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Debate kit Grade 6 Science

Removing Birch Hollow Dam to Restore Fish Passage: A Grade 6 Debate

A grade 6 debate kit on whether a fictional town should remove an aging dam to restore fish passage, weighed against its park pond and flood protection.

Objectives

  1. Students will evaluate evidence on both sides of a dam-removal resolution.
  2. Students will present a claim supported by evidence during a structured classroom debate.

Vocabulary

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: fish passage, flood risk, sediment

Teacher overview

This is a two-team structured debate for a single 50-minute class period, a good first structured debate for grade 6, since students are just beginning to build claim-and-evidence argument writing this year. Students argue for or against removing an aging dam that blocks fish migration but also supplies a community pond and some flood protection, a resolution with genuine trade-offs that a reasonable, informed adult could decide either way.

Removing Birch Hollow Dam to Restore Fish Passage: A Grade 6 Debate — Grade 6 Science
Name: ____________________________ Date: ______________

Resolution & Background

Resolution: "Birch Hollow should remove its aging dam to bring back fish passage on Birch Creek, even though this will drain the pond behind it."

Background: Birch Hollow Dam is a fictional dam on Birch Creek. Workers built it decades ago. It made a pond for the town park. It also helps hold back floodwater during big storms. But the dam blocks native trout. The trout cannot swim upstream to lay their eggs on the gravel beds. Sediment also piles up behind the dam instead of washing downstream. Removing the dam would let the creek flow freely again. Fish could swim upstream and downstream once more. But removing the dam would drain the park pond. It would also remove the flood protection the dam gives now, unless the town builds something new in its place.

Roles and format. Two teams of four students argue the resolution, one for removing the dam and one against. One student moderates and keeps time. The rest of the class acts as the town council, scoring each team with the rubric and voting at the end. The period runs in this order: 15 minutes for teams to read the evidence cards and plan, a three-minute opening statement from each team, five minutes to prepare rebuttals, a three-minute rebuttal from each team, a two-minute closing from each team, and 14 minutes for the council to finish its rubric scores, vote, and discuss which evidence was strongest.

Evidence File

Case for removing the dam:

  1. Dams that block fish passage usually cut down how many fish can reach their spawning grounds. Fish that cannot swim upstream cannot lay eggs on the gravel beds they need. Scientists have shown this link between a blocked stream and a smaller fish population.
  2. A fictional biologist's survey, made for this debate, found something important. Trout counts above the dam are far lower than counts in a nearby free-flowing stream with similar habitat. This suggests the dam itself, not poor habitat, is limiting the fish. (Illustrative survey created for this debate, not a documented figure.)
  3. Removing an old, low-value dam is a common way to restore a stream's natural flow. Communities across the country use this strategy when a dam no longer serves a major purpose, such as drinking water or electricity. Birch Hollow Dam serves neither purpose.

Case against removing the dam:

  1. The pond behind Birch Hollow Dam is a town park resource. Residents use it for fishing, boating, and community events. Removing the dam would drain that pond completely.
  2. A fictional neighborhood group, the Willow Bend Residents Council, wrote testimony for this debate. The group argues the dam also lowers flood risk during big storms by holding back water upstream. Removing the dam without new flood protection could flood their neighborhood. (Illustrative testimony created for this debate.)
  3. Removing a dam releases sediment that has built up behind it for decades. That sediment can cloud the water for a while. It can also harm fish and other aquatic life right after construction, even though the long-term goal is a healthier stream.

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 States an opinion with no evidence from the Evidence File Mentions one piece of evidence without explaining how it supports the team's position Uses at least two pieces of evidence and explains how each supports the team's claim Uses multiple pieces of evidence, explains each one's relevance, and connects them to a clear overall claim
Organization & clarity Argument is hard to follow, with no clear claim States a claim but does not connect it clearly to the evidence presented Presents a clear claim followed by organized, relevant evidence Presents a clear claim, organized evidence, and a brief closing statement that ties the argument together
Listening & response Does not acknowledge anything the other team said Repeats the team's own point without addressing the other side Responds respectfully to at least one specific point the other team raised Responds to a specific point from the other team and explains, using evidence, why the team's own position still holds

Differentiation

Support

Provide each team with note cards that already list their three evidence points in simple language, so students can focus on choosing which points to present rather than generating their own summaries. Offer a sentence starter for the claim: "Birch Hollow should ___ the dam because ___."

Extension

Ask students to identify which single piece of evidence from the opposing side is hardest to argue against, and to prepare, using only the Evidence File provided, one sentence acknowledging that point before restating why their team's position still makes sense overall.

ELL supports

Pre-teach "fish passage," "reservoir," "flood risk," and "sediment" with a labeled diagram of a dam showing water backed up behind it to form the park pond, and fish blocked from swimming upstream. Allow students to present from written note cards rather than speaking without notes.