Which risk increases when unconfined aquifers are heavily pumped in alluvial valley?

💡 Explanation

When groundwater is heavily pumped from unconfined aquifers within an alluvial valley, the effective stress increases as pore water pressure decreases because the overburden pressure is now supported by the soil and sediments, leading to compaction and ground subsidence. Therefore subsidence results, rather than desertification, salinization, or flooding, which do not directly result from reduced aquifer pore pressure.

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