abstract
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Development of an Open Source GIS Interface to the USDA Soil and Water Assessment Tool (SWAT) Jeyakanthan (Jey) Veluppillai 1 , Daniel P Ames 2 , Raghavan ("Srini") Srinivasan 3. Abstract - PowerPoint PPT PresentationTRANSCRIPT
Abstract The Soil and Water Assessment Tool (SWAT) is a physically-based watershed and landscape
simulation model developed by the USDA-ARS and particularly suited to non-point source
pollutant analysis. The Idaho State University Geospatial Software Lab is developing an
interface to SWAT using MapWindow GIS which is a free and open source product that can
be redistributed to modelers, developers, and end-users free of charge.
Introduction OpenSWAT is free and open source software (FOSS) plug-in for the existing MapWindow
GIS desktop application (www.mapwindow.org). The main purpose of OpenSWAT is to
perform watershed modeling and analysis tasks using an automated software toolkit. The
main components of OpenSWAT are; project setup, automatic watershed delineation, land
use and land cover definition, soil definition, slope definition, and weather data definition.
MethodsOpenSWAT is dependant on the existing desktop MapWindow GIS application and the development
is purely based on Microsoft products. MS VB.Net is the language used to develop the graphical user
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.
parameter sensitivity analysis) can be done using the SWAT Editor tool which was developed by
Texas A&M University. SWAT Editor is launched from the OpenSWAT toolbar. Conclusions and DiscussionThe input raw data sets for OpenSWAT can be automatically or manually retrieved from many
different online and other sources. OpenSWAT supports a large number of raster and vector
data formats, although most of the underlying processes use raster grids. MapWindow GIS has
proven to be a suitable GIS platform for an open source implementation of SWAT because it
supports all of the required data formats and necessary operations. It is expected that this effort
will result in a tool that can be used throughout the world because it does not require license
fees.
Root Zone
Shallow (unconfined) Aquifer
Vadose (unsaturated) Zone
Confining Layer
Deep (confined) Aquifer
Precipitation
Evaporation and Transpiration
Infiltration/plant uptake/ Soil moisture redistribution
Surface Runoff
Lateral Flow
Return Flow
Revap from shallow aquifer
Percolation to shallow aquifer
Recharge to deep aquifer
Flow out of watershed
Hydrologic Balance
Stream Flow (m3/s)(2005)
0.00E+00
1.00E-02
2.00E-02
3.00E-02
4.00E-02
5.00E-02
6.00E-02
0 50 100 150 200 250 300 350 400
Days
Str
eam
flo
w (
m3/s
)
Stream Flow (m3/s)
Stream Flow (2006)
0.00E+00
5.00E+01
1.00E+02
1.50E+02
2.00E+02
2.50E+02
3.00E+02
3.50E+02
0 50 100 150 200 250
Days
Str
eam
flo
w (
m3/s
)
Stream Flow (2006)
NO3 (mg/L)
0.00E+00
5.00E-01
1.00E+00
1.50E+00
2.00E+00
2.50E+00
3.00E+00
3.50E+00
4.00E+00
4.50E+00
0 50 100 150 200 250 300 350 400
Time (days)
Co
n (
mg
/l)
NO3mg/L
2.) Primary Advisor
Dr. Daniel P Ames
Idaho State University
Geospatial Software Laboratory, Idaho Falls, Idaho
3.) Mentor
Dr. Raghavan ("Srini") Srinivasan
Texas A&M University and Texas Agricultural Experiment Station
Department of Biological and Agricultural Engineering
Results and Sample OutputThe major outputs of OpenSWAT are stored in the form of raster grids, MS Access database
tables, and text files. Example raster operation outputs are shown in the figure below, including
delineated watersheds, soil definitions, etc. The next important form of OpenSWAT output is
reports, in the end of each and every raster operation OpenSWAT produces specific watershed
reports used for evaluation of land use, and ultimately streamflow and water quality in the
watershed.
The hydrological life cycle of OpenSWAT
MapWindow GIS Application and a sample project
The important steps involved in OpenSWAT Modeling
Project Setup Window of OpenSWAT
Land Use Definition Window of OpenSWAT
Watershed Delineation Window of OpenSWAT
HRU Definition Window of OpenSWAT
Delineated Watershed
After Land Use Definition After Slope Definition
Delineated Watershed with IDs
Final Output
After Soil Definition
Sample simulation output results
MapWindow GIS Based BASINS (BASINS 4.0)
1.) Graduate Student
Veluppillai (“Jey") Jeyakanthan
Idaho State University
Geospatial Software Laboratory, Idaho Falls, Idaho
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
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