What is groundwater?

Groundwater refers to the water that exists below the water table, filling the spaces and fractures in soil, sediment, and rock formations. This underground reservoir is crucial for many ecosystems and human needs, as it is a primary source of drinking water for many communities and supports agricultural activities. The water table itself is the upper surface of this saturated zone, where soil and rock are completely filled with water.

Understanding groundwater is essential because it plays a significant role in the hydrological cycle, influencing surface water bodies through processes like groundwater discharge, where it can feed into rivers and lakes, especially during dry periods. Groundwater also contributes to maintaining the overall balance within the environment by supporting plants and wildlife.

The other options do not accurately describe groundwater. Water found above the water table refers to surface water rather than groundwater. Evaporated water returning as rain describes a different process in the hydrological cycle—precipitation—rather than the definition of groundwater. Water in surface reservoirs pertains to lakes, rivers, and other bodies of water found at or above ground level. Each of these terms highlights different components of the water cycle, but groundwater specifically pertains to what lies beneath the water table.