- 期刊
地理資訊系統及HEC-HMS應用於中小集水區降雨逕流模擬
Rainfall-Runoff Simulation Using GIS and HEC-HMS in Small and Medium Watersheds
摘要
降雨逕流模擬為防災與集水區管理的重要分析之一。本研究結合地理資訊系統(GIS)與HEC-HMS模擬集水區降雨－逕流之情形，並評估模擬結果與集水區面積的關係。藉由地理資料及HEC-GeoHMS模組可以快速劃分集水區並獲取地文因子。本研究應用HEC-HMS模擬降雨逕流時，降水損失以SCS之CN法估計，單位歷線轉換則以SCS三角歷線法為之，退水段以退水常數進行模擬。其中參數之設定，以程式提供之參數優選為之。模擬結果以體積誤差(EQ)、洪峰流量誤差(EQp)、峰值到達時刻誤差(ETp)及效率係數(CE)等四項標準評估模式之適用性。本研究選取全台15個中小集水區進行模擬，以淡水河流域之寶橋站為例，模擬結果其平均CE值可達0.87，平均EQ與EQp分別為14.04%與16.2%，而ETp值平均為1.2小時。結果顯示，結合地理資訊系統與HEC-HMS可以快速獲取集水區地文、水文資料而有效率地進行水文降雨逕流模擬，且可得到良好模擬結果。而由結果亦可發現集水面積愈小愈能符合降雨空間分布均勻的假設，故小集水區模擬結果較佳。
並列摘要
Rainfall-runoff simulation is one of the major analyses for hydrological design and watershed management. In this study, we integrated Geographic Information System (GIS) and HEC-HMS to simulate catchment rainfall-runoff and assessed the advantages and disadvantages of simulation results. Watershed can be divided quickly by using geographic data and HEC-Geo HMS module. When it was under HEC-HMS rainfall-runoff simulation, the precipitation loss is estimated by SCS CN method, unit hydrograph is translated by SCS UH and recession is simulated by recession constant. The parameters were decided by parameter optimum function offered by this program. The simulation results were evaluated by Error of Total Discharge (EQ), Error of Peak Discharge (EQp), Error of Time to Peak (ETp) and the efficiency coefficient (CE). The results showed that combination of geographic information system and the Hec-HMS can quickly obtain the hydrological and geological parameters of watershed and simulation results show good performance. Bao-chou watershed, for example, the average CE value was 0.87, average EQ and EQp were 14.04% and 16.2% respectively and average ETp was 1.2 hours. The results show that GIS and HEC-HMS are extremely effective and can be powerful tools for rainfall-runoff simulation. Under the uniform assumption of rainfall spatial distribution, the smaller the catchment area is, the better the simulation result is.