Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
Surface runoff refers to water that flows over the land surface rather than infiltrating into the ground. It occurs when rainfall or snowmelt exceeds the soil's ability to absorb it or when the ground is already saturated.
A watershed is an area of land where all water drains into a common outlet such as a river, lake, or ocean. Surface runoff plays a crucial role in shaping watersheds.
Erosion is the process by which soil and rock particles are loosened and transported by natural forces such as wind or water. Surface runoff can contribute to erosion by carrying away sediment.
Urbanization refers to the process of population growth and expansion of cities. It often leads to increased amounts of impervious surfaces (e.g., roads, buildings), which can result in higher rates of surface runoff due to reduced infiltration capacity.