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Lesson plan Grade 4 Science

Protecting Fenwick's Water Plant From a Flood: Two Solutions

A grade 4 lesson where students compare a levee and a detention pond to protect a fictional town's water treatment plant.

Objectives

  1. Students will compare two flood-protection solutions for a water treatment plant against three stated criteria.
  2. Students will calculate the minimum height needed for a levee, given a flood height and a required safety buffer.
  3. Students will write a short recommendation that justifies a chosen solution using at least two criteria.

Vocabulary

Levee
A long earthen wall built along a river to keep floodwater out of the nearby land. Levees protect many towns, but they can fail if water rises too high.

Also: detention pond, criteria, constraint, flood

Teacher overview

Last spring, a heavy storm raised the Fenwick River until floodwater came within a few feet of the town's water treatment plant, and the town council now wants a plan so that never happens again. This lesson asks students to act as junior engineers who compare two real flood-protection strategies, an earthen levee built around the plant and a detention pond dug uphill to catch extra rainwater before it reaches the river. Students often assume the "biggest" or most expensive-looking solution must be the best one, so the comparison chart deliberately forces them to weigh three separate criteria instead of picking on size alone.

Procedure

Hook (5 min): Read the scenario aloud: last year's storm raised the river to 2 feet above its normal level, and water came close enough to worry the plant's operators. Ask students, "What could protect the plant the next time this happens?"

Direct instruction (10 min): Introduce the two proposed solutions using criteria cards: Solution A, a levee (an earthen wall built around the plant), and Solution B, a detention pond (a dug basin uphill that catches extra rainwater before it reaches the river). Explain that any levee built must be at least as tall as last year's flood height plus a safety buffer. Model the height calculation on the board: last year's flood rose 2 feet above normal, and the town wants at least a 1-foot safety buffer above that, so the levee must be built at least 2 + 1 = 3 feet tall.

Guided practice (15 min): In small groups, students use the criteria cards (protection level, build time, and land needed) to score Solution A and Solution B from 1 to 3 on each criterion on their comparison chart, discussing their reasoning as a group before recording a score.

Independent practice (10 min): Each student writes a short paragraph recommending Solution A or Solution B, citing at least two of the three criteria from the comparison chart to support the choice.

Closure / exit ticket (10 min): Take a quick class vote on which solution most students recommended, then ask the formative-assessment question aloud for a thumbs-up/thumbs-down check: "If the council instead requires a 2-foot safety buffer above last year's 2-foot flood height, would the levee need to be taller or shorter than the 3 feet we calculated earlier, and what is the new height?" Nearly every thumb should point up on the correct direction (taller) before moving on; review the addition step with any group that is unsure.

Protecting Fenwick's Water Plant From a Flood: Two Solutions — Grade 4 Science
Name: ____________________________ Date: ______________

Student Handout

Fenwick's town council wants to protect the water treatment plant from the next flood. Two solutions are on the table: Solution A, a levee (an earthen wall built around the plant), and Solution B, a detention pond (a dug basin uphill that catches extra rainwater before it reaches the river). Any levee must be built at least as tall as last spring's flood height plus a safety buffer.

Criteria cards. Solution A (levee): protects the plant building itself but not its neighbors; takes about 2 months to build; needs only a narrow strip of land around the plant. Solution B (detention pond): lowers floodwater for the plant and for neighbors downhill; takes about 6 months to dig; needs a large field uphill.

  1. Last spring's flood rose 2 feet above the river's normal level. The council wants a safety buffer of 1 foot above that flood height. How tall must the levee be, in feet?
  2. Suppose the council instead requires a safety buffer of 2 feet above the same 2-foot flood height. How tall must the levee be, in feet?
  3. Score Solution A and Solution B from 1 to 3 on each of the three criteria on your comparison chart: protection level, build time, and land needed. Write one short reason for each score.
  4. Write a paragraph recommending Solution A or Solution B. Use at least two of the three criteria from your comparison chart to explain your choice.

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: 3 ft.
    Levee height with a 1-foot buffer. Flood height (2 ft) + safety buffer (1 ft) = 3 ft minimum levee height.

  2. Answer: 4 ft.
    Levee height with a 2-foot buffer (exit ticket). Flood height (2 ft) + safety buffer (2 ft) = 4 ft, which is taller than the 3-foot levee calculated with the smaller buffer.

  3. Answer: Answers will vary by group.
    Comparison chart reasoning. A complete answer scores both Solution A and Solution B on all three criteria (protection level, build time, land needed) using the criteria cards, with a brief reason recorded for each score rather than a number alone.

  4. Answer: Answers will vary.
    Independent recommendation. A full-credit paragraph names either Solution A or Solution B and supports the choice with at least two of the three criteria from the comparison chart, such as noting that a levee protects the exact building site while a detention pond also reduces flooding for neighbors downhill.

Differentiation

Support (below grade level)

Provide the levee height calculation as a fill-in addition sentence (flood height + buffer = ___) rather than an open word problem, and offer a partly completed comparison chart with one row's scores already filled in as a model.

Extension (above grade level)

Ask students to propose a third solution that combines features of both (for example, a shorter levee paired with a smaller detention pond) and to predict, using the same three criteria, whether the combined solution would score better than either single solution alone.

ELL supports

Pre-teach levee, detention pond, criteria, and constraint with simple side-view sketches: a wall around a building for the levee, and a dug basin with an arrow showing water flowing in for the detention pond. Allow the independent recommendation to be given orally to a partner and recorded by the partner, rather than written independently.