不同網格解析度與流向演算法對蓮華池集水區地形指標之影響

The purpose of this paper is to study the effects of different grid resolutions and flow direction algorithms on the topographic index in the Lien-Hwa-Chi watersheds No.4 and No.5. The results show that topographic indices with higher values are located near valleys or streams where there are greater cumulative upslope areas and flatter gradient. In addition, when the grid resolution decreases, the mean value of topographic indices will increase due to the decrease of slope. Because the multiple flow direction algorithm results in lower gradient than those of the deterministic-8 and deterministic-infinity flow direction algorithms, the mean value of topographic indices calculated by the multiple flow direction algorithm is the highest on the basis of the same gird resolution. Furthermore, the hydrological similarity is compared between the Lien-Hwa-Chi watersheds using the Kolmogorov-Smirnov test. Based on the topographic index, Lien-Hwa-Chi watersheds No.4 and No.5 have the same hydrological similarity.