Users Manual - Central Plains Center for BioAssessment - The

GIS INTERFACE FOR ANNAGNPS

ARCVIEW EXTENSION

VOLUME 1: USERS MANUAL

GIS INTERFACE FOR ANNAGNPS

ARCVIEW EXTENSION

VOLUME 1: USERS MANUAL

SEPTEMBER 2003

CENTRAL PLAINS CENTER FOR BIOASSESSMENT KANSAS BIOLOGICAL SURVEY

AND KANSAS GEOLOGICAL SURVEY

UNIVERSITY OF KANSAS AND

NATURAL RESOURCES CONSERVATION SERVICE U.S. DEPARTMENT OF AGRICULTURE

AND U.S. ENVIRONMENTAL PROTECTION AGENCY

REGION VII

ACKNOWLEDGMENT

This AnnAGNPS-GIS interface was initially programmed by Dr. Mingshu Tsou of Kansas Biological Survey (former employee of the Kansas Geological Survey) and Girmay Misgna of the Kansas Geological Survey, and is undergoing modification (including updating) by Jude Kastens of the Kansas Biological Survey under the guidance of Dr. Steven Wang, Project PI, of the Kansas Biological Survey. Technical support from Dr. Xiaoyoung Zhan of the Kansas Geological Survey is gratefully acknowledged.

Special thanks are given to Drs. Ronald L. Bingner, Fred D. Theurer, and Yongping Yuan of the Agricultural Research Service, U.S. Department of Agriculture; Su Liu, Chad Volkman, and Lyle Frees of the Natural Resource Conservation Service, U.S. Department of Agriculture; Dr. Sean Kruger of the Department of Environment and Natural Resources, South Dakota for their help in assisting the interface development and/or reviewing the report.

Appreciation is extended to Drs. Kyle Mankin, Philip L. Barnes, and Samar J. Bhuyan and Qianhong Tang at Kansas State University for sharing their experience in AGNPS and AnnAGNPS, to Jeremy Bartley of the Kansas Geological Survey for data preparation.

The assistance, advice, and comments of the Center Plains Center for BioAssessment director, Dr. Donald G. Huggins, have been of great value in developing this interface and preparing this report. Editorial comments from associate director of Center Plains Center for BioAssessment, Debbie Baker, greatly enhance the quality of this report. This project is funded from the U.S. Environmental Protection Agency through award number X-99797001-0 to the Kansas Biological Survey.

PREFACE

Water quality is a major concern, especially in the agricultural states of the Midwest United States. Several common water quality problems have been noted in lakes and reservoirs of the Central Plains. There have been reports of elevated plant nutrient levels, with concurrent elevations in plant biomass (Smith, 1998). Suspended solids and siltation have increased, and increases in these factors reduce light penetration, aesthetics, lake depth and volume, leading to alteration of aquatic habitats (deNoyelles et al., 1999). Water quality assessments have shown elevated levels of pesticides and other toxic chemicals (Scribner et al., 1996). Further, local and state regulatory agencies have fielded complaints regarding objectionable taste and odor conditions (e.g., KDHE, 1999). All these problems contribute to or are symptomatic of water quality degradation. However, excess nutrients and siltation, both of which result from intensive agricultural activities, are the water quality factors that contribute most to eutrophication (Carpenter et al., 1998). Eutrophication is itself a serious and widespread problem in the Midwest. According to the National Water Quality Report to Congress, 50% of assessed U.S. lakes and a higher percentage of reservoirs in the agriculturally dominated Midwest were considered eutrophic (USEPA, 2000).

A vital key to the development of a lake/reservoir management strategy is to identify nutrient loading that describes associated eutrophic conditions in lakes and reservoirs. Annualized Agricultural Nonpoint Source (AnnAGNPS 2.22) is a batch-process, continuous-simulation, watershed-scale model designed for agriculturally dominated watersheds, which was developed jointly by U.S. Department of Agriculture's Agricultural Research Service and Natural Resources Conservation services (Bosch et al., 1998; Cronshey and Theurer, 1998; Geter and Theurer, 1998; Theurer and Cronshey, 1998; Johnson et al., 2000).

