Research on soil detachment rate and hydrodynamic parameters of dip/anti-dip slope in simulated karst trough valley

Abstract

Bedding dip has an important influence on soil detachment and flow hydrodynamics in a karst trough valley. The laboratory rainfall simulation was conducted with three bedding dips (bare slope, dip slope and anti-dip slope) under three rainfall intensities (30, 60, 90 mm h−1). The characteristics of soil detachment and hydrodynamic parameters were assessed, including water flow shear stress, stream power, unit stream power and unit flow energy. The significant effects of bedding dips and rainfall intensities and their interactions on soil detachment and hydrodynamic parameters were examined. The results showed that (1) the soil detachment rate decreased with increasing rainfall duration, and the soil detachment rate in 30° bedding dip of dip slope was much larger than those in bare slope and anti-dip slope in most rainfall intensities; (2) the 60° bedding dip of dip slope was the threshold that controlled the stream power, unit stream power and unit flow energy increased or decreased under different rainfall intensities; and (3) the soil detachment rate had extremely significant positive power relationships with water flow shear stress, stream power, unit stream power and unit flow energy. Meanwhile, the stream power was the most suitable parameter for predicting soil detachment in a karst trough valley slope. Therefore, these results could provide useful information for soil erosion prediction in a karst trough valley.