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Worksheet Grade 8 Social Studies & Civics

Vellum Springs Drought Stages: Reading a Shortage Plan

A grade 8 worksheet in which students read a town's four-stage drought plan, model falling reservoir storage with a linear equation, and predict when each stage begins.

Objectives

  1. Students will write a linear equation for reservoir storage from a table of measurements.
  2. Students will predict the week each drought stage begins by solving that equation.
  3. Students will explain how a staged shortage plan divides authority and distributes burdens.

Vocabulary

Key words: reservoir storage, trigger, drought stage, exemption, ordinance

Teacher overview

A drought plan is a policy written before the emergency, and it does two things at once: it sets numerical triggers and it assigns authority. This worksheet gives students a fictional town's four-stage plan alongside six weeks of reservoir measurements, so the reading task and the mathematics support each other. Students find the weekly rate of decline, write the linear function, and use it to predict when each stage would begin. The common error to watch for is a student who divides a stage trigger by the weekly loss instead of subtracting the trigger from the starting storage first, which produces a week number far too large. The final items move from prediction to judgment, asking who the plan's exemptions protect.

Vellum Springs Drought Stages: Reading a Shortage Plan — Grade 8 Social Studies & Civics
Name: ____________________________ Date: ______________

Student Worksheet

The fictional town of Vellum Springs draws its water from Kettlefield Reservoir. The town council has adopted a shortage plan with four stages. The plan is shown below.

Stage Storage trigger (million gallons) Main restriction Fine for a second violation
1, Advisory 580 The town asks residents to water less None
2, Warning 520 Lawn watering on two days a week $50
3, Emergency 448 No lawn watering; cars washed only at businesses that recycle water $150
4, Crisis 400 Indoor use only; the town may shut off outdoor taps $300

The plan also states three rules. The town manager declares a stage when storage drops past a trigger. The council must confirm that stage at a public meeting within 10 days. Vegetable gardens, new lawns in their first 30 days, and businesses that wash vehicles with recycled water are exempt from the watering limits.

Staff measured the reservoir every two weeks this summer.

Week Storage (million gallons)
0 640
2 616
4 592
6 568

Assume the reservoir keeps dropping at the same steady rate.

  1. How much storage does the reservoir lose each week?
  2. Write an equation for the storage S, in million gallons, after w weeks.
  3. Stage 2 begins at 520 million gallons. In which week does the reservoir reach that trigger?
  4. Stage 3 begins at 448 million gallons. In which week does the reservoir reach that trigger?
  5. Stage 4 begins at 400 million gallons. In which week does the reservoir reach that trigger?
  6. Under Stage 3, where may a resident wash a car?
  7. Under the plan, who declares that a new stage has begun?
  8. What must the council do after a stage is declared?
  9. A household waters its lawn twice during Stage 3 and is cited both times. What is the fine for the second violation?
  10. The plan tightens the rules in four steps instead of imposing every rule at once. Give one reason a town would write a plan that way.
  11. Name one group the vegetable garden exemption protects, and explain why the council might have wanted to protect it.

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: 12 million gallons per week.
    Storage falls 640 - 616 = 24 million gallons over two weeks, so the weekly loss is 24 divided by 2, or 12 million gallons. The same drop appears between every pair of rows.
  2. Answer: S = 640 - 12w.
    The initial value is the week 0 storage of 640 million gallons, and the rate of change is a loss of 12 million gallons per week, which makes the coefficient negative.
  3. Answer: week 10.
    640 - 12w = 520, so 12w = 120 and w = 10 weeks.
  4. Answer: week 16.
    640 - 12w = 448, so 12w = 192 and w = 16 weeks.
  5. Answer: week 20.
    640 - 12w = 400, so 12w = 240 and w = 20 weeks. Stage 4 arrives four weeks after Stage 3, because the Stage 4 trigger sits 48 million gallons below the Stage 3 trigger.
  6. Answer: Only at a business that recycles its wash water.
    Stage 3 bans lawn watering and allows car washing only at businesses that recycle water.
  7. Answer: The town manager.
    The plan gives the manager the power to declare a stage once storage drops past a trigger.
  8. Answer: Confirm the stage at a public meeting within 10 days.
    The plan splits the decision: the manager acts quickly, and the elected council reviews that action in public soon afterward.
  9. Answer: $150.
    The plan sets the second-violation fine in Stage 3 at 150 dollars.
  10. Answer: Accept any reasonable explanation of staged restrictions.
    Strong answers note that early stages ask for voluntary savings, which may be enough to avoid harsher rules; that residents and businesses get warning and time to adjust; or that the town can match the burden to how much water is left rather than guessing at the start of the summer.
  11. Answer: Accept any group the exemption protects, with a reason.
    Households that grow part of their food and community gardens are the clearest answers. Reasons might include that food production is a higher-value use than lawn appearance, that a vegetable garden dies within days without water while a lawn recovers, or that the council wanted the plan to appear fair enough to gain public support.

Differentiation

Support

Provide the storage table with the differences already written between rows, so item 1 becomes a matter of dividing a stated drop by two weeks. Give these students items 1 through 4 and items 6 through 9 only, and supply the equation frame for item 2 with the initial value filled in.

Extension

Ask students to determine how much less water the town would need to lose each week to keep the fictional reservoir above the Stage 3 trigger through week 20, and to state what that reduction would mean for the restrictions the town chooses.

ELL supports

Pre-teach "trigger," "violation," "exemption," and "declare" using the plan table itself, pointing to the column that shows each term in use. Provide sentence frames for items 10 and 11, such as "The town uses four stages because ___" and "The exemption protects ___ because ___."

Extensions

Many water utilities publish their own drought or water shortage plan. Students can find one, compare its number of stages with the four in the fictional plan here, and write a paragraph on one restriction the real plan includes that the classroom version does not.