One objective of an introductory course of open-channel flow is the analysis of gradually varied flow profiles. This paper shows a teaching-learning strategy that might improve the university practices for teaching hydraulics. It is well known the depth-specific energy curve (y-E) for describing and interpreting open-channel flow hydraulics. It is proposed to complement that curve with the depth-energy slope curve (y-s f ). By using a graphic comparison, it aims to illustrate the concepts of the subcritical (y>y critical , v y normal , v<v normal ), normal y supernormal flow concepts. This way, it is proposed to explain the behavior of the twelve possible gradually varied flow profiles.