AnnAGNPS requires more than 400 parameters in 34 data categories, including land use, topography, hydrology, soils, feedlot operation, field management, and climate. AnnAGNPS uses up-to-date technologies that expand the original modeling capabilities of AGNPS. For example, soil loss from each field is predicted based on the Revised Universal Soil Loss Equation (RUSLE) (Renard et al, 1997) and the sediment yield leaving each field is based on the Hydrogeomorphic Universal Soil Loss Equation (HUSLE) (Theurer and Clarke, 1991).

AnnAGNPS is an effective tool for watershed assessment. However, the complexity of modeling procedures and massive data preparation render its application tedious and time consuming. Therefore, automation of the preparation and processing of repetitive data is required. ArcView® Spatial AnnAGNPS interface is a user-friendly tool developed to assist decision-makers to conduct easier, effective watershed assessments. The Spatial AnnAGNPS interface not only assists users to extract the required soil data from the National Soil Survey Geographic Database (SSURGO) but also helps users organize input files, run the model, and visualize modeling results.

USERS MANUAL CHAPTER 1

1. TOPAGNPS/WATERSHED DELINEATION

The initial step of AnnAGNPS-ArcView interface (i.e., watershed delineation) is to help users identify and quantify topographic features and/or land-surface processes based on values of hydrology, drainage characteristics, and elevation, and later, it assist users in determining the most dominant soil and field (or land use) characteristics within the modeled area. This watershed delineation procedure is important because numerous input parameters required by AnnAGNPS are derived from these values. A unique cell number (subwatershed identification) is assigned to each individual cell or subwatershed. This cell number serves as a referencing number for the receiving cell/subwatershed attribute and is used later as a common key to relate model output attributes, such sediment yield and nutrient export, back to the cell of origin. 1.1. Loading ArcView Extensions

Initiate ArcView GIS program (version 3.3). Click on File in the menu bar to get the pull-down file menu, and then click on Extensions. Load Spatial Analyst first and then Spatial AnnAGNPS (Figure 1-1).

Figure 1-1. A dialog box of ArcView� extensions.

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1.2. Processing DEM and Delineating Watershed Add a study DEM into a new View (Figure 1-2) and start TopAGNPS from

the menu AnnAGNPS (Figure 1-3).

Figure 1-2. DEM for the study area.

Figure 1-3. A dialog box of TopAGNPS module.

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1.2.1. Select a Small Region for DEM Processing The DEM can be trimmed to a smaller size if the area of an interest is a small

portion of the DEM (Figure 1-4). This will save time of processing the DEM to generate the files that are required to delineate a watershed boundary. Click the button Select a portion of DEM by dragging a rectangle in the panel (TopAGNPS dialog) to start trimming the DEM.

Figure 1-4. Trimming the study DEM.

1.2.2. Process DEM

Make the DEM_SUBSET the active theme (Figure 1-4) and then click on the Process DEM button to generate shape files for delineating a watershed boundary (Figure 1-3). A dialog box will appear while the program is processing (Figure 1-5). This dialog box was designed to assist a user to delineate streams. A user can either accept a default cell number or enter a new value, depending upon the size of the study watershed. In general, large cell numbers (e.g., 10,000) are used for large or hilly watersheds while small numbers (e.g., 300) are ideal for the opposite (watersheds with flat landscape features). A user can experiment with the cell value to obtain the desired stream delineation results. In this example, the value of 300 was entered for this watershed (State Fishing Lake Watershed, Brown County, Kansas) because of its flat topography.

Figure 1-5. A dialog box of cells for initiating a stream.

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Click on OK, and the Outlets, fillDem, FlowDir (flow direction), FlowAcc (flow accumulation), StreamGrd (stream grid), LinkGrd (link grid), and WatshdGrd (watershed grid) themes will be added into the View. Make Outlets and StreamGrd themes visible by click the check box. This will generate Figure 1-6.

