Accurate representation of groundwater-surface water interactions is critical to modeling low river flow periods in riparian environments in the semi-arid southwestern United States. A link between the objectoriented decision support model RiverWare and MODFLOW was developed to incorporate critical features such as riparian evapotranspiration, localized variations in seepage rates, irrigation r...

Introduction MT3DMS is a three-dimensional (3D) multispecies contaminant transport model with a modular structure to permit simulation of solute transport processes independently or jointly (Zheng and Wang 1999; Zheng 2009). MT3DMS interfaces directly with the U.S. Geological Survey’s finite-difference ground water flow model, MODFLOW, for the flow solution, and supports all the hydrologic and ...

Introduction The development and application of ground-water models has been an important component of USGS hydrologic investigations since the early 1970s. During the past 35 years, the USGS has developed a wide range of computer models to simulate saturated and unsaturated subsurface flow, solute transport, and chemical reactions. The most widely used of these programs is the MODFLOW model, w...

Groundwater monitoring and water level predictions have been a challenging issue due to the complexity of groundwater movement. Simplified numerical simulation models used represent system; these however only provide conservative approximation system may not always capture local variations. Several other efforts such as coupling with hydrological using geostatistical methods are being practiced...

A ground-water flow and transport model simulating contaminant movement to public supply wells in the High Plains aquifer near York, Nebraska was developed as part of the U.S. Geological Survey National Water-Quality Assessment Program. Water-quality samples were collected from wells screened in unconfined and confined units. Samples collected from a public supply well and selected monitoring w...

MOC3D is a general-purpose computer model developed by the U.S. Geological Survey (USGS) for simulation of three-dimensional solute transport in ground water (Konikow and others, 1996). The model is an update to the widely used USGS two-dimensional solutetransport model (MOC) and is implemented as an optional “package” for the ground-water flow model MODFLOW (Harbaugh and McDonald, 1996). Direc...

This paper presents an approach for coupling MODFLOW and MT3DMS for the simulation of variable-density ground water flow. MODFLOW routines were modified to solve a variable-density form of the ground water flow equation in which the density terms are calculated using an equation of state and the simulated MT3DMS solute concentrations. Changes to the MODFLOW and MT3DMS input files were kept to a...

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FRACK is a fractured media freeware flow and solute transport suite currently under development that is intended to serve as both a preand post-processor to MODFLOW. As a pre-processor, FRACK generates and maps networks of deterministic and/or stochastic fractures onto a regularly-spaced finitedifference grid, according to a fracture continuum method that closely approximates flow solutions to ...

This paper describes a combined field, laboratory, and numerical study of electromagnetic borehole flowmeter measurements acquired without the use of a packer or skirt to block bypass flow around the flowmeter. The most significant finding is that inflow through the wellbore screen changes the ratio of flow through the flowmeter to wellbore flow. Experiments reveal up to a factor of two differe...