Final answer:
In an unconfined aquifer around a pumping well, drawdown leads to a cone of depression, and continuous pumping may cause land subsidence and potentially saltwater intrusion if near the coast.
Step-by-step explanation:
The changes likely to occur in an unconfined aquifer around a pumping well include primarily a phenomenon known as drawdown. Drawdown is the lowering of the water table around the well, which results in the formation of a cone of depression in the aquifer. Activities such as heavy well pumping can exacerbate drawdown. Moreover, continuous drawdown can lead to issues such as subsidence, which is a gradual sinking of the land's surface, and can affect areas like the Death Valley basin. Additionally, if an unconfined aquifer is located near a coastline, over-pumping can cause saltwater intrusion, altering the quality of groundwater.
Maintaining the current level of the water table is critical, as alterations can affect local ecosystems, such as the aforementioned river and riparian areas, private wells, and water available for irrigation and personal use. Lastly, adding water to a recharge area, where surface water infiltrates the ground, would have the practical effect of increasing the amount of groundwater, thus helping to mitigate the adverse effects of over-pumping.