Abstract
Abstract General guidance for reservoir operation can be referred to as the Standard Operation Procedure (SOP). Real circumstances such as drought, however, do not necessarily comply with these ideal assumptions, which then trigger the studies on optimal hedging rules. More frequent mild droughts are preferred to less frequent severe droughts. In the present work, the-constrained-based multi-objective optimization model was developed to optimize hedging rules for a reservoir located in Lombok Island, Central Indonesia. The rules were aimed to minimize two objective functions namely maximum Single Shortage (S S ) and Total Deficit (T D ). The former is a measure of reservoir operation during drought in short-term, whereas the latter is for long-term evaluation. Results show that these two measures are conflicting in nature, that is, the greater the S S , the smaller the T D and vice versa. The tradeoffs between S S and T D can be a helpful assist for water operators in executing their routine daily tasks by providing water allocation alternatives.