Decision Analysis for Expansion of Mahaweli Multipurpose Reservoir System in Sri Lanka

Abstract

Water resource management is a complex process involving multiple stakeholders with different interests and different expertise. Typically, planning and management of water resources incorporate the analysis of social, economic, and environmental impacts as well as the consideration of hydrology and energy aspects. This study demonstrated the applicability of multicriteria decision analysis (MCDA) methods for the planning and management of a system of multipurpose reservoirs given competing development goals. We applied the methodology to the Mahaweli multipurpose project of Sri Lanka. The economic, social, and environmental planning goals were evaluated using multicriteria decision analysis techniques with multiple attributes measured in several units and trade-off weights elicited from multiple decision makers. Results showed that decision makers tend to prioritize objectives according to their institutional affiliations; however, they also demonstrate an understanding of the importance of other, less preferred objectives. The best alternative chosen by the models performed well across all objectives, decision makers, and MCDA methods. Sensitivity analyses confirmed the robustness of the best alternative under varying input parameters.