||今年莫拉克颱風(Morakot)為近50年來最嚴重之水患事件，超出設計標準之驚人降雨量導致河川、區域排水之防洪系統失敗(failure)，加上許多重要流域之地面降雨、河川水位等即時監測資訊相當不足，無法有效掌握流域危險程度及未來災情分析研判而衍生導致相當慘重之複合型災害。因此，藉由整合多水文模式以建立複合型之洪氾淹水風險評估方法實有其必要性。 本整合型計畫主要目的為整合各計畫成果產出之多元水文氣象觀測資料與多種預報模式連結，提供詳盡的預報模擬資訊內容供決策支援平台使用，提出規劃與建置縣市層級之颱洪災防決策支援系統為研究總目標之「颱洪災防數位境況決策支援系統之建立及測試應用」整合型計畫。本研究計畫屬於整合型計畫之第一子計畫：「多水文整合模式模擬與流域颱洪災害風險評估之研究」，計畫中擬銜接目前國內及FEWS_Taiwan中整合之多氣候資料預報模式，如QPESUM、WRF等模式之降水量系集預報成果，並整合包含半分布並聯型線性水庫(semi-distributed parallel-type linear reservoir, SDPLR)及寬度函數瞬時單位歷線(width-function based instantaneous unit hydrograph, WF-IUH)、可調式串列水筒模式(adaptive serial tank, AST)及擴散波模式(diffusive wave)等多水文模式，以提供河川洪水及區域排水系統在多水文模式下之各種可能逕流演算之推估結果組合，並由河川洪氾及區排淹水等相關子計畫進行相關洪災之模擬演算。 研究中擬利用灰關聯分析(gray relational analysis)及模糊隸屬函數進行歷次重大災害之暴雨中心、總雨量、不同降雨長、短延時等降雨型態及降雨強度面積遞減條件，對應逕流及水位上升速率關係及區域暴雨特徵之災害敏感度關係之建立。此外，擬採用多目標分割風險分析法(partitioned multiobjective risk method, PMRM)，進一步以不同降雨水文情境條件輸入多水文模式並銜接河川與區排模式，以進行各種洪氾(flood)與淹水(inundation)之模擬，利用所模擬之各種不同情境結果，計算多水文情境之條件機率值，進而作為颱洪時期在綜合河川系統及排水系統之風險評估(risk assessment)。 本子計畫分年之研究重點，第一年擬利用過去歷史洪災事件及不同水文情境條件進行暴雨情勢特徵與致災風險之關連性分析，進行複合型洪災原因及風險因子篩選研究，並建立區域致災風險因子之關連性與權重，亦即利用歷次重大颱洪或暴雨災害之暴雨中心、總雨量、不同降雨長、短延時等降雨型態及降雨強度面積遞減條件，進一步對應逕流及水位上升速率關係。第二年，擬結合多水文模式之FEWS_Taiwan平台整合，建立多輸入水文資訊之綜合性機率指標及災害風險評估模式。第三年，本計畫預計完成上述多水文模式之整合與流域颱洪災害風險評估模式之發展，並進一步以歷史重大颱洪水文事件之即時水情資料為情境，以進行整合模式分析、研判及災害風險評估等實際案例模擬、測試與驗證。最後，利用氣象、雨情、水情等綜合信息特徵，進行多種水文情境及所引致之複合型淹水災害風險程度評估，並與相關子計畫共同建立輔助各種暴雨水情災害風險模擬與資訊展示、查詢平台。
Typhoon Morakot, hitting Taiwan this year, triggered the worst flooding the island’s seen in half a century. It dumped as much as two meters of rain on parts of Taiwan, and it caused a lot of the flood mitigation facilities for river and drainage systems in some regions. Additionally, the insufficient of the hydrologic monitoring, such as precipitation, river level and discharge, cannot help the authority making the right judgment and decision to prevent the multi-flood damage occurring. Hence, it is needed to establish the risk assessment approach by multi-hydrologic integrated model for multi-flood damage. The main purpose of this integrated project is to offer multi-information forecasting and support to make decision in a frame of decision support system(DSS) by multi-hydrologic models integrating. Therefore, the project, Establishment of the digital DSS for typhoon mitigation and its test application, is proposed for the governments of county and city. This subproject number one, “A study of the simulation of multi-hydrologic integrated model and establish of the risk assessment approach for typhoon flood damage,” belongs the part of the integrated project as above mentioned. First of all, the multi-hydrologic integrated model link the rainfall forecasting productions, such as QPESUM and WRF. Besides, some hydrologic model, such as semi-distributed parallel-type linear reservoir(SDPLR), width-function based instantaneous unit hydrograph(WF-IUH), adaptive serial tank(AST) and diffusive wave based runoff model, are also adopted in this project. Thus, the adopted models are integrated as multi-hydrologic model for the simulation in different kinds of rainfall conditions. In this study, the approach of gray relational analysis is adopted for risk factors screen. Based on the rainfall characteristics of historic flood events, such as storm rainfall center, total rainfall, rainfall pattern, intensity and areal precipitation, to find out the more sensitive risk factors for build the relationship between rainfall characteristics and damage risk. Nevertheless, the method of partitioned multiobjective risk(PMRM) is also adopted for risk assessment The main works in the next three years are described as below: the first year, using the historic record to explore the risk factors, and furthering to build the relationship between rainfall characteristic and river level rising rate. The second year, we have to integrating some rainfall-runoff model as multi-hydrologic in FEWS_Taiwan platform and developing risk assessment for flood damage. The third year, the multi-hydrologic model will be built successful with FEWS_Taiwan platform, and a risk assessment method is also completed establishment for historic events test. Finally, we have to corporate the other subprojects to build the display and inquire system.