Explanation: Upper Course / Stage of Youth (Erosion dominates): Streams are few, with poor integration. As the river flows down with high velocity, vertical erosion or downward cutting will be high which results in the formation of V-Shaped Valleys. Waterfalls, rapids, and gorges exist where the local hard rock bodies are exposed. Hence, Delta does not depict the youthful stage of rivers. Deltas are formed when a river enters a standing or low-energy body of water (a lake, lagoon or sea). Velocity drops partly because of the lack of tidal currents (which would transport sediment away), but also because of the shallower gradient at the mouth of a river.