AutoCAD Civil 3D :: Draw Second Alignment Perpendicular To First

I have an alignment going up the center of a draw.  I'd like to extract cross sections of this alignment and existing ground.  What is a good way to do this? 

I don't do cross sections very often, so when I need one, I draw a second alignment perpendicular to the first and profile that alignment to give me a bare bones cross section.  I'd like to do these cross sections on a given interval, and at every change in direction.  How should I go about it?