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Water Software > Groundwater Software > MODFLOW and Related Programs > MODFLOW-2005

MODFLOW-2005: USGS three-dimensional finite-difference ground-water model

Overview of MODFLOW-2005

[Image: Cover of software documentation report. ]

Note: MODFLOW 6 is presently the core MODFLOW version distributed by the USGS, but MODFLOW-2005 (the previous core version) is still actively maintained and supported.

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.

MODFLOW-2005, v. 1.12.00

The current version of MODFLOW-2005 is v.1.12.00, released February 3, 2017. 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.

Note: Click on a column header to sort the table by that column.

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 Fenske 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]

Previous Core Versions

See a list of previous core versions of MODFLOW, with links to download.

How to Cite

This USGS software has two citations associated with it.

  1. The report citation is for the original report or article documenting the underlying theory, methods, instructions, and (or) applications at the time the initial version of the software was released. This digital object identifier (DOI) is for the report.
  2. The software release citation is for the software/code itself (now referred to by USGS as a "Software Release") and references a specific version of the code and associated release date. This DOI links to the code.

In instances where an author is citing use of this software, it would be appropriate to cite both the report documenting the code and the specific software release version that was used.

Report Citation for MODFLOW-2005

Harbaugh, A.W., 2005, MODFLOW-2005, the U.S. Geological Survey modular ground-water model -- the Ground-Water Flow Process: U.S. Geological Survey Techniques and Methods 6-A16.

Software/Code Citation for MODFLOW-2005 v1.12.00

Harbaugh, A.W., Langevin, C.D., Hughes, J.D., Niswonger, R.N., and Konikow, L. F., 2017, MODFLOW-2005 version 1.12.00, the U.S. Geological Survey modular groundwater model: U.S. Geological Survey Software Release, 03 February 2017,

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, 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

This software has been approved for release by the U.S. Geological Survey (USGS). Although the software has been subjected to rigorous review, the USGS reserves the right to update the software as needed pursuant to further analysis and review. No warranty, expressed or implied, is made by the USGS or the U.S. Government as to the functionality of the software and related material nor shall the fact of release constitute any such warranty. Furthermore, the software is released on condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from its authorized or unauthorized use. Also refer to the USGS Water Resources Software User Rights Notice for complete use, copyright, and distribution information.

Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

See also, USGS policy on linking to non-Federal web sites.

Software License and Purchase Information

This software is a product of the U.S. Geological Survey, which is part of the U.S. Government.


This software is freely distributed. There is no fee to download and (or) use this software.


Users do not need a license or permission from the USGS to use this software. Users can download and install as many copies of the software as they need.

Public Domain:

As a work of the United States Government, this USGS product is in the public domain within the United States. You can copy, modify, distribute, and perform the work, even for commercial purposes, all without asking permission. Additionally, USGS waives copyright and related rights in the work worldwide through CC0 1.0 Universal Public Domain Dedication ( [Link exits USGS]).

Note: Some or all of this information is presented in Portable Document Format (PDF); the latest version of Adobe Reader or similar software is required to view it. Download the latest version of the free Adobe Reader from the Adobe web site. [Link exits USGS] Visit [Link exits USGS] for free tools that allow visually impaired users to read PDF files.

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Page Last Modified: Thursday, 10-Aug-2017 10:58:20 EDT