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Quiz & test questions Grade 7 Engineering & Design

Delta Vale Stormwater Retrofit: Engineering Design Unit Test

A grade 7 engineering unit test on a fictional stormwater retrofit, mixing multiple-choice, short-answer, and computation items on runoff and percent reduction.

Objectives

  1. Students will identify the steps and tools of the engineering design process applied to a stormwater problem.
  2. Students will calculate runoff, percent reduction, and proportional capture for a stormwater retrofit.

Vocabulary

Permeable pavement
Permeable pavement is a special kind of pavement full of tiny gaps that let rainwater soak straight through it into the ground below, instead of running off like it would on regular pavement. Parking lots and sidewalks can be built with it to reduce stormwater runoff.

Also: runoff, retrofit, decision matrix

Teacher overview

This 35-minute unit test is worth 25 points. It checks whether students can apply the engineering design process to a stormwater problem in the fictional town of Delta Vale, which is retrofitting a paved area to soak up more rain. The test mixes three multiple-choice items, two short-answer items, and three computation items. The computation items use runoff estimates, percent reduction, and proportional reasoning at the grade 7 level.

Delta Vale Stormwater Retrofit: Engineering Design Unit Test — Grade 7 Engineering & Design
Name: ____________________________ Date: ______________

Assessment

Use these values for the fictional Delta Vale retrofit. Runoff from a paved surface is estimated as: gallons = area (square feet) × rainfall (inches) × 0.623.

  1. (2 points) What is the first step an engineer takes on a new design problem?

    • A) Define the criteria and constraints.
    • B) Build the final version.
    • C) Order all the materials.
    • D) Choose a color.

  2. (2 points) During a storm, which surface produces the most runoff?

    • A) A grass lawn.
    • B) A rain garden.
    • C) An asphalt parking lot.
    • D) A gravel path.

  3. (4 points) Delta Vale's parking lot is 4,000 square feet. For 1 inch of rain, use the runoff formula (gallons = area × rainfall × 0.623) to find the gallons of runoff the lot produces.

  4. (4 points) After the town adds permeable pavement, the runoff from that same storm drops from 2,492 gallons to 500 gallons. What is the percent reduction in runoff? Round to the nearest whole percent.

  5. (3 points) The town has a budget of 15,000 dollars. Permeable pavement costs 9,000 dollars and a rain garden costs 4,000 dollars. If the town builds both, do they fit the budget? By how many dollars is the plan under or over?

  6. (4 points) A rain garden captures runoff in proportion to its size. If 200 square feet of garden captures 500 gallons, how many gallons would 300 square feet capture at the same rate?

  7. (3 points) When engineers compare two designs on cost, water captured, and upkeep, what systematic tool do they use?

    • A) A coin flip.
    • B) A decision matrix.
    • C) A guess.
    • D) The loudest vote.

  8. (3 points) Explain why capturing stormwater where it falls, instead of sending it straight to pipes, helps the creek downstream.

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: A.
    The first step is to define the criteria and constraints. Engineers must know what a design has to do, and what limits it, before building anything.

  2. Answer: C.
    An asphalt parking lot is a hard, sealed surface, so almost all the rain runs off. Lawns, rain gardens, and gravel let more water soak in.

  3. Answer: 2,492 gallons.
    4,000 square feet × 1 inch × 0.623 = 2,492 gallons of runoff.

  4. Answer: 80%.
    The drop is 2,492 − 500 = 1,992 gallons. 1,992 ÷ 2,492 = 0.799, which rounds to about an 80 percent reduction.

  5. Answer: 2,000 dollars under.
    Both together cost 9,000 + 4,000 = 13,000 dollars. 15,000 − 13,000 = 2,000 dollars under budget, so the plan fits.

  6. Answer: 750 gallons.
    Capture is proportional: 500 ÷ 200 = 2.5 gallons per square foot. 2.5 × 300 = 750 gallons.

  7. Answer: B.
    A decision matrix scores each design on shared criteria, so engineers can compare options fairly instead of guessing.

  8. Answer: On-site capture protects the creek.
    Accept any answer explaining that soaking rain into the ground on-site means less water rushes into the creek at once. That lowers flooding and erosion, and it keeps oil, grit, and other pollutants from washing straight into the water.

Differentiation

Support

Provide the runoff formula already set up for item 3 (4,000 × 1 × 0.623 = ___) and allow a calculator on all computation items. Give a word bank for items 1 and 7 so students match terms rather than recall them cold.

Extension

Ask students to find the gallons of runoff from the same lot during a heavier 2-inch storm, then explain why the percent reduction from permeable pavement would still be useful even though the total runoff is larger.

ELL supports

Provide small icons beside items 2 and 3 (a parking lot, a rain garden, a rain cloud) and pre-teach "runoff," "retrofit," and "permeable." Allow item 8 to be answered with a sentence frame: "Capturing rain where it falls helps the creek because ___."