暴潮對沿海地區淹水潛勢與淹水風險之影響

The Impact of Storm Surge on Inundated Potential and Inundated Risk in the Coastland

巫孟璇(Meng-Hsuan Wu) ； 蔡智恆(Chih-Heng Tsai) ； 陳金諾(Ching-Nuo Chen) ； 蔡長泰(Chang-Tai Tsai)

《中國土木水利工程學刊》 22卷4期 (2010/12) Pp. 387-398

https://doi.org/10.6652/JoCICHE.201012_22(4).0004

摘要

本研究應用GIS處理沿海地區龐大之水文及地文特性參數，並考慮洪氾區複雜之地形地物，從而發展出地文性淹水模式。由2005年海棠颱風與2008年卡玫基颱風之模式模擬結果與現場淹水調查資料之比較得知，地文性淹水模式可合理模擬沿海地區之淹水範圍及淹水深度。進一步以重現期距2年、5年、10年、20年、50年、100年及200年等七個不同重現期距年之設計降雨，分別配合各重現期距年沿海之暴潮潮位歷線與天文潮潮位歷線，進行各重現期距年設計洪水事件下研究範圍內淹水潛勢與淹水風險之模擬與比較。模擬比較結果可得知，暴潮除了增加沿海地區之淹水潛勢外，亦會提高淹水風險。由於暴潮上溯阻礙河道排水，受暴潮影響最大的區域主要位於沿海平原附近、潟湖旁以及河道感潮段兩岸，導致淹水深度增加、淹水面積變大、淹水時間變長。

關鍵字

暴潮 ； 淹水潛勢 ； 淹水風險 ； 地文性淹水模式

並列摘要

In this study, an innovative physiographic inundation model that comprehensively accounts for the physical process of overland flow due to both heavy rainfall and typhoon-induced storm surge was applied to describe inundated potential and inundated risk in the coastal area. To represent the complicated landform and configuration, geographic information system was integrated into our model for analyzing a huge amount of the hydrologic and geographic parameters. A comparative study was first conducted to validate our physiographic inundation model, and showed that our simulated results excellently agree with the historic field measurement concerning inundation depth and area recorded as flood occurs due to Typhoons Haitang and Kalmaegi in 2005 and 2008, respectively. Our physiographic inundation model was then applied to calculate the corresponding inundation potential, inundation area, and inundation risk in a flood-prone coastal area we examined under design rainfall of seven return periods (two- year, five-year, ten-year, twenty-year, fifty-year, one-hundred-year, and two-hundred-year) and the given hydrograph of storm surge and astronomical tide. Our simulated result indicates that the inundated depth, area and inundated risk increase with storm surge. It can be also found that the impact of storm surge arises in the lagoon and estuary together with both sides of tide reach of rivers which result in higher inundation depth, area and risk. This can be physically explained because these areas are significantly affected by storm surge.

並列關鍵字

storm surge ； inundated potential ； inundated risk ； physiographic inundation model