Please cite SAGA whenever you use it for your publications:

Extended watershed basin analysis.

Name	Type	Identifier	Constraints
Input
DEM	grid, input	DEM
Drainage Network	grid, input	CHANNELS
Output
Basins	grid, output	BASINS
Subbasins	grid, output	SUBBASINS
Basins	shapes, output	V_BASINS
Subbasins	shapes, output	V_SUBBASINS
River Heads	shapes, output	HEADS
River Mouths	shapes, output	MOUTHS
Options
Flow Distances	boolean	DISTANCE	Default: 0