The groundwater table is the level below which soil pores are generally saturated, though conditions vary by location and time.
Definition
The groundwater table is the level below which soil pores are generally saturated, although local conditions may vary. Its depth can change with season, weather, nearby pumping, or site work. An investigation records observations at particular locations and times, and geotechnical professionals interpret those readings for the project while stating data limits. A measured level is not necessarily a permanent site condition or a complete picture of groundwater behavior. It is also distinct from surface water and from water pressure acting at a specific point. For owners, groundwater information can affect excavation planning, foundation assumptions, drainage, and temporary works. Investigation timing and the limits of available observations are useful parts of project planning and communication. The ASCE resource provides professional engineering context for geotechnical work.
How owners use it
- Review the time and location of groundwater observations when considering whether they represent project conditions.
- Coordinate groundwater assumptions with excavation, foundation, drainage, and temporary works discussions.
- Example: If the ground surface is at elevation 110 ft and the observed water level is at 104 ft, the level is 110 - 104 = 6 ft below the surface.
- Document the observation conditions and data limits in project discussions.
