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Transparency Map
Transparency Trends
Secchi
Depth Statistics
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Quality
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Contact the Dip-In at:
dipin@kent.edu
Web Site Updated:
June 17, 2008
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Secchi Dip-In Results
The
Transparency of North American
Waterbodies 1994-2004
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Notice the concentration of
waterbodies of greater transparency in the northern tier of US
states and Canada. The agricultural heartland of the
continent tends to have smaller transparencies, in part because of
the fertile soils that make agriculture possible, in part because
of agricultural practices, and, in part because of the
predominance of reservoirs rather tan lakes.
The Canadian depths are represented by the
individual lake for which coordinates could be found. The
United States transparencies are given as county averages and do
not infer that all lakes in the county have the same Secchi depth.
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| Although the Secchi Dip-In has concentrated on North
American waterbodies, we welcome participants from other parts of
the world. |
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Transparency Trends
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By 2005,
1,743 waterbodies had 5 or more years of data. Of these, 197 had
significant changes in transparency; 83 had
significant decreases in transparency (Blue
dots); 113 had significant increases (Red
dots). However there were few discernable patterns that can be
related to climate, land use, or population
change that might explain
which lakes exhibited change.
In Image below, the blue markers
indicate waterbodies that have
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Water
Quality in
North American Waterbodies
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During the Dip-Ins, the questionnaire
has included questions of water quality. We hoped to gain
some knowledge of the state of our waterbodies and the nature of
problems as perceived by the volunteers. Although
some people reported that they had no problems, more than 2,100
volunteers reported at least one problem.
Algal scums, weeds (aquatic macrophytes), turbidity, boats, and
personal watercraft are the major problems reported. |
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We have tracked what
volunteers report as to the quality of their waterbody and compared
their perception with the Secchi depth. It is interesting to
note that there are strong regional differences in the average
Secchi depth of waterbodies that volunteers consider to be in
excellent condition (Left). |
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Conversely, volunteers from different regions have
different perceptions of what constitutes an impaired waterbody.
Again in the regions that have relatively clear waters the
volunteers are less tolerant of smaller Secchi depths and more apt
to consider the waterbody's use to be impaired. |
| Despite the problems listed, most of the volunteers
felt that their waterbody was slightly impaired. Very few
reported that the waterbody was unusable. |
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For Information About Past
Dip-Ins,
Click here to view the Following Publications
For more information on the Dip-In, contact us at: DipIn@kent.edu
or write
Secchi Dip-In
Department of Biological Sciences
Kent State University
Kent OH 44242
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