Why do deltas form at river mouths?
Show answer & explanation
Answer: Sediment deposits build land
Rivers split into branches — Wrong. Rivers do branch (distributaries), but deltas form because slowing water deposits sediment, building new land at the river mouth.
Sediment deposits build land ✓ — Correct! Rivers carry sediment. At the mouth, water slows as it enters the ocean/lake, losing energy to transport particles. Sediment drops, accumulating over time. This builds new land extending into the water—a delta! Nile, Mississippi, and Ganges have massive deltas. Shape depends on sediment supply vs wave/tide erosion!
Ocean pushes water back — Wrong. Ocean doesn't push water back. Deltas form because slowing river water deposits sediment, not from ocean resistance.