QUANTITATIVE ANALYSIS USING GEOSPATIAL MODELING OF AL-RAHIMAWI WATERSHED'S SHAPE PROPERTIES IN THE IRAQI SOUTHERN DESERT

Abstract

This paper included the study of Al-Rahimawi drainage basin, one of the watersheds in the Iraqi southern desert. It represents one of the hydro-geomorphological systems so-called Lower Valleys Region, according to the geomorphological division of Iraq. A set of geomorphometric parameters were used for the morphological characteristics of the Al-Rahimawi watershed, which gave precise consequences about this valley's geomorphological features and the erosive phase. The parameters used in this study are the circulatory ratio (RC), form factor (Ff), elongation ratio (Re), compactness factor (CC ), lemniscate ratio (k), and length/width ratio (R/W). In addition to using the digital elevation model (DEM) type SRTM and the satellite image of the American satellite Landsat ETM+8. The results indicated that the circulatory ratio was 0.154, suggesting that the watershed moved away from the circular shape. Also, the value of the form factor was low, reaching 0.098, which suggest that the watershed is close to the triangular shape. The results also demonstrated that the elongation ratio was low, reaching 0.353, indicating that the watershed is close to the rectangular shape. In addition, the value of the compactness factor was high, reaching 2.415. There is a rise in the lemniscate ratio, with a value of 2.551, indicating progress in the erosion cycle stages. The results suggested that the length-to-width ratio reached 5.054, which is a high percentage.