fr en es pt
Astronomy
Asteroids and Comets Black Holes Children Chemical Elements Constellations Earth Eclipses Environment Equations Evolution Exoplanets Galaxies Light Matter Moons Nebulas Planets Probes and Telescopes Scientists Stars Sun Universe Volcanoes Zodiac New Articles Shorts Glossary
RSS astronoo
Follow me on X
Follow me on Bluesky
Follow me on Pinterest
English
Français
Español
Português
 


Last update: August 20, 2025

Earth's Water Reservoirs: From Oceans to Groundwater

Distribution of Earth's water

Introduction to Water Reservoirs

Water on Earth is stored in various reservoirs, from oceans to deep groundwater. These reservoirs are essential for maintaining ecosystems and supplying freshwater to humanity.

Distribution of Water on Earth

Most of Earth's water is found in the oceans, about 97.5% of the total volume. Freshwater accounts for only 2.5%, most of which is frozen in polar ice caps or glaciers.

Main Water Reservoirs on Earth and Their Volume
ReservoirEstimated Volume (km³)% of TotalComment
Oceans1,350,000,00097.5%Main saltwater reservoir
Glaciers and Polar Ice Caps24,000,0001.7%Frozen freshwater, mainly in Antarctica and Greenland
Groundwater13,500,0001.6%Includes accessible and deep aquifers
Lakes and Rivers200,0000.015%Surface freshwater available for consumption and irrigation
Atmosphere12,9000.001%Water in the form of vapor and clouds
Soil Moisture16,5000.0012%Water accessible to plants and microorganisms

Freshwater: Availability and Distribution

Limited Access to Freshwater

Although freshwater represents only about 2.5% of the total water on Earth, its actual availability for ecosystems and human use is even more limited. Most of it is frozen in glaciers and polar ice caps (1.7%), leaving only a small fraction as groundwater, lakes, and rivers.

Accessible freshwater constitutes a tiny fraction of the total terrestrial water, highlighting the importance of sustainable management and protection of aquifers and watercourses for future generations.

Groundwater: The Main Accessible Reservoir

Groundwater is the largest accessible freshwater reservoir, with about 13.5 million km³. It is stored in aquifers at various depths. Renewal is slow, ranging from hundreds to thousands of years, depending on rock permeability and recharge by infiltration. Deep aquifers sometimes contain fossil water, which is non-renewable on a human timescale.

Surface Water: Lakes and Rivers

Surface water (lakes, rivers, artificial reservoirs) represents only 0.015% of the total volume of Earth's water but is vital for drinking water, irrigation, and industry. Its availability varies greatly by region and season. Major tropical rivers concentrate a significant portion of this water, while arid areas rely mainly on groundwater.

Atmosphere and Soil Moisture

The atmosphere and soil moisture, although representing a small volume compared to oceans or aquifers, are essential to the hydrological cycle. They ensure the redistribution of freshwater through precipitation and the direct supply of terrestrial ecosystems.

Articles on the same theme

The Demographic Transition: Growth or Decline? The Demographic Transition: Growth or Decline?
Lake Agassiz: A Deluge that Changed the Climate Lake Agassiz: A Deluge that Changed the Climate
Drunken Forests: Understanding the Phenomenon of Permafrost Thaw Drunken Forests: Understanding the Phenomenon of Permafrost Thaw
There is Electricity in the Air! There is Electricity in the Air!
Why Doesn't CO2 Fall to the Ground? Why Doesn't CO2 Fall to the Ground?
Dramatic Consequences of the El Niño Phenomenon Dramatic Consequences of the El Niño Phenomenon
Will man be the biggest animal on Earth? Will man be the biggest animal on Earth?
Acid rain beyond the natural Acid rain beyond the natural
Global warming Global warming
Habitable zones or ecosphere of stars Habitable zones or ecosphere of stars
Ocean water from elsewhere Ocean water from elsewhere
Sustainable development, the living are watching us Sustainable development, the living are watching us
The Aral Sea: A Lesson for Humanity The Aral Sea: A Lesson for Humanity
The largest dam in the world The largest dam in the world
The Hottest Years Since Records Began The Hottest Years Since Records Began
Magnitude of future global warming Magnitude of future global warming
Earth in Crisis: Collapse or Renaissance? Earth in Crisis: Collapse or Renaissance?
Ice on the Brink: The Inevitable Decline of Arctic Sea Ice Ice on the Brink: The Inevitable Decline of Arctic Sea Ice
Earth's Water Reservoirs: From Oceans to Groundwater Earth's Water Reservoirs: From Oceans to Groundwater
Sea Levels Are Rising, But How Fast? Sea Levels Are Rising, But How Fast?
Global Dimming: A Dangerous Respite in the Climate Crisis Global Dimming: A Dangerous Respite in the Climate Crisis
The Age of the Sahara: From Green Prairie to Stone Desert The Age of the Sahara: From Green Prairie to Stone Desert
World Population from 1800 to 2100 World Population from 1800 to 2100
Oil: The Fall of a Giant in the Era of Renewable Energy Oil: The Fall of a Giant in the Era of Renewable Energy
Kamchatka King Crab: A Giant of the Oceans Kamchatka King Crab: A Giant of the Oceans
The collapse of a society The collapse of a society
Slight Progress in the Global Ecological Footprint Slight Progress in the Global Ecological Footprint
The South Atlantic Anomaly The South Atlantic Anomaly
The phenomenon of soil sinking is called subsidence The phenomenon of soil sinking is called subsidence
The disturbing cloud cover of the Earth The disturbing cloud cover of the Earth
The Planet's New Clouds: Asperatus, Mammatus, Morning Glory and Other Remarkable Clouds The Planet's New Clouds

1997 © Astronoo.com − Astronomy, Astrophysics, Evolution and Ecology.
"The data available on this site may be used provided that the source is duly acknowledged."
How Google uses data
Legal mentions
English Sitemap − Full Sitemap
Contact the author