Lesson plan Grade 6 Social Studies & Civics
Hoover Dam: Weighing the Tradeoffs of a Depression-Era Project
A grade 6 lesson using Hoover Dam's real generating capacity to examine how a 1930s public works project brought jobs and power at a real environmental cost.
Objectives
- Students will identify at least two benefits and two tradeoffs of building Hoover Dam.
- Students will calculate electricity produced over time using the dam's generating capacity.
- Students will explain how a decision made decades ago still affects people living near the Colorado River today.
Vocabulary
- Public works
- The city department that builds and takes care of shared things everyone uses, like streets, water pipes, and sewers. Many water careers are part of public works.
- Reservoir
- A human-made lake, usually created by a dam, that stores water for later. Reservoirs supply cities and farms and help control floods.
Also: hydroelectric, tradeoff
Teacher overview
During the Great Depression, Hoover Dam on the Colorado River became one of the largest federal construction projects in the country, employing thousands of workers when jobs were scarce. This lesson uses the dam's real generating capacity to anchor a discussion of who benefited from the project and who bore its costs, rather than treating it only as an engineering triumph. A common misconception is that a major infrastructure project like this one is purely a success story; the guided practice is built so students weigh genuine tradeoffs, including flooded canyon land and a changed river ecosystem, alongside the jobs, irrigation water, and electricity the dam provided.
Procedure
Hook (5 min): Show a photo or projected image of Hoover Dam and ask students to guess why the federal government would build something this large in a desert canyon during the 1930s. Record two or three guesses on the board.
Direct instruction (12 min): Explain that Congress approved Hoover Dam in 1928, shortly before the Great Depression, and that its construction from 1931 to 1936 gave thousands of people work at a time when millions of Americans were unemployed. Describe how the dam holds back the Colorado River, creating a reservoir now known as Lake Mead, and how it provides three things at once: flood control downstream, irrigation water for farms in the region, and hydroelectric power. State the dam's real generating capacity: its power plant can produce up to 2,080 megawatts of electricity when running at full capacity, power that still serves homes and businesses across several states today. Explain that 2,080 megawatts is the plant's rated capacity. Years of drought and low water in Lake Mead have cut the dam's power generation by about 30 percent, according to the Bureau of Reclamation, so the plant usually produces less than its full capacity today.
Guided practice (15 min): In small groups, students complete a two-column T-chart labeled "Benefits" and "Tradeoffs." On the benefits side, they list what the dam provided (Depression-era construction jobs, irrigation water for farms, electricity, flood control). On the tradeoffs side, they list what the project cost (canyon land permanently flooded by the reservoir, the Colorado River's natural flow and ecosystem changed below the dam, communities that had to relocate). Groups share one item from each column with the class.
Independent practice (8 min): Each student answers two questions.
- Hoover Dam's power plant can generate up to 2,080 megawatts of electricity at full capacity. If it runs at that full capacity for 3 hours, how many megawatt-hours of electricity does it produce?
- Choose one perspective, either a construction worker who needed a Depression-era job, a farmer who gained irrigation water, or a family whose land was flooded by the new reservoir, and write three to four sentences explaining whether you think the dam's tradeoffs were worth it from that person's point of view.
Closure / exit ticket (5 min): Students answer one question in writing: "In one sentence, explain how a decision made in the 1930s to build Hoover Dam still affects people living near the Colorado River today." Collect responses and scan for a connection to ongoing power generation, water supply, or the river's changed ecosystem before dismissal.
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: 6,240 MWh.
2,080 megawatts × 3 hours = 6,240 megawatt-hours. - Answer: Answers will vary by chosen perspective. A strong response names a specific benefit or cost that person experienced (a paycheck during the Depression, new farmland made possible by irrigation, or a flooded family property) and reaches a clear, supported conclusion about whether the tradeoff was worth it from that viewpoint.
- Exit ticket answer: Answers will vary. A strong response notes that the dam's power plant still generates electricity people use today, or that the reservoir it created still supplies irrigation and drinking water to the region, showing the 1930s decision still shapes daily life nearby.
Differentiation
Support
Provide the T-chart with one example already filled in on each side (for instance, "jobs" under Benefits and "flooded land" under Tradeoffs) so groups have a model before adding their own items. For independent practice item 1, provide the multiplication already set up as 2,080 × 3 = ___ so students only complete the final step.
Extension
Ask students to work out, using only the lesson's figures, what percent of a full day (24 hours) the 3-hour period in item 1 represents, then calculate how many megawatt-hours the dam could produce if it ran at full capacity for a complete day.
ELL supports
Pre-teach "reservoir," "hydroelectric," and "tradeoff" with a simple diagram showing water held behind a dam, then flowing through turbines to make electricity. Allow the T-chart to be completed with single words or short phrases rather than full sentences, and permit the independent practice perspective response to be spoken aloud to a partner before it is written.