Which mechanism creates natural levees bordering a mature alluvial river?

💡 Explanation

When a river overtops its banks during floods, the flow velocity decreases abruptly because of increased surface area, leading to sediment deposition because the flow can no longer carry as much sediment. Therefore sediment deposition forms levees, rather than flocculation, weathering or icelanding that involve different specific compositions or temperature thresholds.

• Which mechanism causes coastal upwelling along western continental streams under specific wind conditions?
• Which effect occurs when increased meltwater influx disrupts thermohaline circulation within North Atlantic gyres?
• Which mechanism is amplified when climate change warms permafrost surrounding a fjord shoreline?
• Which outcome arises when tectonic uplift decreases a lake's catchment area and inflow?
• Which long-term outcome results when construction prevents deep soil horizon bioturbation by earthworms?
• Which phenomenon amplifies seismic wave energy emanating upward through unconsolidated sediments?