What process does an unconfined aquifer undergo when it becomes depleted?

When an unconfined aquifer becomes depleted, it undergoes desaturation. This process occurs when the groundwater levels drop below the level of the soil or sediment that directly overlays the aquifer. As water is extracted or not replenished through precipitation, the water table descends, leaving some of the pores in the soil or ground material without water, leading to a state known as desaturation.

Desaturation is significant because it can affect local water sources, vegetation, and overall ecosystem health. In contrast to desaturation, reinfiltration would refer to the process of water moving back into the soil and replenishing the aquifer, which does not occur when the aquifer is depleted. Evapotranspiration involves the loss of water from the soil and plant surfaces to the atmosphere, which does not directly relate to the depletion of an aquifer. Condensation is the transformation of vapor into liquid water and also does not pertain to the depletion of groundwater resources in the context of an unconfined aquifer.