Robust optimization using a variety of performance indices.

The term “robust optimization” is quite popular, and the descriptor “robust” so commonly applied in the water resources literature that its specific meaning, and its implications for model results, have become elusive. We here provide a brief summary of the applications of robust optimization to water resources planning and management problems in the past 15 years. We describe and demonstrate concerns regarding Mulvey et al.’s (1995) multi-objective approach to robust optimization. We evaluate the idea of minimization of the expected costs as the primary design criterion by contrasting solutions to a simple robust optimization problem in terms of common performance measures, including reliability, vulnerability, and sustainability.