FloPy: Python Package for Creating, Running, and Post-Processing MODFLOW-Based Models

Release Date:

Overview of FloPy

Map from FloPy showing water information for the San Pedro River Basin.

FloPy generated map showing the computed capture fraction of water from head‐dependent boundaries as a function of well location in the Upper San Pedro Basin model layer corresponding to the lower basin fill after 10 years of pumpage. The maximum areal extent of the active model domain and the location of stream boundary conditions in all model layers are also shown.

FloPy is a Python package for creating, running, and post-processing MODFLOW-based models. FloPy includes support for MODFLOW-2000MODFLOW-2005, MODFLOW-NWTMODFLOW-USG, and MODFLOW-LGR. Other supported MODFLOW-based models include MODPATH (version 6), MT3DMT3D-USGS, and SEAWAT.

The most recent provisional (development) version of FloPy and supporting information can be found on the GitHub website, where users can also submit code issues or questions.


Download Current Version of FloPy

FloPy Installation

FloPy can be installed using the Python pip utility. To install the FloPy version distributed from this website, open a command line terminal and enter

pip install https://water.usgs.gov/water-resources/software/FloPy/flopy-3.2.9.zip

If FloPy is already installed on your computer, then type the following command from a terminal window to upgrade to the current version:

pip install https://water.usgs.gov/water-resources/software/FloPy/flopy-3.2.9.zip --upgrade

FloPy requires Python 2.7 or Python 3.3 (or higher). The FloPy software is dependent on a number Python packages. The list of these dependencies can be found on the FloPy GitHub site.


Documentation for FloPy

Bakker, M., Post, V., Langevin, C. D., Hughes, J. D., White, J. T., Starn, J. J. and Fienen, M. N., 2016, Scripting MODFLOW model development using Python and FloPy: Groundwater, doi:10.1111/gwat.12413

FloPy documentation on GitHub

FloPy tutorial on GitHub


Find MODFLOW-Related Software

Visit the MODFLOW and Related Programs page for a list of MODFLOW-related software.


How to Cite FloPy

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 FloPy

Bakker, M., Post, V., Langevin, C. D., Hughes, J. D., White, J. T., Starn, J. J. and Fienen, M. N., 2016, Scripting MODFLOW model development using Python and FloPy: Groundwater, doi:10.1111/gwat.12413

Software/Code Citation for FloPy v3.2.9

Bakker, M., Post, V., Langevin, C.D., Hughes, J.D., White, J.T., Starn, J.J., and Fienen, M.N., 2018, FloPy v3.2.9: U.S. Geological Survey Software Release, 19 February 2018, http://dx.doi.org/10.5066/F7BK19FH


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 (https://creativecommons.org/publicdomain/zero/1.0/ ).



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.