Tracer tomography: design concepts and field experiments using heat as a tracer

Area of Science:

• Geosciences
• Hydrogeology
• Environmental Science

Background:

• Hydraulic tomography combined with tracer tests enhances hydraulic conductivity estimation.
• Field demonstrations of tracer tomography are limited due to experimental difficulties.

Purpose of the Study:

• To present a conceptual design and field-scale application of tracer tomography using heat as a tracer.
• To address experimental challenges in heat tracer testing for improved accuracy and cost-effectiveness.

Main Methods:

• Developed an improved active heat tracer testing method minimizing heat loss, buoyancy, viscosity, and boundary condition effects.
• Utilized a cost-effective approach for high-resolution in situ temperature measurements.
• Applied the method to a heterogeneous sandy gravel alluvial aquifer at the Lauswiesen Hydrogeological Research Site.

Main Results:

• Tomographic heat-tracer experiments align with previous aquifer characterization studies.
• Demonstrated the experimental applicability and suitability of tracer tomography at the field scale using heat.
• Showcased the potential of heat-tracer tomography as a cost-effective tool for aquifer heterogeneity characterization.

Conclusions:

• Tracer tomography using heat is experimentally validated for field-scale aquifer characterization.
• The developed method offers a cost-effective solution for assessing aquifer heterogeneity.
• This approach enhances the estimation of hydraulic conductivity in complex hydrogeological settings.