Modified Numerical Method for Improving the Calculation of Rill Detachment Rate

Abstract

A rational calculation of the rill detachment rate (RDR) and an accurate simulation of the rill detachment process are important for determining the model parameters of hillslope erosion. Here, we found a difference between RDRs calculated using different methods that cannot be ignored. This study proposes a modified numerical method based on the dataset of the measured sediment concentrations along the rill length over a saturated loess soil slope to improve the calculation of RDR. For the saturated loess soil slope, the modified numerical RDR reduced the relative error from 58.3% to 4.6%, thereby demonstrating the efficiency of the modified numerical method. Furthermore, datasets of previous studies on different soil types and rill width verified the accuracy and applicability of the modified numerical method. A measurement strategy with more sampling points set at the forepart of the rill is proposed to enhance the calculation accuracy of RDR in accordance with the absolute error distribution between numerical and modified numerical RDRs. This study contributes to the literature by correcting previous data, improving data for subsequent measurements, and supplying a basis for the accurate estimation of RDR for rill erosion modeling.

Keywords

• detachment rate
• rill erosion
• WEPP model
• modifying
• rill length