Definition - What does Groundwater Table mean?
The groundwater table is the depth at which the ground below is saturated with water. The groundwater table rises or falls depending on rainfall, plants absorbing water and topography. Trenchless construction or rehabilitation projects which are carried out beneath the groundwater table will require that adequate steps are taken to prevent water from entering the pipe under construction or repair.
Trenchlesspedia explains Groundwater Table
The groundwater table separates saturated ground below from aerated ground above. When digging through aerated soil, no precautions need be taken for water ingress into the construction, but this is not true below the groundwater table. When establishing an entrance or exit pit using shoring below the groundwater table, it is necessary to use a sealed shoring design to prevent water from building up in the pit.
A leaking sewer line below the groundwater table picks up additional water flow as the water in the ground pushes into the sewer. This excess water can overload downstream processing units, which is a major justification for trenchless rehabilitation projects.