"East bank" and "west bank" are also used for the sides of a watercourse that flows generally north/south, even for bits of it that are flowing east/west or have curved around to flow south/north. Which is why West St. Paul (Minnesota) is directly south of St. Paul proper -- it's on the "west bank" of the Mississippi, while St. Paul is on the "east bank".

(Same story, mutadis mutandis, for "north bank" and "south bank" of generally east/west-flowing rivers.)