Fuzzy goal programming approach for water quality management in a river basin

Two fuzzy goal programming (FGP) approaches are applied to water quality management in a river basin for solving multiobjective optimization problems involving vague and imprecise information. Several FGP models, including equal weight and unequal weight, nonpreemptive priority and preemptive priority, are proposed to assist water quality management involving multiple conflicting goals. Optimal water quality management involves obtaining optimal analysis of assimilative capacity (also referred to as allowable pollution loading) and treatment cost of wastewater based on models and standards of water quality, as well as an equitable removal of wastewater in a river basin. Two FGP schemes that are capable of maximizing achieved membership function and minimizing the deviation from a set of preferred target assimilative capacity and treatment cost are considered. Moreover, methodologies using two fuzzy decision theories in FGP approaches, i.e., max-min operator and compensatory operator, are also proposed. Those methodologies are illustrated in a case study of multiobjective water quality management in the Tou-Chen River Basin, Taiwan. The case study demonstrates the capability of the two FGP approaches based on variable fuzzy decision theories to work suitably in water quality management in a river basin. (C) 1997 Elsevier Science B.V.