What is the top of the zone of saturation called?

The top of the zone of saturation is referred to as the water table. This is the level at which the soil or rock is fully saturated with water, marking the boundary between the saturated and unsaturated zones. In geological and hydrological contexts, understanding the water table is crucial because it affects various aspects of water movement, availability for wells, and the behavior of groundwater.

In contrast, other terms like groundwater level might imply the depth of groundwater but are not specifically defined as the boundary level itself. The term aquifer boundary suggests more about the limits of an aquifer rather than the specific point of saturation. Lastly, soil saturation point typically refers to the condition of the soil at its maximum holding capacity for water, which may vary based on soil type and structure, rather than the defined level of the water table.