Hydrological modeling for estimating surface runoff volume using SCS-CN in the Jabal Qara Dagh region

Abstract

This study aims to analyze the surface runoff characteristics of the river basins in the Qara Dagh Mountains region, located in the southwestern part of Sulaymaniyah Governorate, between latitudes 34°50' and 35°50' and longitudes 45°40' and 44°40'. The basins, numbering six, cover an area of ​​3526.8 km² and have a geographical perimeter of 360.9 km. They are bordered to the north by the Zagros Mountains, extending towards Sharazur and Dokan; to the south by the Kifri District and some areas of Diyala Governorate; to the east by the city of Sulaymaniyah and some inland plains; and to the west by the border with Kirkuk Governorate towards the Tuz Khurmatu area. The amount of surface runoff resulting from rainfall can be determined through modeling using various river basin parameters. Surface runoff analysis is a fundamental element in water resource management and flood risk assessment. Using spatial modeling and GIS techniques, a watershed can be accurately modeled and runoff distributions analyzed, integrating topographic, climatic, and soil information. The SCS-CN model is used to estimate the amount of surface runoff resulting from rainfall based on soil type, vegetation cover, and moisture retention coefficient, providing a powerful tool for hydrological planning and water management in various basins. (Mahboubeh et al. (2004), 2012, 2011, 2008)

A single method for measuring surface runoff was selected based on the objective, the nature of the study area, and the availability of data. Selecting an appropriate runoff model for a given watershed is crucial for planning, and the model choice depends primarily on its predictive ability to reflect the realities of the river basin. The modified SCS-CN model is