Assign River Order

Description

Calculates river order for input features based on existing NextDownID attribute that must exist. If optional Starting River Order field is provided, it can be used to adjust the internal assignment of river orders with known values (for positive values) or ignoring the feature in river order calculations (for negative values).

Usage

Parameters

Parameter Name	Type	Direction	Data Type	Dialog Reference
Input Feature Class or Table	Required	Input	Table View	Input River or Catchment layer. Must have HydroID and NextDownID fields populated.
Input River Order Field	Required	Input	String	Name of the field to hold computed river order. Field name needs to be typed in. If entered field already exists in the input feature class/table, it will be overwritten. If it does not exist, it will be created.
River Order Type	Required	Input	String	Three types are supported: PU_Order. Whenever 2 (or more) rivers meet, the downstream river order = max of upstream orders + 1. Strahler. Whenever two or more rivers meet, the downstream river order = upstream riverorder+1 if two upstream river order are equal. Shreve. Whenever two or more rivers meet, downstream river order = sum of upstream river orders.
Input Flow Split Table	Optional	Input	Table View	Flow split table associated with the input feature class. It needs FeatureID and NextDownID fields populated.
Input Starting River Order Field	Optional	Input	Field	(Optional) Name of the field holding initial river order. When provided, the field's value will be used as head river's river order value, (instead of 1). Used to handle the situation when upstream processing unit's river order need to be inherited by the current processing unit. If negative, that feature will be ignored in the stream order calculations.