Estimation of the runoff of the Qalatopzan and Parewla Basins using the (SCS-CN) model

In this study, water runoff estimation by SCS-CN model for both Qalatopzan and Parewla watersheds which located in northeastern of Iraq and eastern part of Kurdistan Region in Kalar district, and lies on latitude (34o:51-: 33=) and (35o :04-: 52=) north and longitude (45o:21-: 50=) and(45o :34-: 59=) east thet located in the semi-mountainous area. The total catchment area is about (235.46 km2), and Qalatopzan watershed with an area of ​​(148.74 km2) with a rate of (63.17%) and Parewla drainage with an area of ​​(86.72 km2) and (36.83%) form the research area which distributed into two main streams and (8) Sub-watersheds, each of which includes four minor sub-watersheds. Rainfall irregularities accompanied by environmental and climatic effects have created water shortage problems for the study area, especially during the dry seasons, and in order to achieve the research objective which is to determine the amount of water flowing and appoint the level of utilization of hydrology of both watersheds, each of its files (DEM12.5m), aerial imagery (Landsat8 OLI), Geographic Information Systems and Remote Sensing (GIS & RS) techniques were used. After taking (10) soil samples and determining the numerical value of soil turbidity and humidity and the appearance of (7) different land uses and taking a wave of rainfall. The study concluded that the average depth of the runoff water in the study area is equal to (22.41 mm) which is (24.72 mm) in the main watershed of Qalatopzan and (20.11 mm) in the main watershed of Pariole, and the water flowing is about (2,60m3), while in the main reservoir of Qalatopzan (3.34m3) and in Parewla is (1.77m3). Finally, the results obtained are an important basis for the development of water harvesting and exploiting plans, so as to meet water needs and sustain human activities along the border of both brooks.