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How is the quality of our waters determined?
Every state adopts goals or standards that need to be met for its waters,
based on the intended uses of the waterbodies. Different goals are set
for different waterbody uses. For example, if the water is going to be
used for cooling machinery in a factory, it doesn't have to be as clean
as water used for drinking. Scientists monitor the waters and give them
one of the following scores:
(GOOD) The waterbody fully supports its intended uses.
(IMPAIRED) The waterbody does not support one or more of its intended
uses.
| What
is the quality of our waters?
Surface waters are waters that you can see. These waters include
rivers and streams, lakes, ponds, reservoirs, wetlands, coastal
waters, and estuaries. For the U.S. waterbodies sampled most
recently, about 40% are rated as impaired. The charts here show,
by the type of waterbody, what percentage of the assessed waters
were rated GOOD and what percentage were rated IMPAIRED.
| How
many uses for water can you think of? |
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Make
a list of how water is used by people, plants and
animals. Here are a few ideas: 
- drinking
-
swimmimg
- showering
- watering
the lawn
- homes
for fish, bugs and wildlife
-
irrigating crops
- navigation
Scientists
group these uses into a few overall categories, like
Aquatic Life, Drinking Water, and Recreation. They then
decide what categories of uses a waterbody should support
(for example, virtually all waterbodies should support
aquatic life), and monitor the waterbody to see if it
supports its uses. |
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| What
percentage of all waterbodies are assessed? |
We don't have the money or technology to sample all the waterbodies
in the U.S. The nation has more than 3,600,000 miles of rivers
and streams alone! If all the rivers and streams were placed
end-to-end, they could wrap around the earth 144 times. Each
state assesses only a portion of its waters, Here are the
lates numbers we have for percentage of U.S. waters assessed:
- 19% of rivers and streams
- 43% of lakes, ponds, and reserviors
- 36% of estuaries
- 6% of ocean shorelines
- 92% of Great Lakes shoreline
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