Analysis of water erosion susceptibility at an arid Patagonia watershed in different scenarios

Abstract

Erosion estimates are essential for optimizing soil conservation strategies. Water erosion is one of the main causes of land degradation. Our aim is to study the susceptibility to water erosion and its driving factors of a watershed in the arid northern Patagonia region, using the USLE model (Universal Soil Loss Equation). Remote sensing, GIS and principal component analysis tools have been used to evaluate the average soil loss scenario. In addition, we have also tested soil erosion changes in three possible scenarios according to coverage modifications and anthropic intervention in wetlands. The estimated water erosion rate averaged 27 t ha-1 year-1 but showed high variability in the area. These results concur with the amount of suspended sediments collected in three streams of the basin. The terrain slope factor was shown to exert the greatest control on the variability of water erosion. Among the proposed scenarios, the greatest differences with respect to the average situation corresponded to changes in the erosivity of precipitation rather than changes in coverage or interventios in wetlands. The spatial extension of the analysis was possible due to the combination of the tools used and provided a context that reflected the complexity of the ecological processes. Our results reveal the existence of areas that are sensitive to water erosion, enabling us to establish priorities or scopes of decision with respect to natural resources awareness in arid zones such as this part of Patagonia.