WinBasin: Using improved algorithms and the GIS technique for automated watershed modelling analysis from digital elevation models

Abstract

Abstract WinBasin is a GIS‐based watershed analysis system that can automatically calculate depressionless flow directions, delineate watersheds/sub‐watersheds, extract realistic drainage networks, and calculate geomorphological indices and hydrological responses from digital elevation models. Several improved algorithms coupled with GIS techniques were proposed for automated watershed analysis. First, different from depression fill‐up treatment methods, the depression watershed method coupled with the improved fuzzy c‐mean algorithm allows the depression outlet location and flow directions to be determined. Second, by using the GIS‐based point‐and‐click interface coupled with outlet‐tracing and headwater‐tracing algorithms, watersheds with user‐specified outlets and realistic drainage networks can be easily extracted based on the derived flow directions. The analysed results can be exported to vector format for linkage with other GIS software. Third, the geomorphological indices and hydrological responses (width function and geomorphological instantaneous unit hydrograph) in a watershed can also be instantly derived based on the proposed algorithms and the GIS technique. Keywords: Automated watershed analysisDepression watershed methodOutlet‐tracing algorithm (OTA)Headwater‐tracing algorithm (HTA)Geomorphological instantaneous unit hydrograph (GIUH) Acknowledgement This research was supported by grants (NSC95‐2625‐Z‐451‐001 and NSC95‐2625‐Z‐005–004) from Taiwan's National Science Council.