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Modeling variably saturated multispecies reactive groundwater solute transport with MODFLOW-UZF and RT3D

Ground Water

By:
, , , and
DOI: 10.1111/j.1745-6584.2012.01009.x

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Abstract

A numerical model was developed that is capable of simulating multispecies reactive solute transport in variably saturated porous media. This model consists of a modified version of the reactive transport model RT3D (Reactive Transport in 3 Dimensions) that is linked to the Unsaturated-Zone Flow (UZF1) package and MODFLOW. Referred to as UZF-RT3D, the model is tested against published analytical benchmarks as well as other published contaminant transport models, including HYDRUS-1D, VS2DT, and SUTRA, and the coupled flow and transport modeling system of CATHY and TRAN3D. Comparisons in one-dimensional, two-dimensional, and three-dimensional variably saturated systems are explored. While several test cases are included to verify the correct implementation of variably saturated transport in UZF-RT3D, other cases are included to demonstrate the usefulness of the code in terms of model run-time and handling the reaction kinetics of multiple interacting species in variably saturated subsurface systems. As UZF1 relies on a kinematic-wave approximation for unsaturated flow that neglects the diffusive terms in Richards equation, UZF-RT3D can be used for large-scale aquifer systems for which the UZF1 formulation is reasonable, that is, capillary-pressure gradients can be neglected and soil parameters can be treated as homogeneous. Decreased model run-time and the ability to include site-specific chemical species and chemical reactions make UZF-RT3D an attractive model for efficient simulation of multispecies reactive transport in variably saturated large-scale subsurface systems.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Modeling variably saturated multispecies reactive groundwater solute transport with MODFLOW-UZF and RT3D
Series title:
Ground Water
DOI:
10.1111/j.1745-6584.2012.01009.x
Volume
51
Issue:
5
Year Published:
2013
Language:
English
Publisher:
Wiley
Contributing office(s):
Nevada Water Science Center
Description:
15 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Ground Water
First page:
752
Last page:
761
Number of Pages:
10