What is the main feature of 'Rápidos' in a river context?

In the context of rivers, 'Rápidos' refers to sections where the water flows swiftly over obstacles such as rocks or rapids. This characteristic of being fast-flowing is a fundamental aspect of 'Rápidos', making them distinct in contrast to calmer segments of a river. The increased velocity of water in these areas results in notable turbulence and often creates a whitewater effect, which can be exhilarating for activities such as rafting or kayaking. This feature is essential in understanding river dynamics, as it influences erosion, sediment transport, and aquatic ecosystems.