Which long-term consequence results when a large river's sediment load significantly decreases upstream from a natural levee?

💡 Explanation

When sediment load decreases, the levee's accretion mechanism slows, because less material is available for deposition during flood events which constructs the levee over time. Therefore levee erosion occurs, rather than floodplain aggradation, delta acceleration, or upstream incision which depend on increased sediment supply or altered river dynamics.

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