Application of (SCS-CN) Method in Runoff Estimation in Qoratu Watershed Using (GIS & RS) Techniques

The method of Soil Conservation Service Curve Number (SCS-CN) was applied to assess runoff in Qoratu Watershed, Garmian Administration, (NE-Iraq). Digital Elevation Model (DEM-12.5m) and (Landsat OLI) were both utilized as the stuff of Geographic Information System (GIS) and Remote Sensing (RS) techniques analyzed to obtain accurate hydrological data. Qoratu watershed is a mutual (Iran-Iraq) watershed located within the Iraqi Kurdistan Region adjacent to the Sirwan River. Topographically, the study area is known as the sub-mountain area of the Kurdistan Region. At its sixth order, the watershed drains into the Sirwan River. The total area of the Qoratu watershed Was found to be (808.34 Km2); so, approximately (44.9%) of this area is located within the Iraqi Kurdistan Region. This study aimed to (i) Estimate the Runoff of the Qoratu watershed for dam construction purposes, (ii) estimate the water harvest of the Qoratu sub-watershed to achieve the best state of water management in the study area, (iii) estimate groundwater levels rise, and (iv) to control floods during the rainy season. The study concluded that the water inflow is high; thus, the possibility of constructing a dam and/or ponds in the area is beneficial.