Structure validation of an integrated waterworks model for trihalomethanes simulation by applying regional sensitivity analysis Original Research Article

A previously developed integrated waterworks model for trihalomethanes simulation was validated by applying a new framework for comprehensive model structure validation. The proposed framework followed the procedure of regional sensitivity analysis and also involved correlation analysis and frequency distribution analysis. Through such an analysis framework, a deep insight into model structure and parameters could be gained besides the traditional focuses on model validation, i.e. model performance and rationality of model parameters. The integrated waterworks model, to which the framework was applied, was proved to give good predictions of the simulated variables, and the identified values of model parameters coincided well with the reported values in the literature. The model was also found to have a large proportion of sensitive parameters, no distinct correlations among parameters, and thus a balanced structure. Moreover, most of the sensitive parameters could be well identified and the associated uncertainties significantly reduced. A detailed investigation into the sensitivity, identifiability, and uncertainty of model parameters showed that the model conceptualization was in good agreement with accepted scientific principles and anticipated system behaviors. All these results, therefore, supported the validity and trustworthiness of the model. In addition, further opportunities for refining the model were also proposed.