Parameter identification in models of hydrologic systems using the digital simulation language PDEL

Hydrologic systems, like most environmental systems, are usually characterized by partial differential equations. In order to develop a suitable mathematical model for the analysis of such systems, it is first necessary to make use of observed data in order to identify or estimate the system parameters. The digital simulation language PDEL has been extended so as to facilitate this type of parameter identification. The extended version of the language has been named PDEL-ID. In this paper, two hydrologic modeling problems taken from recent water-resources studies are used as examples to illustrate the parameter identification facilities of PDEL. The solution of these two problems demonstrates that little programming effort and virtually no knowledge of optimization techniques are required.