In
hydrology
Hydrology () is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and drainage basin sustainability. A practitioner of hydrology is called a hydro ...
, throughfall is the process which describes how wet leaves shed excess
water
Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...
onto the ground surface. These drops have greater erosive power because they are heavier than
rain
Rain is a form of precipitation where water drop (liquid), droplets that have condensation, condensed from Water vapor#In Earth's atmosphere, atmospheric water vapor fall under gravity. Rain is a major component of the water cycle and is res ...
drops. Furthermore, where there is a high canopy, falling drops may reach
terminal velocity
Terminal velocity is the maximum speed attainable by an object as it falls through a fluid (air is the most common example). It is reached when the sum of the drag force (''Fd'') and the buoyancy is equal to the downward force of gravity (''FG ...
, about , thus maximizing the drop's erosive potential.
Rates of throughfall are higher in areas of
forest
A forest is an ecosystem characterized by a dense ecological community, community of trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, ...
where the leaves are broad-leaved. This is because the flat leaves allow water to collect.
Drip-tips also facilitate throughfall. Rates of throughfall are lower in
coniferous
Conifers () are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a sin ...
forests as conifers can only hold individual droplets of water on their needles.
Throughfall is a crucial process when designing pesticides for foliar application since it will condition their washing and the fate of potential pollutants in the environment.
See also
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Stemflow
In hydrology, stemflow is the flow of intercepted water down the trunk or stem of a plant. Stemflow, along with throughfall, is responsible for the transferral of precipitation and nutrients from the canopy to the soil. In tropical rainforests, ...
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Canopy interception
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Forest floor interception
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Tree shape
Notes
Hydrology
Forest ecology
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