Hydrogeology

-- Name -- Aquifer -- Definition -- A wet underground layer of water-bearing permeable rock or unconsolidated materials (gravel, sand, silt, or clay) from which groundwater can be usefully extracted using a water well. -- Description -- An underground geological formation able to store and yield water.

-- Name -- Hydrogeological Object -- Definition -- An abstract class for man-made facilities or natural features that have an interaction with the hydrogeological system. -- Description -- Hydrogeological objects may be natural (eg. spring) or the manmade (eg. wells). The vast majority of hydrogeological objects are manmade.

-- Name -- Active Well -- Definition -- A well influencing the groundwater resources of the aquifer. -- Description -- The most common examples of Active Well are: extracting, artificial recharging, or dewatering wells. NOTE: ActiveWell by extracting, recharging or dewatering influences and changes the state of groundwater resources.

-- Name -- Hydrogeological Unit -- Definition -- A part of the lithosphere with distinctive parameters for water storage and conduction.

Norsk ... Engelsk definisjon-- A saturated, but poorly permeable bed that impedes groundwater movement. Engelsk bestrivelse -- It does not yield water freely to wells, but may transmit appreciable water to or from adjacent aquifers and, where sufficiently thick, may constitute an important ground-water storage unit. Aquitards are characterized by values of leakance that may range from relatively low to relatively high. A really extensive aquitard of relatively low leakance may function regionally as boundaries of aquifer flow systems.

-- Name -- Hydrogeological Object Man-made -- Definition -- A man-made hydrogeological object. -- Description -- Examples of manmade hydrogeological objects are: well, groundwater intake, groundwater monitoring station or monitoring well.

-- Name -- Hydrogeological Object Natural -- Definition -- HydrogeologicalObject which was created by natural processes. -- Description -- Examples of natural hydrogeological objects are: a source, vanishing point and geyser.

-- Name -- Groundwater Body -- Definition -- A distinct volume of groundwater within an aquifer or system of aquifers, which is hydraulically isolated from nearby groundwater bodies. -- Description -- Groundwater bodies form the principal management units under the European Water Framework Directive (2000/60/CE, 2000). They should be hydraulically continuous entities, and must be defined on the basis of flow or abstraction, and are inextricably linked to surface water bodies.

-- Name -- Aquiclude -- Definition -- An impermeable body of rock or stratum of sediment that acts as a barrier to the flow of groundwater. -- Description -- A formation which, although porous and capable of absorbing water slowly, will not transmit water fast enough to furnish an appreciable supply for a well or spring. Aquicludes are characterized by very low values of "leakage" (the ratio of vertical Hydraulic Conductivity to thickness), so that they transmit only minor inter-aquifer flow and also have very low rates of yield from compressible storage. Therefore, they constitute boundaries of aquifer flow systems.

-- Name -- Aquifer System -- Definition -- A collection of aquifers and aquitards, which together constitute the environment of groundwater - "communicating vessels", that are filled or can be filled with water. -- Description -- Attributes of Aquifer System and its components determine the feasibility of water collection, its movement, as well as the impact on its chemical state. NOTE: The Aquifer System components and their attributes (including geometry) are relatively stable over time except in special cases.