Project Grade 6 Math
Sunridge Community Garden: An Irrigation Budget Design Project
A grade 6 multi-session project where teams calculate a fictional garden's water demand, then design a watering plan that fits a fixed weekly gallon budget.
Objectives
- Students will calculate each garden bed's weekly water demand from its area and a given application rate.
- Students will write and evaluate an algebraic expression for a garden's total weekly water use.
- Students will design a watering plan that fits within a fixed weekly water budget.
Vocabulary
Key words: expression, budget constraint, application rate
Teacher overview
Sunridge Community Garden (a fictional garden used for this project) has six raised beds of different sizes and a fixed weekly water budget. Over three sessions, teams calculate how much water the garden would need if every bed were watered at full strength, compare that amount to the budget, and design a plan that keeps the garden within its limit.
A common misconception is assuming every bed can simply receive full watering regardless of the budget. This project is built so that the numbers themselves force a decision: teams must choose, using their calculations, which beds are watered less often instead of assuming the budget will stretch to cover everyone.
Project Brief
Driving question: How can Sunridge Community Garden water its six raised beds each week and stay within a 900-gallon budget?
Scenario: Sunridge Community Garden (fictional) has a volunteer committee. The committee wants a weekly watering plan for six raised beds. Each watering uses 0.5 gallons per square foot. This rate is set for this project.
Constraints:
- Weekly water budget: 900 gallons total. This budget is fixed for this project.
- Each bed needs 0.5 gallons per square foot every time it is watered. The garden waters up to three times a week when the budget allows.
- Bed areas: Bed A, 120 square feet. Bed B, 80 square feet. Bed C, 150 square feet. Bed D, 60 square feet. Bed E, 100 square feet. Bed F, 140 square feet.
- The proposal must include an expression for total weekly water use. It must show the plan uses 900 gallons or less.
Final deliverable: A labeled garden map that shows the watering plan for each bed. A one-page proposal for the garden committee. The proposal must include the team's expression, its evaluated total, and a note on any bed that gets less water.
Milestones
Session 1 -- Find the full demand: Teams use the garden map and the 0.5-gallon-per-square-foot rate. For each bed, find the water needed for one watering. Multiply by three for the full weekly demand. Add up all six beds. Compare the total to the 900-gallon budget. Output: a calculation sheet with each bed's demand, the garden's total demand, and the size of the gap, if any.
Session 2 -- Draft two plans: Teams draft two plans that bring the total to 900 gallons or less. A plan might water some beds less often. A plan might use a lighter rate on some beds. Each plan must show the math, not just a description. Output: two draft plans, each with a total at or under 900 gallons.
Final session (Session 3) -- Choose, write, and present: Teams compare their two drafts and pick one. They write it as one expression for total weekly water use, based on bed area. They check that the expression meets the 900-gallon budget. They finish their labeled map. Then they present the map and the plan to the class, who play the role of the garden committee. Output: a finished proposal, a finished map, and a short team talk.
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 |
|---|---|---|---|---|
| Water-budget constraint | Total weekly water use is not calculated, or clearly exceeds 900 gallons | Total is close to 900 gallons but the calculation has an error or is not itemized by bed | Total weekly water use is calculated correctly, itemized by bed, and at or under 900 gallons | Total is correctly calculated and at or under 900 gallons, with a clear written explanation of which beds were reduced and why |
| Algebraic expression | No expression is written, or it does not represent the plan's water use | An expression is written but does not evaluate to match the team's stated total | A correct expression is written and evaluated, matching the team's stated total | A correct expression is written, evaluated, and the team explains what each term of the expression represents |
| Garden map and proposal | Map or proposal is missing key information or difficult to follow | Map and proposal are present but do not clearly match each other | Map and proposal clearly match and explain the watering plan for every bed | Map and proposal clearly match, explain every bed, and anticipate a likely question from the garden committee about the reduced beds |
Differentiation
Support (below grade level)
Provide the full-demand calculation for Session 1 already completed for four of the six beds, so teams only need to calculate the remaining two and add them to the total. Provide a simplified plan template listing the possible adjustments (reduce frequency, reduce rate) as choices rather than requiring teams to invent them.
Extension (above grade level)
Ask teams to calculate what the garden's total weekly water use would be if a seventh bed of 90 square feet were added under the same watering schedule, and to explain how their chosen plan from Session 3 would need to change to stay within the same 900-gallon budget.
ELL supports
Provide a labeled garden map with each bed's area already written directly on the map, in large text, before Session 1 begins. Allow the written proposal in Session 3 to include labeled sketches and short phrases alongside the required expression, rather than full paragraphs throughout.