Transition Profiles in Nonuniform Channels

If a water-surface profile passes without abrupt change from tranquil to rapid flow, or from rapid to tranquil flow, the point at which it does so lies on a profile that can conveniently be called a “transition profile,” and the depth at that point can be termed a “transition depth.” Such a profile is fixed in that it does not vary in position with changes in discharge as do normal-depth profiles and critical-depth profiles. Mathematically, the point of transition is a singular point, and the solution to the differential equation for steady flow does not yield the traditional vertical water-surface profile at that point. A graphical practical method for constructing transition profiles is outlined herein.