Definition - What does Silt mean?

Silt consists of small particles or grains of soil and minerals that are easily carried and deposited by water. Each particle is smaller than a grain of sand but larger than a clay particle. When heavy rains pound the soil some of these fine granular particles are carried by the runoff water as silt.

MaximumYield explains Silt

Silt carried by water runoff is deposited in lowlands, rivers or ponds as a sediment. The environmental impact of silt is enormous, as once it settles into a river or lowland it provides valuable nutrients for plants and insects in the sediment it creates.

Silt carried down the Nile River, for example, created an oasis of rich, fertile soil for the ancient Egyptians. Silt is carried down the Mississippi and other rivers to the ocean where it also provides a rich habitat for plants and fish.

But silt can also be a source of problems by clogging pipes and drains. When too much silt is dumped into waterways or rivers, it can become a pollutant known as siltation. This can cause a number of environmental problems, including killing fish by clogging their gills, and by reducing the water's dissolved oxygen level.

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