River discharge is affected by physical and human factors in the drainage basin. The physical size and characteristics of the drainage basin, including rock and soil permeability, vegetation cover, and relief or slope, determine how much water runs off into the river channel from precipitation events. Human activities like urbanization and deforestation can increase surface runoff, while dams can regulate river flow. Flood hydrographs show how river discharge responds to rain, with peaks in flow and lag times between precipitation and flooding influenced by drainage basin properties.