Cubicación de cuñas de sedimentos mediante GPS de precisión y comparación de modelos digitales del terrenoestimación de la erosión en la sierra de Ávila

Abstract

Determining the volume of trapped sediment in retaining check dams is of great interest to estimate erosion rates. Many forest-hydrological restorations were carried out in our country to stop soil degradation because of great losses of soil, which generates serious problems such as reservoirs siltation. There are different methods to calculate the retained sediment volume and determine the erosion rates in their basins. The aim of this paper is to show a new method to determine the volume of retained sediment in check dams, based on the use of differential GPS, computer programs for spatial data processing, and comparing digital terrain models. The method is applied to a sample of ten check dams, which were built in 1964 by the Duero Hydrographic Agency. Erosion rates were also calculated based on the volume of retained sediment and the obtained results were compared with those obtained by means of the geometric Prism method. It can be concluded that the proposed method is reliable and highly accurate. The estimated values __are higher up to 20% on average than those obtained by means of the geometric Prism method. The accuracy of the proposed method is interesting for future researching and designing in forest-hydrological restorations.