Knowra Water table Water table The water table is the upper surface of a groundwater body, below which soil and rock are saturated with water at atmospheric pressure. Its depth changes with geology, recharge, and groundwater discharge.
Groundwater recharge : The process by which water moves from the land surface into an aquifer. Recharge adds water that can raise the water table.
Aquifer : A permeable geological formation that stores and transmits usable quantities of groundwater. An unconfined aquifer has the water table as its upper boundary.
Water well : A shaft or borehole that accesses groundwater for use or observation. A well's water level can indicate the local water table.
Baseflow : The portion of streamflow supplied by delayed sources, chiefly groundwater. Where a water table intersects a stream, groundwater can maintain flow between storms.
Confined aquifer : An aquifer bounded by low-permeability layers, with groundwater under pressure above atmospheric pressure. Its upper boundary is not a water table because the water is confined under pressure.
Groundwater discharge : The movement of groundwater out of an aquifer to springs, streams, wetlands, or the sea. Discharge removes water and can lower the water table.
Water-bearing layer : A geological layer that impedes groundwater flow, though it may transmit small amounts of water. An aquiclude can redirect groundwater and affect the water table's shape.
Piezometer : A narrow instrument used to measure groundwater pressure or hydraulic head at a specific depth. Piezometers help map water-table elevations across an area.
Groundwater contamination : The degradation of groundwater quality by chemicals, pathogens, or other pollutants. Contaminants can move downward through soil and reach the water table.
Artesian well : A well in a confined aquifer where pressure raises water above the aquifer's top. Its water level reflects pressure in a confined aquifer, not the nearby water table.
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