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How To: Create a basin model using a digital elevation model in ArcMap

Summary

The Basin tool from the Spatial Analyst toolbox creates a delineated drainage basins raster by identifying ridge lines between basins.

Procedure

The following instructions provide a workflow to create a basin model using the Hydrology toolset from the Spatial Analyst toolbox.

  1. Run the Fill tool to correct the data resolution or to round elevations to the nearest integer value.

    a. In ArcCatalog, navigate to Toolboxes > System Toolboxes > Spatial Analyst Tools > Hydrology > Fill.
    b. Use a digital elevation model (DEM) as the 'Input surface raster'.
    c. Verify the path name for the 'Output surface raster'.
    d. If necessary, input the Z-limit.
    e. Click OK.


    [O-Image] Fill tool results
    Note:
    The Fill tool fills sinks to remove imperfections from the DEM. It is recommended to state the Z-limit if the depths of the sinks are known. The Sink (Spatial Analyst) tool can be used to identify sinks and sink depths prior to using the Fill tool. If the Z-limit is not specified in the Fill tool window, all sinks, regardless of depth, are filled.

  2. Run the Flow Direction tool.

    a. In ArcCatalog, navigate to Toolboxes > System Toolboxes > Spatial Analyst Tools > Hydrology > Flow Direction.
    b. Use the output from Step 1 as the 'Input surface raster'.
    c. Verify the path name for the 'Output flow direction raster'.
    d. Click OK.


    [O-Image] Flow Direction tool results
    Note:
    The Flow Direction tool determines the direction of flow from each cell to its steepest downslope neighbor.

  3. Run the Basin tool.

    a. In ArcCatalog, navigate to Toolboxes > System Toolboxes > Spatial Analyst Tools > Hydrology > Basin.
    b. Use the output from Step 2 as the Input flow direction raster.
    c. Verify the path name for the Output raster.


    [O-Image] Basin tool results

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