Abstract
Abstract. This study has developed optimal hedging policies for the multi-purpose Ubonratana Reservoir in northeastern Thailand based on its existing rule curves. The hedging policy was applied whenever the reservoir storage falls below a critical level for each month of the year. The decision variables, i.e. the set of monthly storages defining the critical rule curve that triggers rationing and the rationing ratio, were optimized by genetic algorithm (GA). Both single stage (i.e. with one critical rule curve and one rationing ratio) and two-stage (with two critical rule curves and ratios) of the hedging policy were considered in the optimization. To test the effect of the optimized hedging policies on reservoir performance, simulations were carried out, forced alternatively with the existing rule curves (i.e. without hedging) and the two optimized hedging policies. Performance was summarized in terms of reliability (time- and volume-based) and vulnerability. The results showed that the vulnerability was significantly reduced by using the optimized hedging rules. However, the number of water shortages increased with the optimized rules, causing the time-based reliability to worsen significantly. This should not be of concern since, although the number of shortages increased, the associated shortage quantities on most of these additional occasions were small, leaving the volumetric reliability largely unchanged.
Highlights
Drought is one of the most serious water resources problems in northeastern Thailand due to the uncertainty in monsoon rainfall patterns
The nohedging policy is denoted by H0, while the single-stage and two-stage integrated hedging rules curves are denoted by H1 and H2, respectively
This study has developed optimised hedging policies based on the existing rule curves at Ubonratana Reservoir in northeastern Thailand
Summary
Drought is one of the most serious water resources problems in northeastern Thailand due to the uncertainty in monsoon rainfall patterns. Agricultural production in northeastern Thailand relies heavily on irrigation and the Ubonratana Reservoir is the main infrastructure regulating river flows for irrigation, as well other consumptive uses including domestic and industrial water supply, hydropower generation and low flows augmentation. The operation of Ubonratana has been guided for a long time using rule curves Such an approach saves no water for impending droughts and the consequence is that the resulting shortage during such droughts can be very large. The way the hedging problem has been traditionally approached is to use optimisation techniques to develop hedging rules by modifying the standard operating policy (SOP) during droughts and impending droughts (Tu et al 2008). This work has developed an optimised hedging policy for the Ubonratana based on the existing rule curves for the multipurpose reservoir. The optimisation used Genetic Algorithms (GA) whose fitness function was the sum of squares of the water deficits
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Proceedings of the International Association of Hydrological Sciences
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
