RightBank(Distances, Elevations, Stage)
Returns coordinates defining right bank of channel at the given stage.
Input:       Distances = Horizontal distances across the channel (numbers)                   Elevations = Channel bed elevations at each horizontal location (numbers)                 
Stage = Stage at which to calculate the location of the right bank (number)
Output:      Coordinates defining the right edge of the channel (vector) |
Notes: To get return both horizontal and vertical coordinates, see the Vector Functions reference