Groundwater Morphology

Abstract

In addition to knowledge of the regional geological composition, a detailed record of groundwater morphology is of great significance for hydrogeologists. This is because the shape of the groundwater level, and the level of the free or confined groundwater level, reflect the ongoing state of equilibrium in the geohydraulic dynamics of the area in question. Therefore, the definition of hydrogeological regimes and issues usually begins with the evaluation of the groundwater morphology. The following terms (as defined DIN 4049-3) are important for the description of groundwater morphology:

• Groundwater level represents the upper boundary surface of a groundwater body.

• Groundwater longitudinal section shows the section through a groundwater body normal to its lines of equal hydraulic head (The groundwater longitudinal section often corresponds to a good approximation of a vertical section along a flow-line of the groundwater level).

• Hydraulic head (i.e. hydraulic pressure head) is the sum of the geodetic height and pressure head for a point in an observed groundwater body.

• Total hydraulic head gradient is the gradient of the hydraulic/piezometric heads between two measuring points.

• Piezometric surface describes the surface of all hydraulic heads of a groundwater level/surface from the geometric location of the endpoints (The general morphological designations can be used for the description of the piezometric surface, e.g. groundwater depression).

• Groundwater equipotential lines (also known as groundwater contour lines) are lines of equal elevation of a piezometric surface.

• Groundwater gradient consists of the gradients of the piezometric surface.

• Groundwater flow lines represent an idealized movement path of groundwater particles in the potential field of a groundwater body (Groundwater flow lines are perpendicular to the potentiometric surface of a groundwater body).

• Direction of groundwater current (also called direction of groundwater flow) takes place in the direction of the groundwater flow lines.

• Potentiometric surface of a groundwater body is the geometric location of all points in the observed groundwater body with the same total hydraulic head (Applies only with negligible differences in density).

• Equipotential line corresponds to the intersection line between the potentiometric surface of a groundwater body and the groundwater longitudinal section. It is an imaginary line at right angles to the groundwater flow line (Fig. 15.10).