Project Grade 9 Engineering & Design

Cravenmoor Ridge After the Fire: A Backup Water Supply Design

A five-session grade 9 project where students design a backup supply for a fictional mountain water district under a fixed budget and a minimum pressure requirement.

Grade: Grade 9
Subject: Engineering & Design
Material: Project
Time: 5 sessions, ~300 min total
Prep: Moderate prep
Materials: Calculator, Graph paper or a spreadsheet, Printed cost sheet for the three supply options, Poster board or slide software for the final presentation

Standards

HS-ETS1-1 NGSS

Analyze a major global challenge to specify qualitative and quantitative criteria and constraints for solutions that account for societal needs and wants.

How this material aligns: Milestone 1 requires a written memo stating measurable criteria and constraints for the district's backup supply before any option is drawn.

All materials for HS-ETS1-1 →

HS-ETS1-3 NGSS

Evaluate a solution to a complex real-world problem based on prioritized criteria and trade-offs that account for a range of constraints, including cost, safety, reliability, and aesthetics as well as possible social, cultural, and environmental impacts.

How this material aligns: Milestone 4 scores three options in a weighted trade-off matrix covering cost, reliability, construction time, and effects on downstream neighbors.

All materials for HS-ETS1-3 →

HSN-Q.A.1 Common Core Math

Use units as a way to understand problems and to guide the solution of multi-step problems; choose and interpret units consistently in formulas; choose and interpret the scale and the origin in graphs and data displays.

How this material aligns: Milestone 2 converts connections to daily demand, then to a three-day volume in gallons, and checks a fire flow in gallons per minute against storage.

All materials for HSN-Q.A.1 →

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This material is in the public domain (CC0) and may be copied, edited, and shared freely, without attribution. Updated 2026-07-23.

Objectives

Students will state measurable criteria and constraints for an emergency water supply project.
Students will calculate a district's daily demand, three-day storage need, and fire flow volume.
Students will score competing options in a weighted trade-off matrix and defend one recommendation.

Vocabulary

Key words: criterion, constraint, fire flow, trade-off matrix, interconnection

Teacher overview

The driving question of this project is how a small mountain utility should spend a limited grant to keep water flowing after a wildfire. Cravenmoor Ridge is a fictional water district whose watershed burned last summer, leaving its creek intake fouled with ash after every rainstorm and its single power feed exposed to shutoffs on windy days. Students take the district's stated budget and performance requirements, size the demand and storage the system must cover, evaluate three competing options, and deliver a written proposal and a presentation to the fictional district board. The work follows the same path as a consulting engineer's resilience study, which ends in a recommendation supported by numbers.

Cravenmoor Ridge After the Fire: A Backup Water Supply Design — Grade 9 Engineering & Design

Name: ____________________________ Date: ______________

Project Brief

Your team is the engineering consultant to the fictional Cravenmoor Ridge Water District. Every figure below belongs to this scenario.

The district serves 1,400 connections from one creek intake, one treatment plant, one 300,000-gallon storage tank, and one backup well rated at 250 gpm. Average use runs 250 gallons per connection per day. The district received a grant and can spend up to $250,000 in total.

The board has written four requirements:

The system must supply three days of average demand with no grid power and no creek intake.
The system must deliver 1,000 gpm of fire flow for 2 hours while holding at least 20 psi everywhere in the distribution system, which is the minimum most states require to keep contamination from entering through backflow.
The project must be in service within eighteen months.
Added operating cost must stay under $12,000 per year.

The board has priced three options and asks teams to evaluate those three:

Option A: A standby generator at the well and plant, plus controls. Cost $95,000. Adds $4,000 per year in fuel, testing, and maintenance. Does nothing for storage volume.
Option B: A second 300,000-gallon storage tank on the existing site. Cost $240,000. Adds $3,000 per year in maintenance and tank mixing. Does nothing during a power outage unless gravity can still deliver.
Option C: An emergency interconnection with the neighboring Yarrowbank district, including a meter vault, a check valve, and 1,800 feet of pipe. Cost $150,000. Adds $7,000 per year in standby charges and annual testing. Yarrowbank can supply 400 gpm and only when its own system is not stressed.

Your team turns in two things. The first is a written proposal of four to six pages containing the criteria and constraints memo, the demand and storage calculations, the option comparison, the weighted trade-off matrix, and a single recommendation with its reasoning. The second is a presentation of eight to ten minutes to the board, in which every claim about performance points back to a number in the proposal.

