Terrestrial Tour: Freshwater—A Precious Resource

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Satellite observations bring us closer to understanding both the freshwater cycle and the ways humans are affecting this precious resource. 

Produced by the Space Telescope Science Institute’s Office of Public Outreach in collaboration with the NASA Earth Observatory.

All images, illustrations, and videos courtesy of NASA except:
·       Dinosaur illustration courtesy of Mariana Ruiz Villarreal
·       Sea creature illustration copyright The National Library of Israel, Shapell Family Digitization Project _and The Hebrew University of Jerusalem, Department of Geography – Historic Cities Research Project
·       Waterfall photos courtesy of Wikimedia users Karduelis and MattiPaavola
·       Molecule illustration by Marc Lussier (STScI) based on illustration by Luis Javier Rodriguez Lopez
·       Photo of water droplets on leaf courtesy of Thomas Bresson
·       Photo of ocean waves courtesy of Sean O’Flaherty
·       Photo of beach on the Pacific Ocean courtesy of Wikimedia user Marlith
·       “All the Water on Earth” animation by Jack Cook, copyright Woods Hole Oceanographic Institution
·       Photo of artesian spring courtesy of Marc Averette
·       Photo of Santa Lucia Cloud Forest in Ecuador courtesy of Hettie van Nes
·       Photo of red panda courtesy of Jennifer Dunne
·       Photo of Graylag goose courtesy of David Graus
·       Photo of pail of dirty water copyright Pierre Holtz, UNICEF
·       Photo of bottled water on store shelf courtesy of Ivy Main
·       Photo of water park courtesy of Wikimedia user Stu pendousmat
·       Photo of pivot irrigation system courtesy of Gene Alexander, USDA Natural Resources Conservation Service
·       Photo of Arizona golf course courtesy of Bernard Gagnon
·       Panoramic photo of Glen Canyon Dam courtesy of Christian Mehlführer
·       Photo of man at terminus of Colorado River copyright Peter McBride, The Colorado River: Flowing Through Conflict
·       Photo of dry riverbed of Colorado River copyright Peter McBride, The Colorado River: Flowing Through Conflict
·       Photo of boy drinking from well courtesy of U.S. Air Force Master Sgt. Eric Kreps
·       Photos of artesian wells courtesy of Michael Gäbler, Père Igor, and Wikimedia user Nikater
·       Photos of a spring in Indiana courtesy of Huw Williams
·       U.S. groundwater map created by Chris Poulsen, National Drought Mitigation Center at the University of Nebraska-Lincoln, _based on data from Matt Rodell, NASA Goddard Space Flight Center, and the GRACE science team
Music courtesy of Associated Production Music
Written by Tracy Vogel
Designed by Marc Lussier

Droplets on a blade of grass. Text, Freshwater, a precious resource.
Earth. Text, Viewed from a distance, the blue hue is the first thing we notice about our home planet.
Ocean waves. Text, So much of our planet is water.
It covers 70 percent of Earth's surface. To all appearances, Earth has water in plenty.
But this is what Earth's water would look like if we could pull all the water off this globe and gather it together.
In an animation, blue dots stream off Earth. They form a blue orb, labeled All of Earth's Water. Text, And only about 2.5 percent of that water is usable, essential "freshwater." A smaller blue orb labeled, Usable Freshwater.
Great Lakes Region, USA-Canada. Freshwater, which is low in salts and dissolved solids, is critical to life on Earth.
Water empties into a bucket. Text, But human-caused pressures on the environment are endangering this precious resource.
Photos of bottled water, a water park, a golf course and farm irrigation. Text, The demand for water by both people and industry has doubled since 1960.
A city skyline. Text, Pollution, climate change, and lack of conservation are affecting the world's finite supply of freshwater.
Lake Valencia, Venezuela. Untreated wastewater from urban areas, farms, and industries causes swirling algae blooms like this one in Lake Valencia, the largest freshwater lake in Venezuela.
Lake Mead, Arizona-Nevada, USA. 1985. In 2016, Lake Mead the United States' largest reservoir, reached its lowest level since 1937.
2016. According to the US National Park Service, the water being removed and evaporating from Lake Mead has exceeded incoming water in recent years.
Lake Powell, Arizona-Utah, USA. 1999. In Utah and Arizona, the vital Lake Powell reservoir has been low for nearly two decades.
Water levels change between the years 2004 and 2010. Text, Severe drought and rising human and agricultural consumption have kept levels low.
In 2011, heavy snowfall in rainfall delivered extra water to the lake.
But by 2013, Lake Powell was again less than half full.
Water levels change between the years 2014 and 2019.
Glen Canyon Dam, Colorado River, USA. Climate change and the siphoning off of water for irrigation and dams have caused visible changes in the world's rivers.
Yellow River Delta, Dongying, China. 1995, and 2009. For the past 35 years, China 's immense Yellow River has frequently died off before reaching the ocean, victimized by irrigation and vanishing glaciers.
Water flows from a pipe. A man drinks from his hand. Text, The danger to our freshwater supply runs deeper than the visible damage.
An abundant supply of Earth's freshwater - 20 to 30 percent - is groundwater, located beneath the surface in aquifers.
Half the people in the United States get their water from groundwater.
A map depicts U.S. Groundwater Levels, September 2012. Red for low, blue for high. Text, However, groundwater supplies have been decreasing in the United States and around the world.
The crops in this image of Southwestern Kansas are fed partly by the Ogallala Aquifer, which covers eight states from South Dakota to Texas.
A map of the US highlights the Extent of Ogallala Aquifer. Scientists estimate that the Ogallala Aquifer has lost volume equal to two-thirds of the water in Lake Erie.
NASA is using satellites to track and study Earth's supply of freshwater.
Mesopotamian Marshes, Iraq. Satellites examine shrinking wetlands. The Al Hawizeh Marsh in 2000, 2003, 2006 and 2009.
They map the snow that replenishes rivers and lakes.
Indus River, Pakistan. They watch the changes that occur in rivers through both human intervention and natural cycles.
These observations bring us closer to understanding both the fresh water cycle and the ways humans are affecting this precious resource.