1 post I should be thankful if any would help in writing the PID rule for radial gate in HEC Ras. Allow me to briefly introduce myself as free lancer Hydraulic engineer working in Lebanon, I have modeled successfully a mixed system (canal + gates + Pressurized tunnel) under unsteady state with HEC RAS but End user is forcing me into the use of Mike 11 due to the fact MIKE 11 is able to accept direct input PID control for the radial gate, whereas HEC RAS accepts only for similar case “user defined rule” PID is intended to control gate operation in order to maintain Constant Head downstream. I wonder if you have an example or any reference that helps producing a similar rule.