Surface runoff is the flow of water that occurs when excess rainwater, melted snow, or irrigation water flows over the ground. This happens when the soil is saturated and cannot absorb any more water, leading to the movement of water across the land surface. Surface runoff can carry nutrients, sediments, and pollutants into nearby water bodies. This process is a crucial part of the water cycle, as it helps to replenish rivers, lakes, and oceans. However, excessive surface runoff can lead to erosion, flooding, and water quality issues, making it important to manage land use and implement effective drainage systems.