Inlet transitions with sub-critical flow from trapezoidal to rectangular sections are studied. The water depths range from 5 to 10 feet and the bottom widths range from 5 to 12.5 feet. Graphs were constructed to design these types of transitions.

The behavior of a given transition with different discharges is also studied. It was found that more efficiency is gained when a given transition is used with a discharge greater than the design discharge, than when the transition is used with a discharge less than the design discharge.