Which term refers to a geological formation that impedes water movement and is sometimes used interchangeably with aquiclude?

The term that best fits the description of a geological formation that impedes water movement and is often used interchangeably with aquiclude is "confining unit." A confining unit is typically composed of materials such as clay or silt that do not allow water to flow freely, effectively limiting the movement of groundwater. This term emphasizes the ability of the formation to restrict water migration, which is a crucial characteristic when discussing groundwater flow and management.

In contrast, an aquifer is a geological formation that can store and transmit water effectively, serving the opposite function of a confining unit. An aquitard is appropriate in some contexts as it also refers to a layer that impedes water movement but is not synonymous with aquiclude in all usage. Aquifuge refers to a geological layer that completely prevents water movement, but it is not commonly used in practice and does not align perfectly with the broader concept of a confining unit. Thus, "confining unit" is the most accurate term in this context.