A Physically—Based Geometry Model for Transport Distance Estimation of Rainfall-Eroded Soil Sediment

Qian-Gui Zhang,Wen Nie,Guo-Qiang Li,Run-Qiu Huang,Xiao-Peng Su,Yi-Xin Liu

doi:10.3390/app6020034

Abstract

Estimations of rainfall-induced soil erosion are mostly derived from the weight of sediment measured in natural runoff. The transport distance of eroded soil is important for evaluating landscape evolution but is difficult to estimate, mainly because it cannot be linked directly to the eroded sediment weight. The volume of eroded soil is easier to calculate visually using popular imaging tools, which can aid in estimating the transport distance of eroded soil through geometry relationships. In this study, we present a straightforward geometry model to predict the maximum sediment transport distance incurred by rainfall events of various intensity and duration. In order to verify our geometry prediction model, a series of experiments are reported in the form of a sediment volume. The results show that cumulative rainfall has a linear relationship with the total volume of eroded soil. The geometry model can accurately estimate the maximum transport distance of eroded soil by cumulative rainfall, with a low root-mean-square error (4.7–4.8) and a strong linear correlation (0.74–0.86).

Highlights

Surface transport distance of sediment is an important consideration when evaluating and predicting sediment transportation and landscape evolution resulting from rainfall-induced soil erosion in mountainous regions
(1) For example, Limburg Soil Erosion Model (LISEM) is a physically based, hydrological, and soil erosion model for simulating the hydrology and sediment transport during and immediately after a single rainfall event applied in an agricultural catchment of a size ranging from 1 hectare up to approximately 100 km2 [6]; Bennett [7] provides three equations that describe the movement of suspended sediment particles in a one-dimensional, infinitely wide, free-surface flow
High simulated rainfall intensities in our experiments result in the rapid appearance of surface water runoff

Summary

Introduction

Surface transport distance of sediment is an important consideration when evaluating and predicting sediment transportation and landscape evolution resulting from rainfall-induced soil erosion in mountainous regions. (1) For example, Limburg Soil Erosion Model (LISEM) is a physically based, hydrological, and soil erosion model for simulating the hydrology and sediment transport during and immediately after a single rainfall event applied in an agricultural catchment of a size ranging from 1 hectare up to approximately 100 km2 [6]; Bennett [7] provides three equations that describe the movement of suspended sediment particles in a one-dimensional, infinitely wide, free-surface flow. Widespread overland flow is simulated using an exponential distribution parameterized by the calculated median travel distance These data only relate to relatively coarse particle sizes, Parsons et al [9] find that they adequately predict rates of movement of finer particles. Concentrated flows are simulated with an exponential distribution function parameterized using the median transport distances, based on the review of available data by Hassan et al [10]

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Discussion

Conclusion