SWB — A Modified Thornthwaite-Mather Soil-Water-Balance
Code for Estimating Groundwater Recharge
The Soil-Water-Balance 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. Data
requirements include several commonly available tabular and
gridded data types:
|(1) precipitation, and minimum and maximum air
||Tabular or gridded
|(2) land-use classification
|(3) hydrologic soil group
|(4) flow direction
|(5) soil-water capacity
The data and formats required are designed to take advantage
of widely available GIS datasets and file structures.
Information and Downloads
User Guides and Technical Information
Westenbroek, S.M., Kelson, V.A., Dripps, W.R., Hunt, R.J., and
Bradbury,K.R., 2010, SWB-A modified Thornthwaite-Mather
Soil-Water-Balance code for estimating groundwater recharge:
U.S. Geological Survey
Techniques and Methods 6-A31, 60 p.
Complete documentation of the SWB source code may be found at:
Supported Computing Platforms and Source Code
SWB is known to run on Windows (XP/7) and Linux platforms.
There should be no problems running the code on Macintosh
hardware, but this has not been attempted by the authors.
The SWB code is written entirely in Fortran 95/2003. Compilation
of the code has been routinely accomplished using the G95,
gfortran, and Intel Fortran compilers.
Point of Contact
Support is provided for correcting bugs and clarification of
how the code is intended to work. Only limited assistance can be
provided for applying SWB to specific problems. For support or
comments regarding this site contact:
U.S. Geological Survey
8505 Research Way
Middleton, WI 53562
Software User Rights Notice
This software, documentation, and example data sets are made
available by the U.S. Geological Survey (USGS) to be used in the
public interest and in the advancement of science. You may,
without any fee or cost, use, copy, modify, or distribute this
software, and any derivative works thereof, and its supporting
documentation, subject to the restrictions and understandings
found at: http://water.usgs.gov/software/help/notice/