水庫預放流操作的理論解析

Theoretical Model of Prerelease Operation Under Inflow Variation and Uncertainty

郭承翰(Cheng-Han Kuo)

指導教授 ： 游景雲

國立臺灣大學/工學院/土木工程學研究所/碩士(2018年)

https://doi.org/10.6342/NTU201802771

摘要

為了降低降雨時空分布不均對供水所造成的影響，水庫便成為了台灣相當重要的水資源來源。然而近年來，由於氣候變遷的關係；逐漸增加的豪大雨事件大大的增加了水庫操作上的風險。如何同時兼顧穩定供水和防洪操作便成了水庫操作相當重要的議題。水庫預排放操作便是一種新的操作概念，目的是希望在在洪水洪峰抵達前先釋放部分水，希望能降低洪水對下游所造成的災害。Hedging rule也擁有類似的水資源時空分配概念，然而一開始這個方法是應用在乾旱時的用水調度。兩個方法皆是希望透過水資源的時空重新分配來降低各自災害帶來的損失。
本研究期望結合Hedging rule的概念從理論的角度分析水庫的預排放操作操作策略。根據質量守恆及卡羅需－庫恩－塔克最佳化(Karesh-Kuhn-Tucker Optimality (KKT))，我們建立了一個和兩個入流的預放流操作模型。此外，在此模型架構下加入入流不確定亦可觀察與分析對水庫預放流操作所造成的影響。本研究目的是希望在同時考慮入流變異性和不確定性的條件下，能提供一個較佳的水庫預排放操作策略，有效的降低洪水帶來的災害損失。

關鍵字

水庫操作 ； 不確定性 ； 最佳化

並列摘要

Reservoirs plays an important role in water supply to mitigate the impact of uneven distribution in spatiotemporal scale. In recent years, more and more extreme rainfall or storm events have been observed which make the operation of reservoir more and more difficult. A new concept, reservoir pre-release is proposed to alleviate the flood loss by releasing water before the flood peak arrives. Similar idea, hedging rules, has been well discussed in drought management. These two operational concept are similar, both reduce the magnitude of loss by temporal allocation of water. For this concern, this study wants to focus on the theoretical analysis of pre-release operation with the concept of hedging rule. We develop two- and three-period conceptual model based on mass conservation and Karesh-Kuhn-Tucker Optimality (KKT) scheme. With this framework, the inflow uncertainty can be further investigated its influence in reservoir operation. For this results, we will be able to understand the operation concept with variation of inflow. This study expects to provide a better suggestion to determine the prerelease volume for reservoir operator with the consideration of inflow variation and uncertainty, and we would be able reduce the risk and loss of flooding by better operation.

並列關鍵字

Water resources ； Reservoir operation ； Optimality

參考文獻

林郁雯 (2015). 水庫排砂即時操作之研究. 碩士論文. 國立臺灣大學土木工程學研究所, 台北.

Chou, F. N. F., & Wu, C. W. (2013). Expected shortage based pre-release strategy for reservoir flood control. Journal of hydrology, 497, 1-14.

Draper, A. J., & Lund, J. R. (2004). Optimal hedging and carryover storage value. Journal of Water Resources Planning and Management, 130(1), 83-87.

Hui, R., & Lund, J. R. (2014). Flood Storage Allocation Rules for Parallel Reservoirs. Journal of Water Resources Planning and Management, 141(5), 04014075.

Hui, R., & Lund, J. R. (2015). Optimal flood pre-releases—flood hedging for a single reservoir. In World Environmental and Water Resources Congress 2015 (pp. 2192-2201).