What best defines groundwater recharge?

• A. The input process where water from precipitation percolates through soil and enters an aquifer.
• B. Water stored in lakes and rivers on the surface.
• C. The vaporization of water from soil into the atmosphere.
• D. The natural upwelling of groundwater at springs.

Answer: (A)

Groundwater recharge is the input process by which water from precipitation infiltrates through the soil and moves downward to replenish the saturated zone in an aquifer. This infiltration and percolation fill the groundwater, restoring its storage. The other descriptions refer to different parts of the water cycle: surface water storage in lakes and rivers, evaporation from soil, and groundwater discharging as springs. So the option that describes water entering an aquifer via infiltration best captures recharge.