Terrain morphometry and soil erosion topographic factor (LS) in upper Alazani basin (Georgia)

Abstract

Terrain morphometry, landforms, and the resulting LS component are generally acknowledged as important factors in soil erosion studies. The aim of this research was to identify and analyze terrain morphometric elements in the upper Alazani basin, as well as determine their impact on soil erosion. We examine terrain morphometry, identify landforms, and calculate the LS factor for the upper Alazani valley in this analysis. Arc map 10.8 was used to perform all calculations. For the measurements, an SRTM 1 arc-second DEM (resolution 30m) was used. The slope angle and slope aspect were calculated using the D8 algorithm. MFD analysis was used in order to calculate the flow path. As a result of it The flow accumulation was computed. Stahler’s method was chosen to calculate stream order, which allows drainage density to be calculated. The slope position and the topographic position index (TPI) were computed. TPI values were obtained in order to obtain landforms. The MFD algorithm was used to compute the LS factor. In general, the LS factor is higher in Alazani’s left tributaries than in its right tributaries. The maximum values were found in the Alazani headwaters, in the Samkuristskali channel, which is a tributary of the Alazani, and in the Stori channel. These results demonstrate that the upper Alazani valley has a high erosion potential. Future work should concentrate on the DEM resolution, which also has an impact on overall soil loss.