This paper studies the influence of urbanization on the natural overland flow paths on topography. The main objectives of this study are to: measure the effectiveness of drainage networks, study the influences of urban structure, compare the pre-and post-urban overland flow paths, and provide recommendations for flood prevention. The study was conducted on a catchment (81 km2) in Qatar that lies between Doha and Al-Rayan. Land cover, soil data, rain data, and digital elevation model (DEM) were the main inputs of the study to obtain run-off depths, time of concentration, and peak flows. The Soil Conservation Service (SCS) method was applied, where Curve Numbers (CNs) were identified for each land cover based on soil groups concerning the infiltration rate. A geographic information system (GIS) integration has provided better results. ArcMap tools have been used to study flow changes such as flow direction, flow accumulation, and stream definition. The result of the study shows that urbanization has a significant effect on the characteristics of the flow path as it causes the time of concentration to decrease, resulting in increased run-off depth and peak flow.