Figure 1-6. Adding new generated themes.

1.2.3. Delineate Watershed The watershed boundary is delineated based on the location of the selected

outlet. The tool Delineate Watershed in the TopAGNPS dialog box is to assist delineating the watershed based on a user-defined point at a DEM. It is important to note that the outlet point needs to be placed directly on the raster channel network (StreamGrd). Otherwise, the study watershed may not be delineated properly. Therefore, we recommend that users zoom into the desired outlet point prior to initiating watershed delineation (Figure 1-7). After a desired outlet is selected, click the button Delineate Watershed (Figure 1-3).

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Figure 1-7. Locate an outlet of a watershed.

Then, accept the default name (OutWat) in the dialog box or change the default name in the output theme. Leave the name of the input theme as it is (Figure 1-8).

Figure 1-8. Enter names for the themes.

When the process is accomplished, the OutWat theme, a delineated watershed boundary, will be added to the View (Figure 1-9).

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Figure 1-9. A new theme of a watershed boundary is added.

1.2.4. Clip a Smaller Region of DEM to Cover the Watershed

It is recommended to clip the DEM again so that the size of the DEM is closer to the newly delineated watershed boundary. Doing this would also avoid a possible error occurring in the following steps. To do so, make the DEM_SUBSET active and repeat the steps in Section 1.2.1. for trimming a portion of DEM from the entire DEM. A new DEM with the same name DEM_SUBSET will be added to the View after the execution (Figure 1-10).

Figure 1-10. Re-clipped DEM.

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1.3. Prepare Input Files and Run TOPAZ The required TOPAZ input files: DEDNM.inp, DNMCNT.inp, and

NTGCOD.inp, need to be prepared based on the information extracted from the DEM. To create these input files, a user needs to carefully examine and choose the location of an outlet. After the outlet is selected, TOPAZ in the dialog TopAGNPS will generate the required files (i.e., DEDNM.inp, DNMCNT.inp, and NTGCOD.inp) plus three additional files named RASPRO.inp, AgFlow_RasFor.inp, and ArcView_RasFor.inp that will be copied directly from the folder \OR_Mission_Creek\1_TopAGNPS_DataSets. 1.3.1. Select the Outlet for Preparing the Input File

Make the selected DEM theme active before proceeding to the following operations. The function Select from DEM is for assigning row and column identification numbers from the associated DEM according to the location that the user has selected. The user can select a point on the DEM by pressing down the button XY. The exact coordinates will then display in the panel (Figure 1-11).

Figure 1-11. Coordinates of the selected outlet in the clipped DEM. Another way to assign row and column numbers is to directly enter the

coordinates from the function Enter Row and Column (Figure 1-12).

Figure 1-12. A dialog box of Enter Row and Column coordinates.

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1.3.2. Generate the Input Dataset for TOPAZ Select the function Create default input files and an input file dialog will

appear (Figure 1-13). Change the directory to 1_TopAGNPS_DataSets and then click OK.

Figure 1-13. Directory of storing TopAGNPS input files.

Six input files will then be generated in this directory (Figure 1-14).

Figure 1-14. The generated TopAGNPS input files.

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To revise the parameters in the DNMCNT file, open the DNMCNT PARAMETERS dialog box by clicking on the button Revise DNMCNT file (Figure 5-15). After making the changes, click the Create button. This updates the previous DNMCNT file. To access this updated file, click on the View button.

Figure 1-15. A dialog box of DNMCNT parameters.

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1.3.3. Run TOPAZ The first step in running TopAGNPS is to create a program directory --

change the directory to 0_batch_files and select the batch file 1_execute_topagnps.bat, and then click the Run Batch File button (Figure 3). The program will automatically re-write the batch file based on the current patch, and run the batch file (Figure 1-16). A user can examine the batch file by clicking the View Batch File button to make sure the batch file executing the correct files. Remember that the batch file can be updated anytime by clicking Edit Batch File.

