when used indirectly e.g. by comparing tracer-based ages with numerical model-based ages. Bridging this gap is the key problem that will be addressed in this CRP.


The primary focus of the CRP will be to achieve a tighter integration of environmental tracers, in particular age indicators, with lumped parameter modelling and numerical groundwater modelling. This will help to promote the usefulness of environmental tracer data for sustainable groundwater management and other topics. The focus will be on working in aquifer system with pre-existing environmental tracer data such as recently available long-lived radionuclides, isotope age tracers, and noble gases (carbon-14, krypton-81, chlorine-36, helium-4, tritium, etc.) to develop improved workflows and build capability for using this data in modelling. Most member states lack the most advanced isotope techniques and modelling capability.

Specific objectives

Improve the expertise among participating countries in integrating multiple isotope tracers for establishing and improving conceptual groundwater age models, lumped parameter models and numerical flow models.

Improve existing age models based on 4He and 81Kr.

Start collaborative work between member state teams, isotope geochemists and numerical modellers to develop isotopic/numerical-based model to simulate flow and transport of aquifer system using pre-existing isotope data (as 81Kr, 4He, 36Cl/Cl, 14C, and 3H ages).

Assess the usefulness of different age tracers in the modelling processes.

Built a complete workflow for future studies which contain all steps learned/developed during the previous CRP and the new one and consist of precise sample and isotopic analyses protocols, lumped models use, numerical modelling development.

The IAEA’s Global Water Analysis Laboratory (GloWAL) Network can expand its analytical activities by mentoring and supporting analytically member states in doing isotopic analyses of 4He and 81Kr for supporting future studies in old groundwater management.

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