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Investigative Case: The Nancy Creek Challenge

Developed for Lifelines Online by J.Bland, S. Carter, S. Mattox, and T. McCrary (www.bioquest.org/lifleines/ ( This site may be offline. ) )
This material is replicated on a number of sites as part of the SERC Pedagogic Service Project
Initial Publication Date: May 13, 2008


A picture of a fillkill event.

Students examine a case study of fish kill in Nancy Creek and identify the environmental conditions that favor life in a fresh water ecosystem. Students will work in small groups to assess the situation. The group will be allowed to gather resources from various places in an effort to develop a possible solution for the situation.

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Learning Goals

Students will:
  1. Analyze and interpret data
  2. Design and construct a scientific experiment
  3. Produce written reports of laboratory activities in accepted formats
  4. Investigate the components of a fresh water ecosystem

Context for Use

This case is appropriate for entry level Environmental Science, Biology, Ecology and/or Chemistry.

Considering Class Size - Different types of objectives can be accomplished by implementing case-based learning in different sized classes.

How Do Investigative Cases Fit into Courses?- What issues need to be taken into account before introducing cases to your class?

Teaching Materials

Article 1: Officials say chlorine killed 15,000 area fish
Alfred Charles - Atlanta-Journal Constitution
Tuesday, July 11, 2000

State environmental officials said Monday that chlorine was the contaminant that killed up to 15,000 fish last week in the Nancy Creek watershed.

Although state Environmental Protection Division administrators won't be able to conclusively identify where the chlorine came from until later this week, they said it is possible that the chemical may have originated from two different sources.

"We're in the process of figuring out where the discharge came from," said Vince Dollard, an EPD spokesman. "This was a serious fish kill."

Thousands of dead fish were found last week along the 18-mile length of Nancy Creek, which stretches from the Chamblee-Dunwoody area in DeKalb County to the Chattahoochee River in Fulton County.

State environmental authorities said enforcement action is likely once they determine the source of the chlorine, which they suspect was discharged from DeKalb's water plant on Winters Chapel Road in Doraville and a nearby swimming pool.

DeKalb officials have denied that their treatment plant released the large levels of chlorine that would lead to the fish kill. They point to environmental tests they conducted in the days after the fish kill that found only a trace of chlorine.

Article 2: Officials probe massive Nancy Creek fish kill
Alfred Charles - Atlanta-Journal Constitution
Saturday, July 8, 2000

State environmental officials are trying to determine what caused a catastrophic fish kill this week in the Nancy Creek watershed.

In what experts are calling one of the worst kills in metro Atlanta history, thousands of dead fish have been spotted along the 18-mile length of the creek from where it begins in the Chamblee/Dunwoody area in DeKalb County down to where it joins the Chattahoochee River in Fulton County.

Officials of the state Environment Protection Division said Friday that they have detected unusually large levels of chlorine in Nancy Creek, but they declined to say where the chemical may have come from, citing the ongoing investigation.

If it is determined that a chlorine discharge is to blame, the source of the contaminant could be facing several thousand dollars in fines and a review of any operating permits.

"This is a significant incident if it is attributed to chlorine," said Sally Bethea, executive director of the Upper Chattahoochee Riverkeeper, an environmental activist group.

State officials have reported several other disastrous spills in recent years. Two years ago, Georgia Power Co. agreed to pay a $215,000 fine for discharging superheated water from one of its generating plants into Lake Sinclair near Milledgeville, killing up to 20,000 fish.

In February, a kaolin processing plant in Twiggs County in Middle Georgia released a chemical in Big Sandy Creek, killing about 11,000 fish.

The scope of this week's incident along the Nancy Creek is still being tabulated, but it will rank as one of the worst considering that dead fish, including sunfish, bass, catfish and darters, have been found along the entire length of the tributary.

"We found high levels of chlorine," said Lisa Klein a fisheries biologist for the state Department of Natural Resources Wildlife Resources Division.

Margo Howse, deputy director of the DeKalb Water and Sewer Department, denied that chlorine from the county's water plant on Winters Chapel Road in Doraville was the source of the spill.

"The chlorine residue was very slight and a very long distance from where the dead fish were," she said, adding that county tests detected only traces of chlorine.

Howse said state officials have told the county that the fish kill resulted from "weather stress," a natural phenomenon in which summer heat affects the water's oxygen. The same phenomenon is blamed for killing thousands of freshwater clams in the Ogeechee River in Bulloch County.

Klein said, however, the Nancy Creek kill is related to a chemical contaminant. "There had to be some type of toxin," she said.

Investigative Activity:

Students will complete research on their own. Students should access MapQuest for location of Nancy Creek in the Atlanta area. Some research time should be allotted during the class period, but most of the research can be completed as a homework assignment. Students will be given a chance to discuss their findings in small groups in an effort to develop the best possible solution.

After the group develops their solution, students will present their findings to the class in the form of poster presentations, power-point presentations, skits etc.

Case Analysis Worksheet - A helpful aid in guiding students through the use of cases.

Teaching Notes and Tips

Suggested schedule:
  • Thirty minutes of time for collaboration to develop a hypothesis
  • Two class periods of discussion and reviewing outside resources within the small groups
  • Forty-five minutes to complete the salmon challenge
  • Twenty minutes per group to make oral presentations
How To Use Investigative Cases with Examples - This area of the site lays out the phases Investigative Case Based Learning and key strategies for using it in your class.

Preparing Students for Cases and Collaborative Learning - Hints and advice on how to introduce cases into your class.


Production of the final oral presentation.
Successful completion of the Salmon Challenge interactive web tutorial.

References and Resources