Hierarchical Characteristics of River Network in Hanjiang Basin

The structural characteristics of river network in the Hanjiang basin were investigated based on the extracted high-precision digital river network. Combined with surface water frequency maps and river width remote sensing datasets, we analyzed the self-similarity of geometric and topological structure of the river network, as well as the hierarchical characteristics of river width. The results show that convergences of bifurcation ratio, river length ratio, area ratio, and side-branching ratio happen to rivers at stream-orders 1-6, which implies that geometric and topological self-similarity of river networks was fairly fitted at stream orders of 1-6. Moreover, the statistics of hierarchical characteristics of river width show that within the range of self-similar stream-orders, the average river width presents an approximate exponential distribution. The river width ratio is relatively stable at stream-orders 1-6 and the average value is 1.87, indicating that Horton's law is applicable to river width. By comparing the river network parameters before and after exclusion of pseudo-rivers, it is found that rivers with smaller stream-order, length, width and basin area are more likely to dry up, leading to the deviations of the real river network from the structure of self-similarity. © 2021 Peking University.