Regional Inundation Analysis for Flat Irrigation Areas under Extreme Rainfall Conditions

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Project title

Code/計畫編號

99農科-7.4.1-利-b1(18)

Translated Name/計畫中文名

考慮極端降雨情況下之平坦灌區淹水範圍分析

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=2160780

Year

2010

Start date/計畫起

01-04-2010

Expected Completion/計畫迄

31-12-2010

Bugetid/研究經費

333千元

ResearchField/研究領域

農田水利
土木水利工程

" 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。然而一般低窪地區淹水分析，通常採用二維淹水模式以進行模擬；分析過程除了需要地形基本資料之外，尚需要大量土地利用資料以及局部排水資料，因此難以在短時間之內完成大面積之分析工作。有鑑於目前數值高程資料之解析度已逐漸提昇，詳細的高程資料足以判定水流匯集方向以及局部排水區域，因此僅藉由高解析度之數值高程資料，以判定極端降雨情況下之淹水範圍，應為可行之方式。本研究擬修正傳統數值高程模式之窪陷填平方法，建立新的窪陷判定方式與窪陷區域內之流向決定，以改善計算效率不彰之缺失。此外，有鑑於高解析度之數值高程資料數據量甚為龐大，一般個人電腦無法處理大面積的集水區高程資料，因此本研究將透過空間資料群組之分割與接合方式，以發展數值高程資料之系統性快速分析模式。本計畫研究過程將以台灣地區數個集水區下游之平坦灌區為例，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. A 2-D inundation model is usually applied for flooding analysis in flat areas. In performing the 2-D model, detail topographic data, land use data, and local drainage system record are required, which is a complicate and time-consuming work for a large watershed. Since high resolution digital elevation data is now available in Taiwan, detail digital elevation data can be used to determine flow direction and local drainage boundary. Consequently, delineating the inundation regions under extreme rainfall conditions only based on high resolution digital elevation data is possible. In this study, new methods dealing with “depression area determination” and “flow direction determination in depression area” will be developed to alleviate the computational inefficiency of the conventional digital elevation models (DEMs). Moreover, since the size of the high resolution DEM data is quite large for a large watershed, the data processing can not be conducted in a PC. For this reason, a systematically analytical procedure will be developed through a series of “partition” and “assembling” of the DEM database. The methodology develops in this study will be verified using the topographic data collected from several watersheds including downstream flat irrigation fields in Taiwan. 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)

窪陷填平
數值高程模式
分割與接合
Depressionless
Digital Elevation Model
Partion and Assembling

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Regional Inundation Analysis for Flat Irrigation Areas under Extreme Rainfall Conditions

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