📖 Read the Case Study

The Mystery of Millbrook Creek

Every summer, the students of Jefferson Elementary School visited Millbrook Creek for their annual science field trip. The creek had always been full of fish, frogs, and clear, sparkling water. But this year, something was terribly wrong.

When fifth-grader Maya arrived at the creek on June 5th, she noticed the water looked murky and brownish-green. Dead fish floated near the bank, and the frogs that usually sang loudly were nowhere to be found. Maya's science teacher, Mr. Ortega, looked concerned. He collected water samples to test back at school.

The next day, the class analyzed the samples. The results showed that the water had very high levels of a chemical called nitrogen — the same chemical found in fertilizers. Maya remembered seeing a large farm about half a mile upstream that had recently expanded. She also recalled that it had rained heavily the week before, on May 28th.

Maya proposed that rainwater had washed fertilizer from the farm's fields into Millbrook Creek. Mr. Ortega called this process runoff. The class decided to write a letter to the local town council to report the problem and suggest solutions, such as planting trees near the creek to act as a natural filter.

Word Count: ~200 words | Lexile Level: ~820L

✅ Part 1: Multiple Choice

Circle the best answer for each question.

✏️ Part 2: Short Answer & Critical Thinking

Answer each question using complete sentences and evidence from the passage.

I think murky means _______________________________________________ because _______________________________________________.