The influence of topography on the subsidence processes of loess-like deposits from Sălcuța Plain (South-Western Romania)

Abstract

This paper aims to establish the role of the local topography of Sălcuța Plain (subdivision of the Oltenia Plain) in the subsidence process of loess-like deposits. The relevant features of the topography, especially the slope, were generated using SAGA GIS v.7.8.0 and QGIS v.3.22 software based on an altimetric terrain model. The results obtained highlight the fact that 303 microdepressions were formed following the chemical and mechanical subsidence of the loess deposits. The most important characteristic, which conditions the genesis of the subsidence process and implicitly the formation of microdepressions, is the slope; in this case, the subsidence process occurs in areas where the slope has values lower than 2 degrees. The research advanced by generating the Topographic Wetness Index (TWI) in order to identify areas with moisture excess, the moistening of loess-like deposits being one of the basic conditions in the genesis of the subsidence process. The highest values of the Topographic Wetness Index (TWI), over 10, were recorded in the areas with microdepressions.