Testing Water Clarity using a Secchi Disk
Julia John, Ithaca, NY
2nd Place, Middle School Category
Immaculate Conception School
The warm sun felt great as I laid on the dock with my cousin Meg.
We didn’t feel like going in the Lake. It was gross and covered
with algae. Meg then said, "Julia, lets figure out how to test
the water clarity of Cayuga Lake. Then we’ll know how clean
the water really is.”
“Great idea.” Then I thought about it. “Last year,
my class went on a boat called the Haendel, and we used this thing
called a Secchi disk, to test the clarity of the water.”
Meg thought about it for a few seconds, and then said, “What's
a Secchi disk?"
"Oh, it’s a black and white disk, kind of like a Frisbee,
that you drop in the water and see how far it sinks. Come on, we’ll
use my dad’s computer and look it up.”
We went inside the cottage, where we saw my dad working on his laptop.
“Hey dad.” I said. “Can Meg and I borrow your
computer to look up how to test the clarity of the lake water?”...
Meg went straight to the Internet and typed in ‘how to test
the clarity of water using a Secchi disk.’
We got online and found all sorts of information really fast like;
You shouldn’t wear sunglasses while testing, data should be
recorded at the time measured, how to use a Secchi disc, and how
to make one.
We taped a rope to a white and black Frisbee. We got in the canoe,
and rowed out by the big red buoy. We dipped our Secchi disc in
the water on the sunny side of the boat, just like the directions
said. Meg lowered it down to wear the rope said thirteen feet. We
couldn’t see it any more.
We did the exact same thing the next three days, and in that spot
the average was twelve feet.
Testing the water clarity was fun, and easy. The information we
recorded was that Cayuga Lake tests as Mesotrophic, which means
the Secchi disc is visible from a 6.5 to 16 feet range. Water clarity
is the visibility through the water. It is based on three main things;
algae, sediment, and water color.
People like you and I need to help save our water sources. The world
needs water, especially clean, clear water that is safe to drink,
wash with, and water our plants with. Saving our water is something
everyone can do by: building rain gardens, reusing water, not dumping
sewage into our lakes, taking care of toxic and medical waste the
right way, using energy star* products, and so many other easy ways.
Clear water is an important part of our society. We use it all the
time. Without it, we’d have nothing to drink, wash with, cook
with, or even water the plants with. Look around you, a lot of what
you see is run by water that we take for granted. Clear water is
keeping the world an eco-friendly place!
REFERENCES
Green, Linda.The Great north American Secchi dip-In.http://dipin.kent.edu/makedisk.htm.
Last Updated-June 6, 2005
The Secchi Disk-What is it? http://www.mlswa.org/secchi.htm.Last
Updated-1997
Why a black and white Secchi disk?http://dipin.kent.edu/black_and_white.htm
Last Updated-November 18, 2003
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