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 Macroinvertebrates
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Elementary and middle school
students may not be testing for all nine parameters when doing water
quality. The most important ones would be dissolved
oxygen, fecal coliform, pH, and temperature. For an
in-depth look at these parameters, click on the links to the left.
High school students may be
doing more in-depth studies and finding the actual Water Quality
Index. A Water Quality Index
(WQI)
can be used to measure water quality changes in a particular river over
time, compare water quality from different sites along the same
river, and compare water quality of different rivers. After
completing the nine tests listed to the left, the results are recorded and
transferred to a weighting curve chart where a numerical value is obtained
(page 71, Chart 10 in the 12th edition of the Mitchell and Stapp book
"Field Manual for Water Quality Monitoring"). For each
test, a numerical value or Q-Value is multiplied by a "weighting
factor". For example, dissolved oxygen has the highest
weighting factor of .17 because it is more significant in determining
water quality than total solids, which has the lowest weighting factor of
.07.
The parameters to the left are
in order of importance, following how they are covered in Mitchell
and Stapp's book. Dissolved Oxygen is the most important water
quality testing parameter, while Total Solids is the least.
While identifying
macroinvertebrates is not a testing parameter, the determination of
the types of macros living in a stream is a very important factor in
determining the health of a stream. |
