Author(s): Rocío A. Céspedes; And Carlos A. Bonill
Linked Author(s):
Keywords: Largest events; Sediment yield; USLE; Water erosion; WEPP
Abstract: Sediment delivery to rivers and streams affects water quality and aquatic ecosystems. Nonetheless, its measurement is not common. The objective of this study was to build a relationship between soil loss, rainfall erosivity and soil erodibilit y at event scale in order to obtain a simple linear model for sediment delivery prediction. A series of Universal Soil Loss Equation (USLE) plots were simulated with the Water Erosion Prediction Project (WEPP) model for 83 sites located in Central Chile. The analysis included 56 actual soil series and more than 12, 000 water erosion events. The USLE at event scale performed well for soils with less than 4%organic matter. However, almost half of the soil series used had organic matter contents> 4%, thus an additional model for soils in this range of organic matter content was built. Results showed a strong linear relationship between storm erosivity and sediment delivery, so this regression was used as a predictive model (Model 1) .Model efficiency was improved by adding the baseline rill erodibility to the model (Model 2) .Model 2 had a good performance for both soils with less and more than 4%organic matter. On the other hand, it was found that the top 20%of soil erosion events at each site explained 75%of total soil loss in the study area. Therefore, the models were also evaluated considering only these events. The results are encouraging in terms of building a simple model for predicting the sediment discharge.
Year: 2015