EVALUATION OF DECISION MAKING METHODS FOR INTEGRATED WATER RESOURCE MANAGEMENT UNDER UNCERTAINTY

摘要

This paper evaluates two established decision making methods and analyses their performance and suitability within an Integrated Water Resources Management (IWRM) problem. The methods under assessment are Info-Gap decision theory (IG) and Robust Optimisation (RO). These methods have been designed to aid decision making under severe uncertainty but differences exist in their approach and attitude to robustness and risk. For example, the Info-Gap methodology offers solutions that provide a localised robustness of sufficing over a wide range of uncertainty, but is highly dependent on the selection of the starting point. Robust Optimisation concentrates on optimising for a global robustness and cost, independent of likelihood assumptions. These methods were applied to a case study resembling the Sussex North region in England, assessing their applicability at improving the IWRM problem and highlighting the strengths and weaknesses of each method at selecting suitable adaptation strategies under climate change and future population uncertainties. Both methods show potential in water resource adaptation planning, but present conflicts in their global vs local definitions of robustness. Pareto sets of robustness to cost were produced for both methods and highlight RO as producing the lower costing strategies for the vast majority of varying target robustness levels. However, IG generally produces strategies that provide greater maximum and average risk reduction across the range of potential scenarios, indicating a trade-off of higher costing solutions for greater risk aversion.