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The Water Cycle: Nature’s Recycling System
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The Sun’s energy warms the water, water
becomes water vapor and enters the atmosphere
00:00:16
where it forms clouds.
00:00:18
The clouds, carried by winds, release condensed
water back to the earth’s surface as precipitation,
00:00:24
which accumulates on the surface and as snowpack
in the mountains.
00:00:30
Small amounts of water held by plants, animals,
automobiles and buildings are evaporated back
00:00:35
into the atmosphere.
00:00:42
Most of the water that returns to the earth’s
surface as precipitation will infiltrate the
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soil, percolating into underground aquifers,
or running off the surface into bodies of
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Smaller amounts are drawn up by plants, transpired
through leaves, and evaporate back into the
00:00:59
We cannot control the hydrologic cycle. And
the water supply is fixed. So water must be
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conserved and properly managed.
00:01:08
When it rains, each drop of water hits the
earth like a small bomb, loosening particles
00:01:14
of soil which flow into waterways as sediment.
00:01:17
Riparian buffers, living barriers of tree
and brush, can prevent sediment and pollutants
00:01:23
from entering waterways.
00:01:24
Contour strip cropping, ribbons of vegetation
between row crops, prevents water erosion
00:01:30
from taking topsoil.
00:01:32
Crop residue left on fields also helps prevent
erosion. It lessens the impact of falling
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rain and holds topsoil on the land.
00:01:41
Cities and built up areas, where the land
is largely covered by pavement, prevent water
00:01:45
from soaking into the soil.
00:01:48
In these areas, water runs off in high velocity
through storm drains and sewers, carrying
00:01:53
pollutants into the water system.
00:01:56
As the earth’s population grows, the demand
for water will grow with it.
00:02:00
Sound management of water will be key to maintaining
a safe, abundant water supply.
00:02:06
UDSA NRCS: Helping People Help the Land
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