Flow velocity
Flow Velocities can vary significantly from place to place along a stream channel, as well as over time, in response to variations in the amount and intensity of precipitation. If you have ever waded into a stream, you know that velocity increases as you move into deeper parts of the channel. This is the result of frictional resistance, which is greatest near the banks and beds of stream channels
Scientists determine flow velocities at gaging stations by averaging measurements taken at various locations across the streams channel (Figure 5.6). Some sluggish streams have flow velocities of less than 1 kilometer per hour, whereas stretches of some fast flowing rivers may exceed 30 kilometers per hour.