What type of areas typically exhibit higher velocity flow in streams?

Riffles are characterized by shallower, faster-moving sections of a stream, where water flows over rocks and substrate, creating turbulence. This rapid flow is essential for maintaining oxygen levels in the water, which benefits aquatic life. The velocity in riffles is typically higher due to the reduced cross-sectional area as the water flows over the rocks and pebbles, which forces it to accelerate. In contrast, deep pools generally have slower moving water because they are deeper and allow sediment and other materials to settle, leading to a more tranquil environment. Bars, while they may create variations in flow, do not inherently lead to increased velocity compared to riffles. Floodplains are usually connected to the larger river system during high flow events, but they often have slower-moving water because of the wider cross-section and the settling of sediment.