What is the focus of this module? Studying in teams, students examine a broad array of information on the Lower Wheeling Creek and the Wheeling Creek watersheds in Wheeling, West Virginia. The Lower Wheeling Creek Situation presents a sub-section of the larger Wheeling Creek watershed database. In order to resolve Situation 2 (Wheeling Creek Watershed), it is essential that students solve Situation 1 (Lower Wheeling Creek).

What are the compelling problems that students will face in this module?
In Situation 1, Lower Wheeling Creek, students are asked to "wrestle with this mess" of data and decide if there is a water quality problem in lower Wheeling Creek. If so, what is the source of the problem?

About the data
These are real data collected in May 1993:

The biological data points represent the average of three macroinvertebrate samples. The chemical and physical data points are single readings. 

The data are continuous from upstream to downstream, left to right.

Distance from the Ohio River (mouth of Wheeling Creek) is a continuous gradient; therefore, the use of lines to connect the points is appropriate.

It is accurate to interpret changes in the lines as changes in water quality characteristics as you pass from one point to the next.

Lower Wheeling Creek impacts:
Sites F and E (lower 2 sites), 2.6 and 5.4 km upstream have sewage from a leaky CSO; dredging of the streambed beginning over 100 years ago; and some acid mine drainage.

Site D, 6.2 km upstream from the Ohio River has proximity to urban sites, and a parking lot. Recent dredging produced a in few large rocks and siltation.

Sites C and B, 7.4 and 10.6 km upstream are good sites on Lower Wheeling Creek. They show green space with no dredging.

Site A, 12 km upstream is a relatively good site but appears to suffer from its proximity to urban areas around Elm Grove.

In Situation 2, Wheeling Creek Watershed, data from six sites in the Wheeling Creek watershed are displayed from the small headwater tributaries to a large, swimmable creek. Students are asked to answer several questions based on their experience with the Lower Wheeling Creek problem and the data provided regarding the entire Wheeling Creek watershed:

• Would you swim in Wheeling Creek?
• How would you know if the water was safe?
• If you caught a fish, would you eat it?
• What are the most important influences on Wheeling Creek?
• Is there anything that can be done to improve water quality in the Wheeling Creek watershed ecosystem?
  

What tasks will students encounter as they work through this module? Each team should identify a water quality variable (macroinvertebrates, number of taxa, diversity index, EPT index, pH, Conductivity, Hardness, oxygen, velocity, depth, rock size, and forest canopy) and analyze it for the following:

• What does the variable represent?
• How is it measured?
• What does it tell you about pollution?
• How does it change from site to site?
• How do the values at the six sites on Lower Wheeling Creek compare with the average of all 100 sites in the watershed?

What is the role of remote sensing in this module? The role of remote sensing in this module is limited to helping students answer the question, "Is decreasing forest canopy directly related to the decline in macroinvertebrates?" If not, lack of tree cover is certainly symptomatic of the larger (urbanization) problem, which may in turn account for the decline in some way. The amount of concrete and the tree cover differences between sites are very apparent in the low-level aerial photos. Ask students to compare (visually) or measure (using image analysis) the amount of green space and the amount of concrete in the photos. Do the patterns parallel those of the biological data?

Preparation Checklist--have you thought of everything?

Creating a Working Problem Statement
To help students create a Working Problem Statement (WPS), you may want to pose some introductory questions such as the following:

Make a list of all of the variables that could have caused changes in stream water quality.

Which of these variables could change the water quality in Lower Wheeling Creek?

Some Additional Questions and Answers
Can you recognize a water quality problem?

The abrupt decrease in the number of macroinvertebrates at 5 kilometers is particularly noteworthy. Note also the low diversity and quality (EPT) values at the 5 km site and the site just upstream. This is a complicated problem but students should note that some changes occur in the biological communities in the lower portion of the creek. The ultimate challenge is for the student to investigate and determine what the problems may be.

Can you make an assessment of water quality by looking at the macroinvertebrate population?

Macroinvertebrates are abundant at most sites, except downstream, where pollution causes populations to dwindle. The number of kinds of organisms (taxa), a measure of diversity, drops off as well. The macroinvertebrate quality index EPT shows a rather dramatic response through the Lower Wheeling Creek area, indicating an increase, followed by a decrease in the most pollution-sensitive organisms.

How many macroinvertebrates occur at each of the six sites?

From 15,000 at the lowest to 100,000 per square meter at the highest site.

How many kinds (taxa) of organisms were found at each sites?

Between 9 and 28 kinds of organisms.

What are the similarities and differences between sites? Is there a pattern?

The decline in numbers and kinds at the site that is 5 kilometers above the mouth indicates pollution. Judging by the EPT index, the sites at 6 kilometers downstream and beyond appear to have lower numbers of mayflies, stoneflies, and caddisflies.

Does water chemistry change from site to site? What does water chemistry data tell you?

Note that there is slight pH level decline through Lower Wheeling Creek. There is also an increase in conductivity associated with higher hardness values, indicating an increase in metal and ion concentrations. These may be attributed to greater amounts of concrete, urban runoff, CSOs, and some mine drainage coming in 5 km upstream of the site. Note particularly the decline in dissolved oxygen concentrations at the lower two sites. This decline is related directly to the leaky CSO pictured in the site description. This outlet, now fixed, was leaking raw sewage into the stream at the time of sampling. The low dissolved oxygen levels are probably most responsible for the decline in macroinvertebrate abundance and diversity at the lower two sites. Other forms of pollution are difficult to identify. Thus, in one sense the lower two sites represent the cumulative impact of human settlement on the biological communities of Lower Wheeling Creek.

Do trends in water chemistry parallel the biological data?

It is especially challenging for students to relate two or more kinds of data. Note the similarity between the macroinvertebrate and the dissolved oxygen data. Both decline tremendously at the lower two sites. Note the contrast between the macroinvertebrate and the other chemistry variables.

Do the physical characteristics of the sites play a role in determining biological water quality?

Certainly the relationships between width, depth, and flow help shape the habitat for macroinvertebrates. Note that forest canopy and stream rock size parallel the patterns seen in the macroinvertebrate data, whereas depth and velocity do not.

The size of the rocks in the streambed is a determinant of the types of organisms that will live in any particular spot in a stream. Note that reduction in rock size most characteristically follows the pattern shown in the EPT index data. Is rock size important to survial of the mayflies (E), stoneflies (P), and caddisflies (T)?

Finally, what is the most important factor in determining the composition of the stream community? This is a good subject for debate.

Resources for this module

Teacher to Teacher
Water Quality Module Rubric

Sewage Runoff into Wheeling Creek: Let's Stop It!

A Letter to Teachers

Assignment Ideas
Have teams report their findings for each of the variables. They may wish to use the blackboard or poster boards so they can easily compare their findings.

Have students compare chemical and physical data to biological data. Which chemical or physical variables mimic the trends in the biological data from upstream to downstream?

Ask students to prepare a list of the most (to least) likely causes of deteriorated water quality in Lower Wheeling Creek. Eliminate variables that don't seem to be associated with the deteriorated water quality. Which of the variables that appear to be associated with deteriorated water quality show the most dramatic change?