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Polluted Runoff: Nonpoint Source (NPS) Pollution

Guide for Using STEPL Online Data Access System

View of STEPL Input Data ServerThe STEPL Input Data Server uses the ArcGIS Viewer for Flex 2.1. The ArcGIS Viewer for Flex is a ready-to-deploy, configurable client application that is built on the ArcGIS API for Flex. The Viewer application is designed to work with ArcGIS Server and ArcGIS Online Web services.

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The web interface of this “Online Data Access System” has the following key features:

Top Panel

Search watershed boundary feature is selected by default.
STEPL bookmark Add bookmark to the current extent of the map or zoom to the previously saved bookmark location.
STEPL search Search watershed boundary and report STEPL model input data.
STEPL identify Identify feature on the map (select at least one from the list of background maps).
STEPL print Print the current view of the map.

Mid Panel 

An extent of United States of America elevation map is shown by default.

Right Panel 

Select background map and additional GIS data layers as an optional feature.
STEPL map views Switch background map to view street, aerial, or elevation map.
STEPL layers Select check box to view additional background map layers.

Left Panel

STEPL pan  Zoom to full extent of the map (to see the entire map). Pan the map (right, left, up, and down).
STEPL zoom next  Zoom to previous or next extent of the map.
STEPL slider  Zoom in or out sliding bar.
STEPL map pan  Pan the map (move the map in the view).
STEPL zoom in and out  Zoom in to, and out from, a location on the map (by rectangle).

Bottom Panel

STEPL overview Overview map window.
STEPL scale View map scale, and the location (latitude and longitude) of the cursor on the map.

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Steps for Using the STEPL Online Data Access System

  1. On the watershed search window, select a State name from the state list.  The map will zoom to the State you have selected.
  2. Select a County name from the County list. The map will zoom to the County you have selected.
  3. Click the run report button STEPL run report to obtain a report in a new window which provides data for the entire county, or go to Step 4.
  4. Select one or moresubwatershed(s) names from the HUC12 subwatershed list.  The map will zoom to thesubwaterhsed(s) you have selected.
  5. Click the run report button STEPL run report to obtain a report in a new window.  The report will provide the following tables for the HUC12 subwatershed(s) you have selected:

    The table format is consistent with the required table format in the STEPL model.

    Landuse areas in the Landuse Area table include feedlots. Feedlot areas are estimated based on the following minimum space requirement by farm animals:
    • Beef cow: 25 ft2
    • Dairy cow: 40 ft2
    • Swine: 15 ft2
    • Chicken: 1 ft2
    • Horse: 45 ft2
    • Sheep: 8 ft2
    • Turkey: 6 ft2
    • Duck: 3 ft2
  6. Export the results from the report tables to an Excel spreadsheet for use in STEPL model to estimating the pollutant loads.

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Rules/Assumptions Made for STEPL Online Data Access System

  • The user can select only one State and one County name from each list.
  • The user can select one or more HUC12 subwatershed(s) boundary names from the list.
  • The results are generated at HUC12 level.
  • The landuse data source is NLCD and USDA Cropland Data Layer (CDL), 2011.
  • The agricultural animal data source is at the County level and is summarized at the HUC12 level based on the pastureland area weighted ratio.
  • The septic system data source is at the County level and is summarized at the HUC12 level based on the low-density residential area weighted ratio.
  • The Hydrologic Soil Group (HSG) is summarized at the HUC12 subwatershed.

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Web Services Used in this Application

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