The water cycle, or hydrologic cycle, is the continuous circulation of water within the Earth–atmosphere system, driven primarily by solar radiation and gravity. It encompasses phase changes and fluxes such as evaporation and transpiration from surface and biotic reservoirs, condensation in the atmosphere, cloud formation, and subsequent precipitation as rain, snow, or other hydrometeors. Infiltration, percolation, and groundwater flow redistribute water within subsurface reservoirs, while surface runoff and riverine transport return water to oceans and lakes. The water cycle regulates climate, controls energy and mass exchanges, and governs biogeochemical transport across terrestrial, aquatic, and atmospheric compartments.
Climate change is altering water availability—across the globe, and right on our doorstep. With a new interactive map, users can now see online how renewable water resources, groundwater recharge, and evapotranspiration might ...
Environment
May 6, 2025
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Though wildly different in so many ways, Earth and Saturn's moon Titan have something important in common. Among all the objects in the solar system, they're the only two with liquids on their surfaces. There are parallels ...
Planetary Sciences
Apr 3, 2025
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The Panama Canal is one of the most important waterways in the world, with about 7% of global trade passing through. It also relies heavily on rainfall. Without enough freshwater flowing in, the canal's locks can't raise ...
Environment
Mar 31, 2025
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University of Melbourne hydrology professor Dongryeol Ryu and his collaborator Ki-Weon Seo were on a train to visit Ryu's family when they found something startling. Stopped at a station for technical issues, Seo had pulled ...
Environment
Mar 27, 2025
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Prolonged droughts, wildfires and water shortages. Torrential downpours that overwhelm dams and cause catastrophic flooding.
Environment
Mar 24, 2025
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Stretching from Montana to Missouri, the Missouri River basin is one of the country's largest river systems. Over the past century, its average streamflow has increased by about 40%, with multiple years since 1990 experiencing ...
Earth Sciences
Mar 18, 2025
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Just over half the world's population shares a river or lake basin with at least one other country. To sustainably manage those water resources for the health of people, ecosystems and economies, neighboring countries must ...
Environment
Mar 18, 2025
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When Earth first formed, it was too hot to retain ice. This means all the water on our planet must have originated from extraterrestrial sources. Studies of ancient terrestrial rocks suggest liquid water existed on Earth ...
Astrobiology
Feb 17, 2025
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Summer heat has significant effects in the mountainous regions of the western United States. Melted snow washes from snowy peaks into the rivers, reservoirs, and streams that supply millions of Americans with freshwater—as ...
Planetary Sciences
Oct 29, 2024
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A rash of storms in Texas in recent years—from Hurricane Harvey in 2017 to the deep freeze in 2021—has put big chunks of the population in danger and left millions without electricity or water for long periods.
Nanomaterials
Aug 2, 2023
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