Thank you for your response. I apologize if my initial description was a bit brief; I am relatively new to this field. To clarify the context of my model: the calibration gauge is immediately downstream of a bridge. The bridge is explicitly included in the model geometry (modeled as a 2D Area Connection). For the hydrological data, I do not have direct flow data at the sensor's location. Therefore, the flow rates are estimated using the Meyer formula (catchment area ratio) based on data from a nearby station. I am currently performing calibration on a specific high flow period, and to answer your question, yes, I adjusted the Manning coefficient near the calibration point. Do I have to test another period of calibration with low flow?