Where do rivers tend to flow faster and smoother?

The middle of a river is where the flow tends to be faster and smoother due to the dynamics of water movement. In the middle section of a river, there is typically less friction because there are fewer obstructions such as rocks, vegetation, or the riverbank that can disrupt the flow. The water has a direct path to follow, allowing it to gain speed as gravity pulls it downward.

Additionally, the flow patterns in the middle section create a more streamlined current, which contributes to the overall smoothness. In contrast, the edges of rivers often experience slower flow due to increased turbulence and friction from contact with the banks and debris. Confluences, where two rivers meet, can create complex currents and eddies that disrupt the flow, making it less predictable. Estuaries, where fresh and saltwater mix, also exhibit varied flow conditions due to tidal influences and the merging of different water bodies, which can complicate the current rather than establish a smooth, fast flow. Thus, the middle of the river stands out as the area where the current is both faster and smoother, making it the correct answer.