Mapping Environmental Risk Degradation Under Climate Stress and Anthropogenic Pressure: Case Study of Abdeladim Watershed, Tunisia

Abstract

Nowadays, natural resources are exposed to an increased risk of degradation due to climatic constraints and human pressure. In this context, our research aims to study of the sensitivity of agricultural land in the Abdeladim watershed by mapping the evolution of the hydrographic network (between 1963 and 2016) and assess the susceptibility to soil quality and loss degradation. The objective of this typology was the selection of typical or most representative catchment areas of the Tunisian Dorsale. Among the watersheds studied, the latter is the least watered but the most eroded. It is typical of the aggressiveness of the semi-arid climate of central Tunisia and the sensitivity of the environment to water erosion. To explain this situation, our research was based on a diachronic study of the water system and on a multi-factor study (pedology, slope, land use…) all within the framework of a GIS. Thus, the study of the evolution of the river system (1963–2016) showed a tendency to increase the number of wadis, their length and their width. This development is mainly achieved by the processes and mechanisms of water erosion carried out by concentrated flow (linear, regressive and lateral erosion). This results from the action of two main factors, one is anthropogenic the other is natural. On the other hand, the study of the potential sensitivity of agricultural land in the Abdeladim watershed reveals a growing sensitivity to the degradation of its agricultural potential both by soil loss and by the reduction of quality of the latter. This is the result, on the one hand, of climatic conditions (aridity) and, on the other hand, of anthropogenic use not adapted to the potential of soils. Thus, several measures must be taken to combat the erosion of agricultural land in the Abdeladim watershed. The main aim is to rationalise the human use of soil and water resources and to treat the slopes of waterways by installing anti erosion scheme.