Figure 1-16. Select a batch file to run.

The file FlowGen.inp will be generated in the directory 2_AgFlow_Datasets.

Run AGFLOW after selecting the batch file 2_execute_Agflow.bat. After running AGFLOW, cell and reach data are generated and stored in the directory 2_AgFlow_Datasets. 1.3.4. View Results of TOPAZ

To view the TopAGNPS results, both cell subdivision (subwta.arc) and stream network (netw.arc) need to be imported as Grid files into ArcView (Figure 1-17).

Figure 1-17. The directory of the TOPAZ results

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As shown in Figure 1-18, the example watershed boundary is delineated. The watershed is divided into numerous cells, each of which connects to one segment of the stream network system. The index of cells is listed in the legend box.

Figure 1-18. The watershed delineation of the study watershed.

After an AnnAGNPS input has been prepared, the function of Import AnnAGNPS input file into a reach table allows users to view and edit the results of AGFLOW while the Export reach table to AnnAGNPS function allows users to export the file after editing. If the input is not ready at the time when you have done AGFLOW, you can use Notepad to view the program results.

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2. IDENTIFICATION OF DOMINANT SOIL AND LAND USE (OR FIELD) The dominant soil and land use within each sub-basin is considered to be the

soil and land use of the sub-basin. In AnnAGNPS, the way the dominant soil and land use are chosen is that, first the dominant land use is determined within the sub-basin, and within this land use the dominant soil prevalent is determined.

Convert Subwat.arc into a shape file (a polygon of the watershed boundary).

Use this polygon to clip soil and land use coverages by using the Geoprocessing ArcView� extension (Figures 2-1 and 2-2).

Figure 2-1. A dialog box of the Geoprocessing.

Figure 2-2. Clipped soil and land use coverages.

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Make the button Determine the dominant soil (or field) ID in each cell active in the Import_Reference_Data dialog box (Figure 2-3).

Figure 2-3. A dialog box of Import_Reference_Data.

Select Row Theme as subwat, Row Field as Value, Column Theme as soil.shp, and Column Field as Muid (Figure 2-4).

Figure 2-4. A dialog box for selecting dominant soil IDs

on a cell.

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Then, export and save soil ID as a delimited text file for later use (Figure 2-5).

Figure 2-5. Directory of storing the soil IDs file.

The soil ID file is shown as Figure 2-6.

Figure 2-6. The file showing the dominant soil types.

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Click on the button Determine the dominant soil (or land use/field) ID in each cell to generate dominant land use (or field) groups. Then, Select coverage and items (Figure 2-7).

Figure 2-7. A dialog box for selecting dominant land use IDs

on a cell.

Export and save land use (or field) ID for later use (Figure 2-8).

Figure 2-8. Directory of storing the land use IDs file.

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The land use (or field) ID file is shown as Figure 2-9.

Figure 2-9. The file showing the dominant land use types.

Start the AnnAGNPS Input Editor from the AnnAGNPS dialog (or initiate Input Editor directly from 0_Batch_files of the program folders) and select New AnnAGNPS File under the option File in the Input Editor. Enter basic information such as input/output unit codes (0), CONCEPT output unit code (0), and watershed name, and click the button Accept. Import the Flownet Generator Reach File (AnnAGNPS_Reach.dat) and Flownet Generator Cell File (AnnAGNPS_Cell.dat) under the option Import. Both files can be imported from the folder of (2_AgFlow DataSets). Users can evaluate these imported data in the Input Editor’s menu Data (A-N) and Data (O-Z)

Import the generated land use (or filed) and soil IDs through Field IDs from

ArcView and Soil IDs from ArcView. Prior to importing these IDs data, open these text files created previously and remove the headers “id” and “Maximum”. And then import them to the AnnAGNPS input file. For importing field IDs, the land use IDs need to be converted to the field IDs (Figure 2-10). The field IDs can be obtained from an Access� database created by the Natural Resource Conservation Service (NRCS, Lyle Frees, per. comm.), which is discussed in the following chapter.

