156 Protec ting Watersheds
How Watersheds Work
Everyone’s health is affected if the
watershed is damaged. To understand
how important watersheds are to the
environment, it helps to think of rivers
and streams as the veins of the earth.
They carry and move water through
the land the way our veins carry blood
through our bodies. Just as we depend
on blood for life, the environment
depends on water for life.
The boundaries of any watershed are
the peaks and ridges of the hills.
These small
watersheds...
The water cycle
Water is always moving.
Sometimes it moves by flowing
along, like a river. Sometimes
...are parts of the
larger watershed.
it moves by changing from a liquid
(water) to a gas (steam or water vapor) or to a solid (ice or snow). But the
total amount of water in the world never changes. All the water there is moves
from the sky to the earth, soaking into the ground, flowing into rivers, lakes,
and oceans, and then evaporates back into the sky. This movement of water is
called the water cycle.
Clouds carry water and release it
back to the earth as rain and snow.
Heat from the sun causes water to evaporate
from the surface of lakes, rivers and
oceans into the sky. Water is
also released from plants
and from the soil.
Water runs across
the earth’s surface
into streams, lakes
and rivers.
Water seeps into the soil where it nourishes plants and trees. It sinks underground
where it is stored as groundwater, the source of water in wells and springs.
A Community Guide to Environmental Health 2012