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Modeling Software

The USGS has been a leader in the development of hydrologic and geochemical simulation models since the 1960's. USGS models are widely used to predict responses of hydrologic systems to changing stresses, such as increases in precipitation or ground-water pumping rates, as well as to predict the fate and movement of solutes and contaminants in water. Today, many USGS models are available for free on the Internet.

Coupled Ground Water and Surface Water Flow Model (GSFLOW)

Screenshot from GSFLOW output.Ground-water and Surface-water FLOW (GSFLOW) was developed to simulate coupled ground-water and surface-water resources. The model is based on the integration of the U.S. Geological Survey Precipitation-Runoff Modeling System (PRMS) and the U.S. Geological Survey Modular Ground-Water Flow Model (MODFLOW).

Visit the GSFLOW website for more information and to download the software.

The Global Climate Change Viewer

Screenshot from The Global Climate Change Viewer.The Global Climate Change Viewer (GCCV) is used to visualize future temperature and precipitation changes simulated by global climate models in the Coupled Model Intercomparison Project Phase 5 (CMIP5). The application allows the user to visualize projected climate change (temperature and precipitation) for each country, for all available models and all Representative Concentration Pathways (RCP) emission scenarios (2.6, 4.5, 6.0 and 8.5).

Visit the GCCV website for more information, or access the GCCV web application directly.


Screenshot from HYDROTHERM.The HYDROTHERM computer program simulates multi-phase ground-water flow and associated thermal energy transport in three dimensions. It can handle high fluid pressures, up to 1 x 109 Pa (104 atm), and high temperatures, up to 1,200 °C.

Visit the HYDROTHERM site for more information and to download the software.


Screenshot from ModelMuse.ModelMuse is a graphical user interface (GUI) for the U.S. Geological Survey (USGS) models MODFLOW-2005, MODFLOW-LGR, MODFLOW-NWT, MODPATH, ZONEBUDGET, and PHAST and for MT3DMS. This software package provides a GUI for creating the flow and transport input file for PHAST and the input files for MODFLOW-2005. In ModelMuse, the spatial data for the model are independent of the grid, and the temporal data are independent of the stress periods. Being able to input these data independently allows the user to redefine the spatial and temporal discretization at will. This report describes the basic concepts required to work with ModelMuse. These basic concepts include the model grid, data sets, formulas, objects, the method used to assign values to data sets, and model features.

Visit the ModelMuse site for more information and to download the software.


Screenshot from MODFLOW-NWT.MODFLOW-NWT, a Newton Formulation for MODFLOW-2005, is a standalone program that is intended for solving problems involving drying and rewetting nonlinearities of the unconfined groundwater-flow equation. MODFLOW-NWT must be used with the Upstream-Weighting (UPW) Package for calculating intercell conductances in a different manner than is done in the Block-Centered Flow (BCF), Layer Property Flow (LPF), or Hydrogeologic-Unit Flow (HUF; Anderman and Hill, 2000) Packages.

Visit the MODFLOW-NWT site for more information and to download the software.

Multidimensional Surface-Water Modeling System

Screenshot from The Multidimensional Surface-Water Modeling System.The U.S. Geological Survey’s (USGS) Multi-Dimensional Surface-Water Modeling System (MD_SWMS) is a pre- and post-processing application for computational models of surface-water hydraulics. The system is both a tool and framework that provides an easy to use interface to a variety of environmental hydraulic models.

Visit the Multidimensional Surface-Water Modeling System website for more information and to download the software.


Screenshot from PHAST.PHAST is a 3D groundwater flow and solute transport model that has extensive capabilities to simulate water-rock and biogeochemical reactions that include all of the reactions available in PHREEQC. Simulations of reactive-transport of are useful for studies of naturally occurring toxic substances, such as selenium and arsenic, and anthropogenic organic and inorganic contaminant plumes. Phast4Windows is a Windows-based, intuitive, 3D graphical user interface for defining model features and execution of PHAST.

Visit the PHAST web site for more information and to download the software.


Screenshot from PHREEQC.PHREEQC is a general purpose geochemical model for reactions in water and between water and rocks and sediments. Reactions include aqueous equilibria, mineral dissolution and precipitation, ion exchange, surface complexation, solid solutions, gas-water equilibrium, and kinetic biogeochemical reactions. PHREEQC has been applied to regional aquifer studies, nuclear waste disposal, carbon sequestration, acid mine drainage, and a multitude of other environments as diverse as paper making, concrete science, and dental research. IPhreeqc and IPhreeqcCOM are interfaces that allow PHREEQC to be implemented in other software. PhreeqcI is a Windows-based user interface that allows defining input, running simulations, and plotting results.

Visit the PHREEQC web site for more information and to download the software.

Precipitation Runoff Modeling System (PRMS)

Screenshot from PRMS manual.The Precipitation-Runoff Modeling System (PRMS) is a deterministic, distributed-parameter, physical process based modeling system developed to evaluate the response of various combinations of climate and land use on streamflow and general watershed hydrology.

Visit the PRMS website for more information and to download the software.


Screenshot from VS2DI.The VS2DI package contains all the tools that a user needs to create, run, and view results for a simulation of flow and transport through variably saturated porous media. The package seamlessly integrates a graphical user interface - within which the user can draw the simulated domain and enter or modify model parameters - with existing USGS models of flow and solute transport, and a postprocessor that displays simulation results.

Visit the VS2DIweb site for more information and to download the software.

Water, Energy, and Biogeochemical Model (WEBMOD)

Water flow diagram from WEBMOD.The Water, Energy, and Biogeochemical Model (WEBMOD) uses the framework of the U.S. Geological Survey (USGS) Modular Modeling System (MMS) to simulate fluxes of water and solutes through watersheds. WEBMOD divides watersheds into model response units (MRU) where fluxes and reactions are simulated for the following eight hillslope reservoir types: canopy; snowpack; ponding on impervious surfaces; O-horizon; two reservoirs in the unsaturated zone, which represent preferential flow and matrix flow; two reservoirs in the saturated zone, which also represent preferential flow and matrix flow.

Visit the WEBMOD site for more information and to download the software.

You can obtain more software at, including general-use, water quality and chemistry, groundwater, statistics and graphics, and surface water applicaitons.

Software and related material (data and documentation) are made available by the U.S. Geological Survey (USGS) to be used in the public interest and the advancement of science. You may, without any fee or cost, use, copy, modify, or distribute the software, and any derivative works thereof, and its supporting documentation, subject to the USGS software User's Rights Notice.