Final answer:
The zone of saturation is the area below Earth's surface where rock and soil pores are fully filled with water, contrasted with the zone of aeration where pores contain both air and water. Porosity and permeability are crucial properties affecting groundwater movement.
Step-by-step explanation:
The zone of saturation refers to the area beneath the Earth's surface where the pores and fractures of rocks and soil are completely filled with water. This contrasts with the zone of aeration (also known as the zone of unsaturation), where the pores contain air and water. The boundary between these two zones is known as the water table. Within the zone of saturation, groundwater moves slowly, influenced by the porosity and permeability of the materials. Porosity is the percentage of rock that is void or open space, which can vary with rock type and determines how much water the rock can hold.
High porosity rocks, like well-sorted sedimentary rocks, can hold more water than those with tightly interlocking crystals, such as igneous and metamorphic rocks. Permeability refers to the capacity of rock or soil to transmit water, which also affects the movement and availability of groundwater. It's important to understand the behavior of the zone of saturation for proper water resource management and to prevent overexploitation of groundwater.