Watershed function

Available with Spatial Analyst license.


Determines the contributing area above a set of cells in a raster. Watersheds are delineated from a flow direction raster which identifies the flow direction from every cell.

For more information, see the How watershed works topic.

This is a global raster function.


You will need to provide the locations from which to determine the catchment area. When a threshold is used to define a watershed, the pour points for the watershed will be the junctions of a stream network derived from flow accumulation. Therefore, a flow accumulation raster must be specified as well as the minimum number of cells that constitute a stream (the threshold value).

The value of each delineated watershed will be taken from the cell value of the pour point in the input raster.



Flow Direction Raster

The input raster that shows the direction of flow out of each cell.

The flow direction raster can be created by running the Flow Direction function.

Pour Point(s) Raster

The input pour point locations.

This raster represents cells above which the contributing area, or catchment, will be determined. All cells that are not NoData will be used as source cells.

Pour Point Field

The field used to assign values to the pour point locations.

For a raster pour point dataset, Value is used by default.

Related topics

In this topic
  1. Overview
  2. Notes
  3. Parameters