Which risk increases when excessive sediment deposition occurs landward of a natural levee along a floodplain river system?

💡 Explanation

When excessive sediment deposition occurs landward of a levee, it reduces the gradient from the river to the floodplain surface because the land behind the levee builds up, which reduces the storage capacity of the floodplain and exacerbates flooding. Therefore reduced channel capacity is the result, rather than the other effects such as recharge, erosion or enhancement of biodiversity, each requiring different hydrological drivers.

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