Algorithm for Delineating and Extracting Hillslopes and Hillslope Width Functions from Gridded Elevation Data

Abstract

AbstractThe subdivision of catchments into appropriate topography-based hydrologic units is an essential step in rainfall-runoff modeling, with the hillslope serving as a common fundamental unit for this purpose. Hillslope-based modeling approaches can utilize, for instance, the hillslope width function as a one-dimensional representation of three-dimensional landscapes by introducing profile curvatures and plan shapes. In this work, an algorithm was developed to delineate and extract hillslopes and hillslope width functions based on a new approach to calculate average profile curvatures and plan shapes from digital terrain data. The proposed method uses fuzzy logic rules and provides a quick and reliable assessment of hillslope characteristics, classifying hillslopes according to nine elementary landscapes (the so-called Dikau shapes). The algorithm was first tested on two contrasting (flat and steep) catchments in Quebec, Canada. The hillslope width functions obtained with the proposed method were able ...