| Summary: | 博士 === 國立臺灣海洋大學 === 河海工程學系 === 93 === In practice, “rule curve”generally regulates reservoir operation. In an area of uneven water distribution, reservoir can stabilize the water flow to mitigate water problems. Therefore, a task to operate reservoirs efficiently is essential.However, operating by rule curves can’t fit the demand efficiently during dry season, and the operation of rule curves by single reservoir also works inefficiently. In addition, drought events hit Taiwan frequently in recent years, and which brought immense impacts to people’s daily life. Unfortunately, the drought early warning system in Taiwan is not well developed, and the alert categories are in their infancy and quite vague in their definitions.
This study gives an example as the two-parallel joint operation between Feitsui and Shismen reservoir in northern Taiwan. The objectives are：(1)to select the optimum reservoir operating alternative for single use. (2)to develop the joint long-term reservoir operating rule curves for conjunctive use.(3)to build a handy early warning system for drought management to reduce the impacts.
In this study, a lexicographic method is used to select the operation alternative for the Feitsui reservoir. Simulation results show that the alternative, the limitation of water supply by Taipei city government during the fight against 2002 drought, would be the best in terms of minimum shortage. On the other hand, the alternative, the new rules after May 31 2004, would be selected in terms of maximum water utilization. However, alternative of new rules need an assistance of the Drought Early Warning System to reduce its high risk of reservoir emptiness.
Furthermore, the joint operation between Feitsui and Shihmen reservoir system is selected to demonstrace its applicability of the GA-based simulation model on a complex water resource system. In the multiple reservoir model, simulation results show Feitsui's surplus water can be utilized efficiently to fill Shihmen's deficit water without affecting Feitsui's main purpose as Taipei city's water supply. The optimal joint operation suggests that Feitsui, on average, can provide 650,000 m3/day and 850,000 m3/day to Shihmen during the wet season and dry season, respectively.
In this research, a color-coded early warning system is also developed and proposed for drought management on the real-time reservoir operation. The system consists of three essential elements, namely, (a) drought watch, (b) water consumption measure, and (c) policy making. A new Drought Alert Index is used to characterize the alert level of drought severity. For demonstration, the drought warning procedures were effectively applied to historical droughts from dry condition to wet situation. The implementation of such a system proves that the decision support-like system can help the water authorities concerned take a timely action while confronting drought threats.
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