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Figure 2-10. Dominant land use types (above) and field IDs (bottom).

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For importing soil IDs, the pre-text “Muid_” needs to be removed prior to the data importation (Figure 2-11).

Figure 2-11. Dominant soil IDs after removing the pretext of Muid.

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3. SOIL DATA PREPARATION

Soil characteristics and properties contain extremely important information that is used within AnnAGNPS to generate output estimates. The AnnAGNPS model requires about 30 soil variables for each soil map unit identified in a study watershed. Most of these required soil parameters are available in the Soil Survey Geographic (SSURGO, version 2.0) soil database exported from the National Soil Information System (NASIS). In order to use the SSURGO data in AnnAGNPS, it is necessary to calculate some derived variables from the available ones, to convert soil parameter units, and to process data for the AnnAGNPS required input format. Due to the large amount of data involved, manual processing and entry of these required soil data for AnnAGNPS is very difficult, extremely time consuming, and prone to errors. An ArcView SSURGO to AnnAGNPS tool in the dialog completely automates these soil data processing efforts for AnnAGNPS in the required model format thus saving the user considerable time and effort while increasing data input precision. 3.1. Processing SSURGO Data

Click the button after Import soil data from SSURGO 2 from the dialog Import_Reference_Data to open the SSURGO dialog box (Figure 3-1).

Figure 3-1. A dialog box of Import_Reference_Data.

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In the SSURGO dialog, navigate to the directory that contains the SSURGO text files by clicking on the left Directory list box (Figure 3-2). A list of the text files of the current folder is displayed on the right Files list directory box. Choose an appropriate option button indicating the soil parameter (English or Metric) unit of user’s choice, and then Click OK to finish the selection.

Figure 3-2. Directory of SSURGO files.

A dialog box will appear and prompt you to enter a unique value (not more than 3 character string) to specially identify each soil map unit symbol. This ID value can be a soil survey area ID number, county name abbreviation or others. Enter a value and click OK (Figure 3-3).

Figure 3-3. Identification of a county.

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Six tables will be generated and saved in the directory you previously navigated (Figure 3-4). They will be added to the current ArcView� project in Tables view.

�� Ann_unit_id (Ann_English_013 [Brown County]): This AnnAGNPS soil parameters table contains a complete data set of soil parameters for AnnAGNPS

�� Comp_id (Comp013): This table consists of soil parameters from the component table.

�� Compmat_id (Compmat013): This table is composed of soil parameters from the component parent material group table. This table is a reference table to help users assign values for the volcanic code parameter for AnnAGNPS if desired.

�� Layer_id (Layer013): This table consists of soil parameters for individual soil layers.

�� Mapu_id (Mapu013): This table consists of mapping units for soil parameters.

�� Texgrp_id (Texgrp013): This table consists of soil parameters from the texture group table. It is used to calculate soil structure codes for AnnAGNPS.

Figure 3-4. A list of AnnAGNPS soil data generated from the SSURGO database.

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Click the button Create soil table to AnnAGNPS input file in the Import_Reference_Data dialog. Select the complete AnnAGNPS (Ann_unit_id) table generated previously in the list box of the dialog, and then select the AnnAGNPS input file, where users want the results to be placed, in the folder of 6_Editor_DataSets. Click OK to execute the task.

Figure 3-5. Creation and exportation of the required soil data to AnnAGNPS. 3.2. Editing SSURGO Data

The values of some soil variables provided in the SSURGO database are theoretical or default (e.g., organic nitrogen or phosphorous). These default values need to be adjusted to reflect actual watershed conditions. The functions of Import soil data from AnnAGNPS input file and Export soil table to AnnAGNPS input file facilitate data organization in the process of model calibration. The dialog reads in soil values from the AnnAGNPS input file as an ArcView� table so that the soil data and values can be easily edited. After editing, the updated data are exported back to the AnnAGNPS input file through the dialog.

