EPA/600/C-13/148
                                                                                                  ARS/296053
                                    The Automated Geospatial
                                    Watershed Assessment Tool  Version 3.0
Planning and assessment in land and water resource management are evolving from simple, local-scale problems toward
complex, spatially-explicit, regional ones. Such problems have to be  addressed with distributed models that can compute
runoff  and erosion at different spatial and temporal scales. The extensive data requirements and the difficult task of
building input parameter files, however, have long represented an obstacle to the timely and cost-effective  use of such
complex models by resource managers.
                                               Q Untilfed - ArcMap
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                                                                                              EPA/600/C-13/148
                                                                                                   ARS/296053
t practices on water, sediment and agricultural chemical yields in large, complex watersheds with varying soils, land use and
management conditions over long periods of time (> 1 year). SWAT is a continuous-simulation model, i.e. a long-term yield
model, using daily average input values, and is not designed to simulate detailed, single-event flood  routing.  For more
information on SWAT, please visit www.brc.tamus.edu/swat.
AGWA DESCRIPTION  AND USES
Using digital data in combination with the automated functionality of
AGWA greatly reduces the time  required to  use these two watershed
models. Through  a  robust and  intuitive interface the user selects an
outlet from which AGWA delineates and discretizes the watershed using
Digital  Elevation Model (DEM) information. The watershed elements are
then intersected with soil, land-use/cover, and precipitation (uniform or
distributed) data layers to derive the requisite model input parameters.
The model is then run, and the results are imported back into AGWA for
visual display.

Model  outputs that can be displayed in AGWA are shown in the table to
the right. This feature allows managers to identify problem areas for
further monitoring and management activities.  Additional functionality
can generate alternative future  land-use/cover scenarios  and  display
differences between simulation outputs (potential change), designed to
provide decision support when combined with planning efforts.

AGWA is designed to provide qualitative estimates of runoff and erosion
relative to  landscape change. It  cannot provide  reliable quantitative
estimates of  runoff and erosion without careful calibration. It is  also
subject to the assumptions and limitations of its component models.
                                           Digital Elrvirloa Model

                                                                   Output variables that can be displayed in AGWA.
AVAILABILITY
There are currently several versions of AGWA available: AGWA 1.5
for Environmental Systems Research  Institute (ESRI) ArcView 3.x,
AGWA 2.x for ESRI ArcGIS 9.x, and AGWA 3.X for ESRI ArcGIS 10.x. In
addition to ArcView 3.x, ArcGIS 9.x, or ArcGIS 10.x, AGWA requires
the  Spatial  Analyst extension  corresponding  to the  respective
software                                              platform.
                                                                 KINEROS
                                                                                         SWAT
          Infiltration (mm, m /km)
          Infiltration (in, ac-ft/mi)
          Runoff (mm, m3)
          Peak flow (m3/s, mm/hr)
          Sediment yield (kg/ha)
          Channel scour (mm/m2)
          Sediment discharge (kg/s)
          Erosion (depth/area)
Precipitation (mm)
ET(mm)
Percolation (mm)
Surface runoff (mm)
Transmission loss (mm)
Sediment Yield (t/ha)
Water Yield (mm)
Nitrate (kg N/ha)
Phosphorous (kg P/ha)
FOR FURTHER INFORMATION CONTACT:
David C. Goodrich or Shea Burns
USDA-ARS Southwest Watershed Research Center
2000 East Allen Road
Tucson, AZ 85719-1596
http://www.tucson.ars.ag.gov/agwa
                    USDA
William G. Kepner
U.S. Environmental Protection Agency
P.O. Box 93478
Las Vegas, NV 89193-3478
http://www.epa.gov/nerlesdl/land-sci/agwa/index.htm

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