The Watershed tool determines the contributing area above a set of cells in a raster.
The output is a hosted imagery layer.
Learn how the Watershed tool works
Example
Given an input point on the Mississippi River in Louisiana, you can use the tool to identify the contributing area above the point. The contributing area, or watershed, will extend to include areas from New York to Montana and into Canada.
Usage notes
Watershed includes configurations for input layers and the result layer.
Input layers
The Input layers group includes the following parameters:
Input flow direction raster is the direction of flow out of each cell.
The flow direction must have been determined using the D8 method.
Input pour point raster or features defines the locations above which the contributing area will be determined. You can choose a layer using the Layer button, or you can create a sketch layer to use as the input using the Draw input features button. For feature inputs, a count of features is displayed below the layer name. The count includes all features in the layer, except features that have been removed using a filter. Environment settings, such as Processing extent, are not reflected in the feature count.
This input can be a raster or point feature.
In the case of a raster, each cell with a valid value will be considered a location.
In the case of a point feature layer, each point will be considered a location, and the default field will be the first available valid field.
If no other valid fields exist, the ObjectID field (for example, OID or FID) will be the default.
Pour point field is the field used to assign values to the pour point locations.
If a raster was specified for the Input pour point raster or features parameter, the Value field is used by default. This field corresponds to the cell values in the raster. Each cell value will be used to assign a value to the identified watershed given the cell.
If a feature layer was specified for the Input pour point raster or features parameter, any numeric field can be used. If the field contains floating-point values, they will be truncated into integers. By default, the first available valid field will be used. If no valid fields exist, the ObjectID field (for example, OID or FID) will be the default.
Result layer
The Result layer group includes the following parameters:
Output raster name is the name of the raster that contains the watershed areas differentiated by the pixel value derived from the Pour point field parameter.
The name must be unique. If a layer with the same name already exists in your organization, the tool will fail and you will be prompted to use a different name.
- Output layer type specifies the type of raster output that will be created. The output can be either a tiled imagery layer or a dynamic imagery layer.
- Save in folder specifies the name of a folder in My content where the result will be saved.
Limitations
The Watershed tool only supports a D8 input flow direction raster layer.
Environments
Analysis environment settings are additional parameters that affect a tool's results. You can access the tool's analysis environment settings from the Environment settings parameter group.
This tool honors the following analysis environments:
- Output coordinate system
- Geographic transformations
- Processing extent
Note:
The default processing extent is Full extent. This default is different from Map Viewer Classic in which Use current map extent is enabled by default.
- Snap raster
- Cell size
- Mask
Credits
This tool consumes credits.
Use Estimate credits to calculate the number of credits that will be required to run the tool. For more information, see Understand credits for spatial analysis.
Outputs
The output is an integer raster with the watersheds identified at each given location.
Usage requirements
This tool requires the following user type and configurations:
- Professional or Professional Plus user type
- Publisher, Facilitator, or Administrator role, or an equivalent custom role with the Imagery Analysis privilege
Resources
Use the following resources to learn more:
- How Watershed works
- Watershed in ArcGIS REST API
- watershed in ArcGIS API for Python
- Watershed in ArcGIS Pro with the ArcGIS Spatial Analyst extension