Debate kit Grade 10 Science
Kestrel Dam: Fish Passage Restoration Versus Continued Hydropower
A grade 10 debate kit on whether a fictional dam should be removed for fish passage, weighing ecosystem restoration against continued hydropower generation.
Objectives
- Students will evaluate evidence on both sides of a dam-removal resolution grounded in ecosystem and energy trade-offs.
- Students will construct a discipline-specific argument supported by named evidence from the Evidence File.
- Students will deliver a rebuttal that directly responds to the opposing side's strongest point.
Vocabulary
- Hydropower
- Electricity made from moving water, usually water falling through a dam. It is a renewable power source that can start up quickly when the electric grid needs it.
Also: fish passage, river connectivity, carbon-free
Teacher overview
This is a two-team structured debate for a 50 to 60 minute class block, with additional prep time available in a second session. Students argue for or against removing the fictional Kestrel Dam from the fictional Kestrel River to restore fish passage, a resolution with genuine tension between ecosystem restoration and the dam's ongoing hydropower generation.
Resolution & Background
Resolution: "The city should remove Kestrel Dam from the Kestrel River to restore fish passage for migratory fish, even though the dam currently generates hydroelectric power for the community."
Background: Kestrel Dam (a fictional dam used for this debate) was built decades ago on the fictional Kestrel River. It stores water and also generates a modest amount of hydroelectric power. The dam blocks migratory fish from reaching spawning grounds upstream, which is a known ecosystem effect of dam building. Communities have responded to that effect in different ways, including removing the dam, adding a fish ladder, or releasing water on a managed schedule. Hydropower is also a carbon-free source of electricity, so if the dam were removed, the community would need to replace that power from somewhere else.
Evidence File
Case for removing the dam:
- Blocking fish migration is a known ecosystem impact of dam building. Engineers can design and test a solution to that impact. Options include removal, a fish ladder, or managed flow releases. This is the kind of engineering response called for when a structure damages a river's ecosystem and its biodiversity.
- A fictional state fisheries survey, created for this debate, estimates that migratory fish counts upstream of Kestrel Dam have dropped sharply since the dam was built. This illustrates the kind of long-term ecosystem effect that dam removal is meant to reverse. (Illustrative estimate created for this debate, not a documented figure.)
- Removing small, aging dams has become a common strategy nationally for restoring river connectivity. Many older dams also carry rising safety and maintenance costs as their structures age. Those costs matter regardless of the ecosystem question.
Case against removing the dam:
- Hydropower is a major source of carbon-free electricity at scale. Hoover Dam's power plant, for comparison, has a nameplate capacity of about 2,080 megawatts. Even a much smaller facility like the fictional Kestrel Dam still supplies carbon-free electricity. That power would need to be replaced if the dam were removed. (Source for the Hoover Dam figure: US Bureau of Reclamation.)
- A fictional local utility manager's testimony, written for this debate, argues that removing Kestrel Dam would force the community to buy replacement power. That power would likely come from sources that are not carbon-free. This shifts the environmental trade-off rather than solving it. (Illustrative testimony created for this debate.)
- Dam removal projects involve major construction costs. Permitting alone can take several years. The ecological benefits of removal would not arrive quickly, even if the city approved the project right away.
From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.
Rubric
| Criterion | Emerging | Developing | Proficient | Advanced |
|---|---|---|---|---|
| Evidence use | Repeats a claim with no cited evidence | Cites one piece of evidence without explaining its relevance | Cites at least two pieces of evidence and explains how each supports the team's position | Cites multiple pieces of evidence, explains their relevance, and anticipates the opposing side's likely response |
| Rebuttal quality | Does not respond to the opposing team's points | Responds to an opposing point but without new evidence | Directly rebuts a specific opposing point using evidence from the file | Rebuts multiple opposing points and explains why the team's evidence outweighs them |
| Organization & delivery | Argument is difficult to follow, with no clear structure | Argument has a structure, but transitions between points are unclear | Argument follows a clear claim-evidence-conclusion structure | Argument is clearly structured, confidently delivered, and directly responsive to the resolution |
Differentiation
Support (below grade level)
Provide a simplified evidence card for each side listing only its single strongest point, and give sentence starters for rebuttals: "Our opponents claim ___, but the evidence shows ___."
Extension (above grade level)
Ask students to research what a fish ladder or managed flow release, mentioned in the "for removal" case, would involve as a middle-ground alternative to full dam removal, and incorporate that option into a stronger rebuttal.
ELL supports
Pre-teach "fish passage," "hydropower," "river connectivity," and "carbon-free" with simple definitions and a labeled diagram of a dam blocking fish from swimming upstream. Allow students to deliver rebuttals from written notes rather than extemporaneously.