Hydrological Estimation for the Runoff of Qalachwalan Basin Using Hydrological Estimation for the Runoff of Qalachwalan Basin Using (SCS – CN) Method (2000 – 2020)

The surface water is a reflection of the climatic and topographical conditions basin in study area, affects estimation amount runoff on inside basin. It also possible to measure running know periods increase, scarcity this quantity, other hand, take advantage from for all fields uses. Qalachwalan one basins located at north city Sulaymaniyah with an area (876.1) km2, its sources are within borders Kurdistan Region Iraq. Due unsteady rain heavy precipitation recent years, therefore, it was necessary conduct some researches size runoff, besides, see if benefit development investment areas. Accordingly, Soil Conservation Service- Curve Number (SCS – CN) Method has been used estimate depth annual runoff. From became clear us that seven uses )Bodies water, dense forests, agricultural lands, grasslands, residential barren paved roads. Besides, appeared greatest which lies grassland equals (588523320) m3, smallest (4442480) m3 forest area. So, we discover total reached about (700141140) m3. Finally, our data very vital local government stakeholders future how deal especially precipitations.