Click on the button Import AnnAGNPS input file to a soil table to import the created AnnAGNPS soil data into an ArcView� table (Figure 3-6).

Figure 3-6. Importation of the AnnAGNPS input file to an ArcView� soil table.

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To edit inorganic P values (inorgp), for example, activate Query Builder to construct a query and then click on New Set. In here, {[inorgp]=500} is used. Initiate Start Editing under the Table menu in ArcView to lunch the function of editing. Then, start Field Calculator to request a change (100) and click OK for the request (Figure 3-7).

Figure 3-7. Edition of soil parameters (e.g., inorgp). After editing, initiate Stop Editing under the Table menu and save the change. Then, export the adjusted AnnAGNPS soil data back into the original file through the button Export soil table to AnnAGNPS input file (Figure 3-8).

Figure 3-8. Exportation of the edited soil data to the AnnAGNPS input file.

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4. FIELD AND OPERATION DATA PREPARATION

Field and operation data need to be identified, located, and quantified before they can be used as model input variables. These data are used to determine imperviousness, runoff and other variables required in AnnAGNPS. These reference data associated with land use, which can be obtained from standard resources databases and field survey, are stored in an Access� database. The database contains field management, operation, operation-reference, crop, crop growth, land use, and curve number data. They are linked together through the use of unique identification codes. The reference data can be exported as AnnAGNPS input format through the dialog from the data tables that are imported from the Access� database. 4.1. Exporting Field Data

Open the Access� file containing the appropriate data and export the field-table data as a database file to the folder of 6_Editor_DataSets (Figure 4-1).

Figure 4-1. Exportation of the field-table data to AnnAGNPS.

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Then, import it into an ArcView� table (Figure 4-2).

Figure 4-2. Importation of the field-table data to ArcView�.

Click on the button Export field table to AnnAGNPS input file of the

Import_Reference_Data dialog to export the field-table data to the model input file (Figure 4-3).

Figure 4-3. Exportation of the field-table data to the AnnAGNPS input file.

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4.2. Exporting Field Management and Operation Data

From MS Access� file, export the operation-table data as a database file to the folder of 6_Editor_DataSets (Figure 4-4).

Figure 4-4. Exportation of the operation-table data to AnnAGNPS.

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Figure 4-5. Importation of the field-table data to ArcView�.

Click on the button Export operation (with field management) table to a text

file of the Import_Reference_Data dialog to export the management and operation data to a text file (e.g., oper1.txt) for a later use in organizing the AnnAGNPS input file (Figure 4-6).

Figure 4-6. Exportation of the field-table data to the AnnAGNPS input file.

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4.3. Exporting Operation Reference Data

From MS Access� file, export the table operation_reference_data as a database file to the folder of 6_Editor_DataSets (Figure 4-7).

Figure 4-7. Exportation of the operation_reference_data to AnnAGNPS.

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Figure 4-8. Importation of the operation_reference_data to ArcView�.

Click on the button Export operation reference table to AnnAGNPS input file of the Import_Reference_Data dialog to export the reference data to the model input file (Figure 4-9).

Figure 4-9. Exportation of the operation_reference_data to the AnnAGNPS input file.

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4.4. Exporting Land Use Data

From MS Access� file, export the landuse data as a database file to the folder of 6_Editor_DataSets (Figure 4-10).

Figure 4-10. Exportation of the landuse data to AnnAGNPS.

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Then, import it into an ArcView� table (Figure 4-11)

Figure 4-11. Importation of the landuse data to ArcView�.

Click on the button Export land use table to AnnAGNPS input file of the

Import_Reference_Data dialog to export the land use reference data to the model input file (Figure 4-12).

Figure 4-12. Exportation of the landuse data to the AnnAGNPS input file.

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4.5. Exporting Crop and Its Associated Data

From MS Access� file, export crop data tables (crop_data and crop_growth_data) as database files to the folder of 6_Editor_DataSets (Figure 4-13).

