Which process restricts floodplain development alongside a steep alluvial fan?

💡 Explanation

When rainfall concentrates, alluvial fans experience flash floods because the unconfined channel rapidly conveys water and mobile sediment downwards, increasing the risk of avulsion—sudden channel shifts preventing permanent structures. Therefore, flood avulsion is the primary risk, rather than faulting, liquefaction, or groundwater contamination, which are related to independent geological conditions.

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