Groundwater in its natural state is invariably moving . This movement is governed by established hydraulic principle and can be expressed by Darcy's Law, which states "Flow rate through porous media is proportional to the head loss and inversely proportional to the length of the flow path"

                K (h1-h2)
Q   =   -------------------
                 L
Q : Specific discharge ;

K : Hydraulic conductivity ;

h1-h2 : Head loss

L : Distance of travel by groundwater

It is generally believed that movement of Groundwater follows ground elevation or the general topography of the area.

Aquifer System

In terms of potential for storage and permeability the aquifers are the most sought-after geologic medium in hydro-geological studies. 'Water Bearing Formation' and 'Groundwater Reservoirs' both are synonyms for the word 'Aquifer'. Water as such can exist in aquifers under two completely different physical conditions. The most common conditions is when the water table is exposed to the atmosphere through openings in the overlying medium This type of aquifer is referred to as an 'unconfined aquifer'.

Groundwater may also occur under 'confined conditions'. Confined groundwater is isolated from the atmosphere at the point of discharge by impermeable geologic formations. The confined aquifer is generally subjected to pressure higher than atmospheric than atmospheric pressure.

In some geologic settings, a local zone of saturation may also exist at some level above the regional water. The upper surface in such localized zone is called perched water tables and such local water bearing zones are called 'perched aquifers'.