groundwater

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Images & Videos

A cross-sectional diagram of land shows the water table as the upper boundary of groundwater, with a stream and pond representing surface water where the water table meets the land surface. Unsaturated soil lies above the water table.

Searching for sustainable water supplies in Namibia

A cross-sectional diagram showing how a geyser and hot spring form above a magma chamber. Arrows illustrate heat rising from magma, groundwater moving through porous rock, and steam or hot water reaching the surface as a geyser or hot spring. Labels identify each layer and process.

Diagram showing three stages of saltwater intrusion into a coastal aquifer: the first panel shows normal conditions with a stable interface between ocean saltwater and fresh groundwater; the second shows increased saltwater intrusion and a cone of depression when groundwater is pumped; the third shows how an injection well restores pressure and blocks saltwater intrusion. Labels identify ocean, aquifer, potentiometric surface, and water flow directions.

How stalactites and stalagmites form in caves

Can reed beds clean contaminated groundwater?

At a Glance

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groundwater summary

groundwater: References & Edit History

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Article Contributors

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The Editors of Encyclopaedia Britannica
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Article History

Type	Description	Contributor	Date
	Modified link of Web site: Oklahoma State University Extension - Introduction to Groundwater Hydrology and Management.	Grace Young	Nov 01, 2026
	Add new Web site: Open Library Publishing Platform - Physical Geology - Groundwater and Aquifers.	Grace Young	Nov 14, 2025
	Add new Web site: U.S. Geological Survey - Aquifers and Groundwater.	Gloria Lotha	Sep 19, 2025
	Add new Web site: UC ANR - Groundwater in Working Landscapes - Nora S. Gustavsson Endowed Professorship and Cooperative Extension - Basic Concepts of Groundwater Hydrology (PDF).	Gloria Lotha	May 03, 2025
	Add new Web site: Geosciences LibreTexts - Groundwater and Aquifers.	Gloria Lotha	May 02, 2025
	Add new Web site: Oklahoma State University Extension - Introduction to Groundwater Hydrology and Management.	Yamini Chauhan	Jan 21, 2025
	Add new Web site: Nature - Rapid groundwater decline and some cases of recovery in aquifers globally.	Emily Rodriguez	Oct 03, 2024
	Add new Web site: Thompson Rivers University - Environmental Geology - Groundwater.	Emily Rodriguez	Dec 01, 2023
	Add new Web site: U.S. Environmental Protection Agency - Groundwater.	Gloria Lotha	Sep 29, 2023
	Add new Web site: USGS - Water Science School - Aquifers and Groundwater.	Emily Rodriguez	Feb 28, 2023
	Add new Web site: Geosciences LibreTexts - Groundwater.	Emily Rodriguez	Feb 12, 2023
	Added information on groundwater contamination.	Melissa Petruzzello	Jan 22, 2019
	Added estimate that some 5.97 quintillion gallons (22.6 million cubic km) of groundwater reside in upper 2 km (1.2 miles) of Earth's crust.	John P. Rafferty	Nov 24, 2015
	Added video.	Amy Tikkanen	Mar 13, 2015
	Added new Web site: Window To The Universe - Groundwater.	Shiveta Singh	Apr 23, 2009
	Article revised and updated.	Adam Augustyn	Apr 24, 2008
	Added new Web site: U. S. Environmental Protection Agency - Drinking Water Ground Water Kids' Stuff.	Gaurav Shukla	Nov 01, 2006
	Article added to new online database.	The Editors of Encyclopaedia Britannica	Jul 20, 1998