In this study, the CCHE-2D model was adopted to simulate a river segment of the upper Bie River below bridges No. 5 and No. 6. The target species for the simulation was Onychostoma alticorpus because this fish population is small and it is an endangered species. Before the suitability index were calculated for each element and
importing the data into ArcGIS, three tools for spatial interpolation—Natural Neighbor, Kriging, and Inverse Distance Weighting—were adopted from ArcGIS to calculate the weighted usable area and the percent of usable area under low flow discharge. Then, the ecological base flow was assessed from the results of weighted usable area and percent of usable area. According to the results, the percent of usable area is more suitable for calculating the ecological base flow.The ecological base flow of Bie River was determined to be 0.5 cms.
Keywords: suitability index value, spatial interpolation analysis, ecological base flow, Onychostoma alticorpus