Influence of Extreme Rainfall Distribution on Inundation in Flat Irrigation Areas

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Project title

Code/計畫編號

100農科-7.4.1-利-b1(16)

Translated Name/計畫中文名

極端降雨分佈型態對平坦灌區淹水影響之研究

Project Coordinator/計畫主持人

Kwan-Tun Lee

Funding Organization/主管機關

Council of Agriculture,Executive Yuan

Department/Unit

Department of Harbor and River Engineering

Website

https://www.grb.gov.tw/search/planDetail?id=2366098

Year

2011

Start date/計畫起

01-06-2011

Expected Completion/計畫迄

31-12-2011

ResearchField/研究領域

農田水利

"隨著全球氣候變遷，水文異常現象頻繁發生，工程師必須妥善因應超過工程保護標準之降雨情況，所帶來的巨大災害。為考慮集水區下游平坦灌區淹水問題，研究中將建立零慣性波模式，並將模式計算範圍內之格點區分為漫地流與渠流格點，藉以推求計算範圍內任一格點之逕流量與逕流深度。囿於現有的雨量測站與目前衛星遙測技術於降雨預測之不確定性，水文模式演算所需的降雨輸入，一般多仍藉由點降雨資料經徐昇式法、等雨量線法或算術平均等數學方式處理後，而忽略降雨因地形或區域對流特性所導致之空間變異。研究中將採因次分析方式，探討影響研究灌區逕流特性之相關控制變因；而後擬採用Luyckx et al. (1998)所提出之雙變量高斯分佈(bivariate Gaussian distribution)函數，建立可反應空間與時間分佈之降雨模式，以推估不同極端降雨情況之假設條件。本計畫研究過程將以花蓮縣玉里鎮之春日排水集水區為研究區域，分析極端降雨情況，所產生之平坦地淹水範圍。分析結果將有助於相關單位瞭解超過設計保護標準之狀況下，所將產生之鉅額農業損失。" "The global climate change has resulted in frequently hydrological disasters recently; consequently, engineers should prepare for disaster mitigation under the possible extreme rainfall conditions. To further consider flooding problem in downstream flat areas, a noninertia-wave model was developed for inundation. And grids in computing area will be divided into overland flow and channel flow grids to obtain each grid’s flow discharge and runoff depth. Due to limited available rain gauging stations and the uncertainty of current remote sensing technique in rainfall prediction, the rainfall input in hydrological simulations was usually through Thiessen polygons method, isohyetal method or arithmetical averaging method with available rainfall data. Consequently, the rainfall heterogeneity induced from topography or local convection is not considered. Dimensional analysis will be used to explore the impact of the?relevant control variables in irrigation?runoff characteristics and adopted bivariate Gaussian distribution function proposed by Luyckx et al. (1998) to develop a fully-distributed rainfall model which can reflect the?space and time to obtain?the assumptions in different extreme?rainfall?situation. The methodology develops in this study will be verified using the topographic data collected from Chun-Jih Drainage basin in Hualien county. Extreme rainfall conditions will be performed to investigate the extent of the inundated regions. The analysis results can provide helps for the authorities to realize the possible agricultural losses under extreme hydrological cases."

Keyword(s)

零慣性波
空間變異降雨
高斯降雨分佈
Non-inertia Wave
Spatial-Variability Rainfall
Gaussian Rainfall Distribution

DSpace CRIS

Influence of Extreme Rainfall Distribution on Inundation in Flat Irrigation Areas

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