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Water Software > Groundwater Software > MODFLOW and Related Programs > MODFLOW

MODFLOW: USGS three-dimensional finite-difference ground-water model

Overview of MODFLOW

[Image: Cover of software documentation report. ]

MODFLOW is a three-dimensional (3D) finite-difference groundwater model that was first published in 1984. It has a modular structure that allows it to be easily modified to adapt the code for a particular application. Many new capabilities have been added to the original model. MODFLOW-2005 is the most current release of MODFLOW.

MODFLOW-2005 (Harbaugh, 2005) simulates steady and nonsteady flow in an irregularly shaped flow system in which aquifer layers can be confined, unconfined, or a combination of confined and unconfined. Flow from external stresses, such as flow to wells, areal recharge, evapotranspiration, flow to drains, and flow through river beds, can be simulated. Hydraulic conductivities or transmissivities for any layer may differ spatially and be anisotropic (restricted to having the principal directions aligned with the grid axes), and the storage coefficient may be heterogeneous. Specified head and specified flux boundaries can be simulated as can a head dependent flux across the model's outer boundary that allows water to be supplied to a boundary block in the modeled area at a rate proportional to the current head difference between a "source" of water outside the modeled area and the boundary block.


Current Version: MODFLOW-2005, v. 1.11.00

The current version of MODFLOW-2005 is v.1.11.00, released August 8, 2013. For a complete explanation of the changes in this release and a history of past releases, refer to:

Downloads and Documentation

Software Downloads

Note: Users are encouraged to read the documents that are provided in the 'doc' directory of this software distribution.

Documentation of MODFLOW-2005

Documentation of MODFLOW Processes and Packages

The table below provides quick access to the key documentation for MODFLOW processes and packages:

  • Report: The official USGS report describes the theory and input instructions at the time the package or process was first released.
  • Online Guide: Packages and processes often evolve over time. The Online MODFLOW User's Guide includes the most up-to-date input instructions and related details.

Functionality Package or Process Name Online Guide Report
BAS Basic Package BAS Online Help Harbaugh, 2005
BCF Block-Centered Flow Package BCF Online Help Harbaugh, 2005
LPF Layer-Property Flow Package LPF Online Help Harbaugh, 2005
HFB Horizontal Flow Barrier Package HFB Online Help Harbaugh, 2005
CHD Time-Variant Specified-Head Option CHD Online Help Harbaugh, 2005
RIV River Package RIV Online Help Harbaugh, 2005
DRN Drain Package DRN Online Help Harbaugh, 2005
WEL Well Package WEL Online Help Harbaugh, 2005
GHB General Head Boundary Package GHB Online Help Harbaugh, 2005
RCH Recharge Package RCH Online Help Harbaugh, 2005
EVT Evapotranspiration Package EVT Online Help Harbaugh, 2005
SIP Strongly Implicit Procedure Package SIP Online Help Harbaugh, 2005
PCG Preconditioned-Conjugate Gradient Package PCG Online Help Harbaugh, 2005
DE4 Direct Solver DE4 Online Help Harbaugh, 2005
STR Stream Package STR Online Help Prudic, 1989
FHB Flow and Head Boundary Package FHB Online Help Leake and Lilly, 1997
IBS Interbed Storage Package IBS Online Help Leake and Prudic, 1991
GMG Geometric MultiGrid Solver Package GMG Online Help Wilson and Naff, 2004
HUF Hydrogeologic-Unit Flow Package HUF Online Help Anderman and Hill, 2000; Anderman and others, 2002; and Anderman and Hill, 2003
MNW1 Version 1 of Multi-Node Well Package MNW1 Online Help Halford and Hanson, 2002
MNW2 Version 2 of the Multi-Node Well Package MNW2 Online Help Konikow and others, 2009
ETS Evapotranspiration with a Segmented Function Package ETS Online Help Banta, 2000
DRT Drains with Return Flow Package DRT Online Help Banta, 2000
RES Reservoir Package RES Online Help Fenseke and others, 1996
SUB Subsidence Package SUB Online Help Hoffman and others, 2003
OBS Observation Process OBS Online Help Hill and others, 2000
SFR Streamflow-Routing Package SFR Online Help Prudic and others, 2004; and Niswonger and Prudic, 2005
LAK Lake Package LAK Online Help Merritt and Konikow, 2000
UZF Unsaturated Zone Package UZF Online Help Niswonger and others, 2006
GAG Gage Package GAG Online Help Prudic and others, 2004; Niswonger and Prudic, 2005; and Merritt and Konikow, 2000
SWT Subsidence and Aquifer-System Compaction Package for Water-Table Aquifers SWT Online Help Leake and Galloway, 2007
LMT Link to the MT3DMS contaminant-transport model LMT Online Help Zheng and others, 2001
HYDMOD Hydrograph capability HYDMOD Online Help Hanson and Leake, 1999
PCGN Preconditioned Conjugate Gradient solver with improved nonlinear control PCGN Online Help Naff and Banta, 2008
SWI2 Seawater Intrusion Package SWI2 Online Help Bakker and others, 2013; and 
SWI2 Example Problems [66MB ZIP]

Superseded Versions

The following software is not actively supported by the USGS. The software has been superseded by MODFLOW-2005. The software versions below are provided online for historical reference only, and the pages may contain outdated information or broken links.

Point of Contact

Support is provided for correcting bugs and clarification of how MODFLOW-2005 is intended to work. Only limited assistance can be provided for applying MODFLOW-2005 to specific problems by contacting the point of contact listed below:

U.S. Geological Survey
Office of Groundwater
411 National Center
12201 Sunrise Valley Drive
Reston, VA 20192

Other USGS Groundwater Software

The USGS develops groundwater RSS, water-quality, surface-water, and other water-resources software for use by the USGS in fulfilling its mission. Most of this software is available online for download at no charge.

Disclaimers and Notices

Please refer to the USGS Software User Rights Notice for complete use, copyright, and distribution information. The USGS provides no warranty, expressed or implied, as to the correctness of the furnished software or the suitability for any purpose. The software has been tested, but as with any complex software, there could be undetected errors. Users who find errors are requested to report them to the USGS.

References to non-USGS products, trade names, and (or) services are provided for information purposes only and do not constitute endorsement or warranty, express or implied, by the USGS, U.S. Department of Interior, or U.S. Government, as to their suitability, content, usefulness, functioning, completeness, or accuracy.


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Page Last Modified: Friday, 21-Mar-2014 18:17:55 EDT