A Preprocessing Program for Hydrologic Model—A Case Study in the Wei River Basin

Works of hydrologic model development at the preliminary stage, e.g., determination of flow direction and the order of flow concentration, extraction of drainage network, and spatial interpolation, are very important. In this paper, a preprocessing program is developed with multiple functions for data preparation in hydrologic model. The method in graph theory is used to determine the flow direction, and filling of sink is avoided in this study. A new method, the so-called leaf clipping method, is proposed for watershed division, and the order of runoff concentration is determined according to the flow direction and DEM data. This preprocessing program is developed by using Visual Basic language, detailed algorithms are presented and the program is demonstrated through a case study in the Wei River basin. It shows that this program is useful and helpful for the application of hydrologic models which only needs digital elevation data sets.