AGNPS Watershed Modeling with GIS Databases U S Department of Interior U S Geological Survey AGNPS Watershed Modeling with GIS Databases Michael P Finn

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AGNPS Watershed Modeling with GIS Databases U S Department of Interior U S Geological Survey AGNPS Watershed Modeling with GIS Databases Michael P Finn Powered By Docstoc
					AGNPS Watershed Modeling with
GIS Databases




U.S. Department of Interior
U.S. Geological Survey
AGNPS Watershed Modeling with GIS Databases
                Michael P. Finn
                 E. Lynn Usery
               Douglas J. Scheidt
                 Thomas Beard
                  Sheila Ruhl
                Morgan Bearden

             U.S. Geological Survey
          Mid-Continent Mapping Center
                    Rolla, MO
Outline
 Introduction
 Study Areas
 GIS Databases for Parameter Extraction
 AGNPS Parameter Generation
 Creating AGNPS Input, Output, and Images
 Results
Objectives
Use GIS databases as input to AGNPS Pollution
Model
Demonstrate automatic extraction of input
parameters
Create a tool for generating input, executing the
model, and analyzing output
Introduction

Agricultural NonPoint Source (AGNPS) Pollution
Model – USDA lead agency
AGNPS operates on a cell basis and is a distributed
parameter, event-based model
AGNPS requires 22 input parameters
Elevation, land cover, and soil data served as the
base of extraction for the input
Study Areas
 Four Watersheds
   Little River, GA
   Piscola Creek, GA
   Sugar Creek, IN
   EL68D Wasteway, WA
 Watershed Boundaries
   NAWQA Boundary
   GIS Weasel
Georgia Watersheds
Indiana Watershed
Washington Watershed
GIS Databases for Parameter
Extraction
 USGS 30-m DEMs
 USGS 30-m National Land Characteristics Data
   Augmented with recent Landsat TM data
 Soil databases from USDA soil surveys
   Scanned separates, rectified, vectorized, and tagged
 Resampled the 30-m data to 60, 120, 210, 240, 480,
 960, and 1920 meters
   210-m roughly matches 10 acre grid size
AGNPS Parameter Generation
 AGNPS Data Generator
 Input parameter generation
 Details on generation of parameters
 Extraction methods
AGNPS Data Generator
 Created to provide interface between GIS software
 (Imagine) and AGNPS
 Developed interface for Imagine 8.4, running on
 WinNT/ 2000
AGNPS Data Generator
Input Parameter Generation
 22 parameters; varying degrees of computational
 development
   Simple, straightforward, complex
Input Parameter Generation
Details on Generation of Parameters
 Cell Number
 Receiving Cell Number




 SCS Curve Number
   Uses both soil and land cover to resolve curve number
Details on Generation of Parameters
(continued)
 Slope Shape Factor
Details on Generation of Parameters
(continued)
 Slope Length
    A concern; max value should be 300 ft.
 Parameters 10, 11, 12, 14, 15, 16, and 17
    Uses Spatial Modeler to look up attributes from soils or land cover
    Example: p10 is Overland Manning’s Coefficient
 Parameters 13, 18, 19, 20, and 21
    Hard coded on advice from experts
    Example: p13 is Practice Factor (conservation) coded to 1 (worst
    case)
Details on Generation of Parameters
(continued)
 Type of Channel
   Uses TARDEM program
   Creates a Strahler steam order
Extraction Methods
 Used object-oriented programming and macro
 languages
   C/ C++ and EML
 Manipulated the raster GIS databases with Imagine
 Extracted parameters for each resolution for both
 boundaries using AGNPS Data Generator
Creating AGNPS Input, Output, and
Images
 Input Data File Creation
   Format generated parameters into AGNPS input file
   Use a “stacked” image file to create AGNPS data file
   (“.dat”) -- ASCII
Creating AGNPS Input, Output, and
Images (continued)
 Output Image Creation
   AGNPS Creates a nonpoint source (“.nps”) file
   ASCII File like the input; tabular/ numerical form
Creating AGNPS Input, Output, and
Images (continued)
Creating AGNPS Input, Output, and
Images (continued)
 Output Image Creation (continued)
   Combined “.nps” file with Parameter 1 to create
   multidimensional images
   Users can graphically display AGNPS output
   Process: create image with “n” layers, fill layers with
   AGNPS output data, set projection and stats for
   image
   Multi-layered (bands) images per model event
Creating AGNPS Input, Output, and
Images (continued)
Creating AGNPS Input, Output, and
Images (continued)
Creating AGNPS Input, Output, and
Images (continued)
Creating AGNPS Input, Output, and
Images (continued)
Results
 Collaboration continues to quantify the impact of
 spatial resolution on model results
 Demonstrated the use of GIS databases as
 sources in watershed modeling, particularly with
 AGNPS
 Demonstrated methods of automatic extraction
 of AGNPS input parameters from GIS databases
 Showed implications of results for 4 watersheds
 Demonstrated the practicality of AGNPS Data
 Generator as an AGNPS – GIS interface
AGNPS Watershed Modeling with
GIS Databases




U.S. Department of Interior
U.S. Geological Survey