Extraction and Preference Ordering of Multireservoir Water Supply Rules in Dry Years

This paper presents a new methodology of combined use of the nondominated sorting genetic algorithm II (NSGA-II) and the approach of successive elimination of alternatives based on order and degree of efficiency (SEABODE) in identifying the most preferred multireservoir water supply rules in dry years. First, the suggested operation rules consists of a two-point type time-varying hedging policy for a single reservoir and a simple proportional allocation policy of common water demand between two parallel reservoirs. Then, the NSGA-II is employed to derive enough noninferior operation rules (design alternatives) in terms of two conflicting objectives (1) minimizing the total deficit ratio (TDR) of all demands of the entire system in operation horizon, and (2) minimizing the maximum deficit ratio (MDR) of water supply in a single period. Next, the SEABODE, a multicriteria decision making (MCDM) procedure, is applied to further eliminate alternatives based on the concept of efficiency of order k with degree p. In SEABODE, the reservoir performance indices and water shortage indices are selected as evaluation criteria for preference ordering among the design alternatives obtained by NSGA-II. The proposed methodology was tested on a regional water supply system with three reservoirs located in the Jialing River, China, where the results demonstrate its applicability and merits.