Which best defines aquifuge?

An aquifuge is best defined as a layer of the earth that allows no water movement. This term describes geological formations that completely hinder the transmission of groundwater, making them impenetrable to water flow. Essentially, an aquifuge can be thought of as a barrier that prevents water from passing through, distinguishing it from aquifers, which are saturated layers of rock or sediment that can store and transmit water.

This definition emphasizes the role of aquifuges in hydrology, particularly in the context of water resource management, as they impact the movement and availability of groundwater. Other choices, such as references to water-saturated layers or areas that promote groundwater movement, do not accurately capture the restrictive nature of an aquifuge.