Relier Pairs Stages of a river: features and characteristicsVersion en ligne To relate key information about the different parts of a river. par Elvira Garcia Arnal 1 Lower course 2 Source 3 Middle course 4 Upper course 5 Mouth Initial stage of the river. You can find rapids and waterfalls. The start. It is often a place in the mountains. The water flows more slowly than in the upper course and there are meanders. The end. A delta or estuary can be there. The final stage near the coast.