應用禁忌演算法於都市淹水預警機制之建置

Applying the tabu search to develop an urban flood warning system

廖晧宇(Hao-Yu Liao)

指導教授 ： 蘇明道

共同指導教授 ： 譚義績(Yih-Chi Tan)

國立臺灣大學/生物資源暨農學院/生物環境系統工程學研究所/碩士(2016年)

https://doi.org/10.6342/NTU201601908

摘要

近年來因為極端氣候變遷的因素，使淹水災害的嚴重程度，比以往來的嚴重，如近年2009年莫拉克颱風事件，其降雨量重現期超過百年重現期，隔年2010年的凡那比颱風的降雨量，也超過百年重現期，這使得目前的水工結構物必須重新檢討是否可以因應未來在極端氣後產生的淹水災害。在過去十年的降雨事件中，最有效的預防淹水災害為工程手段方式，然而近年極端氣候的影響，工程手段方是將可能失去防止淹水的功能，因為在過去建造防災工程，是根據過去未受到極端氣候影響下的災害事件設計，因此面對未來極端氣候影響下的災害，需要重新審視目前水工結構物的防災功能。
因此非工程手段方式，為彌補目前的工程手段對於極端氣候下防災的功能，目前政府建立一套淹水預警系統，來因應預警淹水災害，當淹水預警系統發出警報，民眾將可在淹水災害來襲之前，有足夠的時間逃離淹水災害的傷害，淹水預警系統主要是根據淹水門檻值建構，當累積雨量達到該淹水門檻值，淹水預警系統將會發出警報於當地民眾或政府，可提早準備預防淹水災害，雖然政府有一套的淹水預警系統正在運作，但是目前的淹水門檻值對於災害的預警仍有很大的改善空間，因此重新建立一套有效的機制來改善淹水門檻值的精度。
本研究主要探討一套新的淹水門檻值模式，根據禁忌演算法的搜尋最佳解能力，以及根據目前本研究提出的三種統計公式，重新計算一套新的最佳淹水門檻值，而三種統計公式可以有效降低未有淹水災害而發出預警的誤報率次數，且能提高對於淹水災害的預警精度。研究結果顯示，根據本研究提出的優化淹水門檻值方法，可以有效改善都市淹水預警系統的精度，減少淹水災害造成民眾的生命傷亡及財產損失。

關鍵字

淹水門檻值 ； 淹水災害事件 ； 統計指標 ； 禁忌演算法 ； 雨場分割 ； 徐昇式法 ； 頻率分析

並列摘要

Flood is one of the most damage disaster that always happen around the world. Because of the extreme weather change, the flood disaster damage becomes higher than before. In recent years, Taiwan suffered from flood damage frequently by excessive rainfall induced by extreme weather, like typhoons. Therefore, it is necessary to build an effective flood warning system to reduce the flood damage. The operational flood warning system in Taiwan is based on the rainfall thresholds. When cumulative rainfall over the rainfall thresholds, the flood warning system would alert the local government where region would happen flood disaster. According to the flood warning system alert, the governments have more time to prepare how to face the flood disaster before happens. Although Taiwanese government has a preliminary flood warning system, the system has still lack of theoretical background. For this reason, the alert accuracy of the system is limited. Thus it is important to develop the effective rainfall thresholds that could predict flood disaster successfully.
The research aims to improve the accuracy of the system through statistical methods. When the accumulated rainfall reaches the alert value, the warning message would be announced early to government for dealing with flooding damage which would happen. According to extreme events, the statistical methods are adopted to calculate the optimum rainfall thresholds. The results of this study could be applied to enhance rainfall thresholds forecasting accuracy, and could reduce the risk of floods.

並列關鍵字

rainfall threshold ； flood disaster events ； statistical index ； tabu search ； inter-event time definition ； Thiessen method ； frequency analysis

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