River Features: Upper Course vs. Lower Course

Upper Course (Youthful Stage):

• Source (spring, glacier, lake)
• Steep gradient → fast flow
• Narrow, rocky, V-shaped valley
• Dominant vertical erosion (hydraulic action, abrasion)
• Waterfalls, rapids, interlocking spurs

Lower Course (Mature/Old Stage):

• Gentle gradient → slow flow
• Wide, deep channel; flat floodplain
• Meanders, oxbow lakes
• Lateral erosion & deposition
• Delta or estuary at mouth

Transition reflects decreasing energy and increasing sediment load.