Worksheet Grade 12 Social Studies & Civics
Reading Bellrose's Drought Contingency Plan: A Grade 12 Worksheet
A grade 12 worksheet in which students read a fictional city's drought contingency plan, compute reservoir percentages, and evaluate its staged trigger design.
Objectives
- Students will calculate reservoir storage as a percentage of capacity and match it to the correct drought stage.
- Students will convert between million gallons per day and acre-feet using the standard conversion.
- Students will evaluate the intended and unintended effects of staged drought restrictions on households and utility revenue.
Vocabulary
- Acre-foot
- The amount of water it takes to cover one acre of land, about the size of a football field, one foot deep. Western states use acre-feet to measure large amounts of water.
- Curtailment
- An official order to cut back or stop taking water from a river or stream because there is not enough to go around. In many Western states, the newest water users are cut off first.
Also: contingency plan, trigger, surcharge
Teacher overview
Cities in drought-prone regions adopt drought contingency plans years before they need them, so that restrictions turn on automatically when reservoir storage crosses set triggers. This worksheet gives students the staged plan of the fictional city of Bellrose and asks them to do what a utility board member does: read the trigger table, compute where the city stands, and judge whether the plan's design will hold up. The evaluation items work best after students have finished the calculations, because the numbers reveal how narrow the margin between stages can be.
Student Worksheet
The city of Bellrose, a fictional city written for this worksheet, draws its supply from one reservoir. Its adopted drought contingency plan uses these stages:
| Stage | Trigger (reservoir storage) | Key restrictions |
|---|---|---|
| Stage 1 Watch | below 70 percent of capacity | voluntary conservation requests |
| Stage 2 Warning | below 60 percent of capacity | outdoor watering two days per week; demand-cut target of 15 percent |
| Stage 3 Emergency | below 45 percent of capacity | outdoor watering banned; drought surcharge begins |
| Stage 4 Critical | below 30 percent of capacity | rationing; no new connection permits |
Use the table and the figures stated in each item.
- The Bellrose reservoir holds 36,000 acre-feet when full. Storage today is 23,400 acre-feet. What percent of capacity is in storage?
- Using your answer to item 1 and the trigger table, which drought stage applies today?
- Bellrose normally delivers 12 million gallons per day. Stage 2 sets a demand-cut target of 15 percent. What daily delivery, in million gallons per day, would meet the target?
- One acre-foot is 325,851 gallons. At 12 million gallons per day, about how many acre-feet does Bellrose deliver each day? Round to the nearest whole acre-foot.
- Suppose a Bellrose household uses 320 gallons per day in summer, with 45 percent of that use outdoors. How many gallons per day of the household's use are outdoors?
- If Stage 2 watering limits cut that same household's 144 gallons of daily outdoor use in half, how many gallons per day does the household save?
- At what storage level, in acre-feet, would the 36,000 acre-foot reservoir cross into Stage 3?
- Storage is 23,400 acre-feet and is falling by 600 acre-feet per month with no inflow. If nothing changes, in how many months will Bellrose reach the Stage 3 trigger?
- The plan triggers each stage from storage percentages rather than from calendar dates. In two or three sentences, explain one advantage of that design choice.
- The Stage 3 surcharge is intended to push demand down. Describe one unintended effect the surcharge could have on households or on the utility's finances, and explain why.
From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.
Answer Key
- Answer: 65 percent of capacity. 23,400 divided by 36,000 is 0.65, which is 65 percent.
- Answer: Stage 1 Watch. Storage at 65 percent is below the 70 percent trigger but not below the 60 percent trigger, so only Stage 1 applies.
- Answer: 10.2 million gallons per day. A 15 percent cut leaves 85 percent of demand: 12 x 0.85 = 10.2.
- Answer: 37 acre-feet per day. 12,000,000 divided by 325,851 is about 36.8, which rounds to 37.
- Answer: 144 gallons per day. 320 x 0.45 = 144.
- Answer: 72 gallons per day. Half of 144 is 72.
- Answer: 16,200 acre-feet. Stage 3 begins below 45 percent of capacity, and 0.45 x 36,000 = 16,200.
- Answer: 12 months. The gap is 23,400 minus 16,200, or 7,200 acre-feet; at 600 acre-feet per month, 7,200 divided by 600 is 12.
- Answer: Percentage triggers respond to actual supply conditions. A dry spring can empty a reservoir faster than the calendar predicts, and a wet year can refill it, so tying restrictions to storage means the rules tighten exactly when the physical system worsens rather than on an arbitrary date.
- Answer: Accept any well-reasoned effect. Examples: the surcharge falls hardest on lower-income households, which may already use little outdoor water; or, because customers buy less water while the utility's fixed costs stay the same, revenue can drop during the emergency, pressuring the utility to raise base rates later.
Differentiation
Support
Provide a worked example of a percent-of-capacity calculation using different numbers from the fictional plan, such as a 40,000 acre-foot reservoir holding 30,000 acre-feet, before students attempt item 1, and allow calculators throughout.
Extension
Have students draft a fifth stage for the Bellrose plan, state its storage trigger in both percent and acre-feet, and defend the restriction it adds in terms of which uses the city should protect last.
ELL supports
Pre-teach "trigger," "stage," and "surcharge" with a simple thermometer-style diagram of the four stages. Allow items 9 and 10 to be answered with sentence frames: "A percentage trigger is useful because ___" and "One unintended effect could be ___."