A research undertaken to determine the behaviour of supercritical flow in sewer junction manholes is summarized with an emphasis on small discharge structures. A physical model was implemented to test various configurations. The independent variables representing the characteristics of approach flow, include the Froude number and the filling ratio. The dependent variables representing the characteristics of location and dimension of flow are the various standing wave patterns, namely the start and end locations and the wave heights. The analysis of previous variables allows for an identification of the prevailing wave types and the conditions under which they form. A number of design recommendations are also developed, thereby contributing to the hydraulic problem and the understanding of this particular flow type in sewer junction manholes.