Milestones

Session 1, criteria and constraints memo. Turn the board's four requirements into a one-page memo that separates measurable criteria from constraints. Each criterion states a quantity, a unit, and how it will be verified after construction. Each constraint states the boundary and what sets it. The memo also lists at least two requirements the board did not write down but that your team believes belong in the project, with a sentence of justification for each.
Session 2, demand and storage calculations. Produce a one-page calculation sheet showing the district's average daily demand in gallons, the three-day volume the board requires, the fire flow volume for 1,000 gpm over 2 hours, and the total the system must hold or produce. Compare that total with the existing 300,000-gallon tank and state the shortfall in gallons. Show every conversion, and label every number with its unit.
Session 3, option comparison table. Build a table with one row per option and columns for capital cost, added yearly cost, gallons or flow contributed, months to build, and which of the board's four requirements the option satisfies on its own. Add a short paragraph identifying which single option, if any, can meet all four requirements alone, and which pairs of options fit inside the $250,000 budget.
Session 4, weighted trade-off matrix and recommendation. Score each option and each affordable pair against at least four criteria, using weights your team assigns and defends. Criteria must include cost, reliability during a power outage, construction time, and effect on the neighboring district. Write the recommendation as one paragraph naming the choice, the score that supports it, and the strongest argument against it.
Session 5, board presentation. Deliver the eight to ten minute presentation and hand in the finished written proposal. Each team fields two questions from classmates acting as board members, and at least one question must challenge a weight the team assigned in Milestone 4.

From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.

Rubric

Criteria and constraints (Milestone 1)

Level 4: Every criterion states a quantity, a unit, and a verification method; every constraint names its source; two additional requirements are proposed with sound justification.
Level 3: Criteria and constraints are correctly separated and mostly measurable; at least one additional requirement is proposed.
Level 2: The two categories are mixed in places, or several criteria state goals without quantities.
Level 1: The memo restates the board's requirements without sorting or quantifying them.

Quantitative analysis (Milestone 2)

Level 4: Demand, three-day volume, fire flow volume, and shortfall are all correct, with units carried through every conversion and a stated check on the arithmetic.
Level 3: All four quantities are present and the method is correct, with one arithmetic or unit slip.
Level 2: Some quantities are missing or the conversions drop units, so the shortfall cannot be traced.
Level 1: Numbers appear without visible calculation, or the demand figure does not follow from the connection count.

Trade-off evaluation (Milestones 3 and 4)

Level 4: The matrix scores every option and affordable pair on at least four criteria, the weights are defended in writing, and the recommendation names the strongest counterargument.
Level 3: The matrix is complete and the recommendation follows from the scores, but the weights are asserted rather than defended.
Level 2: Options are compared informally, or the recommendation does not follow from the team's own scoring.
Level 1: One option is favored with no comparison against the budget or the requirements.

Proposal and presentation (Milestone 5)

Level 4: The proposal is organized, every performance claim cites a number from the calculations, and the team answers the challenge question by returning to its evidence.
Level 3: The proposal covers all required sections and the presentation is clear, with one or two claims left unsupported.
Level 2: Sections are missing or the presentation restates the brief without adding the team's analysis.
Level 1: The deliverable is incomplete, or the recommendation is stated without supporting work.

Differentiation

Support

Give these students the Milestone 2 calculation sheet as a partly completed frame with the demand row filled in for this fictional district, so the remaining work is the three-day volume and the fire flow volume. Provide the trade-off matrix as a printed grid with the four criteria already listed and the weights supplied, leaving only the scoring to the team. Allow the presentation to be delivered from a script.

Extension

Ask these teams to add a fourth option of their own design, such as a demand reduction program, a raw water storage pond, or a mobile treatment trailer, and to price it from research they document. Then have them test how sensitive their recommendation is by changing one weight in the matrix and reporting whether the winner changes. Teams can also model what happens to the fictional district's three-day requirement if connections grow by fifteen percent over ten years.

ELL supports

Pre-teach criterion, constraint, fire flow, interconnection, and trade-off with a one-page picture glossary showing the tank, the well, the intake, and the interconnection pipe. Provide sentence frames for the memo, such as "This is a criterion because it can be measured in ___" and "This is a constraint because the design cannot ___." Allow the board presentation to be given in pairs so one student handles the numbers and the other handles the recommendation.

Extensions

Have teams write the one-page public notice the fictional Cravenmoor Ridge district would mail to customers explaining what the project buys them and what it does not. Ask them to state plainly which failure the project protects against and which failures remain, because a notice that overstates what the project can do leaves customers expecting protection the district cannot provide. Teams can then trade notices and mark any sentence a worried customer might read as a promise the district cannot keep.