Lesson Plan Using Water Quality Data - 2
Analyzing Water Quality Data Using Computation Sheets
Students can evaluate water quality in a very limited sense by investigating analyses of a single parameter (e.g., secchi depth, turbidity, color, pH, conductivity, or dissolved oxygen) or in more detail by considering such parameters collectively. This lesson plan introduces a simple method to help students accomplish the latter. (To learn how these and other analyses are made and what each indicates about water quality, go to Manual.)
If the students have collected enough of their own data to evaluate water quality, using that data will likely be most interesting to the students. Otherwise, water quality data is available at the Grand Valley State University (GVSU) Annis Water Resources Institute (AWRI) web page (Water Data). Students collected the data archived there while on cruises aboard GVSU’s D.J. ANGUS (Lake Michigan off Grand Haven, Michigan, and the nearby Grand River and Spring Lake; Figure 1) or the W.G. JACKSON (Lake Michigan off Muskegon, Michigan, and the nearby Muskegon Lake and Muskegon River; Figure 2). To learn how to arrange to take your students on an educational cruise, go to http://www.gvsu.edu/wri/education/
You will need to hold a class discussion concerning the data that is to be
analyzed. Explain that the water in the epilimnion and hypolimnion should
be thought of as two separate water masses and that these water masses likely
have different values for many of the parameters measured (see “Seasonal Lake Stratification”). Therefore,
on the “Water Quality Computation Sheet” below, top and bottom water are listed
separately. If data is available for a river plume (see “The River Plume”), discuss how that data might be
treated. For example, if AWRI data is used, you might see data listed as
“Lake Michigan” for the “Body of Water”, but designated as “Grand Haven Plume”
under “Area”. That means that although the station was physically located
If you elect to use AWRI’s data set you should familiarize yourself with the
station locations by finding them on the attached maps (
You also need to be familiar with the abbreviations used in the AWRI database. “Top” indicates the sample was probably taken 2-3 feet from the surface and normally represents the epilimnion in a lake. Data listed under “Bottom” usually means that the sample was taken 2-3 feet from the lake or river bottom. Normally that depth would represent the hypolimnion in a lake.
You can download the AWRI data files as an Excel spreadsheet at: (Water Data). Students can then make plots and manipulate the files directly, or you can give them a subset of the data and ask them to make plots by hand, depending on the goals of the exercise.
The computation sheets
This exercise uses a computation sheet modified from that developed by Gus
Unseld, III as a simple means by which students can estimate water
quality. To obtain a valid estimate, the students should use data from
numerous stations, probably at least 10 for each water body examined. One
sheet should be used for each water body (e.g.,
If you obtain data for this exercise from the AWRI database, it will not
contain “sediment” data. In that case, you will need to ask your students
to ignore the category for “sediments”. If you have your own sediment
data, or data from a database that includes a description of the sediment, you
can include it in the calculations. In any case, the “sediments” category
is the most difficult to evaluate as the data is not quantitative. If the
sediment is primarily clean (little or no organic debris) sand or clean sand
and gravel, the mark should be in the “green” column. Sediment in the
shallow waters of
You will need to carefully explain to the students how to fill out the
computation sheets. Be sure to provide the students with one sheet for
each of the water bodies to be evaluated (e.g., one sheet for
1. Before estimating the health of each of the water bodies, predict what
you think the outcome of your calculations will be for each (e.g., will
2. Fill out the computation sheets. Please note whether or not you included the plume data and explain your reasoning.
3. Were you surprised by any of the results of your calculations? Did you correctly predict the water quality for each of the water bodies? Do you believe the results, or do you think the calculations themselves are questionable?
4. For each water body discuss which parameters (e.g., pH, conductivity, etc.) appear to be doing the most harm to the overall, calculated water quality.
5. What do you predict for the future of each of the water bodies? For example, for which do you expect water quality to improve? Get worse? Explain.
6. Assume that you are in the state legislature and write a proposal
that will improve the health of
LIVING WITH THE
BROUGHT TO YOU BY:
GRAND VALLEY STATE UNIVERSITY
DEPARTMENT OF GEOLOGY