My bank stations are 0 and 1.2 m, the diameter of the inverted siphon I am trying to model is 1.2 m. As such such my bank stations for the lid is also 0 and 1.2 m, and I use the station in between to define a circular cross section. I am modelling a canal system that begins with an open canal section and it contracts into an inverted siphon for a stretch and then emerges into an open channel again. i am trying to model the system in hecras as one reach. the open canal bank stations are 0 and 3.1, but contracts into a 1.2 m diameter so here i use 0 and 1.2 for lidded cross section to represent siphon bank stations. Now after setting up, I get an error saying the is no opening below the lidded cross-sections. but the bank stations are both 0 and 1.2 for the cross-section and its lid, so it does not lie inside or outside. I am failing to progress from here, what are you gurus out there suggesting where do i need to make adjustments. you could contact me personally through facebook.