This study aimed to figure out how much water flows on the surface in a semi-arid area in Saudi Arabia. Scientists combined computer mapping (GIS), satellite imaging (RS), and a special method called SCS-CN to estimate the runoff amounts in the Wadi-Uranah region. Using data on soil, slopes, and rainfall, they mapped areas and calculated how much water runs off during rain. The results showed that most of the land area had certain types of soil that affect runoff. Different kinds of land, like cities and farmland, also had different runoff estimates. By comparing rainfall and runoff numbers, the researchers found a strong connection. They even predicted how much water would flow during very big rain events every few years. This approach could aid in managing water resources and protecting the environment in similar places.