Dynamic and Gravitational Groundwater Levels-A Two-Layered Groundwater Model

The equipotential sulfate of the rotational and gravitational potentials corresponding to the density of water is known as 'geoid'. A continental geoid surface of water called the hydro-geoid separating two distinct masses of groundwater is proposed. The flow pattern, potential water outflow and water mass balance markedly differ between the groundwater above and below the hydro-geoid level. A two-layered groundwater model with clear distinction between the actual, 'dynamic', groundwater level and the 'gravitational' (hydro-geoid) groundwater level is advocated. The hydro-geoid level is deformed by the tides and, in the long-term range also, by all other factors affecting the gravitational and rotational potentials.