Runoff, in the context of environmental and Earth system topics, refers to the portion of precipitation, snowmelt, or irrigation water that does not infiltrate into the soil or evaporate but instead flows over the land surface or through shallow subsurface pathways to streams, rivers, lakes, or coastal waters. It is a central component of the hydrological cycle, governed by factors such as soil permeability, land cover, topography, antecedent moisture, and rainfall intensity. Runoff mediates fluxes of sediments, nutrients, pollutants, and dissolved organic and inorganic constituents, strongly influencing watershed biogeochemistry, aquatic ecosystem function, flood regimes, and water resource availability.
Collecting rainwater from rooftops and using it to spray buildings during hot weather could help cities cut air conditioning use, lower urban temperatures and lessen the impact of heat waves, according to new research from ...
Environment
Aug 5, 2026
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35
Watersheds that are flatter, drier and warmer are generally more vulnerable to increases in flooding after trees are harvested. Those with greater variation in elevation spread runoff out over time, reducing flood peaks.
Environment
Aug 5, 2026
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7
The small mountain streams that feed many of the West's rivers may face a much drier future. A new study led by NAU researchers found that groundwater-fed streamflow, known as base flow, has been steadily declining across ...
Environment
Aug 2, 2026
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35
Coastal cities are at increasing risk of compound flooding events, such as when heavy rainfall and storm surges occur simultaneously during hurricanes. However, the processes that contribute to urban compound flooding aren't ...
Earth Sciences
Jul 30, 2026
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10
Rowers on the River Po in Turin are battling vast blooms of algae, as high temperatures in northwest Italy and runoff from farms create ideal conditions for rampant plant growth.
Environment
Jul 16, 2026
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44
Warm, sticky nights are becoming increasingly common in the UK.
Environment
Jul 16, 2026
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16
After hours of torrential overnight rain lashed Lagos recently, church pastor Samuel Akpan spent most of the next day bailing water from his flooded parsonage in an upscale district of Nigeria's commercial capital.
Environment
Jul 16, 2026
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6
Heavy precipitation becomes more intense with every degree Earth warms. This affects flooding. Using hourly data from 384 rivers in the Alps, researchers from the WSL Institute for Snow and Avalanche Research SLF modeled ...
Earth Sciences
Jul 16, 2026
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7
A new study finds a widely used technique for assessing the health of freshwater streams is not effective at detecting a range of water quality problems, including those related to acidity, oxygen levels and the presence ...
Environment
Jul 13, 2026
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10
Across a narrow watershed in Asakura, a rural city in Fukuoka Prefecture, centuries-old stone channels still guide water through fields and into the river below. Today, those same systems are the focus of researchers at Kyushu ...
Environment
Jul 11, 2026
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