Modelling sediment transport capacity of loessial slopes based on
effective stream power
Abstract
The sediment transport capacity must be considered because it provides a
theoretical basis for accurate prediction of soil erosion. Existing
studies tended to study sediment transport capacity using a particular
soil, but the models derived from one kind of soil cannot be applicable
to other soil types. To obtain a prediction model for a variety of soils
and evaluate its applicability, sandy loess and loess soil (d50=0.095 mm
and d50’=0.04 mm) were chosen in the indoor artificial simulated
sediment transport experiments. The experimental slopes ranged from 7%
to 38.4% and the unit discharges were adjusted from 0.00014 to
0.00526m2/s. Moreover, this study combined the experimental data with
cohesive soil and cohesionless sand from four scholars so as to analyze
the response relationship between sediment transport capacity and each
flow intensity parameter through dimensionless processing. Results
showed that the dimensionless sediment transport capacity varied with
its power function relationship with the flow intensity parameters.
Through analysis, the effective stream power could be seen as an optimum
indicator (R2=0.9692). After considering the effective stream power and
volume sediment concentration, this study derived a formula for
calculating the sediment transport capacity. It was better than the
ANSWERS (Areal Nonpoint Source Watershed Environment Response
Simulation) model, improved WEPP (Water Erosion Prediction Project)
model, Zhang’s formula and Ali’s model due to its superior applicability
to cohesive soil and cohesionless sand. These findings lay a basis for
establishing prediction models of soil erosion.