Figure 4-13. Exportation of crop data to AnnAGNPS.

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Then, import them into an ArcView� table (Figure 4-14).

Figure 4-14. Importation of the crop data to ArcView�.

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Click on the button Export crop tables to AnnAGNPS input file of the Import_Reference_Data dialog to export the crop reference data [crop_dat.dbf (click on the OK button) and then export crop_gro.dbf] to the AnnAGNPS input file (click on the OK button and select the model input file) (Figure 4-15).

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Figure 4-15. Exportation of the crop data to the AnnAGNPS input file.

4.6. Exporting Runoff Curve Number Data

From MS Access� file, export runoff curve number data as a database file to the folder of 6_Editor_DataSets (Figure 4-16).

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Figure 4-16. Exportation of runoff curve number data to AnnAGNPS.


Figure 4-17. Importation of the runoff curve number data to ArcView�.

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Click on the button Export curve number table to AnnAGNPS input file of the Import_Reference_Data dialog to export the runoff curve data to the model input file (Figure 4-18).

Figure 4-18. Exportation of the runoff curve number data to the AnnAGNPS input file.

4.7. Organizing AnnAGNPS Input Data After importing all the required data (e.g., soil, land use, field operation, and

management), these data need to be organized in the following order before users can actually run AnnAGNPS.

�� Model Version

�� Watershed description information

�� Model Simulation period

�� Cell data

�� Field data

�� Field management data

�� Operation data

�� Operation reference data

�� Reach data

�� Reach nutrient half-life (optional)

�� Crop data

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�� Crop reference data

�� Land use reference data

�� Runoff curve number data

�� Soil data

�� Global output data

�� Reach output data (optional)

�� End data

A file containing daily climatic data is required for AnnAGNPS simulation. Climate data can be historical records, synthetic data, or a combination of the two, and are of great importance in running AnnAGNPS. Daily precipitation, maximum and minimum temperature, dew-point temperature, sky cover, and wind speed are required to run AnnAGNPS (wind direction is currently not used) because daily precipitation is the prime force of the hydrologic cycle and temperature data are used to define frozen conditions, while the remaining climate elements are used to compute potential evapotranspiration. A great consideration should be given to the source of climate data and how many years are analyzed.

Historic data can be obtained from the National Climatic Data Center (http://lwf.ncdc.noaa.gov/oa/ncdc.html) while the following programs should be used to generate synthetic climate data for use in AnnAGNPS; Climate Generator (GEM) generates synthetic climatic data for locations in the United States. GEM generates daily precipitation, maximum and minimum temperature, and solar radiation; Complete Climate generates the daily dew-point temperature, sky cover, and wind speed, and formats the six daily climatic elements to be read by AnnAGNPS. The input files to the Complete Climate program should be named GEM output.inp (GEM generated precipitation and temperatures) and MonClim.inp (monthly average dew points, sky cover, and wind speed) because they are the interim data in the final climatic data preparation for AnnAGNPS.

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http://lwf.ncdc.noaa.gov/oa/ncdc.html


5. OUTPUT DISPLAY

The output processor and display module of the AnnAGNPS-GIS interface is the final stage of the AnnAGNPS simulation process where the output results of the program are converted and imported into ArcView� and made available for visually exploratory investigation. This visualization module consists of three sections; A) importation and graphic display of the event output table, B) importation and spatial view of the source accounting output, and C) land use and soil scenario analyses. 5.1. Event Output Visualization

Initiate the dialog box AnnAGNPS from the interface menu bar (Figure 5-1).

Figure 5-1. A dialog box of AnnAGNPS.

Click the button Select the event output file. From the file selection dialog

box, browse to the directory (8_Output_DataSets) that contains the AnnAGNPS event output table. Select the file named ev_output_table.out and click OK. A selection dialog box that contains a list of available output parameters will appear. Then select the desired parameter and click OK. A selection dialog box that contains a list of available reach IDs will appear to allow users to evaluate the result of the target parameter (water and nutrient outputs) (Figure 5-2).

