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Kansas Geological Survey, Open-file Report 99-25


Documentation of a combined watershed and stream-aquifer modeling program based on Swat and Modflow

Vol. 2, Added or modified source code

by Samuel P. Perkins and Marios Sophocleous

KGS Open File Report 99-25
June 1999, revised Jan. 7, 2000
[Note: Users' manual available as Open-file Rept. 99-24.]

Coordination of Swat and Modflow: program organization

Swat and Modflow are coordinated either by independent execution with data transfer by file, or by linked execution in which data are passed between programs by reference to arrays in subroutine argument lists. Two sets of subroutines, one for Swat and one for Modflow, were developed for this purpose. On Swat's side, subroutine Preswb was written to provide necessary conversions of Swat's results for use in Modflow. A companion program, Swbavg, provides a way to combine results from Swat to represent spatial heterogeneities existing within the watershed by calculating are ally weighted averages of "hydrologic response units" (HRUs), i.e. the various areal components of the watershed with respect to soil type, land use, and management practices. On Modflow's side, a set, or "package" of subroutines referred to as Modswb, was written to make use of Swat's watershed simulations. In addition, Modflow's standard Well and Stream packages have been modified to accommodate the SwatModflow (or Potyldr-Modflow) linkage and to incorporate some extensions of those models. Other packages have been written for Modflow essentially to streamline the analysis of results. These include Modrsd, to analyze water level residuals, and Modpost, to provide some post-processing capabilities that bypass the intermediate steps of writing Modflow's standard output file and then extracting results of interest from that file.

The complete text of this report is available as an Adobe Acrobat PDF file.

OFR 99-25 (Adobe Acrobat, 1.9 MB)


Kansas Geological Survey, Geohydrology
Placed online Jan. 31, 2019
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