Definition - What does Saturated Zone mean?
The saturated zone is that zone beneath the surface that's often incorrectly referred to as the water table. Rather, it is the subterranean soil is the area below the water table where the ground is so saturated in both pockets and vast areas, it forms the underground "rivers" or "streams," that moves groundwater from the aquifer to an outfall to the ocean.
The water pressure in the saturated zone is greater than 14.7 psi and, when the water pressure in the saturated zone is great enough and an area of soil is of low enough density, springs can erupt through the ground's surface to form freshwater Earlakes, streams, rivers or other surface water.
Trenchlesspedia explains Saturated Zone
The saturated zone is a key player in the Earth's hydrologic cycle, the great cycle in which rainwater penetrates the earth to become groundwater that flows to the ocean, where it evaporates and becomes rainwater once more.
Its depth below the surface, its overall depth, and its shape can place restrictions on both design and drilling operations. In areas where the water table is near the surface, potholing may provide some answers, but a sophisticated geotechnical investigation offers both current and historical information on the shape, size, and depth of the water table and the saturated zone beneath it, and its relation to a specific design path.