流域水情模擬與預報模式精度與效能提升之研究-總計畫暨子計畫:河道動床沖淤對防洪水位之影響(I)

Abstract

台灣特殊之地理位置使每年遭受洪水、旱災及地震等天然災害侵襲之機率相當高， 尤其颱洪災害之頻率更為頻繁。故如何利用模式計算及掌握流域之逕流量、水庫排洪 量、洪水位、全流域河道水位、暴潮、溢堤處流量、淹水區域及局部河道水理與動床沖 淤等狀況，於平時進行減災方案之研擬及颱風期間應變時的災害境況模擬預警，為當今 防災治水之重要議題。 本研究第一年主要蒐集近年來水理、輸砂演算相關文獻，並進行各方法之比較。文 獻蒐集後開始建立河道輸砂之數學模型，並進行河道動床模式之檢定與驗證。第二年進 行降雨-水位預報模式與河道動床模式邊界條件之整合，並對研究區域案例進行模式之 檢定與驗證，最後評估動床沖淤對洪水位及溢潰堤之影響。第三年工作為延續第二年的 工作，將整合降雨-水位預報模式與河道動床模式，進行現場案例模擬，並以模擬結果 分析模式演算之穩定性及演算速度。另進行情境模擬，以評析不同模擬情境下研究區域 可能發生災害之位置。最後將整合情境模擬資料回饋給其他子計畫，並建構整合模組之 平台。

Because of Taiwan＇s special location, floods, drought, earthquakes and other natural disasters frequently happen. Flood cause by typhoon is the most common disaster, therefore, it is required by using numerical models to simulate and evaluate rivers discharge, reservoir drainage capacities, water levels along the river, sea level, bank overflow, inundation area and both global and local hydraulic and river migration status. Using simulation results for making reduction program of overall planning of river basin management during ordinary days and preventing disasters during typhoons landing time are important issues of water related damage management. This research project in the first year mainly collects and compares recent computational theories of hydraulic and sediments transporting. After, this project starts constructing, calibrating and verifying river sediments transporting numerical models. In the second year, this project starts combing rainfall-runoff predicting model and sediment transporting model＇s boundary conditions, calibrating and validating models by using associated data, and using models to evaluate river moving beds effects on water levels and bank-break. In the third year, this project uses the combining model to simulate in situ cases, and analyses the models＇ efficiency and stability. In addition, we do scenario simulations to evaluate possible flooding areas. Finally, the simulated results are fed back target watershed to other sub-projects for constructing integrated model for the platform.