I'm looking for some suggestions/advice on my InfoSWMM model and the simulated results after different rain events. Initially calibrated with events of a reasonable size (41mm, 37mm, 45mm etc.) with good results compared to observed field values. The problem I'm having is when I add a bigger event (100yr Design Storm) or an event over a 100mm. Modeled flows during these events appear lower than whats observed. Sometimes substantially lower! I've reviewed several things from pump curves, to increasing pipe roughness to adding rule controls to pumps with no significant changes. My last resort will be to revisit my RTK values but I'm hesitant to do this as my smaller events work well. At this point if anyone could provide some suggestions to look into it would certainly be appreciated! Thank you.