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USGS Groundwater Information

Groundwater Resources Program

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 [Photo: Groundwater flowing out of well.]

New & Noteworthy

* Press Release: Study Explores Groundwater and Geothermal Energy in Drought-Stricken Eastern Oregon and Neighboring States

* Technical Announcement: USGS Issues Revised Framework for Hydrogeology of Floridan Aquifer

* Press Release: High Plains Aquifer Groundwater Levels Continue to Decline

* Regional Groundwater Availability Study Geospatial Data

* Press Release: USGS Assesses Current Groundwater-Quality Conditions in the Williston Basin Oil Production Area

Past listings...

USGS Groundwater Watch

USGS maintains a network of active wells to provide basic statistics about groundwater levels.

 [Image: USGS active water level wells location map.]

Other Water Topics

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*  Water Quality

*  Water Use

USGS in Your State

USGS Water Science Centers are located in each state.

 [Map: There is a USGS Water Science Center office in each State.] Washington Oregon California Idaho Nevada Montana Wyoming Utah Colorado Arizona New Mexico North Dakota South Dakota Nebraska Kansas Oklahoma Texas Minnesota Iowa Missouri Arkansas Louisiana Wisconsin Illinois Mississippi Michigan Indiana Ohio Kentucky Tennessee Alabama Pennsylvania West Virginia Georgia Florida Caribbean Alaska Hawaii and Pacific Islands New York Vermont New Hampshire Maine Massachusetts South Carolina North Carolina Rhode Island Virginia Connecticut New Jersey Maryland-Delaware-D.C.

Groundwater Model Development

The USGS is at the forefront of devising new techniques to solve practical problems in the study of groundwater resources. Predictive models are needed to make informed decisions in many emerging areas related to the effects of groundwater development. New models and methods enhance all USGS water programs. State and local governments as well as groundwater scientists and engineers in the private sector regularly use USGS models as an integral part of their work.

The USGS Modular Groundwater Flow Model (MODFLOW) is the most widely used program in the world for simulating groundwater flow. The USGS developed MODFLOW in the early 1980s. The Groundwater Resources Program (GWRP) continues to support the enhancement of MODFLOW with updates that help scientists and engineers simulate common features in groundwater systems. New features have been added and the software has been updated to incorporate advancements in our understanding of groundwater hydrology, to respond to changes in user needs, and to take advantage of constantly increasing computer power and speeds.

Below are examples of and links to USGS groundwater software:

Selected USGS Groundwater Software

The software packages below are examples of key USGS groundwater software that has been developed with GWRP support.


MODFLOW-USG uses an unstructured-grid approach to simulate groundwater flow and tightly coupled processes using a control volume finite-difference formulation.

GSFLOW: Groundwater and Surface-Water Flow Model

GSFLOW is a coupled groundwater and surface-water flow model based on the USGS Precipitation-Runoff Modeling System (PRMS) and MODFLOW-2005.

GWM-2005 with LGR

Groundwater Management Model Process 2005 is a Groundwater Management Process for the USGS modular three-dimensional groundwater model, MODFLOW-2005, using optimization with local grid refinement (LGR) capability.

Farm Process (FMP)

Farm Process estimates dynamically integrated supply-and-demand components of irrigated agriculture as part of the simulation of surface-water and groundwater flow based on MODFLOW-2000 and MODFLOW-2005.


MODFLOW-LGR is a version of MODFLOW-2005 with local grid refinement.

SEAWAT: 3D Variable-Density Groundwater Flow and Transport

SEAWAT is a generic MODFLOW/MT3DMS-based computer program designed to simulate three-dimensional variable-density groundwater flow coupled with multi-species solute and heat transport.

Seawater Intrusion (SWI2) Package for MODFLOW

The SWI2 Package is the latest release of the Seawater Intrusion (SWI) Package for MODFLOW. The SWI2 Package allows 3D vertically integrated variable-density groundwater flow and seawater intrusion in coastal multiaquifer systems to be simulated using MODFLOW-2005.

SWB: A Modified Thornthwaite-Mather Soil-Water-Balance Code for Estimating Groundwater Recharge

The Soil-Water-Balance (SWB) code has been developed to allow estimates of potential recharge to be made quickly and easily. The code calculates components of the water balance at a daily timestep by means of a modified version of the Thornthwaite-Mather soil-moisture-balance approach.

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Recently Released USGS Groundwater Software RSS

USGS releases new software and updates existing software on an ongoing basis. The USGS software packages listed here are the most recent groundwater software releases and updates.

