ESTIMATION SIZE OF WATER EROSION IN A BASIN OF AL-DOUIGI VALLEY BY USING GEOGRAPHIC INFORMATION SYSTEMS

Abstract

The AL-Douigi basin is one of the seasonal basins in the northeast of the Ali Gharbi district. It is affected by its climatic characteristics within the arid and semi-arid regions and by the nature of rainstorms of varying intensity. It has contributed to the variation in the level of rain falling on the basin areas. In addition, to the contribution of other natural area characteristics to the process of water flow in the basin, especially the terrain, slope, soil and natural vegetation, which affected the form of surface runoff and the occurrence of torrents in the basin. The digital (DEM) using the (ArcGIS) program to extract some of the hydrological characteristics of the basin. The hydrological soils were analyzed using the (SCS-CN) method in classifying land uses. The two layers of hydrological soils and land uses were merged using the (Combine) function in the ArcGIS program, where the value of (CN) was (74-98). The study showed an estimate of the surface runoff depth (Q), which ranged between (119.04-190.23) mm, and the surface runoff volume (QV), which ranged between (0.72-1.61) m³.