The Arizona STEM Acceleration Project

Assessing Our Site’s Water Resources

Rainwater Harvesting Native Garden Design: Calculating the Water Budget

A 9-12 Grade STEM Lesson

Brianne Loya

May 2023

Notes for Teachers

This design challenge was open for any interested students from grades 9-12.

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Students met afterschool over the course of the second semester. This is the 2nd lesson in a series of 2.

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Lesson 1

List of Materials

• Copy of Phoenix Rainfall Averages
• Copy of Supply Worksheet
• Copy of Water Budget Calculator
• Computer
• Calculators
• Measuring tape
• Plant Cards

Standards

Earth Science:

HS.E1U1.12 Develop and use models of the Earth that explains the role of energy and matter in Earth’s constantly changing internal and external systems (geosphere, hydrosphere, atmosphere, biosphere).

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HS+E.E1U1.5 Obtain, evaluate, and communicate information of the effect of water on Earth’s materials, surface processes, and groundwater systems.

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ELA:

9-10.SL.4 Present information, findings and supporting evidence clearly, concisely and logically such that listeners than follow the line of reasoning and the organization, development, substance and style are appropriate to purpose, audience, and task.

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Math:

G.G-GMD.A.3 Use volume formulas for cylinders, pyramids, cones, and spheres to solve problems utilizing real-world context.

Mathematical Practices:

MP.5 Use appropriate tools strategically.

MP.6 Attend to precision.

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Ed Technology:

9-12.5.b. Students collect data or identify relevant data sets, use digital tools to analyze them, and represent data in various ways to facilitate problem-solving and decision-making.

9-12.6.b. Students create original works or responsibly repurpose or remix digital resources into new creations.

Objective(s):

Calculate the amount of water our campus receives on an annual basis to determine the “water budget” we have to work with when choosing plants.

Agenda (215 minutes)

1. Engage : 30 minutes
1. What is a watershed?
2. Tour of our school watershed

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1. Explore : 90 minutes
1. What is a water budget?

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3. Explain : 90 minutes

• Imagining a garden using plant cards

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4. Evaluate : 65 minutes

• Water budget presentations and critiquing

School Tour

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Students first learned about watersheds and made their own 3D models of watersheds using crumpled up sheets of transparency. Once students understood the concept of watersheds they toured the campus as an exploration of the campus as a watershed. Students took pictures and took notes of where water is flowing, where it is coming from and going when it rains.

What is a Water Budget?

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• In groups of 3-4, students will determine how much water our garden could use annually by measuring the square footage of where water will be collected and then multiplying that number by the annual rainfall in Phoenix. Students determine what tools and methods they want to use to help them calculate the square footage. (ex. Google Earth, measuring tape, etc). An Excel sheet is provided to assist with the calculations.

Imagining a Garden

• In groups of 3-4, students work together to analyze a variety of plant cards that provide plant name and water required in gal/yr.

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• Students decide on a group of plants that they could fit into a garden that would not exceed their water budget.

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Water Budget Presentations and Critiquing

Student groups will present to their peers to explain how they calculated the water budget and what they determined their water budget to be.

Student groups will compare results and procedures to find sources of errors and determine if the procedure for determining water budget needs to be re-done.

Differentiation

Flexible grouping throughout this lesson is a great way to differentiate this lesson for all students.

For student groups who are more advanced, they can begin calculating basin sizes while student groups having difficulty with the math can use a simplified worksheet that gets the same idea as the excel and is pictured to the right.