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Worksheet Grade 11 English Language Arts

Anders Fork Watershed: Reading a Turbidity and Streamflow Table

A grade 11 worksheet where students read a field report and a fictional watershed's turbidity data table, calculating percent change and interpreting a spike.

Objectives

  1. Students will calculate percent change in a water-quality measurement using values from a data table.
  2. Students will integrate a narrative description of field conditions with a quantitative data table to explain a trend.
  3. Students will distinguish a temporary spike in a measurement from a lasting change in water quality.

Vocabulary

Turbidity
Turbidity is a measure of how cloudy or murky water looks because of tiny particles floating in it. Clear water has low turbidity, and muddy water has high turbidity.
Streamflow
Streamflow is the amount of water moving past a point in a river or stream in a given amount of time. It rises after storms and snowmelt and drops during dry spells.
Watershed
A watershed is all the land where rain that falls will drain to the same stream, river, or lake. Everyone lives in a watershed, no matter how far from the water they live.

Also: elevated reading

Teacher overview

The Anders Fork Watershed is fictional, invented for this worksheet to give students a realistic monitoring scenario that pairs a short field report with a data table, the two formats a real watershed group typically has to read together. A common misconception is that a single alarming number, such as a turbidity spike, automatically means a permanent problem; this worksheet asks students to weigh the data table against the narrative's explanation of what happened upstream before drawing that conclusion.

Anders Fork Watershed: Reading a Turbidity and Streamflow Table — Grade 11 English Language Arts
Name: ____________________________ Date: ______________

Student Worksheet

Read the field report and data table below, then answer the questions that follow.

Field report (fictional Anders Fork Watershed monitoring station, written for this worksheet). A volunteer monitoring group samples the fictional Anders Fork Watershed at the same station every month. This spring brought unusually heavy rain, and a road-widening project began disturbing soil on a hillside upstream in early May. By late May, the group's field notes describe the water running visibly cloudy at the station for the first time that year, clearing again by early July after the construction crew installed erosion-control fencing along the disturbed slope.

Data table: monthly turbidity and streamflow readings.

Month Turbidity (NTU) Streamflow (cfs)
March 8 120
April 14 145
May 42 310
June 29 210
July 11 150
  1. What was the turbidity reading recorded in May?
  2. By how many NTU did turbidity rise from March to April?
  3. Calculate the percent increase in turbidity from March to May, rounding to the nearest whole percent. (Percent change = (May − March) ÷ March × 100.)
  4. Calculate the percent decrease in turbidity from May to July, rounding to the nearest whole percent.
  5. By how many cubic feet per second did streamflow increase from April to May?
  6. Suppose the monitoring group flags any reading above 25 NTU as "elevated." Which month or months in the table would be flagged, and by how much did each exceed that level?
  7. Based on the field report, what two upstream events likely explain the turbidity spike recorded in May? Cite evidence from the report.
  8. Explain, using both the data table and the field report, why a single high reading like May's does not necessarily mean the watershed has a permanent water-quality problem.
  9. Suppose turbidity in August returns to roughly the March baseline plus a small residual effect of 3 NTU from the completed erosion-control work. About what reading, in NTU, would you expect the August sample to show?

From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.

Answer Key
  1. Answer: 42 NTU. The May row of the data table lists a turbidity reading of 42 NTU.
  2. Answer: 6 NTU. April's reading of 14 NTU minus March's reading of 8 NTU equals 6 NTU.
  3. Answer: 425%. (42 − 8) ÷ 8 × 100 = 34 ÷ 8 × 100 = 425%.
  4. Answer: about 74%. (42 − 11) ÷ 42 × 100 = 31 ÷ 42 × 100 ≈ 73.8%, which rounds to about 74%.
  5. Answer: 165 cfs. May's streamflow of 310 cfs minus April's 145 cfs equals 165 cfs.
  6. Answer: May and June. May's reading of 42 NTU exceeded the 25 NTU flag by 17 NTU, and June's reading of 29 NTU exceeded it by 4 NTU.
  7. Answer: The field report describes unusually heavy spring rain and a road-widening project that began disturbing hillside soil upstream in early May, both of which can wash loose sediment into a stream and raise turbidity.
  8. Answer: The field report explains that turbidity cleared again by early July once the construction crew installed erosion-control fencing, and the data table confirms this: July's reading of 11 NTU is close to March's baseline of 8 NTU, showing the spike was tied to a temporary, identifiable cause rather than an ongoing source of contamination.
  9. Answer: about 11 NTU. March's baseline of 8 NTU plus a residual effect of 3 NTU equals 11 NTU.

Differentiation

Support

Provide the percent-change formula already set up with March and May's values filled in for item 3, so students only need to complete the final division and multiplication, and allow a calculator for every computation item.

Extension

Ask students to calculate the percent change in streamflow from March to May and compare it with the percent change in turbidity over the same months, then explain in a sentence or two whether the two measurements rose at similar rates.

ELL supports

Pre-teach "turbidity," "streamflow," and "elevated" with a simple visual (a clear glass of water beside a cloudy one for turbidity) before reading, and allow items 1, 2, and 5 to be answered as numbers alone without a full sentence.