Assessment of parameter uncertainty in hydrological model using a Markov-Chain-Monte-Carlo-based multilevel-factorial-analysis method

•A Markov-Chain-Monte-Carlo-based multilevel-factorial-analysis method is proposed.•The method is applied to the Kaidu River for addressing uncertain model parameters.•Parameter uncertainty is assessed within a formal Bayesian framework.•Effects of multiple parameters and their interactions are revealed.•The findings are validated using a variance-based sensitivity analysis method.