A new high-performance numerical model (Frehg) is developed to simulate water flow in shallow coastal wetlands. Frehg solves the 2D depth-integrated, hydrostatic, Navier–Stokes equations (i.e., shallow-water equations) surface domain and 3D variably-saturated Richards equation subsurface domain. The two domains are asynchronously coupled surface-subsurface exchange. applied evaluate sensitivity...

Benchmarking coupled surface-subsurface flow models becomes more important as they are increasingly used for operational purposes (e.g. in water management) and long-term analysis (e.g. in climate change research). For this reason we inter-compare the hydrogeological models HydroGeoSphere and OpenGeoSys and present results with emphasis on the parametrization of the surface-soil water coupling ...

Reactive fluid flow and geochemical transport in unsaturated fractured rocks have received increasing attention for studies of contaminant transport, groundwater quality, waste disposal, acid mine drainage remediation, mineral deposits, sedimentary diagenesis, and fluid-rock interactions in hydrothermal systems. This paper presents methods for modeling geochemical systems that emphasize: (1) in...

Early stochastic studies focused on steady-state, gravity-dominated unsaturated flow in unbounded domains In this study, on the basis of the van Genuchten–Mualem constitu(e.g., Yeh et al., 1985a,b; Russo, 1993, 1995a,b; Yang et tive relationship, we develop a general nonstationary stochastic model for transient, variably saturated flow in randomly heterogeneous meal., 1996; Zhang et al., 1998; ...

One possible way of integrating subsurface flow and transport processes with (bio)geochemical reactions is to couple by means of an operator-splitting approach two completely separate codes, one for variably-saturated flow and solute transport and one for equilibrium and kinetic biogeochemical reactions. This paper evaluates the accuracy of the operator-splitting approach for multicomponent sys...

A relatively simple method of characteristics is developed to simulate onedimensional variably saturated water flow. The method uses the Eulerian-Lagrangian approach to separate the governing flow equation into “convection” and “diffusion” parts, which are solved with the method of characteristics and the conventional finite element method, respectively. The method of characteristics combines a...

Electrical Resistivity Tomography (ERT) is increasingly used to investigate moisture distribution in Municipal Waste Landfills, especially when leachate is injected in waste to enhance its biodegradation. It is proposed here to theoretically assess the quality of ERT mapping, using COMSOL Multiphysics' simulations of both hydrodynamical and geophysical aspects. Leachate injection is simulated u...