Hydrostatic Pressure – the actual pressure of water forced against the exterior of a basement floor or wall. Water can be present in the soil by means of a high water table, underground stream, or capillarity. Groundwater is part of the Earth's water cycle that flows underground. |
Water first passes through the zone of aeration or unsaturated zone (the white layer in the diagram). In this zone, a mixture of air and water fills the spaces between the rock and soil particles. From here, water is taken up by plant roots, discharged into a body of water, or flows down to the next zone, which is the zone of saturation or saturated zone (the blue area in the diagram). Here all the spaces between particles are completely filled with water. The top of this zone is called the water table . Contrary to popular belief, groundwater is not an underground river or lake. Rather, it is all the water below the water table stored in subsurface void spaces.) |
