Lesson plan Grade 4 Engineering & Design
Brookvale School's Flooded Bus Loop: A Rain Garden Design Lesson
A grade 4 engineering lesson where students define the flooding problem at a school bus loop and compare two rain garden designs to slow the runoff.
Objectives
- Students will define the bus-loop flooding problem using a success criterion and the constraints of limited curb space and a twelve-plant budget.
- Students will generate and compare two rain garden designs and choose the one that better meets the criteria.
- Students will explain how a rain garden reduces runoff by holding storm water so it can soak into the ground.
Vocabulary
- Rain garden
- A rain garden is a shallow planted dip in the ground that catches rain running off a roof or driveway and lets it soak slowly into the soil. Its deep-rooted plants help clean the water.
Also: runoff, criteria, constraint, soak
Teacher overview
After a hard rain, water sheets off the paved bus loop at the fictional Brookvale School and pools around the curb, so students step off the bus into a wide puddle. This lesson asks students to act as junior engineers who design a rain garden, a low planted bed that catches runoff and lets it soak into the ground instead of running across the pavement. One note for planning: groups often settle on the largest or most decorative layout, so the comparison step asks them to score both of their designs against the same stated criterion and constraints and to write the reason for their recommendation.
Procedure
Before class (site map): Sketch a simple top-down map of the bus loop and copy it for each group. Show the paved loop sloping down toward the curb, arrows for runoff flowing across the pavement, and a shaded puddle at the drop-off spot where students step off the bus. Draw a narrow grass strip along the curb and label it "Curb strip: the only space for a garden." In a corner, write "Plant budget: 12 plants."
Hook (5 min): Show the site map of the bus loop and describe the problem: after a storm, water runs off the pavement and pools where students walk. Ask the class, "Where does that water go now, and where could it go instead?" Collect a few answers on the board without judging them.
Direct instruction (10 min): Introduce the rain garden as one common engineering solution: a shallow, planted bed set beside the pavement that catches runoff so it soaks slowly into the soil. Define the success criterion with the class in plain words: the bus loop should have no standing water where students walk after a normal storm. Then name the two constraints written on the site map, a narrow strip of curb space and a set budget of twelve plants.
Guided practice (15 min): In small groups, students place a rain garden on their copy of the site map using sticky notes for plants. Each group must state, in writing, how their placement meets the success criterion and stays inside the two constraints. Circulate and ask each group to point to where the runoff will enter their garden.
Independent practice (10 min): Each group sketches a second, different rain garden design for the same bus loop, then fills in a two-column comparison that scores Design A and Design B against the success criterion and the two constraints. Groups mark which design they would recommend and write one sentence of reasoning.
Closure / exit ticket (10 min): For a quick formative check, ask every student to answer one prompt on a sticky note: "Name one thing a rain garden does to storm water that a flat paved loop does not." Collect the notes and scan for the key idea that the garden holds water so it can soak in; reteach briefly to any group whose notes miss it 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: No standing water where students walk after a normal storm.
This is the success criterion the class should name. Accept any wording that describes keeping the walking path clear of pooled water, since that is the goal both designs are measured against.Answer: A rain garden holds the runoff and lets it soak into the soil, while the flat paved loop lets water run straight across and pool.
This is the target idea for the exit ticket. Accept any answer that contrasts soaking or holding water with water running off or pooling on pavement.Answer: Answers will vary by group.
A complete comparison scores both Design A and Design B against the success criterion and the two constraints (curb space and the twelve-plant budget) and gives a short reason for the recommendation, not just a circled choice.
Differentiation
Support
Provide a comparison chart with the success criterion and both constraints already written in the first column, so students only add their scores and reasons. Offer a small set of pre-cut plant shapes to place on the map instead of drawing.
Extension
Ask students to add a second problem spot on the site map, such as a low corner of the parking area, and design one rain garden that helps both spots at once while staying inside the same twelve-plant budget. Have them explain the trade-off they made.
ELL supports
Pre-teach "rain garden," "runoff," "criteria," and "constraint" with simple side-view sketches: an arrow of water soaking down into a planted bed, and the same water running off flat pavement. Allow students to record their comparison reasons orally to a partner who writes them down.