Transcript Slide 1

Development of an Open Source GIS Interface to the
USDA Soil and Water Assessment Tool (SWAT)
Jeyakanthan (Jey) Veluppillai1, Daniel P Ames2, Raghavan ("Srini") Srinivasan3
Abstract
Results and Sample Output
The Soil and Water Assessment Tool (SWAT) is a physically-based watershed and landscape
The major outputs of OpenSWAT are stored in the form of raster grids, MS Access database
simulation model developed by the USDA-ARS and particularly suited to non-point source
tables, and text files. Example raster operation outputs are shown in the figure below, including
pollutant analysis. The Idaho State University Geospatial Software Lab is developing an
delineated watersheds, soil definitions, etc. The next important form of OpenSWAT output is
interface to SWAT using MapWindow GIS which is a free and open source product that can
reports, in the end of each and every raster operation OpenSWAT produces specific watershed
be redistributed to modelers, developers, and end-users free of charge.
reports used for evaluation of land use, and ultimately streamflow and water quality in the
watershed.
Hydrologic Balance
Evaporation and
Transpiration
Precipitation
The important steps involved in OpenSWAT Modeling
Root Zone
Infiltration/plant uptake/ Soil moisture
redistribution
Lateral Flow
Vadose
(unsaturated) Zone
Shallow (unconfined)
Aquifer
Surface Runoff
Revap from shallow
aquifer
Percolation to shallow
aquifer
Flow out of watershed
Delineated Watershed
Delineated Watershed with IDs
After Soil Definition
Return Flow
Confining Layer
Deep (confined)
Aquifer
Methods
OpenSWAT is dependant on the existing desktop MapWindow GIS application and the development
Recharge to
deep aquifer
is purely based on Microsoft products. MS VB.Net is the language used to develop the graphical user
The hydrological life cycle of OpenSWAT
interfaces and Microsoft Access is the database management system used to store the output and input
data sets. Many GIS operations can be done with the aid of OpenSWAT including automatic
watershed delineation, soil definition, land used land cover definition, reclassification, slope
definition, and weather data definition. Simulation, calibration and other advanced operations (e.g.
Introduction
After Land Use Definition
After Slope Definition
Final Output
parameter sensitivity analysis) can be done using the SWAT Editor tool which was developed by
OpenSWAT is free and open source software (FOSS) plug-in for the existing MapWindow
Conclusions and Discussion
GIS desktop application (www.mapwindow.org). The main purpose of OpenSWAT is to
The input raw data sets for OpenSWAT can be automatically or manually retrieved from many
perform watershed modeling and analysis tasks using an automated software toolkit. The
different online and other sources. OpenSWAT supports a large number of raster and vector
main components of OpenSWAT are; project setup, automatic watershed delineation, land
data formats, although most of the underlying processes use raster grids. MapWindow GIS has
use and land cover definition, soil definition, slope definition, and weather data definition.
proven to be a suitable GIS platform for an open source implementation of SWAT because it
Texas A&M University. SWAT Editor is launched from the OpenSWAT toolbar.
supports all of the required data formats and necessary operations. It is expected that this effort
Project Setup Window of OpenSWAT
Watershed Delineation Window of OpenSWAT
will result in a tool that can be used throughout the world because it does not require license
fees.
Stream Flow (m3/s)
(2005)
Stream Flow (2006)
NO3 (mg/L)
3.50E+02
6.00E-02
4.50E+00
3.00E+02
4.00E+00
5.00E-02
3.50E+00
2.50E+02
Stream Flow (m3/s)
3.00E+00
2.00E+02
Stream Flow (2006)
1.50E+02
2.00E-02
Con (mg/l)
3.00E-02
Stream flow (m3/s)
Stream flow (m3/s)
4.00E-02
2.50E+00
NO3mg/L
2.00E+00
1.50E+00
1.00E+02
1.00E+00
1.00E-02
MapWindow GIS Application and a sample project
MapWindow GIS Based BASINS (BASINS 4.0)
Land Use Definition Window of OpenSWAT
5.00E+01
HRU Definition Window of OpenSWAT
5.00E-01
0.00E+00
0.00E+00
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1.) Graduate Student
Veluppillai (“Jey") Jeyakanthan
Idaho State University
Geospatial Software Laboratory, Idaho Falls, Idaho
[email protected]
2.) Primary Advisor
Dr. Daniel P Ames
Idaho State University
Geospatial Software Laboratory, Idaho Falls, Idaho
[email protected]
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Sample simulation output results
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Tim e (days)
3.) Mentor
Dr. Raghavan ("Srini") Srinivasan
Texas A&M University and Texas Agricultural Experiment Station
Department of Biological and Agricultural Engineering
[email protected]