Groundwater

Groundwater

Water found in the pores of soil and sediment, plus narrow fractures in bedrock

Zone of soil moisture

A zone where water is held by molecular attraction on soil particles in the near-surface

Zone of saturation

a zone where all of the pore spaces are completely filled with water

Unsaturated zone

The area above the zone of saturation

Gaining stream

Gain water from the inflow of groundwater through the streambed; water table is higher than the stream surface

Losing stream

Lose water to the groundwater system by outflow through the streambed; water table is lower than the stream surface

Porosity

The percentage of pore spaces in a rock or sediment

Permeability

The ability of a material to transmit fluid

Aquitard

An impermeable layer that hinders or prevents water movement

Aquifer

A permeable rock strata or sediment that transmits groundwater freely and is saturated with a significant amount of water

Darcy’s law

A measure of the volume of water that flows through an aquifer

Hydraulic gradient

The water table slope

Hydraulic conductivity

The permeability of the aquifer to determine how fast water will flow through a medium

Well

A hole bored into the zone of saturation

Perched water table

Forms where an aquitard is situated above the main water table

Artesian systems

A natural system that generates water pressure just as a municipal water system does

Spring

A natural outflow of water from the intersection of the water table and the ground surface

Geysers

Intermittent hot springs in which columns of water erupt with force

Subsidence

The ground sinks when water is pumped from aquifers faster than the natural recharge processes can replace it

Saltwater intrusion

Excessive groundwater withdrawal causes saltwater to be drawn into wells, contaminating freshwater supply