Modelización de la pérdida de suelo en una cuenca endorreica del Pirineo oscense

Abstract

Erosion is a serious threat in Mediterranean regions, therefore assessment and quantification of soil losses at watershed scale is necessary. To promote soil conservation and assess the vulnerability of wetlands in the Estanque de arriba catchment, which is located in the province of Huesca (Spain), the semi-empirical soil erosion model SEMMED has been used. This model is based on the assessment of both the splash detachment and the runoff transport capacity rates per raster cell within the catchment to obtain a final map of annual soil erosion rate. Integration of the digital elevation model of the study area and the climatic and analytical database in the ArcGIS 9.0 has allowed generating maps for the different parameters and factors. In order to obtain the required values a field survey was carried out collecting a total of 80 samples of soil. The cumulative overland flow map has been calculated with the single flow, multiple flow and combined flow algorithms. The multiple flow algorithm has showed up as the best approach for modeling the drainage pattern of runoff, especially in flat areas. The mean splash detachment and transport capacity rates are 11.79 and 9641.28 kg m-2, respectively, whereas the mean rate of annual soil loss is 9.02 kg m-2 year-1. Crops of cereal and paths present the highest rates of soil loss, whereas the areas associated with sandy loam textures and high values of saturated hydrological conductivity present the lowest values. The external and internal boundaries of the catchment are characterized by no erosion processes.