Verification of the detachment–transport coupling relationship of rill erosion using colluvium material in steep nonerodible slopes

PeerJ

article

Libo Chen¹  Pengyu Gao¹  Xiaolin Li¹  Qin Zhu¹  Zumei Wang¹  Fang Shuai¹  Yue Zhang¹  Jinshi Lin¹  Yanhe Huang¹  Fangshi Jiang¹ 

[1] Jinshan Soil and Water Conservation Research Center, Fujian Agriculture and Forestry University

关键词: Colluvium deposit;    Flume test;    Rill flow;    Steep slope;    Water erosion;   

DOI  :  10.7717/peerj.14766

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

The detachment–transport coupling equation by Foster and Meyer is a classical equation that describes the relationship between detachment and transport. The equation quantifies the relationship between sediment loads and soil detachment rates, deepens the understanding of soil erosion and provides a reliable basis for the establishment of an erosion model. However, the applicability of this equation to slopes with gradients greater than 47% is limited. In this work, the detachment–transport coupling relationship is investigated using the colluvium material of Benggang. A nonerodible rill flume 4 m long and 0.12 m wide was adopted. The slope gradient ranged from 27% to 70%, the unit flow discharge ranged from 0.56 × 10−3 to 3.33 × 10−3 m2 s−1, and the sediment transport capacity (Tc) was measured under each slope and discharge combination. The sediment was inputted into the flume according to the predetermined sediment addition rate (from 0% to 100% of Tc), and the detachment rate (Dr) under each combination of the slope and discharge was measured. Dr linearly decreased with increasing sediment loads, which is consistent with the detachment–transport coupling equation by Foster and Meyer. The linear equations can predict the detachment capacity (Dc) and Tc well (Nash–Sutcliffe efficiency coefficient (NSE) = 0.98 for Dc, and NSE = 0.99 for Tc). The detachment–transport coupling equation can adequately predict the Dr (NSE = 0.89). However, its applicability to slopes of <47% (NSE: 0.92–0.96) was greater than that to slopes of ≥47% (NSE: 0.81–0.89), and the predicted Dr under Tc levels of 20% and 40% were higher than the measured values, while the predicted value under a Tc level of 80% was lower than the measured value. In summary, the detachment–transport coupling equation by Foster and Meyer can accurately reflect the negative feedback relationship between detachments and transports along steep-slope fixed beds and is suitable for colluvial deposit research. The results provide a basis for the construction of steep-slope colluvial deposit erosion models. In the future, the study of the hydrodynamic characteristics of sediment transport processes should be strengthened to clarify the detachment–transport effect of flows through hydrodynamics.

【 授权许可】

CC BY