Evaluating Calibration Potential in River Hydraulic Modelling Based on Critical Slope: A Case Study of Sungai Pahang Basin

River hydraulic modelling is challenging due to the difficulty of accurately replicating hydraulic behaviors and matching simulated water levels with recorded measurements, necessitating rigorous calibration feasibility assessments.In this study, we present a novel approach to determine the calibration limit for sub-catchments in a river basin using an equation derived from Continuity, Conveyance, Froude, and Manning's formulae.The slope parameter, derived under the assumption of critical flow conditions, serves as an indicator for calibration feasibility.If the river slope exceeds the critical slope, calibration is deemed impossible due to the supercritical conditions.This approach was tested in the Sungai Pahang Basin as a case study.Preliminary results confirmed the methodology's effectiveness in identifying calibration limits, proving that it is a useful tool for determining the feasibility of calibration.This method can save time and resources by identifying infeasible calibration scenarios early in the modelling process.