Water supply planning under interdependence of actions: Theory and application

An ongoing water supply planning problem in the Regional Municipality of Wa terloo, Ontario, Canada, is studied to select the best water supply combina tion, within a multiple-objective framework, when actions are interdependen t,The interdependencies in the problem are described and shown to be essent ial features. The problem is formulated as a multiple-criteria integer prog ram with interdependent actions. Because of the large number of potential a ctions and the nonconvexity of the decision space, it is quite difficult to find nondominated subsets of actions. Instead, a modified goal programming technique is suggested to identify promising subsets. The appropriateness of this technique is explained, and the lessons learned in applying it to t he Waterloo water supply planning problem are described.