Using PHREEQC to Simulate Solute Transport in Fractured Bedrock

• Published in: Ground water Vol. 45; no. 4; pp. 468 - 472
• Main Authors: Lipson, David S, McCray, John E, Thyne, Geoffrey D
• Format: Journal Article
• Language: English
• Published: Malden, USA Malden, USA : Blackwell Publishing Inc 01.07.2007; Blackwell Publishing Inc; Ground Water Publishing Company
• Subjects: analysis; Aquifers; bedrock; Computer based modeling; computers; Flow system; Fresh Water; Fresh Water - analysis; Geochemistry; Groundwater; Models, Theoretical; Porosity; Solute movement; Solute transport; solutes; Water Movements
• ISSN: 0017-467X; 1745-6584
• DOI: 10.1111/j.1745-6584.2007.00318.x

The geochemical computer model PHREEQC can simulate solute transport in fractured bedrock aquifers that can be conceptualized as dual-porosity flow systems subject to one-dimensional advective-dispersive transport in the bedrock fractures and diffusive transport in the bedrock matrix. This article demonstrates how the physical characteristics of such flow systems can be parameterized for use in PHREEQC, it provides a method for minimizing numerical dispersion in PHREEQC simulations, and it compares PHREEQC simulations with results of an analytical solution. The simulations assumed a dual-porosity conceptual model involving advective-reactive-dispersive transport in the mobile zone (bedrock fracture) and diffusive-reactive transport in the immobile zone (bedrock matrix). The results from the PHREEQC dual-porosity transport model that uses a finite-difference approach showed excellent agreement compared with an analytical solution.