臺灣的地形陡峭，地質支離破碎，伴隨強降雨和颱風，使臺灣成為一個易受地質災害、水文災害和復合災害影響的國家。隨著人口與經濟開發的成長，在土地有限的情況下，諸多山坡地地區已被開發成人類居住的地區，且往往許多居住的地區是溪流的谷口。殊不知當土石流發生時，該地區是土砂大量堆積的土石流扇狀地地區，並造成巨大的生命和財產損失。土石流是一種自然現象，如果總是使用工程構造物來抵禦土石流，那麼河流的整體輸砂平衡則失去了平衡。在土石流之災害防治對策上，屬於軟體之土石流預警系統、土石流扇狀地之危險區域範圍劃定，尤為重要。
蔡元芳(1999年)和曾文孝(2002年)先後在開發了二維土石流數值模式，但兩者皆缺少了使用者介面(UI)。本研究採用跳蛙法離散土石流基本方程式，入流邊界位於上游邊界上，入流邊界以外皆為開放邊界。當離散對流項時，因使用上風法將虛擬邊界條件添加到離散方程式。此外，為了使模式有更高的使用效率，並使模式之使用更加容易和廣泛。本研究整合Q-GIS與二維土石流數值模式，並簡化了複雜的跨系統操作，如：數據預處理、土石流入口點設定及參數設置。
最後，本研究成功地將二維土石流數值模式與Q-GIS整合在單一集成系統中。透過自動鍵入輸入圖層之數據資料和高級參數設置，通過允許使用者選擇打開或關閉高級參數設置，構建一個數值模式，以避免複雜的跨系統操作錯誤。本研究以莫拉克颱風期間發生的新開土石流為案例研究，以確認整合系統之有效性。對比整合系統之演算後影響邊界，十分接近歷史影響邊界，重疊率達到81%。模擬結果合理且可接受。

Taiwan’s geology is steep and geologically fragmented coupled with heavy rainfall and tropical cyclones let Taiwan become a country, which is vulnerable to geological disasters, hydrological disasters and compound disasters. The place where human often live on the hillside is the valley of the stream but do not know when the debris flow occurred, the area is a large amount of sediment of the debris-flow fan shaped land, resulting in a great loss of life and property. The debris flow is a natural phenomenon, if always use structures to defense the debris flow, then the overall sand transport balance of the river is lost the main source of gravel materials.
Tsai (1999) and Tseng (2002) developed 2-D debris flow numerical model development in National Cheng Kung University, but both of their models are short of user interface (UI). This study used leap-frog method to discrete basic equation of debris flow. About boundary condition, inflow boundary is on the border in upstream side and all the other sides are the open boundary. Moreover, add the virtual boundary conditions to discrete convection set. In order to improve efficiency and make using of numerical model easier and more widespread. This study uses the Q-GIS as the GIS to integrate. Additionally, this study simplifies the cross-system operational such as preprocessing of data, ensuring the entrance point and setting the parameters in the single integrated system.
Finally, this study integrated the advanced 2-D debris flow numerical model with Q-GIS in the single integrated system successfully. Built a function to avoid simulated wrong stream by automatically modified and advanced parameter function to let the user choose to turn the advanced function on or off. This study choosed the Xinkai debris flow occurred during typhoon Morakot as the case study to improve the efficacy of integrated system. The border of simulated influence area close to the border of historical influence area. Additionally, the overlap rate reached 81%. The simulation result is reasonable and acceptable.

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Web source:
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