Hydrologic signature of intermittent channel networks in small-scale river basin

Abstract

This study aims to figure out the recession flow patterns embedded in the hydrologic data in terms of the geomorphologic features of river basins. To this end, based on the scaling relation of channel networks to source basin areas, we modify the geomorphologic recession flow model originated by Biswal and Marani (2010), and verify its validity through power law distribution of drainage areas and Hack’s law. There exists a distinct difference in the recession flow patterns between the whole body of data and the individual event data for the basin of interest, and the latter tends to have a similar pattern in common at the different scales of discharges. Both geomorphologic recession flow models reflect the recession flow patterns in the hydrologic data. The maximum likelihood method produces reliable estimates of the lower limit of mass aggregation patterns in river basins. The exponentially tempered power law distribution gives rise to very similar results to the scaling relation of channel networks to source basin areas. The recession flow patterns of the basin of interest could be reflected in the behavior of intermittent channel networks which follows the fractal nature of fluvial processes. The inconsistent recession flow patterns inferred from Hack’s law could be attributed to the spatial scale of the basin, implying that Hack’s law might have a valid domain at a larger scale than the basin of interest. Nevertheless, consistent trends could be found between the power law distribution of drainage areas and the scaling relations of channel networks to source basins areas, which are directly related to Horton ratios and the fractal dimensions. So, the geomorphologic recession flow model modified in this study could be a useful tool to analyze the recession flow pattern for river basins regardless of the basin scale.