I have been having trouble trying to come up with a python script that will go through a polyline feature class representing a river system and split all the streams intersecting with a central river at distance of 2km. The added difficulty is that any given stream can be made up of multiple polyline segments. Thus if a stream that intersects with the central river is made up of 2 line segments 1.5km long, the first would need to be unclipped, and the second after 0.5 km.
Does anyone have any suggestions on how to write a script that will accomplish this? I know positionAlongLine tool might help but I am not sure how to implement it.