Influence of surface cover type on sediment transport capacity and sediment retardation benefits based on flume experiments

Abstract

Sediment transport capacity (Tc) is a critical parameter in predicting soil erosion, and surface cover has been found to be an effective means for reducing Tc. However, limited research exists regarding the influence of surface cover types on Tc, and the sediment retardation benefits (SRB) of surface cover types are unknown. The aim of this study was to investigate the impact of different surface cover types on Tc and SRB. Therefore, a sets of flume experiment were conducted under controlled conditions, featuring a fixed slope gradient (S = 25.88 %), a constant unit flow discharge (q = 2.70 ×10^–3 m² s^–1), and three common types of surface cover commonly found on slope farmland: corn residue, rock fragment, and sweet potato). These experiments also included seven coverage levels (C = 0, 5, 10, 20, 30, 50 and 70 %) with water and sediment samples collected at regular intervals. The results showed that the relative sediment transport capacity (R_T) had a negative exponential function with a C under different surface cover types (R²>0.8). Sweet potato exhibited the most effective SRB under the same C. SRB stabilized when the C of different surface cover types reached 30 %. The equations for predicting sediment transport capacity were improved. The results may contribute to the theoretical understanding of sediment transport processes under surface cover conditions and provide a foundation for the informed selection of soil and water conservation measures.