Forest operations and sediment concentration in natural streams II: Analysis of sensibility and comparison with other models

Abstract

In this study, a model to estimate the sediment concentration in natural streams of forest river basins proposed by Fuentes et al. (2001) is analyzed and validated. The estimations are also compared with those obtained using two models proposed by other authors. The results, when using the model, allow estimations with R2 coefficients over 0.90. The model is statistically significant to 99% and does not present auto-correlation.
After comparing the models developed by Dendy and Bolton (1976) and Fleming (1969), it was observed that the best estimation of sediment concentration was obtained using the proposed model by Fuentes et al. (2001). This was because the other models gave an over-estimation of values. On the other hand, and based on the analysis of sensibility, it was possible to conclude in this case that precipitation and discharge explained the main part of sediments. These are increased when the forest harvest leaves the soil bare and susceptible to erosion by rain. These results demonstrate the convenience of using this type of model to estimate the sediment production in a microbasin of the Eighth Region of Chile, which have similar hydrological and forest characteristics.