A robust optimization technique for analysis of multi-tracer experiments

Area of Science:

• Environmental Science
• Hydrogeology
• Geochemistry

Background:

• Solute transport in heterogeneous porous media is influenced by diffusive mass exchange between mobile and immobile water zones.
• Quantifying these exchange processes in aquifers is challenging, often requiring multi-tracer experiments and mathematical modeling.
• The Single Fissure Dispersion Model (SFDM) is a common approach for dual-porosity transport but is difficult to optimize using conventional methods.

Purpose of the Study:

• To develop a rigorous optimization technique for the SFDM.
• To automatically determine hydrogeologically relevant parameters such as effective mobile and immobile porosity and diffusive mass exchange.
• To present a user-friendly software tool (OptSFDM) for SFDM optimization.

Main Methods:

• A novel scatter search optimization algorithm was developed and implemented.
• The algorithm was used to minimize the SFDM to fit experimental data.
• A graphical user interface (GUI) was created for the OptSFDM program.

Main Results:

• The scatter search method effectively optimizes the SFDM, providing accurate parameter estimations.
• The OptSFDM program with its GUI simplifies the optimization process compared to trial-and-error methods.
• Validation against previous experimental case studies demonstrated the program's usability and accuracy.

Conclusions:

• The developed scatter search optimization technique offers a robust and automated solution for SFDM parameter estimation.
• OptSFDM provides a valuable, user-friendly tool for researchers studying solute transport in dual-porosity media.
• This advancement facilitates a better understanding of contaminant transport and groundwater management in heterogeneous aquifers.