Estimation of Surface Runoff Volume in the Wadi Al-Rumaytha Basin in Al-Muthanna Governorate

Abstract

The surface runoff coefficient and index are influenced by several factors, including the basin’s geometric and morphometric characteristics, soil, vegetation cover, geological properties, sediment, and human activities, each of which affects the water runoff volume. This research aims to estimate the surface runoff volume by analyzing the relationship between rainfall and runoff. The study applied a series of mathematical equations recommended by the U.S. Soil Conservation Service (SCS-CN) method and utilized Geographic Information Systems (GIS). The findings indicate that the basin has varying natural characteristics, especially in terms of geological formations, which are distributed across the basin’s surface between the Ghar and Euphrates formations and Quaternary sediments. The CN (Curve Number) index was categorized into three classes (A, B, C) due to variations in land cover and its uses. The estimated surface runoff volume in the basin was approximately 16 million m³.