Which mechanism causes an avulsion event when a river's levee system is overwhelmed by sediment deposition?

💡 Explanation

When sediment deposition overwhelms a levee system, aggradation occurs because the channel bed rises due to sediment accumulation, elevating the channel above the surrounding floodplain. Therefore avulsion becomes more likely as the river seeks a steeper, lower path, rather than isostatic rebound, reduced flow resistance, or tectonic uplift which have different effects.

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