On the similarity of hillslope hydrologic function: a clustering approach based on groundwater changes

Abstract

Abstract. Hillslope similarity is an active topic in hydrology because of its importance in improving our understanding of hydrologic processes and enabling comparisons and paired studies. In this study, we propose a holistic bottom-up hillslope clustering based on a region's integrative hydrodynamic response quantified by the seasonal changes in groundwater levels ΔP. The main advantage of the ΔP clustering is its ability to capture recharge and discharge processes. We test the performance of the ΔP clustering by comparing it to seven other common hillslope clustering approaches. These include clustering approaches based on the aridity index, topographic wetness index, elevation, land cover, and machine-learning that jointly integrate multiple data. We assess the ability of these clustering approaches to identify and categorize hillslopes with similar static characteristics, hydroclimate, land surface processes, and subsurface dynamics in a mountainous watershed – the East River – located in the headwaters of the Upper Colorado River Basin. The ΔP clustering performs very well in identifying hillslopes with six out of the nine characteristics studied. The variability among clusters as quantified by the coefficient of variation (0.2) is less in the ΔP and the machine learning approaches than in the others (> 0.3 for TWI, elevation, and land cover). We further demonstrate the robustness of the ΔP clustering by testing its ability to predict hillslope responses to wet and dry hydrologic conditions, of which it performs well when based on average conditions.

Dynamic mechanism of check dams on evolution of river corridors based on UAV telemetry combined with numerical simulations

“…Driving force, structural elements and hydrodynamics are the three elements of hydrological similarity of watersheds, where driving force (external energy and water input) and structural elements (vegetation, topography, geology, etc.) determine the dynamics mechanism of hydrological cycle of watersheds (Maina et al, 2022; Sawicz et al, 2011). In selecting similar watersheds, we prioritized the proximity of watersheds, which, to some extent, can ensure the consistency of their driving forces (meteorological conditions) and structural elements.…”

Elucidating the response mechanisms of hydrological and sediment connectivity to the river network structure, vegetation, and topographic features in the Jinghe River Basin

“…The TWI is an essential parameter for describing the spatial pattern of soil moisture (Li et al, 2020), which is often used to demonstrate the response of topography to hydrological processes (Maina et al, 2022; Meles et al, 2020) and the potential for possible surface runoff, calculated as follows: where A s is the contributing area above the analysis point and β is the cell slope.…”