PHT3D, a three-dimensional, MODFLOW/MT3DMS-based reactive multicomponent transport model is presented. The model couples, via an operator-splitting method, the transport simulator MT3DMS (Zheng and Wang, 1998) and the geochemical package PHREEQC-2 (Parkhurst and Appelo, 1999). Through the flexible, generic nature of PHREEQC-2, PHT3D can handle a broad range of equilibrium and kinetic reactive p...

FloPy is a Python package for developing, running, and post-processing models that are part of the MODFLOW family of codes. FloPy includes support for MODFLOW-2000, MODFLOW-2005, MODFLOW-NWT, and MODFLOW-USG. Other supported MODFLOW-based models include MODPATH (version 6), MT3DMS and SEAWAT. If you think you have found a bug in FloPy, or if you would like to suggest an improvement or enhanceme...

the current study investigated and compared data generation methods for groundwater modeling. thesemethods can be divided into two classes; geostatistic and probabilistic. by comparing geostatistic methods,the best method was chosen and the hydraulic conductivity of the aquifer was generated for a study area ina grid (9-cell) format. after observing weak spatial correlation between the data, th...

The nonhorizontal-model-layer (NHML) grid system is more accurate than the horizontal-model-layer grid system to describe groundwater flow in an unconfined sloping aquifer on the basis of MODFLOW-2000. However, the finite-difference scheme of NHML was based on the Dupuit-Forchheimer assumption that the streamlines were horizontal, which was acceptable for slope less than 0.10. In this study, we...

The accuracy with which MODFLOW simulates surface water-groundwater interaction is examined for connected and disconnected losing streams. We compare the effect of different vertical and horizontal discretization within MODFLOW and also compare MODFLOW simulations with those produced by HydroGeoSphere. HydroGeoSphere is able to simulate both saturated and unsaturated flow, as well as surface wa...

As a widely used groundwater flow model, MODFLOW offers a set of packages to simulate hydrologic stresses, inflows and outflows, to a groundwater system. Specifically, MODFLOW lacks a general method to process areally distributed recharge and discharge to groundwater. One solution would be to create a new package for MODFLOW. Alternatively, it is also possible to make the best use of existing c...

Prior to using MODFLOW, students need experience with simpler codes that provide “hands-on” experience setting up boundary and initial conditions, coding simple solution algorithms, and handling numerical errors. The best way to do this is using spreadsheet models; faculty no longer can expect students to know a common computer language, but students are familiar with spreadsheets. Many aspects...

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 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...