Analysis of Multiple Objectives in Water Quality

The needs for mathematical models that are susceptible to multiple objective functions in their noncommensurable format and units are presented. Several water quality objectives and goals, classified as primary and secondary objectives, are introduced. The concepts of noninferior (Parento optimum) solution, indifference band, and prefered solution are defined. A general multiobjective model for water quality planning and management is developed. Specific multiple objectives and constraints associated with biological oxygen demand, dissolved oxygen, thermal pollution, and algae bloom are introduced and examined. The Surrogate Worth Tradeoff (SWT) method is reviewed and its application to water quality model is analyzed. In particular, basics in the derivation of the trade-off functions and the surrogate worth functions are given.