Cyclical Hierarchical Modeling for Water Quality Model–Based DSS Module in an Urban River System

Abstract

Environmental systems modeling has always been at the core of gaining insight into the world. Most environmental systems behave very differently from fairly predictable systems because of nonlinearity in approach and behavior. This paper discusses the problem that exists in effectively modeling a multicriterion and nonlinear parametric system. A cyclical hierarchical model was proposed that allows the user to model the effects of various environmental parameters, which not only propagate as forward processes, but also may have dependencies and carryover effects on other primary set of parameters. This is an adaptation from ecological hierarchies for development of parametric modules in an environmental system. This effect was captured by a set of forward and backward carryover functions that are to be generated as process-specific and time-specific functions. The user expresses control over the effect of each parameter on the other and in terms of iterations that are performed within the cyclical hierarchies and the value of the forward and backward functions that need to be developed. This was integrated into the core of an environmental decision support system (EDSS), which prioritizes a parameter set on the basis of analytical hierarchy process (AHP) to establish a global hierarchy that is then studied in perspective to cyclical hierarchies and nodal relations that exist in such hierarchical forms. The study concerns itself with an urban river system, which involves a multitude of such multivariate parameters. Iterations were performed to see the variations in the global hierarchy. The parameterized form can be used to generate criterion-based output for the cyclical hierarchy sets used, and the change may be adapted pertaining to EDSS output.