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Figure 5-2. Selection dialog boxes of AnnAGNPS output parameters.

After the selection, a Yes or No dialog box will appear to ask if the user

would like to append observed data to the simulated output for display (Figure 5-3). If the user has a comma-delimited file of observed values containing monthly field and value columns, s/he clicks Yes and then browse to the file directory to select the file. The observed values for each record will be appended to the simulated values and made available for a joint display. Otherwise, select No and the only simulated result will be shown.

Figure 5-3. Selection of appending observation values.

A user has an option of selecting different types of graphs such as line, scatter,

trend and others (Figure 5-4). Enter the title of your graph and the X- and Y-axis labels in the appropriate boxes. Then select the desired parameters to graph from the drop down boxes. A user can also put a multiplication factor inside the factor text box to multiply the simulated result of the selected parameter. This factor box is located adjacent to the Y dropdown box.

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Figure 5-4. A graphic dialog box

Click the Calculate Graph Properties button to define a page size of the parameter for the graph. Then click the Graph button. A graph of the simulated result will be generated for that parameter (Figure 5-5).

Figure 5-5. An example graph of the simulated soluble P loads.

5.2. Source Accounting Map To generate source account maps, a user needs to click on the button Select

GIS format file and browse to the AnnAGNPS output directory (Figure 5-6). Select a desired GIS file (e.g., gis_sa_sed_class.out) and a list of interest parameters will appear. Select Clay_Ratio and then a select theme dialog will appear and ask the user

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the sub-watershed (cell) theme (Subwat) (Figure 5-7). A joint graph will be generated after the user finishes the selection (Figure 5-8).

Figure 5-6. Selection of the parameters in a GIS file.

Figure 5-7. Selection of a joint watershed theme.

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Figure 5-8. A display of clay ratio source accounting coverage.

5.3. Scenario Analysis Click the button Load soil and land use IDs from AnnAGNPS input file and a

file selection dialog box will appear. Browse to the directory (6_Editor_DataSets) containing the AnnAGNPS input file named AnnAGNPS.inp and select it. The soil and land use IDs will be read from the selected input file and appended to a theme for display. Another dialog box containing the name of themes will also pop up. Select the sub-watershed (cell) theme named as Subwat from the dropdown box in the dialog.

A new theme, for displaying the soil and land use IDs, will be generated and a

file manager dialog box will appear with a default name for the new theme (Figure 5-9). Change the name of the theme to a desired name and browse to a directory to where you want to save the theme. The theme will be added to the active view after a user decides the name and file location.

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Figure 5-9. A new theme generated for scenario analysis.

Select the Feature Selection tool from the view menu. Then select the model

cell (model cells) for which soil/land-use IDs need to be changed (Figure 5-10). The selected feature (cell) will show yellow color (Figure 5-9). Click the Change soil/filed button. A dialog box (Change ID) will show up. Click the button for soil (or filed) IDs. A list of soil (or field) IDs of the selected sub-watershed/cell will appear in the list box. Select a new ID from the list and click Change button to update the ID. Repeat the above procedure for as many as desired numbers of IDs that you want to change.

Figure 5-10. Parameter selection for scenario analysis.

After the selection, click the button Export soil and land use IDs to

AnnAGNPS input file. A file manager for selecting the AnnAGNPS input file to which the IDs are to be exported will appear. Select the AnnAGNPS input file from the box after browsing to the proper directory (6_Editor_DataSets). The new

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selected IDs will replace the original IDs in the input file after clicking on the OK button. A user then re-runs AnnAGNPS for a hypothetical watershed condition.

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U.S. Environmental Protection Agency. 2000. National Water Quality Inventory: 1998 Report to Congress. EPA841-R-00-001. Office of Water. Washington, D.C.

Documents

Users Manual - Central Plains Center for BioAssessment - The