The Create Watersheds tool uses a hosted digital elevation model (DEM) to create water catchment areas. For analysis purposes, hydrologic information has been precomputed by Esri using standard hydrologic models.
The output is a hosted feature service. The service has two layers, one for the watershed polygons and one for the adjusted points.
Examples
The Create Watersheds tool can be used in the following scenarios:
- The Nova Scotia Salmon Association is attempting to increase Atlantic salmon populations by improving habitat connectivity in areas with hydroelectric dams. The Create Watersheds tool can be used to determine how much habitat is made accessible with the construction of a fishway at a chosen dam.
- Many storm drains are connected to rivers, lakes, oceans, or other waterways, making anything entering a drain a potential pollutant for areas downstream. The Create Watersheds tool can be used to determine where the water entering a storm drain originated.
Usage notes
Create Watersheds includes configurations for the input layer, pour point settings, and the result layer.
Input layer
The Input layer group includes Input point features, which defines the locations where the upstream water catchment will be created. You can choose a layer using the Layer button, or use the Draw input features button to create a sketch layer to use as the input. 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.
Pour point settings
The Pour point settings group includes the following parameters:
Search distance is the maximum allowed distance to move the location of an input pour point.
If the input points are located away from a drainage line, the resulting watersheds are likely to be very small. In most cases, input points should be snapped to the nearest drainage line to find the watersheds that flow to a point located on the drainage line.
To find the nearest drainage line, specify a search distance. If there is no drainage line within the specified search distance, the location containing the highest flow accumulation within the search distance is used. If no value is specified for Search distance, the tool will compute and use a conservative search distance.
To use the exact location of an input point, enter the value zero.
Distance units corresponds to the linear units of the Search distance parameter.
Result layer
The Result layer group includes the following parameters:
- Output polygon name is the name of the output feature service that will be created. The service has two layers, Watershed Features, containing the watershed polygons, and Adjusted Points, containing the adjusted points. Each layer name will be prefaced with the value provided for Output polygon name.
- Save in folder specifies the name of a folder in My content where the result will be saved.
Limitations
The following limitations apply to the tool:
- The input must be point features.
- The input has a limit of 1,000 features. If more than 1,000 input features are provided, the service will return an error and will not process.
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
- 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.
Outputs
This tool creates an output feature service that has the following layers:
One feature layer containing the watershed polygons. The watershed layer will contain the same attributes as the points and the following additional fields:
- PourPtID—The unique ID field from the input points feature.
- Area Square Kilometers or Area Square Miles—The area of the watershed. The units of the area field will depend on the Units setting on your profile.
- Description—The description of the source database used in the analysis. The options are as follows:
- US30m, which is derived from the 30m NHDPlusV2.1 for the continental United States.
- 90m HydroSHEDS for the world between 60 degrees North and 56 degrees South, as well as some areas in Canada and Alaska north of 60 degrees.
- DataResolution—The data source resolution that was used in the analysis.
- One feature layer containing the adjusted points. The adjusted points feature layer contains the points placed at the identified locations of high flow accumulation within the search distance. If the search distance is zero, the adjusted points layer will match the input point features provided.
Usage requirements
This tool requires the following user type and configurations:
- Creator, Professional, or Professional Plus user type
- Publisher or Administrator role, or an equivalent custom role
Resources
Use the following resources to learn more:
- Create Watersheds in ArcGIS REST API
- create-watersheds in ArcGIS API for Python
- Watershed in ArcGIS Pro in the Ready to Use toolbox