What measures the volume of water flowing past a certain point in a given unit of time?

Discharge is the term used to describe the volume of water that flows past a specific point in a given unit of time, typically expressed in cubic meters per second (m³/s) or liters per second (L/s). It is a fundamental concept in hydrology and helps to quantify how much water is available in a river or stream at any given moment. Discharge is critical for understanding water resource management, flood forecasting, and the ecological health of aquatic environments.

Flow velocity, while related, refers specifically to the speed at which water moves, not the volume. Channel gradient describes the slope of the riverbed, which influences flow but does not directly measure volume. Stream erosivity pertains to the ability of flowing water to erode materials, and again, does not quantify flow volume. Thus, discharge is the most accurate term to describe the measurement of water volume over time in this context.