FRGT-MST v.1.0

Jun 07, 2016: FRGT-MST v.1.0 has been released. FRGT is an Excel-based tool to assist project managers in selecting the appropritate geophysical tool. This is the initial release.

MODFLOW-USG v.1.3.00

Dec 03, 2015: MODFLOW-USG v.1.3.00 has been released. MODFLOW-USG is an unstructured grid version of MODFLOW for simulating groundwater flow and tightly coupled processes using a control volume finite-difference formulation. MODFLOW-USG v1.3 added DDREFERENCE capability, similar to the capability available in MODFLOW-2005. This change, bug fixes, and other minor changes are described in release.txt.

ListingAnalyst v.1.1

Dec 03, 2015: ListingAnalyst v.1.1 has been released. ListingAnalyst is a Windows(R) program for viewing the main output file from MODFLOW-2005, MODFLOW-NWT, MODFLOW-LGR, MODFLOW-CFP, or MODFLOW-OWHM. The most significant changes are that (1) it no longer requires exclusive access to the file, (2) it handles additional versions of MODFLOW and additional packages in MODFLOW added since ListingAnalyst version 1.0 was released, and (3) it now produces both a table of contents and an index of the MODFLOW listing file.

ModelMuse v.3.6.3

Dec 03, 2015: ModelMuse v.3.6.3 has been released. ModelMuse is a graphical user interface (GUI) for MODFLOW-2005, MODFLOW-LGR, MODFLOW-LGR2, MODFLOW-NWT, MODFLOW-CFP, MODFLOW-OWHM, MT3DMS, SUTRA, PHAST, MODPATH, and ZONEBUDGET. This release includes several enhancements, changes, and bug fixes. Refer to release history for complete summary of changes.

GW_Chart v.

Dec 03, 2015: GW_Chart v. has been released. GW_Chart is a graphing application for MODFLOW, MOC3D, ZONEBUDGET, SUTRA, MT3D, HST3D. UCODE-2005, and OPR-PPR. GW_Chart also draws Piper diagrams and converts binary cell-by-cell flow files to text files. This version added display of farm budgets generated by the Farm Process in MODFLOW-OWHM. GW_Chart can not convert Zeta files that contain only a single Zeta surface. When reading formatted head or drawdown files, the procedure for reading the files can now read values written in the form 1.230000-308. Fixed bug in reading budgets data for SUTRA. Fixed bug in reading cell-by-cell budget files from MODFLOW that could cause GW_Chart to hang.

GRIDGEN v.1.00.01

Oct 30, 2015: GRIDGEN v.1.00.01 has been released. GRIDGEN is a computer program for creating layered quadtree grids for use with numerical models, such as the MODFLOW-USG program for simulation of groundwater flow. This version includes minor updates. The precision was increased for the values written to the *.nod and quadtree grid definition file. For grids that were rotated, the rotation origin was not being calculated correctly; this has been corrected. One of the folders in the previous release could not be extracted; this has been fixed.

GWToolbox v.1.1.1

Oct 27, 2015: GWToolbox v.1.1.1 has been released. The USGS Groundwater Toolbox is a graphical and mapping interface for analysis of hydrologic data. Groundwater Toolbox includes the hydrograph-analysis programs BFI, HYSEP, PART, and RORA (with RECESS). The functionality of version 1.1.1 is the same as version 1.1 The software was modified to access new locations of the data coverages on U.S. Environmental Protection Agency computers.

GSFLOW v.1.2.0

Oct 01, 2015: GSFLOW v.1.2.0 has been released. GSFLOW is a coupled Groundwater and Surface-water FLOW model based on the USGS Precipitation-Runoff Modeling System (PRMS) and Modular Groundwater Flow Model (MODFLOW-2005) . This version of GSFLOW is based on MODFLOW‐NWT version 1.0.9, MODFLOW‐2005 version 1.11.0, and PRMS version 4.0.1. Substantial enhancements were added for this version of the software, in particular the inclusion of a restart capability for GSFLOW (Regan and others, 2015) and the integration of several (but not all) of the new PRMS‐IV modules documented by Markstrom and others (2015). Refer to the release notes from a complete description of changes.

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For More Information:

Browse or download USGS MODFLOW and related programs. Additional USGS groundwater software and supporting documentation can be found through the USGS Groundwater Software web page.

You can also learn more about how the USGS continues to lead in the development and application of groundwater modeling software.

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Page Last Modified: Monday, 24-Nov-2014 21:27:07 EST