Surface Runoff and the Water Cycle

Runoff is nothing more than water "running off" the land surface. Just as the water you wash your car with runs off down the driveway as you work, the rain that Mother Nature covers the landscape with runs off downhill, too (due to gravity). Runoff is an important component of the natural water cycle. Note: This section of the Water Science School discusses the Earth's "natural" water cycle without human interference.