What is the term for water that flows over the surface of the land?

The term for water that flows over the surface of the land is commonly known as surface runoff. This process occurs when precipitation exceeds the soil's infiltration capacity and creates a flow of water across the ground. Surface runoff is significant in the hydrologic cycle, as it is responsible for transporting water from land to water bodies, which can influence ecosystem health, contribute to erosion, and affect water quality.

Overland flow, while often used interchangeably in some contexts with surface runoff, specifically refers to the water that flows laterally over the ground surface as a result of rainfall or irrigation. It is essentially a subset of surface runoff, often distinguishing itself by the type of flow and context of movement. In the case of streamflow and river discharge, these terms refer specifically to water flowing within defined channels, which is different from the broader concept of water flowing across the land surface.