HYDROLOGY

Precipitation

Any atmospheric water coming on Earth’s surface.

Infiltration

Vertical movement of water from Earth’s surface to below Earth’s surface.

Run-off

Horizontal or sub-horizontal movement of water on Earth’s surface.

Types of Groundwater: Connate Water

Sedimentary origin water (Fossil water) formed during compaction of sediments.

Types of Groundwater: Meteoric Water

Atmospheric water formed due to precipitation.

Types of Groundwater: Juvenile Water

Magmatic water formed from magma.

Vertical Distribution: Zone of Aeration

Voids are partially filled with water and air; water lies in this zone is called vadose water.

Vertical Distribution: Zone of Saturation

Also known as phreatic zone; voids are fully saturated with water.

Aquifer

Porous and permeable rock formation, e.g., sandstone.

Aquiclude

Porous and non-permeable rock formation, e.g., clay.

Unconfined Aquifer

Surrounded by impermeable layer only at the bottom; water pressure equals atmospheric pressure.

Confined Aquifer

Surrounded by impermeable layers at both top and bottom; water pressure is greater than atmospheric pressure.

Piezometric Surface

Imaginary surface to which groundwater rises in a confined aquifer.

Porosity

Percentage of void space in the rock.

Primary Porosity

Formed during the deposition of sediments.

Secondary Porosity

Forms later to the time of formation of sedimentary rocks, i.e., during diagenesis.

Intrinsic Permeability

Permeability when saturated with a single type of fluid.

Transmissivity

Product of hydraulic conductivity and thickness of the aquifer.

Influent Stream

A river that recharges the groundwater.

Effluent Stream

A river that is recharged by groundwater.