Hydrologic Response Differences Between Drainage Network Classifications

Basin drainage networks have been grouped into classifications such as dendritic, parallel, pinnate, rectangular and trellis based on their planform structures. While it has long been known that the size and shape of a drainage basin affect its hydrologic response to precipitation events, the effects of the network organization have not been investigated as extensively. The objective of this work is to simulate and analyze the instantaneous unit hydrographs (IUHs) and hydrologic responses of networks from different classifications for potential systematic differences between the classifications. That goal is accomplished by calculating the IUH for ten previously-classified basins of each network type listed above using a spatially-distributed travel time (SDTT) model applied to the outlet flow length distributions (i.e., width functions) of each drainage network. We find that the width functions, IUHs and the resulting hydrologic responses of the different network classifications are each largely distinguishable from one another based on statistical tests of their moments. Additionally, we find that the differences in hydrologic responses are at least partially independent of the differences in the basin vertical characteristics, as represented by the slope-area relationships. The results indicate that network classification-dependent inputs to semi-distributed rainfall-runoff models could improve model performance.