VULNERABLE AREAS, THE STREAM POWER INDEX AND THE SOIL CHARACTERISTICS ON THE SOUTHERN SLOPE OF THE LIPOVEI HILLS

Abstract

The purpose of this study is to calculate SPI (Stream Power Index) in relation with the soil texture and to associate the obtained values with the soil permeability classes and, therefore, to identify the vulnerable areas at the action of the drainage processes, starting by the elementary processes associated with rills erosion and gullys to those ravines and torrential organisms. SPI is the product between the slope and the flow accumulation. SPI values are influenced by the slope. Thus, SPI has high values in areas with high slope and SPI has low values in areas with low slope. In the areas with the high slope, the flow accumulation is low and in the areas with the low slope, the flow accumulation is high. The high values of SPI between +1.94 and +3.49 are on the southern slope of the Lipovei Hills and represent 41.05% of the analyzed area. The inclusion of the soil texture in the SPI calculation formula indicates a medium value of SPI also on the southern slope of the Lipovei Hills and represent 42.71% from the studied territory, which corresponds, in particular, to the loamy texture. The loamy texture has moderate permeability and it is characteristic on 22.81% from the southern slope of the Lipovei Hills. Therefore, the southern slope of the Lipovei Hills is affected by the moderate ravine phenomenon and at the contact with the Timiș-Bega Plain the floods and the puddles phenomenon develops.