How is river velocity calculated?

The calculation of river velocity involves determining how fast water moves through a given section of the river. This is typically done by measuring the distance traveled by a specific object, such as a floating buoy or piece of debris, over a set period of time. The formula used for this calculation is velocity equals distance divided by time (v = d/t). When researchers measure the distance that an object travels and the time it takes to travel that distance, they can accurately determine the velocity of the flowing water.

Given this understanding, the other options do not accurately represent the method of calculating river velocity. Measuring rainfall levels relates to hydrology and can affect river flow but does not directly measure water velocity. Assessing sediment transport type may give insights into river dynamics but does not provide a direct measurement of velocity. Finally, measuring the river's width can be important for other calculations (like cross-sectional area) but does not help in calculating the speed at which the water itself is moving.