Agricultural Engineering Practice Exam

The term that accurately describes a formation blocking water from flowing is aquiclude. An aquiclude is a geological formation that is impermeable or very low in permeability, preventing the movement of groundwater. It acts as a barrier to water flow despite being part of the broader groundwater system. This means that while there may be water present in surrounding formations, the aquiclude effectively confines that water and restricts its movement, which is crucial in hydrogeological studies and water resource management.

In contrast, an aquifer is a saturated geological formation that can both hold and transmit significant amounts of water, making it the opposite of an aquiclude. An aquifuge refers to a formation that does not allow any water transmission at all, but it is a term that's less commonly used compared to aquiclude. A saturated formation simply indicates a zone where all the pores are filled with water, which also does not specifically describe the impermeability characteristic of an aquiclude.